Presumably its been thought through already, but I’ll mention it anyway. To obtain a closer agreement with the observed data, would it be more appropriate to consider the Arctic, Greenland, and Antartica as separate compartments for the purpose of using the linearised equations? Since the rate of temperature increase in the Arctic region is much greater than nonpolar latitudes, treating it as a single compartment with its own parameters would allow a better fit without losing the rationale of using linearised equations. If the compartments use the same $\Delta T(t)$, namely the global $\Delta T(t)$, then there is presumably a different “a” parameter for each compartment, but the “b” is the same parameter for all 3 compartments, giving a total of 4 parameters to tune, instead of 2. Any feedback?
Thanks for a nice review. I have some questions (perhaps from misunderstanding…):
- To what extent is the parameter “b” (the old sea level rise that existed before human perturbation) constrained by data? It can not be arbitrarily adjusted it seems to me. The better constrained “b” is, the more useful the 20th century record would be to pin down the value of “a”.
- The assumed linearity of sea level rise with temperature holds for short timescales and small temperature changes, you write. Said linearity makes sense to hold for thermal expansion and pure melting, but not for mechanical instabilities speeding up the process. Does this mean that this approach doesn’t include the potential effects of icesheet dynamics and how they could speed up sea level rise? Does that mean that this approach gives a lower limit of sea level rise, excluding any bad surprises?
- As to your last question, are data from the Eemian (last interglacial period) not sufficiently accurate to provide stronger constraints?
[Response: Problem here: this is forced by orbital changes, i.e. highly regional and seasonal insolation anomalies, not a global mean forcing.]
- How valid of an analogue is the Eemian for the eventual sea level rise (as opposed to the rate) we’ll experience at a given temperature? If it is anywhere near valid, it would be a strong argument to limit future warming to remain below the Eemian value (when the global average temperature was 2 degrees warmer and sea level was 6 metres higher than now) or at least keep the overshoot as short and limited as possible.
[Response: How do you know it was 2 ºC warmer globally? In our paper on the Eemian we concluded otherwise. -stefan]
I’ve read different numbers about the global average temperature during the Eemian: between 1 and 2 deg C. Here’s an article pointing to a value of 2 degrees:
High rates of sea-level rise during the last interglacial period
E. J. Rohling et al, Nature Geoscience 1, 38 – 42 (2008) http://www.nature.com/ngeo/journal/v1/n1/abs/ngeo.2007.28.html
“During MIS-5e, such rates of sea-level rise occurred when the global mean temperature was 2 °C higher than today,”
In 2007, IPCC notes “Global average sea level rose at an average rate of 1.8 [1.3 to 2.3] mm per year over 1961 to 2003
(IPCC) concluded that “No significant acceleration in the rate of sea level rise during the 20th century has been detected
[Response: See the title of Church and White (2006) in the reference list above. And note that Grinsted et al. get a consistent number for a from a very different sea level data set. -stefan]
Though I appreciate the general comparison of the studies, it would seem rather simplistic when considering expansion, evaporation, eustasy and isostasy, versus melt water being added. Maybe it would help if you outlined the assumptions behind the formula and works contained in the comparison for us laymen?
How complicated would this cause the simple formula, you provided, to become? Would the effects of these additional processes only be a small percentage when compared to added runoff or thermal expansion?
[Response: The basic idea of this approach is not that individual physical processes are modelled (that's actually the more common and traditional approach), but rather that we learn from data about past sea level rise how sea level responds to a temperature change. Those data of past sea level rise of course tell us only one thing: the grand total. So with this approach you cannot easily break down sea level rise into contributions from different processes. -stefan]
Comment by L. David Cooke — 31 Aug 2009 @ 10:29 AM
@6 (John) – A meltwater lake is clearly a surface phenomenon. For it to be caused by a geologic heat source, there would have to be a truly vast amount of melt at the ice/rock level. We’d have noticed that by one means (radar) or another (jökulhlaup).
I have a number of questions on this topic, but most are not sufficiently thought through by me yet to credibly pose. One simple basic question: How can sea level rise (17cm since 1900 e.g.) be measured with any (or much) confidence? In earlier times it relied on dubious tide markers. Even the uncertain tide markers had a very limited scope compared to the entire ocean(s). The steady state sea level varies by tens of meters around the oceans which swamps individual measurements in the cm, let alone mm, range. (Granted the sparse individual measurements can produce their own comparisons – forgetting their own uncertainty, but how can that be projected to an average overall sea level?) Even current satellite measurements — theoretically highly accurate — seems like the old ‘measure with a micrometer, mark with a chalk, cut with an ax’ problem. When a satellite picks up a 1mm (let alone 0.1mm) change, how is the instantaneous tide level, the wave height, even the satellite’s orbit, etc., taken into account to build confidence in the 1mm measurement. Satellites also have the problem with projecting over the entire ocean (what’s the baseline per latitude, longitude, time of day, time of year, lunar phase, etc), though theoretically (again) they could do a much more thorough job than the tide markers.
How do we know with even the slightest confidence the 17cm rise since 1900 (maybe easier than the others), the 5cm rise since 1990, etc? The relative consistency among all of the measurements points in the right direction; but it’s still a long row to hoe. Or are there other metrics and justifications?
Apparently then I am confused, if you were establishing the shift in levels based on warming trends and according to my review of the GHCN data, that the period between 1900 and 1930 would have been slight and the change between 1920 and 1950 should have been dramatically different. Matter of fact, it should appear that the amount of expansion between 1920 and 1950 should be nearly 80% of the change between 1970 and 2000.
This then begs a question, if the evaluation is of change in a variable and the observed effect, should not the evaluations be marked by the extremes or outliers in the series to try to establish the slope relationship of the relationship between temperature and sea level? It would seem if then you were to attempt a comparative study of slopes you should be able to establish a correlation, if a minimum of 10 events can be established.
The benefit is once this is done you could go back to the data sets and establish the contributor sets and begin the isolation of the participation of each to the change (Hmmm, …this seems to be the top down versus a traditional bottom up approach. Not that it is wrong, only that where one begins with the causes and tries to suggest the ends, the other begins with the ends and tries to suggest the cause. This is similar to economic systems, most times both miss major deviations to the hoped for steady state…)
How does this help in the long run? Does this then provide a planning model and a suggestion for the rate that action must be taken? If so then would it not seem that changes that happened between 1920 and 1950 and later again between 1970 and 2000 would be something to investigate to suggest the actions that would be necessary in the future? If true it generally required the simple removal of formerly habitable land from the municipality Zoning and Planning Board and higher expense planning for beach replenishment.
Is there any suggestion that the results of the present data would require any special response or preparedness for disasters or insurance company outlays, that would exceed what has been required in the past? Is it possible that this could lead insurance companies to have a voice in what they are willing to insure based on these models? Sorry for the questions, just I see many interrelated things and worry about the data sets underlying the planning that these models could feed.
Again my undying thanks for your time and effort. I cannot wait to see the outcome of this round of comments. I will check back in a couple of days to see where this has gone.
““Coastal erosion” is and has been an ongoing process for as long as an interface between the oceans and land that is susceptible to displacement / movement has existed.
The process is independent of all physical phenomena and processes discussed in this post.”
Yes but this historical self-regulation is not narrow enough to ensure civilzation’s survival. I assume a refernce to calcium-carbonate weathering cycle. When sea level rises less CO2 goes into space. When fall more land is exposed and more is rock-sequestered. But AFAIK all this means is before you hit runaway cooling at -67C or so when CO2 would be permanently sublimated to space; this cycle has historically kicked in before this. On the warming side obviously this cycle has historically self-cooled before 100C boiled the oceans. My question is I’ve read there is a temperature around 60C-70C where a runaway forcing occurs, maybe from molecules evaporating to space I can’t remember or track the reference down. Does anyone know of what this process is that was hypothesized someone to trigger runaway Venus at around 65C? It is bugging me.
If I understand what you are proposing, combining different rates for different components in a linear manner is degenerate so there is no “better” fit that can be obtained. (m1*x+b1)+(m2*x+b2)+(m3*x+b3)=m*x+b Shifting stuff between m1,m2,and m3 does not make any difference to what m turns out to be.
The more interesting idea is that the actual equation is seriously non-linear on century time-scales. Hansen discusses a scenario where sea level rise could be 5 meters by the end of the century. In terms of policy decisions, one needs to know about that kind of risk.
“Understanding future sea-level rise is one of the most pressing concerns for climate scientists. Recourse to modern observations and modeling are the principal techniques applied to this problem. However, these approaches are not without controversy. Modern observations of ice sheets are of short duration, making it difficult to distinguish variability from secular trends. Contemporary ice sheet models often ignore rapid, dynamic processes such as the collapse of ice sheets and the acceleration of ice streams in response to warming conditions. It is of critical importance to establish whether the specific examples of rapid ice sheet response observed over the last decades represents a trend or a short-term anomaly that will not impact the large expanses of ice sheets distant from ice streams in the longer term. Projections of future sea-level rise require insights into ice-sheet dynamics on centennial timescales. The record of sea-level rise during the termination offers just such insights and can be used as a means to better understand the integrated ice-sheet response to climate change outside the ‘noise’ of the last decades of observations, and the uncertainty of the impact of specific dynamic processes on centennial timescales. We are not considering the termination as a quantitative analog to the future—special consideration must be given to the fact that sea-level rise will not be as rapid today as during the termination because ice sheets are dramatically smaller today compared to the termination.”
This gentleman suffers from a serious case of tunnel vision, which I won’t even bother to explain, since it’s so obvious.
Talk about “phoning it in”. Surely you can do better.
Take a moment longer and explain how a rising sea level would -not- accelerate coastal erosion rates. Can you do that for us, describing how coastlines will magically become immune to erosion where isostatic rebound is not available as an offset against a rising sea?
I had earlier brought up the question of reconciling the ANDRILL data (Pollard and DeConto, Nature, v458, pp329 et seq., 2009; Naish et al. Nature v329, pp322 et seq., 2009) indicating 1 KYr timescales for WAIS breakup with the 2.6KYr time constant in Siddall et al. and Mr. Vermeer was kind enough to comment at:
1) In Pfeffer et al. (Science v321, pp1340 et seq., 2008) an estimate of maximum glacier velocities is used to calculate contributions from WAIS and GIS to sea level rise. Are there more recent attempts in that direction?
2) I notice from Cazenave et al. (Global and Planetary Change, v65, pp 83 et seq., 2009) that, in recent years, mass change is far outstripping steric change in sea level rise, from both ARGO data and GRACE estimates. Would
anyone care to comment on reasons and possible implications ?
3)Lastly, can anyone tell me the correct reference to the Wingham, Shepherd paper supposedly in GRL about Pine Island thinning far quicker than previously imagined? I still can’t find it. Or was this BBC article merely making it all up ?
In defense of the much-maligned Dan Hughes, allow me to point out that coastal erosion and coastal submersion are two different things. In the limit of 10,000 meters of SLR there will be no coastal erosion at all because there will be no coast at all.
Re:Mr. Roberts, Wingham, Shepherd, Pine Island thinning
When the advanced search is restricted to Wingham or Shepherd as authors, GRL as the journal, with 2009 as the relevant year, I find it not. I ask again, does anyone have the reference to the publication mentioned in
“The melt lakes on the Greenland ice sheet are a seasonal phenomenon. Geothermal heat isn’t seasonal…”
And further, the ice is colder below the surface, it’s not melting at the top because of heat from below!
Yes, there’s meltwater at the base during the warm weather (Mauri has commented that in the cold season it refreezes and the ice closes up the openings). There’s frictional heating when the ice moves against the base rock, and maybe along internal fractures/discontinuities.
But there are temperature records you can look up that track the temperature of the rock and of the ice that was above it at different points in time.
who gives the info that it’s not yet been published, it’s still “in press” (and GRL’s website doesn’t show it yet):
Wingham, D.J., D.W. Wallis, and A. Shepherd (2009),
Spatial and temporal evolution of Pine Island Glacier thinning, 1995-2006,
Geophys. Res. Lett., doi:10.1029/2009GL039126, in press.
(accepted 5 August 2009)
The assumption of “Linearity in temperature” is based on observations of systems (Earth & model) in near equilibrium. That assumption only holds as long the system remains near the observed equilibrium state. Current climate forcing perturbs the system, causing it to seek a new equilibrium. The transition to the new equilibrium involves reorganization of ocean and air currents. Such reorganization involves significant changes in heat flows from what was observed in the original system. Models may not reflect all of these changes. These changes result in rapid changes in the climate of various regions relative to the global mean temperature. One such example is “Polar Amplification”. A second example is the warming of the water at the bottom of Disco Bay and the Spitsbergen Current more than the global average warming. Or, heat may be transferred to ice, resulting in ice melt, but no increase in temperature. The suddenness of the effects of these changes can be shown by the breakup of the Larsen Ice Shelf. Thus, we are already outside the useful range of a linear temperature model.
Again, the assumption of linearity of time was based on observations of system(s) near equilibrium, or forced by orbital mechanics. In a forced system, the behavior of ice is not (generally) a function of time. It is a function of total energy. In a system near equilibrium (or forced by orbital mechanics), energy flows at fairly constant rates over time, and the system behavior appears to be a function of time. However, the melting of ice really is a function of energy, not time. If the heat is transferred to the ice in centuries, then the ice melts in centuries. If the heat is transferred in seconds, then the ice melts in seconds. It is the accumulated heat, and not the elapsed time that determines the state of the system.
The assumption that large ice sheets have long response times is based on short term observations of systems in near equilibrium. In view of geologic evidence of rapid ice sheet decay under orbital forcing, we have to consider the possibility of very rapid disintegration of ice sheets under our large, and rapidly increasing AGW forcing.
Today our oceans have more available heat than they had last year. (Despite substantial heat going to melt sea ice.) Next year, they are likely to have more heat than they have now. And, with increasing greenhouse gas concentrations, the rate of heat accumulation in the oceans is likely to be greater. Thus, heat flow to the ice is not likely to be linear with respect to time. Total heat content of the ice is the integral of the area under the heat flow curve, and it will increase in a very nonlinear manner with respect to time.
Sea level is an interesting case because only a small fraction of the ice must actually melt in order to discharge large volumes of ice into the ocean. The structural strength of ice declines in a very nonlinear function of contained heat. While it is difficult to dream of a solid glacier moving at 70 km/year down through a fjord, that volume of ice broken up into a slurry, can be easily flushed through a deep fjord. See for example (http://vulcan.wr.usgs.gov/Glossary/Glaciers/IceSheets/description_lake_missoula.html )
Semi-empirical models are most useful for systems that are near equilibrium, and are expected to remain near equilibrium. We have a climate system that is increasingly forced. Semi-empirical models are best for interpolation, but in this case they are being use to extrapolate on matters critical to public policy. Semi-empirical models require domains that have been carefully scrutinized for discontinuities such as melting points of materials in the system. In this application, we do not know how the melting points of salt water (anchor ice) and fresh water will affect the results of the model.
My estimate is that these models will significantly underestimate sea level rise just as semi-empirical models missed the decline of Arctic Sea Ice. It is really just the same system and the same models. It is the same problem. The system is in transition to a new equilibrium.
Thank you, Mr, Roberts for the NERC article. In light of the comments there, would someone knowledgeable care to speculate on the results of floating the main trunk of Pine Island ? Naively, I would imagine a great increase in ice velocity and mass export as basal drag vanishes but that is probably incorrect…
…in recent years, mass change is far outstripping steric change in sea level rise, from both ARGO data and GRACE estimates.
Yes. Three remarks (Stefan may offer a more considered opinion):
1) It used to be believed that the two contributions were roughly equal, but it seems that the mass part is clearly larger
2) We haven’t had GRACE and ARGO for many years yet; if this same situation has persisted in the past, we wouldn’t necessarily know about it
3) That said, these figures are undoubtedly also affected by natural variability. “Recent years” may be atypical.
Comment by Martin Vermeer — 31 Aug 2009 @ 11:03 PM
Mr. Lewis writes:
“Today our oceans have more available heat than they had last year. (Despite substantial heat going to melt sea ice.)”
The phrase “substantial amounts” might need to be qualified here. I see from Levitus(2008) that oceans are warming at 4e21J/yr. GIS and WAIS melting at about 500Gton/yr absorbing about 1.5e20J/yr, roughly thirty times less than the amount of heat warming the oceans.
These changes result in rapid changes in the climate of various regions relative to the global mean temperature. One such example is “Polar Amplification”.
Aaron, it’s amusing you should bring up this example, as it is precisely what I proposed as an example of positive nonlinearity in preparing for this post, when Stefan corrected me that this is not true: if the ratios between the warming rates at different latitudes remains the same, the warming pattern doesn’t change, and the behaviour is strictly linear…
Comment by Martin Vermeer — 31 Aug 2009 @ 11:24 PM
I do have a few questions, but these relate to a more “classical” type analysis.
The first has to do with changes in the amount of non frozen water stored on land. Both surface and ground water storage in some regions is changing dramatically, for instance the Aral sea is drying up, but a lot of new water is being impounded behind the three gorges dam. Quite a few regions have had water table drops of tens or hundreds of meters (including The San Joachim valley, the Ogalla aquifer, and norther India. I suspect that these “land use” changes in total water stored on land is non-trivial in amount. Does anyone have an order of magnitude estimate of how this compares to the rate of change of ice volume?
I worry somewhat that even given a fixed with time temperature that ice sheet melt rates could increase over time. The mechanism for this increase would be a postulated accumulation of surface dirt from year to year on the ablation zones of ice sheets. I don’t think comparing one or two warm seasons to obtain melt rate fits to temperature would capture this effect. If it does occur it could mean that future rates of sea level rise are significantly underestimated.
Not too sure just where you discern tunnel vision. To me, the idea that sea level rise can’t be faster than at termination does not seem justified. Is that what you mean?
[Response: The question whether future sea level rise can be faster than that during deglaciation at the end of the last Ice Age is an interesting one. There are two competing effects. (i) There was much more ice back then, hence a greater surface area on which any warming could act to melt ice - this argues that melting during deglaciation would have been faster than in future. (ii) The forcing that drove deglaciation changed over a much slower time scale. The increase in insolation that melted those ice sheets took about 10,000 years. Given that Siddall et al. found a 2,700 year response time for the ice sheets, one has to conclude that the rate of melting was limited by the slow change in forcing. In other words, had global temperature increased by 5 ºC within a century (that's like a step function for the ice sheets with their 2,700-year response time), deglaciation would have occurred much faster. In fact, had the forcing changed in a step-function manner from LGM to Holocene conditions, so that sea level from that point would have started to approach the new equilibrium on a time scale of 2,700 years, the first century would have seen a sea level rise of over 4 meters in the framework of the Siddall model (the initial rate is 120 meters divided by 2700 years = 4.4 meters/century).
Given these two competing effects, it is hard to say without detailed calculations which one would dominate, and I don't think one can conclude a priori that future sea level rise cannot be faster than that during deglaciation. -stefan]
Thomas L. Elifritz, re #15: – “a serious case of tunnel vision, which I won’t even bother to explain, since it’s so obvious.” Please do spell it out so people like me, who don’t spot the obvious, can learn something.
Aaron above mentions and gives a pointer a page on to the glacial Lake Missoula/channeled scablands event(s). A while back I dropped a bunch of links in this Stoat thread and pointed back to an even older Prometheus thread arguing for a “quarter inch” sea level rise.
Seems some geological structures we used to think formed slowly may have occurred during events too fast to resolve in the paleo information (e.g. drumlins, recently observed to form very rapidly in glacial outflow under ice in Antarctica, apparently something of a surprise ….). Maybe pingoes too? http://scienceblogs.com/stoat/2007/02/why_do_science_in_antarctica.php
The profile and supporting text notes that the 3 to 6km wide discharge channel is still 1500 metres below sea level at a point 40km from the existing grounding line.
So every kilometre the glacier face pulls back produces another two kilometres to the face, and eventually when the face is back to 40km from the coast the discharge will be over a face 80 kilometres long (40km on either side) and 2500 metres high (1000 metres above sea level) falling into the discharge channel. At what rate? I shudder to think!
The potential for non-linear responses looks pretty high to me!
Thanks for your reply. I had been thinking that the change in available surface area would play a role but also the different rates of warming as a function of latitude. So, faced with the same rate of global warming, the higher rate of temperature increase at the poles could lead to quicker melting of less surface area and so compensate.
Your invocation of faster warming for the whole globe is more important.
Another question is to what degree are contenental ice sheets proping themselves up? The GIS is domed so that in some sense all of it could slide right now. Were contenent scale ice sheets flat for most of their extend and thus had nowhere to slide to and thus no quick dissipation path? The ratio of steep edge surface area to flat central surface area could be important since the (self-made) altitude of an ice sheet plays a role in its preservation. This might also counteract the effects of greater surface area to some degree. If the timescale for gravity assisted disintegration is ten times shorter than for the melt from the middle of a continent timescale, then sea level rise could be faster even with less available ice so long as it is more susceptible to sliding.
It strikes me also that the shape of the curve for sea level rise might be affected by prior climate history. We’ve experiences a period of stable temperatures allowing ice creation to come into equilibrium with ice destruction so that ice sheets slopes are probably at a critical gradient. Thus we might experience more rapid initial sea level rise than if we were transitioning directly from a time of ice sheet growth (by accumulation) to ice sheet loss. The total sea level rise would be governed by the amount of available ice, but we would have some of it front-ended compared to at termination perhaps.
So, I think that the statement that sea level rise will be slower now needs more support or qualification, but I don’t discern tunnel vision in it.
Though their projections of sea level rise are on the low end, the extra ocean they project is nothing to sneeze at, as Siddall tells AFP:
“Fifty centimetres (20 inches) of rise would be very, very dangerous for Bangladesh, it would be very dangerous for all low-lying areas. And not only that, the 50 centimetres (20 inches) is the global mean. Locally, it could be as high as a metre (3.25 feet), perhaps even higher, because water is pushed into different places by the effect of gravity.”
A weird statement for a denialist to make, don’t you think?
There are problems with the paper, but this is silly.
> How can sea level rise (17cm since 1900 e.g.) be measured with any (or much)
Good question… I suggest you try to read Church and White, linked to under the post.
Tidal variation on the open ocean is sub-meter, not “tens of meters”, and can be well modelled, being periodic. It is true that the global geometry of tide gauges is very, very poor, with most of them on the Northern hemisphere and all of them (except some islands) on the coast. And its gets worse going back in time. But OTOH, just like with the surface met stations, there is a lot of long-range correlation in the field measured, especially when averaging over time. That makes a seemingly hopeless job feasible.
Altimetric satellites are a lot better: they scan the whole ocean over their orbital repeat period, not just coast lines adjacent to human habitation. But… they have been around only since about 1992 (the type of altimetric satellite good for this work, i.e., Topex-Poseidon and successors). Their radar footprint on the sea surface is several km across, so waves are averaged out. The orbit is tracked by on-board carrier-phase GPS.
Church and White use the trick of “bootstrapping” the principal modes of sea level variation found from the altimetric era back to the tide-gauge-only era, mostly eliminating the biases caused by the poor tide gauge geometry. The technique used is our good old loved/hated PCA/EOF also used in proxy temperature reconstructions, and in the Steig et al. Antarctica paper ;-)
Summa summarum, it is hard work. One tricky thing to get right, e.g., is the effect of ongoing post-glacial isostatic adjustment, that affects measurements also well outside the once glaciated areas.
I understand your (and others) scepticism, but there is only one remedy for that: dig in the literature. It really holds up.
> a lot of long-range correlation in the field measured,
> especially when averaging over time…. makes a seemingly
> hopeless job feasible.
This is the key. I wish there were an illustration of it somehow to convey to people how you can get strong evidence of tiny changes by using a large number of relatively inaccurate instruments like old glass-bulb thermometers, or yardsticks nailed to piers, inspected by ordinary folks who take notes on them every day.
Take a huge number of instruments. Spread them out very widely. Have them checked — by fallible human beings, and some of them get placed poorly, and some get damaged, and some aren’t exactly perfect. Any one of them can be wrong in some way but each of them day to day, year after year, can be watched and seems in its own small way to be giving believably consistent results for where it is, more or less, although you wouldn’t trust any one of them to tell you some _tiny_little_change_ was real for sure. Whether you’re looking at the daily temperature or the tide height.
But step back and look at the entire field of them. And if you notice that same _tiny_little_change occurring broadly and consistently across the entire collection, you have good reason to say it’s detecting that little change.
That the values would be linear would be accurate if the rate change or flow rate were also linear. However, when you have a greater source energy level and a steady state flow capacity the rate of flow increases or the energy content of the flow would have to be higher, hence there would be large amounts of inter-zonal mixing.
Going further, if you increase the specific and latent energy content near the equator then it is likely the transportation path would have to expand to maintain equilibrium. If as we have seen that there appears to be multiple paths towards the polar emission, then it would seem likely there should be both effects occurring in the attempt to re-achieve equilibrium.
Instead the empirical measurements regarding the oceanic current flow rate in the N. Atlantic appear to be nearly stable. What has happened is that the ocean currents carry a higher temperature instead.
Apparently in the atmosphere the Hadley cell may have greater rate of flow towards the North, interrupting the Walker circulation and Jet Stream. It would appear that the Walker cell interruption and the Northern Jet Stream deviations may result in “sloshing” in the ocean basin related to changes in the wind currents. It would seem imperative that if the intent were to insure that there was clear evidence of expansion that you would need to perform a simultaneous zonal comparative analysis on opposite shores. I suspect non-linariety will be observed near the Hadley and ITCZ and Ferrel cell interfaces.
‘… for correcting … myths. The article suggests that, rather than repeat them … one should just rephrase the statement, eliminating the false portion altogether so as to not reinforce it further (since repetition, even to debunk it, reaffirms the false statement)….”
Read that linked page. It’s important if you want to be effective teaching facts instead of the controversy.
Re the billboards, I’d say something like this if I were talking to your neighbors:
Valero — a Texas company that will suffer greatly from sea level rise (Texas is so darned flat along the coast):
has been putting up misleading billboards in Texas.
They’re overstating — by about triple — how the Waxman bill will change the cost of gasoline, _and_ they are making it sound like an immediate change — leaving out the 20-year time span, for a far smaller increase.
Duh. You buy gasoline from people who lie to you? Why?
The EPA’s estimate is a cost “25 cents per gallon higher by 2030″ — and you can look this up easily for yourself.
40 Martin Vermeer: “Fifty centimetres (20 inches) of rise would be” irrelevant to almost all Americans and other people who are burning the most fossil fuel. Hence, Fifty centimetres (20 inches) of rise would be ignored by the decision makers in Washington, D.C. who are watering down H.R. 2454 even more at this moment. Who cares about the people in Bangladesh when the coal industry in the US stands to loose $100 Billion per year in cash flow if an effective bill passes? Not the stockholders of the coal industry! I stand by my statement.
> Take a huge number of instruments. Spread them out very widely. Have them checked
It’s more than that, Hank. The instruments check each other. It’s called redundancy. If an instrument suddenly shows a skip compared to all its neightbours, it is safe to assume that “something” happened. And that you can fix it.
It’s due to the long-range correlation situation that we have massive redundancy. It’s only when you have large scale systematic error patterns — like the glacial isostatic adjustment that I mentioned — that redundancy doesn’t help, and you have to get the correction right.
I have not read your article yet – but i notice Pfeffer et al’s paper is not referenced. this paper fills the “ice dynamics” component missing from the IGCP projections…is it not a critical piece of work?
Pfeffer, W.T., Harper, J.T., O’Neel, S. (2008) Kinematic constraints on glacier contributions to 21st Century sea-level rise, Science, 321, p. 1340-1343.
“The EPA’s estimate is a cost “25 cents per gallon higher by 2030″ — and you can look this up easily for yourself.”
Which is, I think, nuts.
It was much more expensive than that a little more than a year ago. (Stuck button alert) Peak Oil passed in 2005. They aren’t pulling anymore out of the ground now than they did then and, if and when the recession eases, demand WILL go up.
Peak Oil and increased demand, eheu. Write down what you can remember about 2007-2008 so you can tell your grandkids what The Good Old Days were like.
Edward — you see? The Internet Protocol is distinctly less reliable for packets containing unsubstantiated questioning of a scientist’s integrity. (No, I had nothing to do with the “mishap”. Wouldn’t have posted my response had I noticed in time.)
Re 31: Dr. Vermeer,
I considered that the Arctic atmospheric circulation pattern in the summers 2007 and 2009 was one that had rarely been observed previous to 2007. From this, I concluded that different regions (at the same latitude) could be subject to different degrees of polar amplification, and surmised that the regions subject to the greatest warming could vary as the climate system was forced. If the center of greatest Arctic warming was over Alaska, then there would be one level of ice and snow melt resulting in one level of sea level rise. If the greatest Arctic warming was over Greenland, then there might be more contribution to sea level rise. In both cases, the polar amplification would be at the same latitude, but the effect on sea level would be different.
Then, I had the problem of defining “warming”. Greenland can absorb heat without a change in temperature, while a similar amount of heat added to Alaska, might raise the temperature. On the other hand, a moist summer sea breeze that might cool Alaska, would add heat to Greenland – and raise sea level.
With current trends in Arctic sea ice, I think we can expect some changes in Arctic atmospheric circulation patterns. That is my story, and I am sticking to it until I can finish my beer.
In the end, after corrections, the R07 paper didn’t really produce a good out of sample fit. The reported fits were highly dependent on the choice of periods etc. Perhaps this whole semi-empirical approach is a bit of a dead end given the complexities of what is being modeled. It does seem unlikely that a single global temperature variable can account for thermal expansion as well as all the various glacial melt rates.
[Response: Depends what you call a "good fit" - for those who want to see for themselves, see Figs. 1 and 2 here, showing the fit derived with only half the data and then applied to the other half. -stefan]
> Pfeffer et al’s paper is not referenced.
True… while preparing this post there was discussion on whether to reference and shortly discuss it. We decided to restrict ourselves by focusing on semi-empirical methods only. This doesn’t mean to imply that the paper (and the methodology it represents) would not be important — it is.
Martin (41), a quicky clarification before reading all of your post. My understanding is that the static, not tidal, variation of sea level varies by 10s of meters (which I take is the extreme) among different regions.
Bingo. $0.35, $0.77, whatever… meanwhile in recent memory the price is slewing wildly by 100% or more based on rumors and whispers plus of course escalating demand as well as well-founded uncertainties about supply. Waxman-Markey is the least of the problems we face w/regard to price.
Not that enough people will remember all that once the industry opens the pipeline of lies when the Senate takes up the bill. Prepare for some really serious irritation, just around the corner.
Two commonly used sea-level curves for the last glacial cycle,one constructed from dated raised coral terraces at Huon Peninsula in New Guinea , the other from oxygen isotope determinations from deep-sea cores, show that sea levels in Australasia increased 125meters between 20000yrs and about 5000 yrs ago. with relative stability over the last5000 years.These same proxy data show exactly the same rise between 140000yrs ago and 130000yrs ago, with a stepwise decline on from 120000 to 20000 yrs ago. This is graphically displayed in the textbook “Prehistory of Australia.” Its a good read, for anyone out there who still reads books.
Martin @36, thanks. Unfortunately not being a member of any scientific society I can’t get past the pay wall (OK I didn’t try). I couldn’t tell from the abstract if their estimate included changes in groundwater -or just changes in surface storage. I suspect the change in groundwater storage is trongly negative.
38: I strongly suspect that the determining rate of ice loss wouldn’t be the length of the calving front, but rather the rate of flow of ice from the interior to said front. I would think that initialy the slope of the ice surface would be fairly steep, but as the distance that the increased flow covers increases would decrease with time. Most likely this flow would be strongly influenced by a small number of ice-steams, so it may not be possible to calculate with any certainty.
Edward, 50 cm of rise wipes out the East Coast Barrier islands where a very large number of very expensive homes are. Its not just the average rise, but the annual surges on top of that rise. The cost on Long Island alone easily exceeds 100 billion.
> I assumed the link simply supported your comment.
Chuckle. Never safe on blogs. You’ve always got to check the source and see if it’s even relevant, let alone accurately represented — which was my point.
There’s an academic joke about citation to “guy in bar” — “guy on blog” is even less convincing.
Global ice extent data was just released for August. As we are approaching the fall minimum, I thought interest would be high. I included 30yrs ago, last year and the record ARCTIC low yr for reference.
August (month end averages) NSIDC
30 yrs ago
1980 Southern Hemisphere = 18.1 million sq km
1980 Northern Hemisphere = 8.0 million sq km
Total = 26.1 million sq km
Recorded Arctic min yr.
2007 Southern Hemisphere = 18.0 million sq km
2007 Northern Hemisphere = 5.4 million sq km
Total = 25.4 million sq km
2008 Southern Hemisphere = 17.9 million sq km
2008 Northern Hemisphere = 6.0 million sq km
Total = 23.9 million sq km
2009 Southern Hemisphere = 18.6 million sq km
2009 Northern Hemisphere = 6.3 million sq km
Total = 25.9 million sq km
Martin, even GPS can’t position a satellites orbit within a mm. I can see though how one can get possibly a reasonable small average even if the noise of the individual measurements far exceed the “trend” if you get enough points over a long time, as Hank describes and you imply. It would still seem that the confidence level is no where near, say, 90-95% (though I have no clue what it should be — my uninformed gut guess? maybe 75-80%?) even for decadal periods, let alone annual periods. We haven’t been getting satellite data for two decades yet.
My understanding is that the static, not tidal, variation of sea level varies by 10s of meters (which I take is the extreme) among different regions.
Eh, no. Sea level varies by up to 2 m globally about an equipotential surface (the geoid). Some of this variation is time-independent — the permanent sea-surface topography –, some time-varying, including tidal variation, meso-scale eddies, and inverted-barometer response to air pressure variations.
The geoid again varies by +/- 100 m about the reference ellipsoid — but the latter is a mathematical construct, not to do with what is commonly understood as “sea level”. Is this what you meant? But the geoid is unchanging with time and drops out of the equation when studying time variability. The Topex/Poseidon and Jason satellites sen(t/d) their radar beams down from over 1300 km, measuring with a few cm precision, and a couple hundred m up or down really don’t matter there ;-)
#52 Arron, One moment after a short visit in my Arctic community, and I would convince any skeptic (having reason as its prime motivation) of calamity. All small Glaciers around Resolute have almost completely vanished (very little of the permanent small Glaciers remain . amazing sight they were always present for at least 21 of my last 26 years here. They were always present since people were in Resolute (1947). THis surrounded by wide open warm water. THis despite a very cloudy summer, there were a few big glaciers left, they are gone, leaving the hills completely brown.
Re 31; Dr. Vermeer,
My last post was confused. I am sorry.
Under conditions of the 20th Century sea level rise, conditions in the Arctic basin favored ice, i.e., extensive sea ice. Within the last few years, (as a result of polar amplification) conditions have changed, pushing the equilibrium from ice to water. We see this as loss of Arctic summer ice volume, including sea ice and permafrost.
This change in equilibrium was a sea change, and there is no linear or scalar technique to use data from the old “ice favoring equilibrium” to estimate ice melt under the new “water favoring equilibrium”. Polar amplification has resulted in the Arctic crossing a melting point discontinuity. The Arctic crossed a tipping point.
In the old system, sea ice remained ice for years and years. In the new system, ice melts in the summer. In the old system, Greenland was swept by cold, dry winds coming off the sea ice. In the new system, Greenland is swept by “warm” moist winds from the ice free Arctic and the North Atlantic. Data from the days when the Arctic was substantially covered with sea ice will not help us predict how fast Greenland will melt in the future when the Arctic Ocean has much less ice, and the wind carries more latent heat.
What we can estimate, is that Greenland will melt much faster than in the past. Use of data from prior to the tipping point will cause us to underestimate the rate and extent of that melt.
> Martin, even GPS can’t position a satellites orbit within a mm.
Yes, you’re right — for every individual satellite position in space. But orbit determination using those GPS fixes as constraints is much better. Remember that the satellite describes a Kepler orbit (well it’s a bit more complicated than that…) and the period is very precisely known, giving us the size of the orbit through Kepler’s third law. And through the total mass GM of the Earth, which should be constant.
There’s a calibration offset in the radar though, but that should be a constant as well.
Consider that every mm per decade translates into a cm per century. And Church and White don’t claim any better than 5 cm back to 1870.
Yes, you certainly have a point. We shall find out over time. Note that the nonlinearity you describe is in time, not (necessarily) in temperature. Suppose that both temperature and ice melt increase, but the relationship between them doesn’t change?
I am now coming to the conclusion that we are only going to be able to geo engineer our way out of this issue once we fail to implement the necessary alternative anergy solutions in time to do much about it regardless.
RE: G. Karst, #66. The last time I checked, 18.0 plus 5.4 = 23.4, not 25.4 as you indicated. Also, 18.6 plus 6.3 = 24.9 in my experience, not 25.9 as you indicated. Where did you get those figures, anyway?
Who can discern a trend of significance for the Antarctic gets a hat tip.
Of course does not say a thing about the thickness and volume but we know that Antarctic summer low is much lower than the Arctic, even in these years and practically as flat as winter high, which so happens
PS, and for those wishing to do sums, Plimer style… they wont fly:
2009 Southern Hemisphere = 18.6 million sq km
2009 Northern Hemisphere = 6.3 million sq km
Total = 25.9 million sq km
Martin, yes, I think that’s what I was doing – comparing geoid with ellipsoid. In fact the article (from NASA, and which wasn’t perfectly clear) I was referencing used “100m”, but I didn’t have the courage or guts for that number — so I used “tens of meters”. Plus, I presume the actual level is unimportant compared with the point-by-point anomaly to measure sea level rise. Still the measurement (sometimes loudly trumpeted) of how much the level rose the past year or so actually borders on the meaningless given the noise compared to the measurement. To the extent that is used for projections, it is highly dubious; though I understand physics analysis is the primary process of projection/prediction.
Because I did not cut and paste some math errors are correctly pointed out. I apologize for the sloppiness (I did it on the fly). I will try to better check my numbers better. Thanks for the catch. The data comes directly from the NSIDC plates like these; the addition error was entirely mine, sorry:
Just a suggestion, flood the low lying lands around the globe, some of which are many many metres below sea level. A relatively cheap/simple task which would create huge in land lakes around which, new communities could grow. By helping to lower sea levels around the world, this would go some way to lessen the threat of global flooding of major cities.
Still the measurement (sometimes loudly trumpeted) of how much the level rose the past year or so actually borders on the meaningless given the noise compared to the measurement.
Indeed… but with the understanding that “noise” here refers to natural variability, not to sensor limitations… don’t insult our sensors ;-)
[Response: And, by the way, I had an interestingdiscussion on noise vs signal in the sea level data with Björn Lomborg in the Guardian recently, who had claimed that "over the past two years, sea levels have not increased at all — actually, they show a slight drop. Should we not be told that this is much better than expected?"... -stefan]
If you have a problem with something I have said on another blog… That blog is the proper forum to rebut it. Are we now going to engage in cross blog debates? Should I start combing archives for your comments. Seems like a waste of time to me. If your not adding to the knowledge base… What exactly are you doing??
Look, I don’t know what you were expecting for ice extent numbers, but many seem angry and disappointed. That is not my fault. The numbers are what they are! What they mean is open to discussion. I will listen to any interpretation put forward, however I choose to refrain from lending significance, or comment, to plain numbers.
My errors could indicate, that I am getting too old to blog effectively. That is a possibility and that I will reluctantly review, but I feel I still have somethings to contribute. Sorry you disagree.
I think some have a problem with your #66 post, and “As we are approaching the fall minimum”, and then putting up “Global ice extent” numbers, while the minimum is clearly only for the Arctic. In other words, it’s clear you are trying to prop up your position with the numbers, in a way that appears somewhat, shall we say, false.
“…and then putting up “Global ice extent” numbers, while the minimum is clearly only for the Arctic”
I post the month end averages every month. Sorry you have missed all the others. The posts are all the same (posted without comment). I added the 2007 report this time because we are approaching Arctic minimum and I thought some might find the reference useful. If you like… I can post the Antarctic minimum from my archives (I don’t think you will like it any more), OR you can just wait until 2010 OR you can extract the information yourself. I would be happy to post any month you like… just name it and the year (you might have to check my math. Actually, it’s not my math… It’s my failing eyesight. CRT displays are becoming difficult for me to read. 3s look like 8s, 1s and 7s… well you get the idea).
Have people forgotten that one pole’s minimum is the other pole’s maximum. That is why my report is global NOT regional. Hope this clears up your concerns.
Lomborg’s mindset becomes clear when he told us last October that “over the past two years, sea levels have not increased at all — actually, they show a slight drop. Should we not be told that this is much better than expected?”. As a trained statistician, he must surely have known that he was fooling the public with the “noise” of short-term variability rather than discussing a meaningful trend.
Indeed. At what point, in a matter likely to adversely affect millions, does deliberate deception become criminal?
To complete the numbers of ‘Global’ a chart to go with that. Note wider difference between extent and area, what I’ve dubbed the break up index. It was 1.25 back in 1979 and this August it was 1.34 or alternate, the August Area this year in global terms was 74.1% of the Extent, back then it was 80.1%. Sign of quality of the ice me thinketh.
One Jeff is massaging this as if sea ice has not significantly reduced. It’s a special art form I’ve not grasped… maybe I would accept after nurse Ratched performs a lobotomy on me. I’m convinced that lack of summer cover and sea ice off days has more bearing for the globe than the simple global summation that is commented surely with ‘it’s only 5.5% less’. Add to that the many millions of km square in missing land snow cover and the snow off days that keep increasing. That’s a bunch of Albedo change on the sunny side.
The relationship between ice, water, and water vapor in a particular system is defined by an equation of state. (See for example http://en.wikipedia.org/wiki/Equation_of_state#Redlich.E2.80.93Kwong_equation_of_state, or much better, a good Chemical Engineering text.) Time is not relevant. Ice melt is a function of the energy of the system. As the temperature of ice is raised toward its melting point, no melt occurs. Then, at ~0C, one can add heat to ice and have complete ice melt without raising the temperature. At ice’s melting point, the temperature is not indicate the energy of the ice. Ice above 0.15C is water. From these three curves, we know the relationship between temperature and ice melt does change. If we are considering (Earth’s) global temperatures, then we are working without any knowledge of how forced the system is; or, how close the system is to equilibrium. (If both temperature and ice melt increase, and the relationship does not change, then we know somebody has gone to a lot of effort to tamper with our sample or we are looking at data from a system that is not at equilibrium.) Without knowledge of how close the system is to equilibrium, no useful conclusions can be drawn.
Ice does not care about the global temperature; it cares about the local temperature. (Polar Amplification ensures that the change in the Arctic temperature is greater than the change in the global temperature.) Only by looking at the ice’s local conditions under equilibrium, can we estimate ice melt and sea level rise.
This is not a “We shall find out over time.” matter. Public policy makers are looking to people like you for decision support documents. Like it or not, climate scientists today, find themselves in positions of great social responsibility. If you write something, public policy makers are going to accept it without question, and comments from an old farmer like myself is likely to influence the policy maker’s mind.
I did finish the beer, but it did not make me think that some new Arctic Atmospheric circulation pattern would keep Greenland cold.
Geoff #84 This has been suggested for the Qattara depression west of Cairo. The problem is getting through the mountain range to open the depression to the Med. There have also been similar suggestions for other depressions in the southern sahara
For me a good fit is determined by looking at the coefficients.
As stated in your correction the computed coefficient for the first half would be .42 cm/year/degree. However if you compute the coefficient for the second half of the data you get .24 cm/year/degree. This means that using the model based on the first half of the data you would have overestimated the increase in the rate of sea level rise in the second half of the period by almost a factor of two.
[Response: Agreed. But you're talking of the "increase in the rate", the second derivative of sea level over only a 60-year period. Sea level itself is predicted to within 2 cm of the observed value up to 2000 if the method is trained only on data for 1880-1940. Call that good or bad, but it is certainly better than the physics-based models do. -stefan]
And there are two ways to do it — remove the water by evaporation and fill the basins with fresh water (remembering there are aquifers available to recharge), or just fill the hole with salt water, and let the evaporation happen there, making brine and sending the moisture downwind.
Let’s see, go with cheap and thoughtless, or think about …. ooh, profit! …. yeah, that’s good enough.
This is not a “We shall find out over time.” matter. Public policy makers are looking to people like you for decision support documents.
What I meant is that physical modellers are scrambling to get a handle on these phenomena, cf. Pfeffer et al. Semi-empirical modelling is a blunt instrument, inherently incapable of addressing them, except in a “bulk” fashion — and we can only guess at this point whether it already does that or not.
…and your worry remains rather theoretical until after public policy makers start looking seriously at, and basing policy on, even the conservative projections now lying on the table…
Re flooding depressions in Africa to store water and reduce sea level rise – there may be the unfortunate side effect of more and stronger Atlantic hurricanes.
“That Saharan dust keenly interests Dunion, a research meteorologist from the NOAA Hurricane Research Division in Miami. He said, “The Saharan Air Layer is essentially a huge dust storm that can be the size of the continental United States. Every three to five days during the summertime, these storms roll off of the African coast.” As the dust storms move off northern Africa, convective waves develop farther to the south, pulling moisture up into the atmosphere.
“We think a dust storm has three main components that can suppress a hurricane,” Dunion continued. “One, it’s got super-dry air. Hurricanes don’t like dry air in the middle parts of the atmosphere, and that’s exactly what the Saharan Air Layer has. A Saharan dust storm also has a very strong surge of air embedded within it, called the midlevel easterly jet, that can rip a storm apart that’s trying to develop. We call that vertical wind shear. And then the third piece is all this dust.”
Researchers think the dust itself suppresses cloud formation, playing a role in preventing tropical waves from becoming more intense. Ismail said, “We think that dust aerosols can affect tropical disturbances, sometimes even kill those disturbances. Dust inhibits convection, the process of moisture rising to the higher levels of the atmosphere, and then precipitating as rain. So these Saharan dust layers seem to have a blanketing influence on the development of convection.” http://nasadaacs.eos.nasa.gov/articles/2007/2007_hurricanes.html
I wonder what will be the side effects of geoengineering done to reduce the hurricane side effects of geoengineering – flooding the Bodele & Qattara depression to combat the sea level rise – caused by the inadvertent geoengineering from CO2 emissions? Perhaps it might be better if, finding ourselves in a hole, we learned to stop digging?
The Qattara depression is about 18000 kM^2 and about 133 M deep at its deepest. At its most optimistic this represents less than 2300 cubic kM of sea water which represents about 5 mm of sea level or less than 2 years of sea level rise at the present rate of increase.
Rather underwhelming result I would think.
adding to the previous, I think also the model you propose is too simple and inappropriate. The system is way off equilibrium, and temperatures throughout the area vary over a broad range. There is the “melt line”, where temps are at the melting point; but as bulk temperature varies, this melt line just shifts place. At no point does bulk temperature wait for a large amount of ice to melt. Note also that the Greenland ice sheet has significant vertical extent.
Re: Jeff Davis, if you look at the uni bremen site you will see that now both the NW and NE passages are open again..second time in recorded history! No ice in Hudson bay either. To me this shows from now there’s no going back..the effect of ice albedo is even stronger than seasonal fluctuations as this year was not an exceptionally hot year in the northern hemi. Is there any data out as to how much perennial sea ice has melted this time around? Thanks.
Comment by Lawrence Coleman — 3 Sep 2009 @ 1:34 AM
Rod B #97, about Lomborg:
> He has no way of knowing with any confidence what the sea level did the past two years.
Actually he does… we all have. What we don’t have is a way that actually works of extrapolating that knowledge many decades into the future.
(That’s precisely the point I tried to make about natural variability!)
Eli Rabett, as a UK judge ruled that land use changed the precipitation on Kilimanjaro, such huge inland seas could promote the amount of vapor in the air to such extend to get local climate change even cloud forming and rain. Such an initial massive water draw will have it’s effect on the tributaries though, but on the whole, think it’s a pipe dream. And the Med, well, that lost apparently 40 cm of level through evaporation just in the heatwave summer of 2003 and it still has not returned to same level as then. Gibraltar becoming an inflow instead of an outflow… that could cause changes of deeper currents in the Atlantic… wanna mess with that?
But reminds me of the Brokopondo project in Suriname. Artificial lake and it not filling up in proper due the massive evaporation and permeability of the underlying geology [Not looked at it since probably 40 years, but it had major impact http://www.scielo.br/scielo.php?pid=S1679-62252007000300015&script=sci_arttext. Now I wonder on Three Gorges if that is ever going to fill up to the maximum and hold or find an alternate way out. Saw recently something about large number of land slides there maybe forcing yet another major population displacement. Whatever we do, think it will be a drop in the bucket if the large ice caps start melting in earnest.
I thought Gibraltar was always a net inflow. When did that change?!?
[Response: It is a net inflow, to make up for the net evaporation over the Mediterranean catchment. However, this is achieved by a surface inflow and a deep outflow, which is required because the exchange needs to satisfy two budgets: the water budget and the salt budget. You can't do that with a one-way flow, because that would replace the evaporated freshwater with an inflow of salty sea water from the Atlantic. To make a steady state possible, you've got to get rid of the extra salt by an outflow that is saltier than the inflow. -stefan]
I am at WCC3 and although I can’t quote exactly, (I forgot to turn on my recorder), Dr. Pachauri has just addressed the international panel emphasizing the range estimates by IPCC are (largely reliant?) on thermal expansion and that when you add the melt together with that, the expectations can be imagined. He mentioned we can see this likely in meters. It was carefully worded and I hope to find a copy of the statement after this session.
I imagine (hoping) AR5 will include the combined assessment.
Has anybody looked into how much water could be stored in (say) the Saharan depression? Are we talking about an amount that would make a noticeable difference in sea level rise? It would seem to be a relatively cheap and harmless way of geoengineering, mitigating SLR (but not solving any other problem of course)
As this post was originally about the efficacy of simple models of sea level rise, could you comment on my #97? If the coefficients are so different between the training and the test period then it would seem that the model is not well specified. It isn’t surprising that the graphs look ok by visual inspection since what is being compared there is dominated by the absolute sea level, and the amount of sea level rise during a period where the temperature variation wasn’t all that large.
… aquifers are located beneath large portions of central and eastern Saudi Arabia, including Wasia and Biyadh which contain amounts of both fresh water and salt water ….
The Nubian Sandstone Aquifer System is the world’s largest fossil water aquifer system. It is located underground in the Eastern end of the Sahara Desert and spans the political boundaries of four countries in north-eastern Africa……..
…. water from the Sahara Desert in Libya, from the Nubian Sandstone Aquifer System …. Groundwater recharge for these deep rock aquifers is on the order of thousands of years, thus the aquifers are essentially non-renewable resources….”
The amount of fresh water in the world – about 4 percent of the total — is so limited that deciding to dump sea water into an area that can function over geologic time as a freshwater aquifer would be an act of a class we don’t really even have a good word for yet in human language.
What’s the right word for making a choice that’s so big, so long-lasting, and so short-sighted?
Remember — a spike in precipitation is predictable in geologic terms after a warming; that would be fresh water transported out of the ocean after it’s risen and warmed, that would eventually transport the fresh water to the continents.
If we don’t mess up the process by sowing salt on the continents ahead of the rainfall.
Hank, Aquifers are nonrenewable for another reason. These aren’t underground rivers, but rather water flowing through geologic strata. Once the aquifer dries out, the layer compacifies and it will never again be an aquifer.
Chao, B. F., Wu, Y. H. & Li, Y. S. Impact of artificial reservoir water impoundment on global sea level. Science 320, 212214 (2008).
This paper shows that the equivalent of about 25-30 mm of GMSL (Global-Mean Sea Level) has been retained in man-made dams, mostly since about 1960. This is roughly equivalent to about 0.5 mm/year GMSL over this period. Unfortunately we don’t have good information on the other side of this equation, that is, the amount of water that is being returned to the ocean through ground water mining. While it is almost certainly less, we don’t really know how much less.
A useful rule of thumb here is that 1mm of GMSL is equivalent to about 360 cubic kilometres of water. To put this in some sort of perspective, the Three Gorges Dam in China (water volume: 39 cubic kilometres) is equivalent to about 0.1mm GMSL.
The idea of dumping sea water over a fossil aquifer (“fossil” here means one that isn’t getting recharged with fresh water) sounds like an extremely bad one to me.
Ray, 114, I don’t think it’s quite “never be an aquifer again”, but for millenia, the replenishment will be nil or near enough to make no difference.
At least that’s what I remember from grammar school friends who did geology and I asked about (admittedly ~20 years ago).
The rock is available to hold water, but the amount of water it takes up depends on how much water it already contains (to a maximum rate given by the permeability of the base rock strata), so when there’s no water, the rate of ingest is slow seeps at the edge. Which requires a plentiful supply to the rock strata itself.
And THAT is not sinecure by any standards under AGW changes.
An ice age could get water there and staying there long enough to restart the process, mind.
I hate to put words in other peoples mouths; but, I get the impression that Mr. Lewis may be alluding to the hysteresis between the solid and liquid state. With the 2500 Joules/ccm and a lack of definition of where the ice is in relation to the 2500 Joules, the amount of total energy involved can be quite broad. However, what I suspect is, since we are seeing sever melting over the last 10 years that we are likely on the high side of the range.
The most interesting thing is how fast ice reforms in the Fall here in the NH. Apparently the sea ocean temperatures though warmer are not so warm as to not easily shed the latent heat and fallback to the solid state. It does not appear that in the cooling that 2500 Joules/ccm needs to be lost to return to solid, this begs the question of how much salinity or insolation is playing a part as you alluded to earlier…
This also suggests that the radiant retention issue of water vapor/radiant atmospheric gas vector/and possible lack of Ozone could be involved as well. I will stop now, I am afraid I will only muddy the waters you are trying to clear.
RCM progress report: 20 levels plus ground, 3-layer cloud scheme, ten gases, 54 spectral bands, Ts comes out as 289.5 K, Tmin in the stratosphere is 204.8 K, R^2 with the USSA is 0.989, albedo 0.312, power imbalance 8.3%.
Not great yet, but I’m getting there. If I can figure out why the stratosphere is so cold, I think I’ll have it. That’ll up the outgoing energy and help balance the budget (at the moment I have 235.1 W/m^2 coming in and 215.5 going out, “a no-good way to do arithmetic,” to quote Heinlein).
I have a question that I’d like Gavin Schmidt or any scientist on his level to answer. I want to know why the oil companies are demonized for funding scientists who disagree with global warming theory because the oil companies have given money to promote global warming as well. For instance, Exxon gave a ton of money to some Stanford based research group. My other question is regarding the work of Roy Spencer. If Spencer is correct about negative feedback from clouds, will this nullify the small heat that molecules of Co2 emit?
[Response: Any demonization has occurred not because Exxon funds scientists who 'disagree', but rather they fund(ed?) for many years propaganda efforts full of obvious distortions and misinformation. Research funding is a completely different kettle of fish - as long as the researchers are free to come to whatever conclusion is justified by the science. As for Spencer, there are many independent lines of evidence that indicate that climate sensitivity is not small (see our discussion of Annan and Hargreaves), which makes it very unlikely that Spencer's research is as definitive as some have claimed. Cloud feedbacks are an important uncertainty - but they are exceptionally complicated and differ in the tropics, in the marine stratus regions, in the high latitudes etc. - and don't negate the plentiful evidence for the amplifying impacts of water vapour or ice changes. Hopefully, Spencer's work (as well as that of many other researchers on this topic) will lead to a clearer picture and more precise projections, but hoping that this will magically negate everything else is just wishful thinking. - gavin]
I’ve been on the road for the past few hours and just received from Dr. Pachauri a transcription of his speech. My description was a combination of two sections of the speech:
I would also like to acknowledge a step forward that the G8 leaders took in July of this year when they met in Italy. I would like to quote something that was included in the statement on that occasion and I read what it said “We reaffirm the importance of the work of the Intergovernmental Panel on Climate Change (IPCC) and notably of its Fourth Assessment Report, which constitutes the most comprehensive assessment of the science. We recognise the broad scientific view that the increase in global average temperature above pre-industrial levels ought not to exceed 2°C.” Today I most respectfully submit, however, that there were some dimensions of the scientific reality of the 2°C target that were really not covered and which I think would have added a great deal if they had been addressed in this particular meeting. Two of them that I would like to mention are the fact that firstly even with the 2°C target the IPCC has assessed that on account of thermal expansion alone we could get sea level rise of 0.4 to 1.4 meters. This is due to thermal expansion alone. If you add to this the melting of ice across the globe as the Secretary General of the UN has just reminded us we would have much greater increase in sea level…
and later in the speech
Clearly we need continuous data on this from different parts of the globe. We also need to monitor impacts because as the IPCC has projected in the case of parts of Africa we would see that by 2020 — as early as that — we would have 75 to 250 million people living in a state of water stress brought about by the impacts of climate change. We have also projected that by the same year some countries in Africa would see a decline in agricultural productivity and yields by about 50%. Clearly, if this is going to happen in such a short period of time we need to monitor these developments on a very careful and systematic basis. I also would like to mention that as opposed to these rapid but steady changes that we are going to foresee and which we have projected, we have also highlighted the possibility of abrupt and irreversible changes. What are these changes? Well two of them I would like to bring to your attention are the possibility of collapse of any part of the Greenland or the West Antarctic ice sheets. And if that were to happen in any of these two locations then clearly we would have sea level rise of several meters. That would mean that not only would we change the geography of this planet but create a catastrophe for hundreds of millions of human beings across the globe. So, we really need to ensure that we prevent by every means these abrupt and irreversible changes.
This was a fast transcription and I noticed there may be some words missing so I will try to check it against the video that was recorded if I can find it and maybe post it on the OSS site.
One of my tasks when I worked at Bechtel was review of the designs of long term repositories for nuclear and hazardous materials. I had to think about climate forecast, legal and social responsibility in the long term (defined by US law as 100,000 years).
In 1990, I was told to spend 4 hours a week updating Bechtel Management’s briefing book on climate change. (We were contacting to build large scale public infrastructures, and had to post bonds that it would survive climate change.) I made estimates of sea level rise. And, as a result, Bechtel developed conservative designs that we could easily bond/insure. I still like those SLR numbers. I think Hansen would approve of them. However, the management of this site has called those estimates “alarmist” and told me that my estimates were not based on “science”. The management here was correct. My SLR numbers were based on engineering estimates of what happens to ice when it is heated above its melting point.
Where in the IPCC is there a number that a politician or lawyer or engineer or business man can say, “these are our planning case numbers”? I think the IPCC was irresponsible not to consult with engineers, planners, and risk managers to develop “planning case numbers” suitable to support long term public policy.
Consider the the Rahmstorf line in the table in the post says the model predicts a total model rise [cm] of 16.2. If I build to 17 cm will I really have 0.8 cm freeboard? Or, should I assume a SLR of at least 20 cm and build to 30 cm just to be safe? What is the real expected error in that model? What is the real expected error in the numbers given in FAR Topic 3.2.1? Is it more than the 0.5 cm suggested by the precision of the numbers as written?
I think climate scientists (and weathermen) should be registered like professional engineers, and have to post a performance bond when they issue a climate/weather forecast.
Both you and Ray are partially correct. Whether an aquifer can recharge depends on its nature. An aquiferin a porous rock formation, such as the Edwards and Trinity aquifers here in Texas, can recharge if the inflow exceeds the outflow. Increased precipitation or reduced pumping (extraction) will allow the aquifer to recover.
But an aquifer in an unconsolidated formation, such as the former lake sediments underlying Mexico City, can’t recharge because the pores in the silt which were held open by water collapse when the water is removed. Characteristically, this is evidenced by surface subsidence. Once the water is removed there is no putting Humpty back together.
Sure. I’m writing it in Fortran-95, the “Salford F95 Personal Edition” you can download from Silverfrost Ltd. in the UK (http://www.silverfrost.com). Unfortunately this version comes with an annoying splash screen that runs every time for several seconds, and in addition, you can’t use it commercially or for research. I’m using it for research anyway, since I’m not publishing anything based on it yet. If I do, I’ll just download another Fortran compiler from somewhere and translate.
I started out with a 20-layer radiative equilibrium model Dr. Dave Dempsey posted on the web for a San Francisco State U. course in 1998. From there I built a time-marching version, and over time I added more and more realistic features–or tried to, I went up a lot of blind alleys, too, since I was teaching myself. Adding a convective adjustment (a flat maximum of 6.5 K/km, the average in the troposphere) converted the models from REMs to full-fledged RCMs, though they were grey for a long time.
I actually acquired a copy of Houghton’s “The Physics of Atmospheres” early in the process, so I could have implemented bands a lot earlier than I did. I scoured the web and libraries for band schemes, finding things like Essenhigh’s in his anti-AGW article, which only covered three gases and part of the spectrum. Eventually I learned enough to realize that I could convert the figures in Houghton’s tables to mass absorption features for CO2, H2O and ozone (k = S / d where S is line strength and d band width). I’m still using Essenhigh’s figures for methane. Cloud figures I found on the Hadley site, in a description of UKMO HadCM3. I got a nice cloud scheme from Kiehl and Trenberth (1997). Assorted physics and climatology textbooks gave me albedos, values of physical constants, and a way to numerically integrate the Planck curve.
Along the way I pestered the heck out of people here (Ray Pierrehumbert was especially helpful, and of course I learned a lot from Gavin, Michael Mann, etc.). Dr. Houghton emailed me electronic copies of his book’s tables. Syukuro Manabe gave me suggestions about what parts of my code might be giving me problems (though, like every climatologist I contacted, he refused to actually read the whole source code file, alas. I know, I know, other commitments, and real students to oversee).
I’m still not getting results as accurate as Manabe and Strickler got way back in 1964, but I’m a lot closer than I used to be. Give me another five or ten years and I might–MIGHT–have something research-quality to play with.
I did modifications of early versions for Venus and Mars. I hope to model those accurately in the future, and some day I’d like to add Titan as well, though finding absorption bands for those gases at those temperatures will be a challenge (people like Chris McKay and Ralph Lorenz have done a lot in that area). Under Titan conditions, nitrogen is a greenhouse gas!
Mark, water does not so much flow in an aquifer as percolate. When the rock becomes compactified, there’s no place for the water to go, and it can be lost entirely. These really are finite and fragile resources–seed corn, not feed corn.
119: I live not too far from the California Delta. If I had to make a wild eyed guess as to what level of sea level rise to plan for, I would simply double the IPCC AR4 numbers. But I suspect that a broke state isn’t going to commit the kind of resources needed based on some citizens wild eyed guess. My secondary guess would be that maximum flood stage flow rates in the rivers is probably a greater source of uncertainty as far a maximum water levels are concerned. Here climate change could also be important, as both warmer and wetter storms are likely in the future.
I posted a long post about my RCMs yesterday evening, but as of today it hasn’t shown up–maybe it got deleted for being irrelevant to the thread. If you like I’ll email you something. You can contact me at ReaderMail1960@aol.com.
There is absolutely no reference in AR4 for a .4 to 1.4 sea level rise by 2100 period, let alone for a 2C rise. It is even more outlandish to say that this would be from thermal expansion alone. I have no idea what Dr. Pachauri was referring to.
The collapse of the West Antarctic ice sheet would produce several meters, I’m not sure about Greenland. This was considered extremely unlikely by 2100 by AR4, and everyone else who has studied it.
BPL, your long post popped in above I think:
4 September 2009 at 6:25 PM
Phillip Shaw, thanks for the pointer to Trinity and Edwards aquifers; Scholar finds info on the structural variations that allow recharge of void space in some, like those, while others — like Kettleman– collapse.
Chapter 10.7 talks about SLR due to thermal expansion taken to equilibrium. Figure 10.43c shows thermal expansion causing about 0.6 to 1.4 m of SLR for models projecting ~2 degrees of warming relative to 2000. Pachuri was talking relative to pre-industrial conditions but it’s in the ballpark.
The results will probably help you figure out what was referred to, assuming your results will resemble those I see, including:
CHANGES IN SEA-LEVEL EXTREMES UNDER CONDITIONS OF RISING SEA LEVEL
J Hunter – staff.acecrc.org.au
… “larger values cannot be excluded” (IPCC, 2007b). … to be more reliable than the modelled sea-level projections … suggested a rise of 0.5 to 1.4 metres at 2100 …
Estimating Sea-Level Extremes in a World of Uncertain Sea-Level Rise
JR Hunter – ghcma.vic.gov.au
… Fourth Assessment Report (AR4; IPCC, 2007) … to project sea level into the … suggested a rise of 0.5 to 1.4 metres at 2100 …
Submission to the Senate Select Committee on Climate Policy
B Bahnisch – wopared.aph.gov.au
… Rahmstorf used the information available to the IPCC and came up with a range of 0.5 to 1.4 metres … The IPCC and sea level change. …
“It’s a poor sort of memory that only works backwards” and doesn’t givbe us recent updates to what we last learned — that’s why libraries and search tools have been invented, to add to what we remember. Try one today.
The Fourth Assessment Report (IPCC, 2007a) has indicated a projected global sea-level rise of up to 0.79 metres in 2095 (relative to 1990) with the caveat that, because of uncertainties in future ice sheet flow, larger rises cannot be excluded.
In Australia, at Fremantle and Fort Denison (Sydney), the frequency of sea-level extremes of a given height has already increased by a factor of about three during the 20th century, predominantly due to sea-level rise. Even a mid-range rise of about 0.5 metres during this century would lead to events which now happen every few years happening every few days in 2100, or the present ‘100-year event’ happening every few months.
—– end excerpt—-
Oh, this also merits looking up. Nicholas Nierenberg wrote:
> The collapse of the West Antarctic ice sheet would produce
> several meters, I’m not sure about Greenland.
A recent lowered estimate is here:
“Bamber and his colleagues found a WAIS collapse would only raise sea levels by 3.3 meters, or about 11 feet. Bamber, a professor at the University of Bristol in England, currently is a visiting fellow at the University of Colorado at Boulder’s Cooperative Institute for Research in Environmental Sciences”
That’s the lowest estimate available, and based on optimistic assumptions:
“The study authors assumed that only ice on the downward-sloping and inland-facing side of the basins would be vulnerable to collapse. They also assumed that ice grounded on bedrock that slopes upward inland or on bedrock that lies above sea level likely would survive.”
I think climate scientists (and
weathermen) should be registered
like professional engineers, and
have to post a performance bond
when they issue a climate/weather
Yeah, that’s the way to help science forward… not. I have a better idea. In the interest of bringing good engineering practices to the management of this issue, what about obliging instead the emitters of greenhouse gases to post such bonds?
Seems more logical to address the source of the problem, rather than the source of information on the problem, don’t you think?
#145, cce the figure you are referring to is 10.34 (not 10.43 as that doesn’t exist contains projections out to the year 3000. Perhaps that is what Dr. Pachauri was referring to, but I don’t think most people would think that his remarks were referencing projections to the year 2200 to 3000. I also don’t see any way to use that chart to connect 2C to that estimate. The models that have an equilibrium around 2C seem to have a thermal expansion of less than .7M.
#147 Hank, I am aware that Rahmstorf came up with .5 to 1.4, but it certainly wasn’t just thermal expansion, and it also certainly isn’t the IPCC consensus. As I have pointed out in earlier posts on this thread the Rahmstorf estimate doesn’t even pass an internal test of withholding part of the data to estimate the rest.
Re 149. Martin, you’re just not thinking like a denialist. In J.Bob’s universe, there can never be under-estimates, only over-estimates, and a guesstimate that is 1% wrong is just as bad as a guesstimate that is 100% wrong. You just need to let go of any notion of logic or sanity, and then everything makes sense.
Nicholas, I don’t know precisely what he is referring to, but I also understand that he is watching the leading edge of the science rather intently. Maybe he was not referring only to AR4? If he was speaking extemporaneously then maybe he was mixing knowledge from AR4 with new work? Honestly I don’t know. You might consider the possibility that he has seen something that is not published that may have further relevance. Maybe you should consider being a little patient? The 5th report is coming but good science apparently takes time.
Personally, although unscientific, I think it is not unreasonable to see that we could be in the 2 to 5 meter range in 2100. The sensitivities do seem to indicate that the system in general is more sensitive than we can detect clearly at the moment. So while it is important to continue to clarify the dynamical models and the empirical evidence, even more important is the application of reason when placed in the context of reasonably assessed impacts when synthesized with consideration of energy, economy and environment together.
There were a lot of things I heard this week and I might get some of it wrong due to mixed memory and relationships but here is a grossly inadequate overview:
The world bank and Munich re and a few others did talks on insurance and assessment of risk. It is going to become clearer, but there was much talk of reasonable projections and probability as well, and this is something human intelligence is not incapable of.
There was a lot of talk about refining the resolution. There was talk about getting better information to users. I talked a lot about communicating the message to the public and policy makers, others talked about processing capacity to avoid degrading the resolution in the ocean between the satellite and the argo floats.
But there were a few messages that I noticed that rang clear. We need to work together, this is a global problem and therefore global solutions are in order. We all live in this community so we all have a stake in it. We will not get out unscathed but the faster we act the less costly it will be. It will create jobs. I think Ban Ki Moon said something about a coal plant is 7 persons per megawatt while a solar farm is 23 persons per megawatt. Rapid action is required to avoid higher costs. That is just a taste of the messages I heard. I don’t know when the conference statements will all be online but they are in process.More info can be found here:
I continue to examine from a human relevance perspective with regard to impact potentials.
The UK Met office did a poster presentation (last Wed.) showing that their recent models are showing that the heat wave of 2003 is projected to be happening every other year by 2040 (soon after to be replaced by every year, and rising…).
Let’s hope Copenhagen moves us more than a little bit forward.
“… there were some dimensions of the scientific reality of the 2°C target that were really not covered and which I think would have added a great deal if they had been addressed in this particular meeting. Two of them that I would like to mention are the fact that firstly even with the 2°C target the IPCC has assessed that on account of thermal expansion alone we could get sea level rise of 0.4 to 1.4 meters. This is due to thermal expansion alone….”
That’s, if the transcript posted above is correct, a bit of what he said.
First — check the transcript, rather than assume it’s correct.
Check the transcript for the context as well.
The IPCC last published report had a low sea level rise number — and known to be — when published. They said so.
Nobody has come in with an argument for a lower bound than that known underestimate.
There’s good reason for the concern expressed, and for the concern he voices in his speech — that this issue wasn’t discussed at that particular meeting. That appears to be what he’s talking about — best information we have _now_ is that it’s in the range mentioned. Next IPCC Report will be some years from now. Those numbers will change.
Bets as to whether they’ll go down or up might be taken, but not here.
Anyone who doubts this level of risk is a concern can go back and read the opening post of this topic.
Finding the complete transcript and reading it would seem the best place to start. Else there’s only the strong wish this weren’t likely to happen.
We all share that wish. But wishing doesn’t stop the problem.
#154, I’m just interested in accuracy here. If he wants to make a new estimate that’s fine, but he shouldn’t ascribe it to the IPCC.
What reference can you give me for the IPCC saying that “they” knew the sea level rise number was low?
With regards to new lower estimates I believe that is what this thread was about in the first place, although I tend to agree that the original IPCC estimates are probably still the best.
With reference to the Rahmstorf paper I already followed up on the in line comment. Stefan referenced charts in his reply to comments. I pointed out that the coefficients are a much better statistical test than visual inspection of charts. I received no reply to that assertion.
” I live not too far from the California Delta. If I had to make a wild eyed guess as to what level of sea level rise to plan for, I would simply double the IPCC AR4 numbers.”
On August 31st, the Sacramento Bee published an article “Delta facing a sea change,” which stated that the new administration’s Army Corps of Engineers is now requiring that projects look at a sea level rise of 55 inches (140 cm) by 2100.
This is critically important to California as most of the fresh water delivered to Southern California comes from the rivers in the north. The pumps that now send the water south are nearly at current sea level, so any increase in sea level threatens to shut off the water supply to Los Angeles and farmlands in the San Joaquin Valley. And global warming projections also call for drought in this part of the country, so things are looking a little bleak for Southern California.
By what I have read of the comments above..these sea level predictions are still based on a linear business as usual aproaches..what about the consequences of major tipping points being crossed?..what time frames are we looking at before things get uncomfortable? Ice albedo by it’s nature is exponential..it’s like compound interest, the less ice the warmer the oceans..the faster the remaining ice melts until it’s all annual ice in the winter and permanent and complete loss of arctic sea ice in the summer. This will undoubtedly have rapid and massive effects on the climate in the northern hemisphere as the huge expanses of dark ocean water keep heating up unrestricted. This will cause greatly accelerated melting of the jakobshavn and other glaciers on the greenland mainland. You can bet your bottom dollar that the release of methane hydrates in the norhern temperate and even the arctic latitudes will be well off the scale. What effect will this localised addition of millions of tonnes of CH4 have to the climate of the nothern hemi? Saw in Science daily that it was presumed that most of the methane being released would dissolve back in to the ocean water on the way up..but latest research finding show that the methane is bubbling up too fast and escaping into the atmosphere without much diffusion back into water. This is but one of the tipping points which are being crossed as we type and will and are making an absolute mockery of the IPCC predictions.
Comment by Lawrence Coleman — 6 Sep 2009 @ 3:58 AM
#153 John P. Reisman (OSS Foundation)
“It will create jobs. I think Ban Ki Moon said something about a coal plant is 7 persons per megawatt while a solar farm is 23 persons per megawatt.”
It was Pachauri that mentioned the “7 persons per megawatt while a solar farm is 23 persons per megawatt”. Biomass energy has some good potential also in my opinion but I can not conjecture on quantitatives at this time.
I have gone over the speech a few times and believe the transcript to be reasonably accurate. Download here:
We very much need to address the source of the problem – and that will involve massive and rapid changes in society. Getting society to accept changes that some will see as painful, requires a spokesman with more authority than science currently has.
Currently, anybody can say, ”I am a scientist, and AGW is a non-sense.” If climate scientists and weathermen were registered, only climate scientists that had pasted exams and an internship could stand up and say that. : ) With fewer denialists, we would be more likely to get public support for good public policy.
We need to give climate science more status. We did it for medicine. We did it for law. We did it for engineering. Part of that status is that each of these groups carries professional insurance – members of these professions do post a performance bond.
If you were a registered climate professional, and I was not; you could just tell me that this model was your expert opinion, and I should just go seek another provider. However, if this is all “just science” then I have standing to criticize your model, as a “peer”. After all, I was a “Senior Scientist” for years and years. As a registered professional, you would be in a much higher status position vise-a-vie people who were not registered climate professionals.
[Response: The problem with your proposal in my view is that for medicine, law and engineering you're talking about a registration for people practicing these professions following established codes of practice. You're not talking about cutting-edge scientific research, for which the freedom of science holds. There is already established codes of conduct for scientists, of course, but requiring some kind of registration to be allowed to do scientific research would curtail the freedom of science. Science has its established professional training and status system - for example, a PhD is usually considered the level where you have acquired the credentials to do independent research; while working on the PhD you still need a supervisor. And a PhD (at least in New Zealand, where I obtained mine) comes with swearing to pursue the scientific truth. But climatology being a very interdisciplinary topic, it is still not so clear-cut who can call themselves a climatologist - my PhD is in physical oceanography. In the end, there is a much simpler criterion for who is a climate scientist worth listening to: someone who has a good publication and citation record on relevant topics. You can find out within minutes via Google Scholar. -stefan]
Generally speaking, there is no possiblity of meeting the entire human populations energy “needs” from biomass alone. I do encourage the devlopment of biomass solutions, espec8ially those which can become carbon negative in that, at the end, the carbon dioxide is permanently sequestered away from the active carbon cycle. But laternatives must be found as well.
What is the impact of global warming on companies?
To state it otherwise: If Global warming is truth, what is the impact on the stock market?
Point of this: Companies have the greatest interest to have a growing economy but the global warming scenario, the GDP would go down.
As a side question, can companies who are promoting deniers views can be held accountable for their agenda?
Assuming that Global warming can kill people, can CEO be legally held responsible, in the future (5-15 years) for their actions?
My apologies for not providing context to my post. I was not suggesting biomass could meet the human populations energy needs, at least not at these consumption levels, but rather was suggesting that in the general context of the post that it could also provide a good amount of jobs. I had more than a few conversations at WCC3 about these potentials.
The solutions are still a big pie and biomass in only a slice. Generally speaking I still believe we need:
- energy consumption reduction (non utilitarian first, etc.)
- sustainable renewable
- potentially thorium as a bridge energy source
- new innovations, etc.
Primarily education remains the key to all solutions. Politicians don’t do things unless they think it will get them votes. So education remains the top priority if we are going to deliver a good pie.
Nuclear power can easily provide ALL the world’s energy needs (excepting aircraft). We can cover the landscape with windfarms and artificial trees and gigantic arrays of solar panels or spend a little effort thinking about how to dispose of nuclear waste. E=mc2 you dimwits.
[Response: Perhaps it could, but do the sums. Currently (as of 1 August 2009) there are 435 nuclear power stations in the world (9 fewer than in 2002). They supply 2% of the global end energy use. So to supply ALL (assuming just the current level, no increase in demand) you'd need about 50 times the number of nuclear power stations - roughly 20,000. How fast can you build those - in time to solve the climate crisis? Where do you want to build those - say, Iran? How do you cope with the nuclear proliferation and waste problems, if you scale the current nuclear power industry up by a factor of 50 and spread it to a lot of less-than-well-governed countries? -stefan]
#171 “How do you cope with the nuclear proliferation and waste problems, if you scale the current nuclear power industry up by a factor of 50 and spread it to a lot of less-than-well-governed countries? -stefan”
Start by putting it top of the agenda at Copenhagen.
True, but neither am I expecting all innovation to die off, or redistribution of labor needs based on various market shifts, resource changes, technology changes, etc. Not everyone has to work in the energy sector to keep things running.
Every Uranium and Thorium atom in the Universe had it’s origin in a supernova–so there really isn’t a lot of the stuff out there. True, Earth’s crust is enriched in the actinides due to their lithophilic nature, but even so, the supply is finite. Independent of issues of waste disposal, safety and proliferation, this is not a renewable resource. And as Stefan points out–the plants take forever to build.
Climate change is a difficult problem. Beware of purported two-word solutions to it.
Energy may very well equal mass times the speed of light squared, but from what I can tell you still have not figured out that
2 + 2 = 4
Of course add in, as Stefan pointed out, the cost of waste storage and handling and security. So, add additional weapons grade plutonium to a world of dwindling resources, shifting geopolitical borders and ever more desperate people just trying to get by due to the latitudinal shift.
What’s that add up to?
Anyone can quote Einstein’s equation. I’m just not confident in your math ability when it comes to simple reasoning.
Pierre says, “Companies have the greatest interest to have a growing economy but the global warming scenario, the GDP would go down.”
Who says? We are talking about creating an entirely new global energy infrastructure here–new transport, new energy sources, new grid… We are talking about a massive effort to mitigate climate change–new crops, carbon-capture and storage… Smart companies will see opportunity and benefit.
As to the question of liability for liars…well, we’ve already caught them in the lie. Once there are consequences, I would think that being a lawyer in class action against coal and petroleum giants might also be a lucrative profession.
Of course, this all assumes that we actually DO something to avert the worst consequences. If we do not, falling stock prices will be the least of your worries.
Re 171 Stephan, why are you writing as if nuclear is an all or nothing decision?
For example Britain could easily generate much of its energy from nuclear.
Poor but sunny countries can be encouraged (paid) to harness the sun.
Where wind is most efficeient build turbines.
If the c02 risk is as great as we are led to believe, surely the risks associated with nuclear are tiny in comparison?
Reading the BraveNewWorld is worthwhile -Stefan. New generation plants barely produce waste. It’s almost all recyclable. We have to start building them now, every coal plant in poisinous emissions worse than any nuke. The energy needs are not abating and looking at the preposterous prices for e.g. led lights, a 1 watts equivalent 7 watts asking 14.90 Euro’s manufacturers of course milking it to the last cent, don’t see that coming down. Led flat screen 3,000 Euro. Starting price for another example.
The job numbers sound backwards to me since the Energy Return on Energy Invested is higher for solar. Perhaps these are construction jobs only since they are given per MW rather than per GWh? Solar and wind are especially good right now because the jobs are upfront when we need jobs. But their biggest (economic) benefit is in making energy easier, not harder, to get so that over all prosperity is boosted. One expects the effort per GWh to be lower than for coal, not higher.
One number that is easy to calculate is that given 104,626 coal mining fatalities between 1900 and 2007 in the US and 366,040 MW of nameplate coal generating capacity in 2007 in the US, there are about 0.3 coal mining fatalities in the US per MW of capacity. I do not know of any deaths related to solar farm construction but even if there were one heart attack upon looking at how impressive Nevada Solar One is, the deaths per MW would be less than 0.002 and shrinking. Since coal mining will become more difficult over the next twenty years when coal supply problems will kick in the number of deaths per MW capacity for coal mining is likely only going to increase.
If you come across the calculation that Pachauri was using for the jobs number, I’d be happy to hear about it. Obviously, domestic energy boosts domestic jobs which is a different consideration.
It’s like Godwin’s Law, for climate–you can shut down any subject by starting in on your favorite hobbyhorse. Please don’t.
Look again at the question — have you anything on topic to say?
> the total 20th Century rise is not a useful data constraint on a,
> because one can get this right for any value of a as long as b is
> chosen accordingly. To constrain the value of a – which dominates
> the 21st Century projections — one needs to look at the “new rise”.
> How much has sea level rise accelerated over the 20th Century, in
> response to rising temperatures? That determines how much it will
> accelerate in future when warming continues.
John P. Reisman (OSS Foundation) says:
6 September 2009 at 2:53 PM
#153 John P. Reisman
It was Pachauri that mentioned the “7 persons per megawatt while a solar farm is 23 persons per megawatt”. Biomass energy has some good potential also in my opinion but I can not conjecture on quantitatives at this time.
I have gone over the speech a few times and believe the transcript to be reasonably accurate. Download here:
The litmus test is the experience in Spain which has had an aggressive foray into the so-called green jobs revolution. The outcome was reported by Alvarez et. al. 2009 (http://www.juandemariana.org/pdf/090327-employment-public-aid-renewable.pdf). In essence the outcome is that the US (or anyone else for that matter) can expect the loss of 9 jobs for every 4 jobs created by renewable energy projects that have public aid (as all of them need at this time). It is salient to note in the executive summary of their report:
“5. Despite its hyper-aggressive (expensive and extensive) “green jobs” policies it appears that Spain likely has created a surprisingly low number of jobs, two-thirds of which came in construction, fabrication and installation, one quarter in administrative positions, marketing and projects engineering, and just one out of ten jobs has been created at the more permanent level of actual operation and maintenance of the renewable sources of electricity.
7. The study calculates that since 2000 Spain spent €571,138 to create each
“green job”, including subsidies of more than €1 million per wind industry job. ”
The rest of the points are similarly pessimistic. This is the reality from a country that has tried it. This reality seems to have not caught the attention of Dr. Pachauri et. al.
Comment by Richard Steckis — 7 Sep 2009 @ 10:12 AM
Re #171 where simon abingdon says:
“Nuclear power can easily provide ALL the world’s energy needs”
and Stefan responded
“Perhaps it could, but do the sums. Currently (as of 1 August 2009) there are 435 nuclear power stations in the world (9 fewer than in 2002). They supply 2% of the global end energy use.”
Let me restate my query to make it more on topic for this thread:
To what extent do the estimations of sea level rise take into account major feedbacks such as methane from the tundra and from sea beds? If they haven’t, what are the ranges of estimates for how much higher sea levels might rise with these feedbacks figured in?
Are there just too many unknowns to make even a stab at this?
Or is the possibility of significant methane release considered too remote?
(In spite of many recent studies to the contrary, for example http://eprints.soton.ac.uk/64607/ “Warming of the northward-flowing West Spitsbergen current by 1°C over the last thirty years is likely to have increased the release of methane from the seabed by reducing the extent of the GHSZ, causing the liberation of methane from decomposing hydrate. If this process becomes widespread along Arctic continental margins, tens of Teragrams of methane per year could be released into the ocean.” )
Or are the consequences of such releases just too dire to contemplate?
> New generation plants barely produce waste. It’s almost all recyclable
Actually, that’s not quite true (and I see this misconception all the time). These plants produce less long-lived transuranics by burning them on site — and these are the biggest headaches as they need hundreds of thousands of years of safe storage, not to mention the weapons potential of some of them. This is a good thing of course, but the bulk of the waste is fission products of intermediate atomic weight, mostly having relatively short half lives, like 90Sr with a half life of 29 years, requiring “only” three centuries or so of safe storage.
Yes, the problem can be managed in principle using sound engineering by competent people under good government. I have to side with Stefan here… nothing like a career in climatology to undermine one’s faith in the basic sanity of mankind :-(
Do you actually read the links you post? Like,
“Fast reactor technology would lengthen this period to over 2500 years.”
“However, world uranium resources in total are considered to be much higher. Based on geological evidence and knowledge of uranium in phosphates the study considers more than 35 million tonnes is available for exploitation.”
And then there’s sea water… fuel shortage is never going to be a limiting factor for nuclear fission. That’s because the fuel cost, contrary to fossil fuels, is only a minute fraction of total operating cost. It could go up and up and up, and the economy of nuclear power would be totally unaffected.
“Or is the possibility of significant methane release considered too remote?”
It’s more like saying when they’ll happen is an unanswerable question. When a wing of a jumbo jet develops a small internal crack, there’s no prediction of when it will fail, just that it will fail.
It’s not as if the release of methane will REDUCE sea level rise by any measurable amount, is it.
It’s also very similar to Al Gore’s 10m SLR if 20% of the Antartic Ice Sheets melt (or whatever the values were…). It is correct and he even said that “***IF*** it occurs by 2050, then…”. Yet somehow this got spun as a lie as if he’d predicted that the ice sheet WILL melt, which isn’t supported by the science, and so therefore counted as one of the 9 “errors” in An Inconvenient Truth.
So official predictions leave it out since the denialosphere will jump at any conceivable way to misinterpret the statement of methane release so they can say “SEE! We TOLD you they were alarmists!!!!”.
#162, cce I found what Dr. Pachauri is referring to. In section 10.7.4.1 on page 829 there is a reference to a long term equilibrium value for thermal expansion of .2 to .6M per degree C. Multiplied by 2C this yields the range of .4 to 1.2M. This is a circa year 3000 steady state value assuming the ocean warms uniformly.
Figure 10.37 provides a shorter term (2300) view using the A1B scenario of about .2 to .8M from thermal expansion.
I still haven’t seen a reference from anyone showing that the IPCC “knew” that their sea level estimates were low. I suspect the obvious which is that there were some who thought they were low, and some who thought they were high.
On current nuclear technology or any nuclear technology that produces weapons grade uranium and has storage issues will mostly likely prove ultimately too expensive for a multitude of reasons.
It’s not just the availability of fuel and storage of waste, it’s the two combined with an risky and unpredictable future in a largely predictable resource scarce environment and an uncertain economic structure, while those still interested in power will pay those that can steal or otherwise attain what they want in the nuclear realm to achieve tier ends if so unconstrained by circumstance.
I did read that “Fast reactor technology would lengthen this period to over 2500 years”, but that still applies to 2% of our current energy consumption, and so only gives us another 100 years if energy consumption continues to rise and all fossil fuel burning has to be ended.
But we do not have fast reactor technology yet! By the time it becomes universally available we will have had to burn all our fossil fuels just to maintain our increasing standard of living, and global warming will have passed well beyond dangerous levels.
How soon can we get fast reactor technology on line? How soon before global temperatures have passed the +2C and become dangerous.
“electricity generation rate of demand the amount [of uranium] is sufficient for 85 years”
Except the electricity generation is only part of the problem – transport fuel is more so.
Mackay’s “Sustainable Energy without the Hot Air” has good numbers on nuclear. FBR he concludes would deliver 33kWh/d for everyone on the planet for 1000 years without looking at ocean uranium, and ignoring the risks associated with FBR. His conclusion was that it was part of the solution, especially for some countries. It is not a cheap solution anymore than solar PV is cheap. Lets not have an all or nothing approach. What you need is every country making appropriate commitments to cut CO2- thats what Copenhagen is for. How to achieve that is for each country to sort out on the basis of it resources and cost-sensitivity.
Mark — please withdraw the statement attributed to Al Gore. You’re misremembering something, likely one of the common denial sites’ repetitions.
It’s a poor sort of memory we have. For everything else, there’s Google.
“There have certainly been incorrect assertions and headlines implying that 20 ft of sea level by 2100 was expected, but they are mostly based on a confusion of a transient rise with the eventual sea level rise which might take hundreds to thousands of years. And before someone gets up to say Al Gore, we’ll point out preemptively that he made no prediction for 2100 or any other timescale.” http://www.realclimate.org/index.php/archives/2008/09/how-much-will-sea-level-rise/
“… From 1990 onward the sea level recorded in most Mediterranean tide gauges indicates a rise in sea level at a rate 5–10 times higher than the 20th century mean rate.
While this trend should be regarded with some caution because of the relatively short data series, the trend observed coincides with the increase in global land and marine surface temperatures during the 1990s, and it is important to note that no other short sub-period in the data sets shows such an extreme trend.”
“… There is now better understanding that the risk of additional contributions to sea level rise from melting of both the Greenland and possibly Antarctic ice sheets may be larger than projected by ice sheet models assessed in the AR4, and that several meters of additional sea level rise could occur on century time scales (2, 7, 27, 28). Such risk arises in part from ice dynamical processes apparent in observations since the TAR but not fully included in ice sheet models assessed in AR4. New insights also come from recent paleoclimate studies (29)….”
Nicolas Nierenberg (194), the only way that someone could not have seen the IPCC’s own explicit statement that the IPCC knew that their sea level estimates were low would be for them to deliberately not read it:
Summary for Policymakers, p.14, quote:
“Models used to date do not include uncertainties in climate-carbon cycle feedback nor do they include the full effects of changes in ice sheet fl ow, because a basis in published literature is lacking. The projections include a contribution due to increased ice fl ow from Greenland and Antarctica at the rates observed for 1993 to 2003, but these fl ow rates could increase or decrease in the future. For example, if this contribution were to grow linearly with global average temperature change, the upper ranges of sea level rise for SRES scenarios shown in Table SPM.3 would increase by 0.1 to 0.2 m. Larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.”
Hey, this is old technology… there are safety and cost issues, like there are with nuclear in general, even more so. If however the world decides to go 100% nuclear, this will be the technology chosen. And that’s what any calculation of fuel availability should be based on.
…and I see you didn’t comment on the 35 million tonnes, or the sea water ;-)
I can go earlier than that. The first reactor at Dounreay became critical in 1958. The last reactor was taken of-line in 1998. decommissioning is going to take over 300 years and cost £2.9 billion (approx. $5 billion.)
If fast breeders are such a good idea why have they all been abandoned?
As far as the uranium in sea water is concerned, how much energy is it going to take to extract and refine it? Just pumping a billion tons of water, onto land where the extraction site is built, for each ton of uranium extracted (assuming 100% efficient extraction) is going to use up a lot of energy.
Meanwhile, the Greenland ice sheet will continue to melt, sea levels continue to rise and the coastal extraction plant will be flooded.
I think 90% or more suffer from China Syndromitus when it comes to nuclear. The French continue to smile from ear to ear and have not stopped their research and development and glad they this. Guess, half of Italy would be having rolling power periods without them, no one willing to compromise on their energy needs. In 2003 we were very close already.
Choices have to be made NOW, yet nobody willing.
[Response: Not every thread has to end up with another discussion about nuclear power. This is OT. - gavin]
“If Greenland broke up and melted, or if half of Greenland and half of West Antarctica broke up and melted, this is what would happen to the sea level in Florida… (video graphics of effect of ocean rise of that magnitude)”.
Folks, do we really want to get bogged down on the nuclear power thing again? It may turn out that as we face unpalatable options in the future, nukes may be one of the least bad. However, we have a whole helluva lot more we can do in terms of conservation and renewables before we have to confront those unpalatable options. At the very least, increased conservation is one thing we can all (well maybe not Simon) agree on.
Thanks for your follow up comments wili and mark. I would assume it’s because the scientific community doesn’t yet fully understand the chain of consequences that crossing these tipping points will bring. The IPCC is shit scared of the ‘I told you so’ bleating by the denyalists as Mark mentioned that they wont even acknowlege the possibility of an uncontrollable chain recation. For polititions and leaders of industry to act NOW we need another public megaphone apart from the IPCC. One good analogy of the effect of tipping points being breached is this…imagine the world’s climate as a suspension bridge and the many hundreds of steel cables holding the bridge up as the climate tipping points. If the bridge is under constant pressure such as a force 5 hurricane (CO2, greenhouse gasses in the atmosphere)…and 1 cable snaps (1 tipping point is breached) then all the others are under additional strain as well as the structure not being as well balanced..so soon another one breaks (another tipping point is crossed)..and then another and very soon after that another one goes and so on..very soon the entire bridge is occillating wildely twisting and buckling leading quickly to it’s imminent destruction. I just thought that would be an accurate analogy to keep in mind for those analogy nuts out there..haha!
Comment by Lawrence Coleman — 8 Sep 2009 @ 8:24 AM
#208 Not-so-crazy Bill: energy wise, it could work. Barring calculation errors I get 100 GW for pumping all of current sea level rise up 3000 m… I’m sure there are other valid reasons why this couldn’t possibly work :-)
We could discuss (endlessly!) the pros and cons of nuclear power, the rate at which solar and wind power can be brought online, methods for storing renewable energy, etc. etc. etc. It makes me think of two doctors arguing over whether lung cancer is better treated with radiation or chemotherapy.
That’s all well and good, but the overriding action both doctors agree on is: QUIT SMOKING.
Step 1: pass the ACES bill through the senate, forge a strong agreement on greenhouse gas emissions reduction in Copenhagen.
Greenland or even half of it cannot break up and melt. The Greenland Ice Sheet lies in a basin. Therefore it cannot physically break up, it cannot physically slide into the ocean and the thickness of the cap would require at least 1000 years of above zero temperature for it to fully melt.
Therefore Al Gore was talking a load of bull regardless of whether he gave a time scale or not.
Among other things I learned at WCC3 was the reality that the IPCC founding basis (under the cover) was not a political agenda to promote crazy ideas of human caused global warming. I spoke with several people who were there at the beginning 30 years ago and one was clear in saying that it was formed (in the mind of some of the lead states) to put down the crazy idea that humans were causing cliamte change.
Unfortunately critical examination of the science took it the other way…, oh well.
“The projections include a contribution due to increased ice fl ow from Greenland and Antarctica at the rates observed for 1993 to 2003, but these fl ow rates could increase or decrease in the future.”
Jim, this reads to me like they are saying their estimates could be too low or too high. I can’t read it in such a way that it becomes an explicit statement that they knew their estimates to be too low.
“I would assume it’s because the scientific community doesn’t yet fully understand the chain of consequences that crossing these tipping points will bring.”
No, if the artic ice sheet melts, there are many things that are known and can be modelled.
The effect of albedo changes and rock weathering or biological activity changes are second or third order changes that depend on things we cannot currently measure. E.g. what IS under all that ice. We’ve looked in a few spots, but that’s hardly solid evidence of whats hiding under there.
The biggest problem is working out when they will happen, since these are not climate forcings and are truly chaotic like weather events and not amenable to computational analysis to result in a definitive forecast.
We can figure that blood loss and shock will likely kill a patient if they don’t get to emergency within 30 minutes, but whether they can travel the 12 miles to the hospital in time depends on the traffic, not the patient.
The movie said nothing about the time. The models said that this could *possibly* happen in 2100 or 2050 or whatever.
But what did the denialists do (and get!)?
They said “Al says that the GIS will melt and Florida will flood! This isn’t TRUE!!!!”. And a judge agreed and said that he SHOULD have been more explicit.
b) Denialists then tout that a judge says Al was wrong. And he’s fat. Which isn’t the case.
Which is why I think that tipping points and sudden shifts like methane releases from tundra etc aren’t being done: the denialists have already shown they WILL represent this as unscientific and non-scientific judges WILL agree with them and then the denialists WILL misrepresent the judge’s ruling to make it look like a lie.
lawrence 220, your analogy is fairly good. It can even be taken to what happens with the ONE CABLE.
All fractures start as a small break in the semi-crystalline metallic structure. But all metallic structures have breaks in the semi-crystalline structure. It’s when you get ductility in metals and work-hardening. Which site of lowered structural integrity goes first is inherently intractable under major stress.
Mark (230), they must have a wrong address for me; I haven’t received a skeptic check in a long time — actually ever. Though I seldom use the “alarmist” tag. Do you think I should start, in order to get my money? BTW, who mails the check?
Thanks to all for the discussion and links, but most of the linked sites are at least a year old, and it sounds to me as though we now have a good bit more data about how rapidly methane releases are accelerating with concurring increases in atmospheric methane.
Since this is potentially such a huge new factor in gw, perhaps it would be worth a lead post sometime soon (if I may be so presumptuous as to make such a suggestion)?
A point raised above that I hadn’t thought of (and one more pertinent to the current thread) is whether massive release of seabed methane hydrate would (temporarily) l o w e r sea level as the water rushes down to fill the space evacuated by the escaping gas. Or, short of a sudden, massive release (apparently a quite unlikely prospect), could the steady and increasing release of this methane offset whatever sea level rise is caused by heat expansion and melting ice sheets and glaciers?
stevenc (228), try reading the quoted statement in the context of what was known at the time that the Fourth Assessment Report was released in 2007 that was not known at the May, 2006 cut-off for examining the “current” science:
Estimates of ice flow based on rates observed for 1993 to 2003 were already known to be too low. Why? Because empirical observations between 2003 and release of the report in 2007 showed that the rate had in fact increased, hence the caveat.
Richard Steckis #225 and Mark #235, you both look silly pretending to understand how continental ice sheets behave. Ice is ice, but when you have cubic kilometres of it you get very different physics from the ice cube in your whisky glass.
Better men than you are scratching their heads over it. Until you grasp that, please stick to the whisky.
Jim, this reads to me like they are saying their estimates could be
too low or too high. I can’t read it in such a way that it becomes
an explicit statement that they knew their estimates to be too low.
It’s as explicit as it ever gets in a political compromise text that they had a dark suspicion… why would they speculate on a proportionality with global temperatures? Why saying “Larger values cannot be excluded”, but not “Smaller values cannot be excluded”? Why the disclaimer about an upper bound? Their stated ignorance on ice flow was obviously unsymmetric.
#208 (Bill) #223 (Martin) Can we store sea water in Antarctica?
The question seems interesting enough to look at it a little more.
It seems to me you have to take into account two things:
1. Potential energy (you would have to lift the water over a km or so)
2. Letent heat: you have to freeze all that sea water. Dumping sea water on ice would cool down the water and heat up the ice. If there’s too much water, you would obviously melt the existing ice, rather than freeze the water. The energy you have available for freezing is (say Antarctica is -50 C) 50 deg K times the heat capacity of the ice.
I haven’t done the math. Probably you would also have to factor in input solar radiation, and radiation out to space.
Then there may be the matter of destroying another ecosystem.
Sounds like a biased article and it sounds like Vickys statements are being leaned out of context and possibly Mojib’s as well.
Either the author is unaware of the confusing nature of his subtitles and contexts or it is deliberate.
There were a few sessions on decadal variability and there was a lot of discussion about the problems in that area. Oceanic cycles were on everyones mind. I do not recall Mojib Latif’s comments in those sessions but I was late to one.
The fact that the author uses Vicky Pope’s statement in this piece is used merely to support the assertion regarding the we may be cooling meme (I doubt she said it in that context but was rather answering a different question). There is nothing wrong with her statement but it is used in a way so as to possibly mislead by inference.
My limited knowledge of NAO is that it does have a chunk of the global signal but I don’t think it is so huge as to control the whole climate but rather is a part of the natural variability. As far as I can tell it is largely not predictable beyond a few years. So how can he say it is going to cool us down for 20 years?
The article also contradicts itself. It says it’s going to cool for 20 years and then it says “more agree that the short-term prognosis for climate change is much less that once thought.”
That’s a weird statement too since most everyone in climate science knows that short-term is largely not well understood?
Latif’s statement, if he really said it, (notice there are no quotes there) that “the next few years a natural cooling trend would dominate over warming caused by humans” is actually ridiculous, unless of course the NAO is going to give us -1.6 W/m2, which of course is highly unlikely.
The claim that “Another favourite climate nostrum was upturned when Pope warmed that the dramatic Arctic ice loss in recent summers was partly a product of natural cycles rather than global warming” is equally bizarre and further reveals the bias inference. Of course natural is still involved in the Arctic, to say otherwise would be just as silly.
Then of course the author inserts a weather argument saying it’s less ice loss this year than 07/08. I guess he doesn’t know much about ice mass or climate trends, but climate does not seem to be the subject of his article, but rather the target of his bias.
Fred Pearce, the author sums it up by saying “The world may badly want reliable forecasts of future climate. But such predictions are proving as elusive as the perfect weather forecast.”
In other words, he still does not know the difference between weather and climate. How do these guys get climate reporting jobs in the first place?
Personally, I doubt Vicky would approve of the bias in the article or the way her statements were used to support the idea of global cooling as inferred.
UK Met did a poster presentation showing that 2040 will have 2003 like heat waves every other year. Does not sound like they are predicting much cooling to me.
Also, there is the consensus issue. If Mojib actually does think it will cool for 20 years, he is still outside the consensus. That does not make him wrong, but where’s the beef? In other words on what basis, since the ocean cycles are not that predictable, where does he get a 20 year prediction from?
Vicky was right, we know more about the climate (30+ years) “In many ways we know more about what will happen in the 2050s than next year,” than we do about the weather.
It is unfortunate that the sea level data through the KNMI Climate Explorer isn’t up to date. I would have enjoyed extending those comparisons. And before anyone thinks I’m claiming that ENSO is responsible for all of the changes in sea level, read the post. I’ve qualified it.
John, I don’t think I lept. My comment was that you cannot get an impression of an explicit knowledge of underestimating sea level rise from the statement presented. It was nothing more and nothing less.
Jim, then you should have used a statement that explicitly backed your point and not one that appears to have so many reservations in it and clearly leaves both the upper and lower limits open to adjustment.
Martin, I agree that they left the upper limit of sea level more open to adjustment then the lower limit. It still seems to fail the test of being an explicit statement of knowing they underestimated sea level. As far as politic of statements go; I assume if there was negotiation in how the statement was worded then there was disagreement among the scientists working on the topic. If there wasn’t then there would have been no need for negotiations.
I personally have no opinion on the rate of ice flow. I am not well enough informed to have aquired one at this point.
The physics of heat exchange largely escapes me, but where I live, the more ground that is covered with snow, the less the sun is able to melt it. It is only when the ground is partly exposed that the sun can really get going on it. So, in your response:
“(i) There was much more ice back then, hence a greater surface area on which any warming could act to melt ice – this argues that melting during deglaciation would have been faster than in future.”
Faster? Maybe more ice was melting, but can you please explain how it would have melted faster?
I can see that now maybe there is less ice to melt, but it seems that it will melt faster due to the more heat-absorbent albedos surrounding it.
Stevenc (254), take it up with the IPCC, because that’s how they chose to word their caveat, and it’s meaning is abundantly clear to anyone who was paying attention to how fast ice dynamics and flow rates in Greenland and Antarctica were changing between 2003 and 2007.
Look, this stuff being copypasted is exactly what was cynically predicted — people now who are complaining that the IPCC or the scientists — years ago — didn’t warn them clearly and bluntly enough, early enough to do anything.
Next we’ll hear them complain that why they can’t be responsible for the lack of preparation and if the IPCC had only been clearer of course they’d have done their duty to the future, if someone had only warned them.
The same sort complaining now about insufficient warning were complaining about ‘alarmists’ and ‘so-cia-lists’ and conspiracies to pollute their precious bodily fluids. Some still are.
The warnings were clear. This is the angry beast Wally Broecker warned about.
Hank(244), et al: as quoted from the IPCC: “…do not include uncertainties …”, “…do [not] include the full effects of changes in ice sheet flow…”, “…but these flow rates could increase or decrease in the future….”, “…understanding of these effects is too limited to assess their likelihood or provide a best estimate…” [emphasis mine; quote is not]
I have a very difficult (impossible) time reading into that, “…the IPCC knew that their sea level estimates were low…” Maybe it’s just me. Or maybe you guys read into it whatever you choose, eh?
Rod B, you could start by acquiring an upper-class British accent and a fake title. And you still sound too scientifically curious at times, almost as if you cared about facts. Lose the attitude… don’t let this career opportunity pass you by ;-)
“Martin, I agree that they left the upper limit of sea level more open to adjustment then the lower limit. It still seems to fail the test of being an explicit statement of knowing they underestimated sea level.”
How do you work that one in to it?
When ice sheets melt and you have left it out of your future trends, what do you think REALITY (where ice sheets melt) will say with relation to your future trend model (where ice sheets DON’T melt)?
I understand that sometimes a small step can seem like a giant leap and vice versa. Perspectives can be funny that way.
You seem to be looking for the precision with regard to interpreting a single line. But in the context of the entire report, what was known then, and adding what we are learning… the idea of trying to nail down who was arguing over what in a single line in a report that is greater than the sum of that line… well…
The whole is greater than the sum of its parts. Some can’t see the forest through the trees, and sometimes the lady doth protest too much. Of course that does not mean there is no forest, or there is no reason for a protestation, or, that there may be a problem with a particular part. Context will get you relevance every time.
If it helps you understand, maybe I can clear this up for you. The estimate that sea level rise by 2100 will be 1.4 feet, is too low. How do I know? Well, I don’t. It’s about probability, not precision.
As you often remind us, John, context is key. The context of these speeches was a “climate services” program, so concerns over predictability on local and decadal scales were predictably more of an issue than when taking a long-term view of global warming.
Regarding Fred Pearce’s qualifications, he has been one of New Scientist’s lead environment reporters for more than a decade. But here I don’t think his story reflects Latif’s speech very well.
Latif’s Powerpoint and a recording of the session are online (38-MB MP3; Latif comes in at about 23’35” – 40’45”), so we don’t have to guess.
Your corrections would be very welcome before I drop off a comment at the magazine’s site along the following lines:
Latif showed the 20th century variability around a rising trend, and noted that it could happen that temperatures cooled for a decade or even two, and if that happened, people would say global warming had stopped. He did not predict that this would happen over the next decade or two as the article suggests. His comment on needing to “ask the nasty questions ourselves” was in the context of addressing model biases, not in the context of a decadal cooling.
Latif felt the jury was still out as to the relative contribution of internal decadal variability to the recent warming. He went on to discuss the NAO as one of the important internal modes of the climate system exhibiting low-frequency variability. Putting two and two together, Pearce got “NAO cycles were probably responsible for some of the strong global warming seen in the past three decades”. However, Latif said nothing about an impact of the NAO on global temperature, as opposed to regional, and noting regional (Europe/extratropical northern hemisphere) warming effects of the recent NAM/NAO trend hardly breaks with “orthodoxy” (see AR4, last para of section 188.8.131.52). It was also not explicitly said that the NAO “explained” the recent “recovery” of the Sahel region, but this at least seems to me a reasonable inference from the talk.
In short, in his presentation Latif did suggest — in passing, and very off-hand — that as much as two decades of cooling could happen despite underlying AGW. That would probably upset a few bets. He did not predict “that in the next few years a natural cooling trend would dominate over warming caused by humans” and that the cooling would be down to changes in the NAO. Nor did he mention that the NAO was moving into a “colder phase”. If anything, his speech was about the difficulties attending such predictions and the need to improve our abilities to make them. Maybe he said something later in a discussion session that Pearce picked up on.
Sheesh, there went my whole morning, and I haven’t even looked at what Vicky Pope said about the Arctic. Still, I’m pretty sure it did not overturn any “favourite climate nostrum“… Who’s copy-editing my favorite magazine these days?
Rod @263, the section is a little difficult to parse. Let’s break it down.
First, flow of ice sheets is bound to increase melting, since it increases the rate of flow to lower altitudes (warmer temperatures) and into the oceans (ditto). The current analysis doesn’t consider the contribution of ice sheet flow, and so is an underestimate of what is going on even now. That underestimate could increase if flow increases, or decrease if it decreases. It’s still an underestimate.
I don’t really see the problem with my comments. I am not changing their meaning with my own opinion since I don’t have one. I am reading their words literally. If there are problems with their wording then it is those who are not reading their words literally and are reading their own opinions in between the lines that need to take it up with the IPCC, not I. It really is that simple.
John, I’m not clear what your point is. I can see a forest and it has a lot of trees in it.
Will the aquifers recharge or continue to be depleted?
Will deforestation increase or decrease?
Will temperatures rise faster or slower then IPCC predictions?
Will droughts or ample rain predominate?
What are the dynamics of ice melt?
Will dam construction increase or decrease?
Obviously I have some opinions on some of these but certainly not on all hence I have no opinion on sea level rise being over or under estimated. It doesn’t mean I can’t see the forest it just means I can’t identify all the trees.
Ray, didn’t the models neglect to include ice sheet flow based on an expectation of increased precipitation balancing out the loss of ice mass? Has this hypothesis now been entirely tossed out based on observations or is it still in dispute over what the long term balance will be?
Where did you get this from stevenc? “Ray, didn’t the models neglect to include ice sheet flow based on an expectation of increased precipitation balancing out the loss of ice mass?”
John, I’m not clear what your point is. I can see a forest and it has a lot of trees in it.”
Yup. Read up on what “can’t see the forest for the trees” means.
“Will the aquifers recharge or continue to be depleted?”
How will they recharge? And what does that do to disprove AGW?
“Will temperatures rise faster or slower then IPCC predictions?”
Yes, one of those two. What does that do to disprove AGW?
“Will droughts or ample rain predominate?”
Define “ample”. Bangladesh will get super-ample rain (called flooding). But that rain won’t get further inland. China won’t have the snowmelt keeping the rivers full in summer and so will get droughts. So your query is stupid because it depends on where you live. And what does it do to disprove AGW?
“What are the dynamics of ice melt?”
They take energy to change phase and then becomes runny. And what does it do to disprove AGW?
“Will dam construction increase or decrease?”
What does this have to do with dicussions about AGW?
> didn’t the models neglect …
Stevenc, nope, you’ve got the timing wrong on that one. The notion that the meltwater would fall as permanent snow on top of the icecaps was wishful thinking and by the last IPCC known not to be happening now, and not to have happened during the last big warming episodes.
Nice dream while it lasted, but it didn’t last very long.
CM — excellent debunk of the New Scientist piece. I hope that gets added to the Wiki and other collections for later reference.
Good luck improving New Scientist’s science coverage. I used to try; I eventually got a nice letter from their editorial department pointing out that New Scientist is not a science magazine, it’s an entertainment/lifestyle niche publication, and they didn’t feel it was their job to be accurate but rather to attract people. In current terms they’re selling, you know, the controversy. Look at their “Darwin Wrong/Tree of Life” cover and issue a while back, which quite effectively attracted lots of attention by being not just wrong but prominently wrong.
[Response: I think this is a little strong. The journalists do try hard (most of the time) to get it right, but they do have editorial pressures to be as exciting as possible while still being accurate. Unlike Nature or Science, they can't rely solely on academic subscriptions and so need to stand out on the newsstand alongside Cosmo, GQ and Newsweek. I don't envy them that task. Obviously, when they do mess up, it should be pointed out - but it is inevitable that they will get the balance wrong on occasion. Even if imperfect, having NS out there is better than not having it at all. - gavin]
My perspective regards the bridge between the science and the public perception in the debate. What I am saying is that generally, in the discussion, I think it would be helpful if we discuss things in the larger context and not get too caught up in the minutia without the larger context.
In truth, I can’t identify all the trees either. So I just keep exploring. But some trees have risen above the others and their impact is quite clear.
Ray, Hank, Mark, et al: what is more inexplicable than Jim Eager’s assertion from his IPCC quote(205), is your all’s convoluted almost paranoid defense of it. You’re throwing in statistics theory, how one should project into and interpret the IPCC’s quote, what the IPCC really meant (but didn’t say), a more thorough parsing, how to draw logical conclusions beyond the quoted words, and presumably some knowledge of code words used by the IPCC so that only insiders can know what they are really saying. Now, all of that might very well be true! But it has no bearing on the original extremely simple (as stevenc also points out a couple of times) charge — NONE.
Jim simply presented a direct quote from the IPCC and then drew a definitive conclusion from that quote that logically can not be drawn from that quote. Period. End of point-counterpoint. Jim, IMO, simply misspoke, but it certainly was not a major sin (or even a minor one, really) and did not undercut AGW theory in the least. Why all of the fuss?
Methinks thou dost protest too much. There is a whole helluva lot more reason to think SLR will be worse than IPCC projections than to think it will be better. That’s not paranoia or statistics. That’s physics.
I merely pointed out that since the IPCC was not considering ice sheet flow, that this would only make the projections worse. Now, pray, where do you see paranoia in that.
stevenc, I think the failure to include ice-sheet flow is mainly due to the unsatisfactory knowledge of how to model it more than any precipitation dynamics–though I’m more than happy for someone more knowledgable to set me straight here.
Going all meta, over at the Guardian George Monbiot has lamented over how degraded and pointless the Guardian’s “Comment Is Free” threads become.
Monbiot’s frustration has a simple root cause. Comment should certainly be free, but limitless? What happens when a resource has no cost? One outcome is, it ends up being increasingly exploited for diminishing gain.
The “Tragedy of climate commons” thread on this site is an ironically appropriate example of the “free beer as opposed to Free Speech” tragedy. Go there to find people engaging in boundless yet picayune nattering over matters beyond peripheral to climate change.
It would be a rather simple tweak to impose a limited supply of comments available to any given poster ID over a given period of time. Having only a limited supply of bullets, perhaps we would choose our targets more carefully (and yes I’m guilty of firing wildly in all directions). Governance might include recognition of some kind (executed with scant effort if sensibly implemented) for contributions such as Hank Roberts’ which are so frequent and yet often include useful directions for inquiry.
Hank (#276), thanks for that. I’d have liked to try to head off this meme before it spread, but with 200+ comments on the NS page already, all of them premised on the accuracy of the report, it’s probably a bit late.
I don’t mean to dump on the journalist — Gavin (inline) is spot on. Nor on New Scientist, which I think has excellent coverage of environmental science issues in the multi-decadal mean, internal variability to be expected…. Though I certainly see what you mean by “selling the controversy”. (Hated the “Darwin was wrong” cover — ditto the Einstein one).
Ray, 284, I think (from what I’ve read) that the biggest problem is that you can either say “it will happen before 2200″ which isn’t a lot of help, or say “5% chance by 2050, 30% by 2075, …” which *was* done somewhere.
But that helps not at all when planning what to do. The politics says that you don’t do as much as is needed *for 2100* by 2020 because money is involved and we’ll get the sack.
Rather like the New Orleans levees: politics wouldn’t allow the levees to be rebuilt “this year” for a 20-year event protection. So “we’ll do it next year” (I wonder how many times it then went “Ok. Next year, then. Definite”…).
When money/time/effort is spent on something that doesn’t give a ROI within the next year, it’s called all to hell.
So there is, out there, a “what’s the likelihood of X” wrt ice sheet failures. I *have* read some of one.
But they are left out of policy decisions because policy taken to combat them now would be “courageous” (in the words of Sir Humphrey in Yes Minister…).
In the case of ice, it depends on which bit breaks and what that causes to break (as per steven’s analogy). Therefore predictions are highly uncertain and every “failed” prediction is waved like a flag.
cf UK’s warm winter but with snow in london 3rd Feb therefore showing the climate change was a complete hoax.
Ray and Hank, yes obviously I was mistaken on the ice flow and precipitation balancing and thus not being included in the projections. They actually did take the ice flow from 1993 to 2003 and used this as the basis for their projections. So the question is was this amount of ice flow above or below what the average will be in the future. To state that ice flow was not incorporated in the projections at all seems to be an error also.
> Rod B, no what is inexplicable is your inability to think.
Same words, more politely spoken. How do you explain statistical thinking to folks having not the faintest?
Suffice to say, Jim Eager was perfectly right about the IPCC quote. Don’t take my word for it: use the source Luke. In Chapter 10, Table 10.7 you find the same sea level rise values (5%-95% percentiles) as are summarized in Table SPM.3, on which Jim’s quote is based.
Only, Table 10.7 has an extra row, labeled “Scaled-up ice sheet discharge”. This is the IPCC “guesstimate”.
Please note how mostly positive these values are… for the B1 scenario, they run from 0.00 to 0.09 m. For A1FI, from -0.01 to 0.17 m. Can you say “unsymmetric”? The IPCC didn’t even venture to guess where within this range reality will land… but for our argument it doesn’t matter, now does it.
“… The ice flow changes could have been discussed in the text … one of the reasons provided by the IPCC authors for not adopting our proposal was that the numbers could not be calculated quickly.
…. the models used to derive this projection significantly underestimate past sea level rise. We tried in vain to get this mentioned in the SPM, so you have to go to the main report to find this information….”
#273 Mark “Read up on what “can’t see the forest for the trees” means.”
Actually Mark, the original expression was “can’t see the wood for the trees”, which has two possible meanings. Either “can’t see the big picture” (forest/trees) or “is unaware of important details” (timber/trees). As JPR would say “context is the key”.
Update: The New Scientist “cooling” piece has been reposted. The heading is even stronger, but at least “nostrum” has become “belief” — and there’s a clean slate for comments, so we can remove this OT discussion there.
My, my, my, my! What a mess! You all responded to my critique of your responses by repeating exactly what I accused you of! Example: Ray says (and I’m not picking on Ray; it’s just clearer), “…There is a whole helluva lot more reason to think SLR will be worse than IPCC projections than to think it will be better….” That makes sense and I suspect is probably very true. However it has no relevance, bearing, connection or relationship with the point-counterpoint that kinda started with Jim’s 205 and probably deserved to end with my first retort. Or one maybe can find other parts of the IPCC report, e.g. Martin V, that might justify Jim’s assertion. But that also has no relevance, bearing, connection…. In fact virtually NONE of climate science has any relevance…
I was going to agree with Ray that I protest too much. But actually I’m just keeping it going too much. You all are the guys that protest too much. My (and stevenc’s) retort over a small overstatement probably deserved no challenge, let alone a hubbub that is based on nothing related to the initial contention. Why all that protest? What’s the fear? Hank actually clears it up. While he is trying to accuse me of some wrongdoing, he’s actually right: my contention was ONLY “…about the interpretation of a sentence in an outdated document…” It had nothing to do and made no direct comment or implication “…about changes in the world…” Though he then goes on to support Jim’s quote by citing some other different quote.
Rod B, yes, I happily plead guilty to an immune system oversensitivity to mendacity. Let’s just agree to disagree on this… after all you’re the expert on out-of-context exegesis.
Now can we get back to discussing fast breeders? ;-)
Tenney, it started out with a question, repeated here, by Nicholas Nierenberg. Perhaps he honestly wanted to know (but was too lazy to find out); perhaps he honestly believed it wasn’t true. One always wants to assume honesty.
I hope Nicholas is happy now. And I hope some among the readership appreciate the insight offered, both about the issue at hand and about finding things if you know they’re out there. It’s those people I do this for.
PS the reason why it’s a “mess” is because you have made the mess.
What is your problem with the statement that the IPCC estimate of SLR is going to be low?
PPS stop with the BS about “just the quote”. Since the quote was about the IPCC SLR predictions and the model is the source of those predictions, but not included in the quote, hence making it impossible to answer using “just the quote, nothing else”.
This is a little off topic but I’ve been thinking of ways to retrofit modern airliners to use hydrogen fuel cells as their power source. The only major parts that need retrofitting are the engines and the fuel tanks.
What about plug-in hydrogen fuel cells straight into the wings and fuselage where the fuel reservoir is curently. When a plane need refueling a truck with a modified forklift slots the standardized size hydrogen fuel cells straight into both wings..maybe 5-7 cells per wing and 10 say in the fuselage. Question..which you guys may be able to answer..how does the power/weight ratio of hydo-fuel cells stack up against av-gas/ kerosene? Would the thrust on take-off be comparable to kerosene? How will the extreme cold of higher altitudes (minus 50-60C) effect the cells? How would the flying range compare? What type of engine would best utilize this fuel source? My idea could be completely unfeasible or it might just have a glimmer of hope..we’ll see.
Comment by Lawrence Coleman — 10 Sep 2009 @ 6:14 AM
Mark (301) says, “…What is your problem with the statement that the IPCC estimate of SLR is going to be low?…”
Because in the (not my) referenced quote they didn’t. It ain’t rocket science. Not even climate science. But hang in there; I’m rooting for you! ;-)
We also evaluate the contribution of rapid dynamical
changes under two alternative assumptions (see, e.g., Alley et
al., 2005b). First, the present imbalance might be a rapid shortterm
adjustment, which will diminish during coming decades.
We take an e-folding time of 100 years, on the basis of an
idealised model study (Payne et al., 2004). This assumption
reduces the sea level rise in Table 10.7 by 0.02 m. Second,
the present imbalance might be a response to recent climate
change, perhaps through oceanic or surface warming (Section
10.6.4.2). No models are available for such a link, so we assume
that the imbalance might scale up with global average surface
temperature change, which we take as a measure of the magnitude
of climate change (see Appendix 10.A). This assumption adds
0.1 to 0.2 m to the estimated upper bound for sea level rise
depending on the scenario (Table 10.7). During 2090 to 2099,
the rate of scaled-up antarctic discharge roughly balances the
increased rate of antarctic accumulation (SMB). The central
estimate for the increased antarctic discharge under the SRES
scenario A1FI is about 1.3 mm yr–1, a factor of 5 to 10 greater
than in recent years, and similar to the order-of-magnitude
upper limit of Section 10.6.4.2. It must be emphasized that we
cannot assess the likelihood of any of these three alternatives,
which are presented as illustrative. The state of understanding
prevents a best estimate from being made.
page 821 AR4
There are competing hypotheses. One would increase the sea level projections. They don’t know which one is correct. Perhaps many have an opinion on which one is correct but that is not expressed by the IPCC which clearly states it does not know. Conclusion: the IPCC did not at the time of publication know that their projections were too low. What they know now I cannot say. It is not a matter of probability. It is a matter of which model is correct or at least most correct.
This is my interpretation of what is said as posted here and it fits well with my interpretation of the excerpt we previously discussed.
The Wall Street Journal, SCIENCE JOURNAL SEPTEMBER 11, 2009
New York City Prepares for Era of High Seas
As Ocean Levels Rise, Storm Surges Become More Worrisome for Coastal Cities, Especially Those in the Northeastern U.S.
“… Sea level may rise faster near New York than at most other densely populated ports due to local effects of gravity, water density and ocean currents, four new forecasts of melting ice sheets suggest. Already, the ocean level world-wide is rising twice as fast as predicted two years ago….”
… how does the power/weight ratio of hydo-fuel cells stack up against av-gas/ kerosene?
Hydrogen has a very good energy to mass ratio: 143 MJ/kg . Much better than kerosene (42.8 MJ/kg) or av-gas (46.4 MJ/kg).
The problems with hydrogen are:
(a) it is not an energy source. There is no large source of readily available natural hydrogen that can simply be gathered up for a lower energy cost than the energy it contains. That’s the real advantage of coal, oil, and nuclear over hydrogen. Mining and processing coal, oil, or uranium requires a lot less energy than the energy contained in the coal, oil, or uranium. In the same vein, the energy needed to build and maintain a solar power plant is far less than the energy it can gather from sunlight. Hydrogen is not like those energy sources. Instead – energy from some other source must be converted into hydrogen. Because CH4, oil, and coal are already in chemical form, like hydrogen, it’s much more efficient to produce hydrogen from CH4, oil, or coal than from solar, wind, or nuclear. But hydrogen production from fossil fuels produces about as much CO2 as burning the fuels directly.
(b) Hydrogen has a terrible energy/volume ratio. It requires a huge fuel tanks, which greatly increase the surface area of any aircraft, and complicate the profile design, which both in turn increase drag. Past hydrogen powered aircraft have always suffered severely due to hydrogen’s terrible energy/volume ratio.
(c) Hydrogen is really, really hard to store and transport. A tank that will securely hold O2, N2, CO2, and many other gasses will leak H2 like a sieve. Many otherwise impermeable metal tank walls are quite permeable to H2. Essentially all normal welds are permeable to H2.
I strongly recommend Joe Rohm’s book The Hype About Hydrogen .
> Conclusion: the IPCC did not at the time of publication know that their
> projections were too low.
Nope… they knew but refused to speak out. It follows logically from the numbers… the only situation where their projections would not be too low would be if the “rapid shortterm adjustment” hypothesis were close to 100% certain; an extreme claim.
Oops… the previous went off too early. What I wanted to add was that that’s my understanding of what I read. Admittedly this part of the IPCC report is particularly poorly written. But we knew that.
About it not being a matter of probability: no, not for the scientists, but a policy maker will put subjective probabilities on it; he/she has to. So the IPCC afforded themselves a luxury that their clients don’t have.
To reiterate what Marten Vermeer has stated. Nit picking the statement does not change the overarching understanding. From a scientific point of view nit picking is great when considered in relevant context.
Form a policy standpoint, probability is an important factor in decision making. While risks need to be quantified for action assessment, the overarching probability rules the day. We are going to warm and there will be regional impacts on food production from precipitation changes. This will alter the economy worldwide and it is a negative, not a positive.
Worldwide, we will see the monthly budget for food purchases going up. Crop loss form drought and flooding will be key factors here.
This will force many businesses to lose sales. Everything will change. And it does not stop there, it just keeps warming. Add it up. Connect the dots. Big picture is critical at this point in time. Nit picking the lines and ignoring the reality is a good way to destroy economic capacity.
If you truly hate economic capacity, by all means, promote the insane idea that it won’t be so bad.
Martin, I would doubt anyone that believes they are 100% correct on a complicated process so my instinct tells me that you are correct and the SLR is probably understated. I would join Hank in expressing appreciation for the time you take here in helping those of us from unrelated fields and hope you continue to do so. Perhaps once more data has been attained the IPCC will feel more comfortable making a more definitive statement.
I’m sure that the readership of the WSJ which has kept the paper profitable will be pleased that the city considers storm surge flooding to be equivalent to a snow storm.
‘For Mr. Aggarwala, any changes in climate are best countered by incremental adjustments as science and circumstances demand. “If we have to shut the stock exchange for a day because water is running down Wall Street, that’s not unprecedented,” Mr. Aggarwala says. “A major snowstorm can do that. The key challenge is how quickly we can recover.”‘
One can’t help but feel that this relaxed attitude, encouraged by the denialism of the WSJ itself, is a lot like saying an earthquake could take down the twin towers so lets go slow on preventing terrorism.
How quickly will sea level rise reverse if we just wait to run out of fossil fuels? Wall Street will never recover. Prevention is what is needed. Terminating fossil fuel use is the first step, a step that Wall Street has it in its power to take.
John, you have made an argument over accuracy in citation into an argument over accuracy in results. They are not the same thing but I can understand how viewing it that way might be one’s first reaction. This is why I have tried to state as clearly as I could that I have no opinion on sea level rise projections.
Mark, I’ve done all I wish to, can, or will do to help your reading comprehension. Though it’s simple: you (and the others) read into written words what you wish is there or what you think should have been there, or what, in your (and other’s) view, the authors should have written, or what you infer they really meant to write, not what was actually written. If you claim the quote (205) says the IPCC has absolutely underestimated SLR because they definitely underestimated ice flow or melt (e.g.), you’re hallucinating.
Mark, it does not help that you keep writing that the “(IPCC’s) model didn’t include ice melt from land ice.” It did, but at the average rate for the period 1993 to 2003. The problem is that rate was already outdated well before the report was released.
First, the cut off for the IPCC’s review of the published science was May, 2006. That means no data, observations or analysis from after 2005 would have been incorporated into the IPCC’s analysis and projections. Second, the estimates of sea level rise from the melting of the Greenland and Antarctic ice caps was based on the trend from 1993 to 2003, which pushes the knowledge base and analysis back a further two years. That means that the the IPCC projections were based on data and analysis that was up to four years behind the current science when the report was published in early 2007.
The WGI authors were obviously well aware of this lag, which is precisely why they wrote the caveat that I quoted from the WGI Summary for Policy Makers (@205). As others have pointed out, that quote was greatly expanded upon in sections 10.6 and 10.7 of the full WGI report, which are laced with many more caveats, some of them quite specific, such as:
“The TAR concluded that accelerated sea level rise caused by rapid dynamic response of the ice sheets to climate change is very unlikely during the 21st century (Church et al., 2001). However, new evidence of recent rapid changes in the Antarctic Peninsula, West Antarctica and Greenland (see Section 184.108.40.206) has again raised the possibility of larger dynamical changes in the future than are projected by state-of-the-art continental models, such as cited above, because these models do not incorporate all the processes responsible for the rapid marginal thinning currently taking place (Box 4.1; Alley et al., 2005a; Vaughan, 2007).” Section 10.6.4.2
“Further accelerations in ice flow of the kind recently observed in some Greenland outlet glaciers and West Antarctic ice streams could increase the ice sheet contributions substantially, but quantitative projections cannot be made with confi dence (see Section 10.6.4.2).” Section 10.6.5
How many explicit caveats that the WGI authors did not have high confidence in their own projections of future sea level would you like? Feel free to read through sections 10.6 and 10.7 looking for more.
So, what happened to the understanding of ice dynamics and the cryosphere between 2003 and early 2007, when the Fourth Asesment report was released to warrant so many caveats?
I suggest that you take a look at what papers were published on the subject in that timeframe and shortly afterward showing increases in rate of movement, melt and mass loss in Greenland and Antarctica, not to mention papers showing accelerated ice melt and breakup in the paleorecord, or 2005′s eclipsing of 1998 as the warmest year in the temperature record. Although published too late to be included in the analysis and projections of the report, the authors of Sections 10.6 & 10.5 would certainly have been well aware of the current research prior to release of the report, and thus knew that their projections, based on outdated data, observations and assumptions, were almost certainly too low, and thus insisted on inserting the caveats that they did.
You’ can look up the papers yourself, though, because I have better things to do than help someone who is just trying to pull our collective chain.
#319 Chris Dudley
Terminating Fossil fuel use is the first step? You’ve got it reversed, the first step is to replace fossil fuel electric generation with nuclear and alternative sources. It’s only that you can even think of eliminating fossil fuel use. Realistically, fossil fuels will still be in heavy use 50 years from now. It’s too plentiful and cheap and there is too much available infrastructure for it’s development and transport. Also, you cannot think for a minute that countries with huge reserves are just going to let them sit in the ground and allow their economies to dry up. If the US or China does not use it then it will be sold to other countries that will. We should hit 450 PPM by 2040 or 2050.
Rod, there’s always someone making mistakes and making confident statements about their misunderstanding. You can always find someone picking one sentence from something and posting it as _the_ fact.
If you want an argument, stay with responding to people who do that stuff and don’t cite their sources. You’ll be among others who are equally interested in having arguments, trumping points, and being successful arguing.
Meanwhile there’s work to be done.
If you’re trying to understand the science, look at the references.
You can always find someone’s opinion to argue with.
To understand the science you have to start with reading it. Not someone’s recollection of what they read about it.
Jim Eager did a good job just above here of summarizing and pointing to the material needed.
If you want to be a simon, you can just pick arguments and make fun of the discussion. Your choice, to the extent the moderators allow you to do so.
An example, “IFRs use virtually all of the energy content in the uranium fuel whereas a traditional light water reactor uses less than 1% of that energy content. This means that breeder reactors can power the energy needs of the planet for at least 10,000 years.” (From Wikipedia).
Is this nonsense? Do you dismiss this out of hand? Is Barry Brooks an idiot? Will not sea-level rise be mitigated by embracing nuclear power? Why does Gavin dismiss such a discussion as OT? Why is Ray so opposed to nuclear power as a solution to global warming problems? And why would a scientist have anything whatever to do with any political agenda?
John, because sea level rise is a very complicated issue. For instance take groundwater. Shah 2000 estimated the mining of groundwater to be 750-800km^3 per year. This is a very large amount of water. I don’t know what percentage of this water makes it to the ocean. I don’t know if the mining of groundwater will increase or decrease. Recent trends have been that the use of groundwater is leveling off. Logic says that as the population and wealth of the population increases then water usage will increase also. One would hope that we would conserve our groundwater. History says we won’t. How can I predict such a thing?
Hank, that was all that I was doing and all that I ever claimed I was doing. If one wants to pick a credible argument with me it’s best to make it over something I actually said as opposed to the argument they want to have.
” Why does Gavin dismiss such a discussion as OT?”
Because it is.
And then: “Why is Ray so opposed to nuclear power as a solution to global warming problems?”
Who says I am? I have questions about whether it CAN BE a solution given the technical issues and the time frame. It is also not a renewable resource and means we will yet again have to replace an energy infrastructure in the future when the U-235 and Th-233 run out
And finally, Simon queries: “And why would a scientist have anything whatever to do with any political agenda?”
Oh, bite me! Are you serious? Do you seriously want to deprive scientists of political rights and opinions? Do you really not understand that individual scientists can be political, but that the process of science keeps the political agendas from overly influencing the science? Good lord, Man. Have you ever even taken a science class? Have you ever known a scientist?
Re: simon Monckton comment: “And why would a scientist have anything whatever to do with any political agenda?”
Maybe in simons world scientists should not have voting rights. Hard to imagine why you would want scientists trained in logic and scientific method and reasoning… I mean you really don’t want people that study and research to vote now, do you?
Think of what that would lead to? Scary I tell you.
Much easier to control things if you don’t have scientists muddling up the ballot box.
So, simon, can you give us a list of the people that should be allowed to vote so we can suggest it to our congress?
Hank, I agree this debate has long worn out its welcome. But it is not OT and IMO fairly significant. The thread is about projections of sea level rise. Jim (205) made the assertion, “…the IPCC’s own explicit statement that the IPCC knew that their sea level estimates were low…” That is a solid claim with virtually no reservations. But that claim can not follow logically from the IPCC quote in 205. I agree Jim’s follow-up post (323) is a good and fairly complete summary of the IPCC’s position. But it still does not support the original claim. Some excerpts: “…However, new evidence….has again raised the possibility…”; “…the authors of Sections 10.6 & 10.5 would certainly have been well aware of the current research…” which is a presumption of Jim, reasonably founded no doubt, but a presumption none-the-less. If you read all of the precise words in 323 or its references, you still can not credibly claim that, “…the IPCC knew that their sea level estimates were low…”
For a thread that is discussing the evidence of what the sea level might or might not do because of this or that, those exaggerative conclusions, even if innocuously meant, detracts from the credibility of the science. I think that is relevant and important.
I was obviously talking about the scientist qua scientist.
And on topic may I say that we have not a clue about what is under several kilometres of Greenland or Antarctic icecap and what their response to an increase of temperature might be.
Moreover sea level rise or fall is to me obviously almost exclusively due to thermal expansion/contraction. Given the vast volume of the oceans, the thermal sluggishness of water and the imponderable nature of the resulting hysteresis effects (to say nothing of known large-scale circulations), any associated theories must be at present necessarily no more than speculative and indeed be most probably nugatory.
“… the average rate of volume loss quadrupled from 2.6 ± 0.3 km3 yr−1 in 1995 to 10.1 ± 0.3 km3 yr−1 in 2006. The region of lightly grounded ice at the glacier terminus is extending upstream, and the changes inland are consistent with the effects of a prolonged disturbance to the ice flow, such as the effects of ocean-driven melting. If the acceleration continues at its present rate, the main trunk of PIG will be afloat within some 100 years, six times sooner than anticipated.”
BTW, note the lament in the first chapter that a “relatively obscure” man such as the narrator, who moreover as a geologist is not, “in the strictest sense,” a speci-alist in the fields primarily concerned, has “little chance of making an impression where matters of a wildly bizarre or highly controversial nature are concerned.” Sound familiar? :-)
Hank, thanks for the stats, the links, and the mathematics problem. In an effort to steer the topic back toward sea level, perhaps you or others could help me a bit with crunching numbers. With helf from a friend, this is what we go so far using the figures you provided:
3.53146667*10e10=35,314,666,700=35.3 Billion cubic feet per cubic km.
1 Trillion cu feet= 28,316,846,712 cu meters
Take the high figure of 1 Quintillion cubic feet aka 1,000,000 Trillion cubic feet and convert to meters=
28,316,846,712,000,000 meters cubed
Multiply that figure by .13= 3,681,190,072,560,000 cubic meters of water voided by the Methane escape.
3,681,190,072,560,000/1,000,000,000 cu meters per cubic km=3,681,190 km cubed of water volume reduction.
Divide that by 1,370,000,000 km cubed for the entire ocean and you get .002687 or less that a point 3% drop in ocean volume by extracting all the methane in the clathrates.
The average depth of the sea floor is 3,720,000 mm below mean sea level, so a drop of .002687 would be 9995.64mm or 9.99564 Meters, aka 32 feet 9&1/2 inches.
So, in the extremely unlikely (and horrific) event that all the clathrates were released at once, there would be a considerable drop in sea level if these are rigt. Even if less than one percent a year was released, it could offset a considerable portion of the projected rise, at least.
But I’m thinking we must have gone wrong somewhere with our math. Would it be too much to ask for some smart poster here to point out where we went wrong?
The value of 10^18 cubic feet is released methane (under STP), not clathrate… divide by 160 ;-)
… 1) the global volume of methane contained in hydrate is huge—far exceeding the volumes of methane present in other forms …
Historically, estimates of the total volume of methane in natural gas hydrate have ranged widely, from roughly 100,000 trillion cubic feet (Tcf) to as much as 270,000,000 Tcf. In recent years, as more information is gained and real data slowly replace best guesses, estimates have tended to fall in a narrower range—from 100,000 to 1,000,000 Tcf.
No, that you don’t understand ad hom is evident from your claim of it.
Calling you out on your lack of understanding is not ad hom, it’s a statement of fact.
Else spelling the dry areas of the Sahara “dessert” is not wrong, since you can’t say it is without saying I’m wrong to spell it that way and you take that as an ad hom attack and a priori evidence that your correction should be ignored and considered by default (and no need to check) wrong.
Actually, what Simon said was “And on topic may I say that we have not a clue about what is under several kilometres of Greenland or Antarctic icecap and what their response to an increase of temperature might be.”
So, does he believe that the icecaps might not actually melt as the temperatures rise, because he doesn’t know whether it’s basalt, or sedimentary rock, or turtles all the way down? Maybe if we close our eyes, plug our ears, and tuck our heads under the covers, nothing bad will happen.
I have a question regarding the concept of an expanding earth: Shen, Chen, Li 12/2007 AGU. They state that the Earth is expanding at a rate of around 0.6mm per year. I have been trying to conceptualize how this would be taken into account in the checks and balances of satellite altimetry and, having failed miserably, thought I would just ask. Has the concept of an expanding Earth already been included in calculations? If not would this be picked up as rising sea levels or satellite drift?
Simon, _where_ have you been getting your information?
Seriously, it helps everyone if you’ll say what sources you have been relying on, where you found them, and why you found them trustworthy up til now — because other people will be relying on them too.
Note the page I pointed you, referencing ice core drilling to bedrock, is a decade old (I emailed the maintainer and asked them whether they have an update somewhere).
Looking out for bad information, telling people who maintain it that it needs correction, and letting readers know whether sites _do_ try to update — is part of the game where we’re all playing on the same side, to the extent we want the science to be understood by people.
stevenc #362: thanks, that’s an interesting nut to crack!
The abstract is here.
First off, my hunch is that this is nonsense. Unfortunately I have not found the article itself.
To first answer your question, it would be picked up as rising sea level by the altimetry, but not by the tide gauges. The common time base of those two systems is still too short to decide the matter.
One immediate problem I see with their idea is, they say they derive the change in principal moments of inertia from the spherical harmonic coefficients of the Earth’s gravitational field, specifically C20, C22 and S22. The problem is that this inversion is degenerate: the external field contains no information on the radial mass distribution.
This means that you cannot unambiguously fix the principal moments of inertia based on those spherical harmonic coefficients. Especially their claimed equal increase in all three principal moments is unobservable from spherical harmonics alone.
If they looked at the change in spherical harmonics, converting it naively to a change in moments of inertia, part of the effect they claim to see may be due to the Laurentide glacial isostatic rebound, which is known to produce a secular increase in C20, but no significant change in C22 or S22. But that’s not what they find… so what are they really doing? No idea.
It’s a conference presentation, not peer reviewed I believe.
Looks like China has figured out that Nuclear power is is one way to minimize CO2 and they have plans to build dozens of nuke plants. Too bad the USA has a failure of leadership to do the same. See below:
DALIAN, China, Sept. 11 /PRNewswire-FirstCall/
Mr. Kearney’s panel at the World Economic Forum’s Annual Meeting of the New Champions, known as “Summer Davos, entitled “The New Climate Framework: What Will Copenhagen Mean for Tomorrow’s Global Companies?” focused on the possible global business implications of a new climate change accord. Executives joining Mr. Kearney on the panel to share their expertise included:
Yvo De Boer, Executive Secretary, United Nations Framework Convention on Climate Change; Mark Norbom, President and Chief Executive Officer, GE, People’s Republic of China Caio Koch-Weser, Vice-Chairman, Deutsche Bank Group, Deutsche Bank, United Kingdom; and Wu Changhua, Greater China Director, The Climate Group, People’s Republic of China. “Two of the most promising ways the world can drive increased energy capacity while also addressing climate change are increased investments in nuclear power and efficiency improvement technology for the broader power sector,” said Mr. Kearney in addressing the panel. “Nuclear power is proven, safe and emits zero greenhouse gases, while generating the kind of base load power advanced economies require. China is rapidly building new nuclear capacity. The U.S., which has not built a new nuclear plant in 30 years, needs to do the same.
Hank, that’s exactly what I was looking at. The answers to my questions I could not get from the text although perhaps there is something there I am misinterpreting or just missing somehow.
Martin, yes I was confused over the idea that they gave a published date but I now see that would be the published date of the abstract they gave the presentation from and not an indication of being peer reviewed. I actually do look for the peer reviewed labal before buying. Thank you for your thoughful response.
So maximum possible drop in sea level would be more like 65mm or so, and probably some fraction of a percent of this for real annual decreases even if considerable amounts are released. I suppose the calculation gets further complicated since much of the methane would be dissolved in the water. Presumably this would increase the volume of the water? Enough to off set the tiny sea level drop?
stevenc, yes, Hank’s question, just curiosity: how did you find out about this paper? Did you stumble over it all by yourself?
wili, yes, some 6 cm (your numerical precision is a stretch), corresponding very roughly to 6000 ppm of the atmosphere.
Most of this would be converted quickly, I would assume, to CO2 by reacting with atmospheric oxygen (if not, we’re in even greater trouble). Then we’re already talking CO2 concentrations causing over ten degrees of warming… Then I wouldn’t worry too much about centimetre precision sea level any more ;-)
The reference in the last line of the Shen & al. abstract to “the Dirac large numbers postulate”, in the context of extending their expanding-earth claim from ten years to geological time, sort of trips my crank alarm. But I’m not a physicist. http://en.wikipedia.org/wiki/Dirac_large_numbers_hypothesis
Martin, I can’t actually remember how I stumbled on the expanding earth page. I was not directed there. The expanding earth was either mentioned in something I was reading causing me to look for more information or this paper showed up in a search I conducted on a different topic. It’s location in my saved list indicates it was probably months ago that I found it.
CM, I took the last sentence as saying that the hypothesis of Dirac’s large number postulate meant that it could have been happening for a long time as opposed to the calculations for the last ten years meaning that the hypothesis was correct.
0.6 mm/yr = 600 km / Gyr = 3000 km since the Earth formed… actually I remember reading about such theories many years ago when I was little. It seems that most of them require that either the strength of gravitation G varies strongly over time, or that the total mass of the Earth does. That would certainly have been noticed in Earth satellite motion, way before the radial expansion itself!
The ‘expanding earth’ is a notion to explain how the Americas and Europe got separated, from folks who can’t find time in their religious beliefs for continental drift to occur. As an alternative to continental drift, it explains all those parallel lines in the seabed as stretch marks and the matchup between the continent shapes as indicating how much smaller the Earth was when it was created without changing the landforms at all. Kind of like painting them on a balloon, waiting for the paint to harden, then blowing up the balloon.
I first came across it when I was proofreading for a well respected magazine and an editor slapped a caption on a photo of seafloor spreading saying it illustrated the expanding Earth. I know the details in the, er, theory are more, er, elaborate than that. But that’s the idea in an, er, nutshell.
That searches for all scholarly articles that mention Dirac and this string:
Dirac “large number postulate”
Short answer: nobody else does, just these authors.
They might be talking about — the notion that — over the age of the universe, for values of ‘age’ considerably in excess of 6K years, some physical constants may have varied. Or maybe not. Pretty flaky stuff to be tossing out in any discussion about climate change. Think of the time scales involved.
Hank, actually the material I have read on the expanding earth requires a considerable amount of time. Perhaps there are those that incorporate it in their beliefs and how they do this I am not clear on since I seldom wander into the religious aspects of science.
I would agree that it seems unlikely the hypothesis is correct in it’s entirety. I would be more likely to wonder if periods of expansion and contraction would be possible based on the balance between crust being created and destroyed within the framework of the tectonic plate theory.
Mark, you are confused. “If” the earth is expanding or contracting then it is expanding or contracting regardless of whether it has been given permission to do so or not. Now please stop thowing rocks at me, it does grow tiresome. I am trying to have intelligent conversations and learn things in the process.
Be assured there was no “bad info”. I drew false conclusions from my own inadequate knowledge. And I now see how posting might have been misleading and irresponsible. Shall be more circumspect in future. Thanks for the advice. Respectfully, simon.
Comment by simon abingdon — 15 Sep 2009 @ 12:28 PM
There has been some recent discussion about the effects of melting ice sheets on vulcanism as the declining mass shifts the distribution of weight on the tectonic plates (if I understand this correctly).
I was wondering about the other end:
As sea levels rise, should we expect the increased water weight on the continental shelves to cause more earth quakes?
Re “expanding earth”, it seems their idea is indeed that as the universe ages, gravity weakens, and the planet elastically expands, explaining continental drift without plate tectonics.
Martin #376, your calculation was probably meant ad absurdum. But it seems one L. Egyed (1956?, 1970?) in all seriousness derived the 0.6mm/yr figure over 4.4 billion years from paleogeography data, fitting together bits of the Earth’s crust that could have formed the seamless surface of a far smaller early Earth.
Hank #377, Mark #381, that means it’s not just a young-earther thing. These theories seem to have been fairly respectable in the 1970s, just look at this 1978 textbook. Hank, you will find journal articles and book chapters linking Dirac and expansion.
Stevenc #374, your reading sounds right.
To sum up, I doubt anyone measuring sea-level rise needs to lose sleep over this one. But contrarian ideas seem to attract each other, so I’m sure it will come up again from the more creative fringes of denialism.
OK, so I looked at the flyer for the symposium, and under session three I found the following:
“Short time-scale drivers of geological and geomorphological hazards
Addresses environmental processes and mechanisms with the potential to trigger geological and geomorphological hazards at short time-scales, which may also have implications for climate modulation of hazardous Earth processes at longer time scales. Examples include tidal, meteorological and ocean loading effects on volcanism and seismicity.”
The last bit suggests that there are or could be tidal and ocean loading effects on volcanism and seismicity. Is that what you wanted me to find?
I have to apologize if I’m just being completely dense, here.
Were you suggesting that issues of possible effects of sea level rise would not be relevant to a discussion of sea level rise? Hey, at least I’m not talking about an expanding earth or endlessly harping on nuclear power;-]
I’m just asking if there’s anything there yet, Willi. Is it a future event? A publication already available? Something with anything we can read? Just a promise of something to come? Named speakers or authors? Look them up in Scholar and see if their papers are available. Do they mention probabilities? climate forcing, how much difference any of these events might make in temperature trends?
Willi, shorter answer: I’m just another reader, I know nothing about it, it’s interesting, you found it, you can probably describe it well enough after you read up on it to attract the attention of a scientist or two to help you. Ask informed and helpful questions, and likely you can to attract their attention.
I was wondering about the other end:
As sea levels rise, should we expect the increased water weight on
the continental shelves to cause more earth quakes?
Wili, most certainly. And there will also be a “wedge effect”: the greater weight on the sea floor will try to depress it, and the displaced material will try to uplift the adjoining continents. But expect all this to be fairly minor.
It is similar to the small tremors that often accompany filling artificial reservoirs. And in Fennoscandia, seismic activity has been attributed by some to the ongoing post-glacial uplift.
Comment by Martin Vermeer — 16 Sep 2009 @ 12:05 AM
> Martin #376, your calculation was probably meant ad absurdum.
Actually, no… just showing how the abstract referred to fitted in with Dirac’s notion of a changing G and expanding-Earth ideas based on (or related to) it.
But yes, the idea itself is absurd based on current knowledge. Like, can you say ‘mechanism’? And plate tectonics, with subduction, is real, period. And then, we now know the universe to be 13.6 Ga old… those ideas could have more traction when the age of the universe was still held to be only slightly more than that of the Earth and Solar system, i.e., 4.6 Ga… crank stuff.
Comment by Martin Vermeer — 16 Sep 2009 @ 12:20 AM
Wili #383 asked: “As sea levels rise, should we expect the increased water weight on the continental shelves to cause more earth quakes?” Bill McGuire at UCL has been raising that possibility in the popular press (NS, Guardian), making reference to the end of the last ice age. Don’t know about the published science (a Keating and McGuire paper in Adv. Geophysics 47 may be relevant). Presumably after the symposium you link to, more will be known…
“The last bit suggests that there are or could be tidal and ocean loading effects on volcanism and seismicity. Is that what you wanted me to find?”
How does that reading make this statement:
“Were you suggesting that issues of possible effects of sea level rise would not be relevant to a discussion of sea level rise?”
Since that earlier prognosis doesn’t say anything about sea level rise and the selected quote from the symposium doesn’t say that tidal is a cause for sea level rise.
The tide is about moving the ocean about. Unless you have some way of keeping the tides high in an area, this doesn’t change sea levels in anything more than the trivial way that waves cause sea level rise.
CM, if the Earth expands by 0.6mm per year for a deacade then contracts by 0.6mm per year for the next decade, then the satellites would register that as a 0.6mm decrease in the rise of sea level. I don’t see this as an issue that can be written off based on the numbers. The methodology of the researchers appears to be the real issue but that is difficult to follow for me period and for those that understand it better based on the information available.
Martin, or anyone, did you have any thoughts on the possibility that the Earth may expand and contract based upon the amount of crust being formed and dissolved? I understand it is widely accepted that the Earth has a long term trend of contraction but most trends in nature fail to follow a straight line.
Mark, so the Earth never changes size. Have a reference for that? We are similar in some ways Mark. We are both often wrong in our understanding of the science. Where we part ways is that I am perfectly willing to accept when I am in error, acknowledge that I made an error, and move on better informed then I previously was. Your only purpose here seems to be to badger other posters if you percieve they disagree with your point of view.
To the other posters, what makes a troll? It this solely based on which point of view they are blindly regurgitating?
stevenc #400: how would that work? The total volume of crustal material is a very small fraction of that of the whole Earth. Yes, it could undergo phase transitions when subducting into the mantle, and when coming out again, but this would not amount to more than a small fraction of even that small volume.
Dog’s posting of 402 is quite apt after stevenc’s posting of 401.
Nope, I didn’t say the earth never changes size.
I said it doesn’t change at a positive rate that is measurable. 0.6mm a year is right out.
It can get bigger and smaller and likely does to maybe a tiny fraction of a mm because the moon gets closer or further away, or there’s more subduction than creation of basalt (or the reverse). But it’s not consistently growing.
So, dog says I just misconstrue people’s post JUST AFTER steven makes up a strawman or misconstrues my statement.
Martin, the closest thing I can find to what I was thinking is the pulsating Earth hypothesis where the crust forms, contracts, applies pressure to the interior magma which then forces the plates apart causing expansion. I’ll try to find a good paper on this later when I am not pressed for time. It is used by both contraction and expansion hypotheses so should you have seen it in an expansion hypothesis don’t dismiss it out of hand until I have had a chance to see if it can be properly supported. Thanks!
The Earth is probably growing over time as a result of meteorite infall. The mass thereof may exceed the mass lost every year from the atmosphere by Jeans escape. I haven’t made a quantitative estimate, though.
Comment by David B. Benson — 16 Sep 2009 @ 6:20 PM
Stevenc (#400), *if* the Earth expanded by 0.6mm a year for a decade it would no doubt raise many interesting questions. And merit a prominent headline in /Nature/ after careful peer review. Then we could start thinking about what it means for sea-level measurements, and we can come back to discuss it on this site, and lose some sleep productively. But did you read what Martin Vermeer replied (#365) before I got us sidetracked? Bottom line, their method sounds likely to be plain wrong, in which case they haven’t measured what they think, in which case there’s no need for us to be having this discussion. Since Martin measures the earth for a living, I’m inclined to take his word for it, especially considering that we are just discussing a conference abstract exhibiting telltale signs of mild crackpottery.
CM, I agree there seems to be something wrong with their premise since nothing seems to have been followed up on in the two years since the presentation was given and even with the some of the information missing Martin had already indentified items that made no sense to him. I am also more inclined towards your interpretation of their last sentence and believe mine to have been too lenient since the proper term for them to have used would have been possible not concluded. Perhaps expanding earth enthusiasts. Anyway, my many hours of searching have produced little in the way of results for expansion and contraction of the Earth other then in general terms and nothing with supporting data. From what I have read the gravity measurements from satellite will pick this up should it be happening.
What about hydrogen fuel cells straight into the wing. When a plane need refueling a truck with a modified forklift slots the standardized size hydrogen fuel cells straight into both wings… maybe 5-7 cells per wing and 10 say in the fuselage. Question.? Which you guys may be able to answer. How does the power/weight ratio of hydo-fuel cells stack up against av-gas/ kerosene? Would the thrust on take-off be comparable to kerosene? How will the extreme cold of higher altitudes (minus 50-60C) effect the cells? How would the flying range compare? What type of engine would best utilize this fuel source? My idea could be completely unfeasible or it might just have a glimmer of hope… We’ll see.
Hydrogen fuel cells in the wings? Fuel cells produce electricity, but the rest of your statement seems to assume otherwise.
Liquid hydrogen could work for planes. The fuel weight is less but the volume is much larger: Completely new planes are probably required. It might be cheaper just to synthesize jet fuel from atmospheric carbon dioxide.
I expect we’ll just continue what we’re doing now for a long time. There are many easier places to reduce our carbon usage.
Did you actually read the paper of Ornstein et al. At 1000 trees/ha you are talking about an ITP rather than a tropical savannah. There are also proposing to plant a fairly narrow variety of species i.e. their main target species seems to be Eucalyptus grandis, but then sort of add in a few Acacia and other species for good measures – but don’t revise their sequestration estimates based on a mixed species plantation.
A few of their figures/estimates – gives me the impression that they know next to nothing about forestry/ecology.