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This Week

Filed under: — mike @ 4 May 2007 - (Türkçe)

There are a few minor items this week worthy of mention:

1. The CO2 rise. Who dunnit?

Here at RealClimate, we have been (naively, apparently) operating under the assumption that climate change contrarians had long ago moved on from the untenable position that humans are not even responsible for the observed increase in CO2 concentrations over the past two centuries. The dubious paper by Ernst Beck we commented on the other day indicates that there is indeed still a rear guard attack being waged. As if to drive the point home further, pundit Alexander Cockburn, known generally for his progressive views, has perplexingly disputed the existence of any link between CO2 emissions and rising CO2 concentrations in the atmosphere in a screed he penned this week for the online journal “Counterpunch” (also printed in The Nation). It’s hard to know where to start, since his piece is so over the top and gets just about everything so thoroughly wrong, it’s almost comical. So we’ll just hit the low points: (a) Cockburn claims that there is zero empirical evidence that anthropogenic production of CO2 is making any measurable contribution to the world’s present warming trend, despite the fact that not even such strident climate change contrarians as Pat Michaels dispute that there is a measurable influence of anthropogenic greenhouse gases on global temperature. Plus there’s all the empirical evidence of course (see the new IPCC report). (b) Going further, Cockburn brazenly opines that ‘it is impossible to assert that the increase in atmospheric CO2 stems from human burning of fossil fuels’ despite the fact that there is an isotopic smoking gun for this connection. He then (c) fails to understand that water vapor is a feedback not a forcing, and citing ‘expert’ Dr. Martin Hertzberg, quite remarkably states that ‘It is the warming of the earth that is causing the increase of carbon dioxide and not the reverse.’ Never mind that isotopic evidence proves otherwise. Upon what evidence does he base this assertion?

Since no anti-global warming op-ed these days is complete without it, Cockburn (d) resorts to the usual misrepresentation of lag/lead relationships between CO2 and temperatures during glacial/interglacial cycles as if they disprove the causal relationship between greenhouse gas concentrations and surface temperatures (see our most recent debunking of this favorite contrarian talking point here). Oh dear.

2. The other (Glenn) Beck–Even Worse!

CNN gave their resident shock-jock Glenn Beck a forum for spreading more disinformation on global warming in an hour-long segment entitled Exposed: The Climate of Fear (see also this discussion by “Media Matters”). We could pick apart his (rather thin) arguments, which constitute the usual cocktail of long debunked contrarian talking points. Suffice it to say, however, that the moment a rhetorician invokes Hitler, Nazi Germany, and Eugenics, it is the moment they are no longer worthy of being listened to (cf Godwin’s Law of usenet debates). We don’t seem to be alone in our opinion here. Beck’s performance earned him the dubious title of “worst person in the world” from analyst Keith Olbermann.

However, there was one amusing moment: Beck asked Christopher ‘Incorrect’ Horner what the key thing to google was that would show that Al Gore was wrong. Horner suggested the lag between CO2 and temperature in the ice cores. Of course, if you do Google that, the first hit is the RealClimate debunking of the issue. Thanks!

3. Nature’s new blog

Nature has started a new blog called “Climate Feedback”, which says of itself ‘Climate Feedback is a blog hosted by Nature Reports: Climate Change to facilitate lively and informative discussion on the science and wider implications of global warming. The blog aims to be an informal forum for debate and commentary on climate science in our journals and others, in the news, and in the world at large.’

We wish it well, remembering their welcome for RealClimate, though early reviews based on the first few posts are decidedly mixed.

280 Responses to “This Week”

  1. 101
    Ray Ladbury says:

    Actually climate change morphed into global warming when the press needed an intuitive term they could use. Global warming is not really a scientific term, because what is happening is that the energy in the climate system is increasing. While this can lead to increased temperature, it could also affect ocean currents, climate patterns etc. and, at least locally, lead to cooling. Just because you want things to be simple doesn’t mean they will be. To be accurate, climate change is more proper than global warming.

  2. 102
    Hank Roberts says:

    There’s increasing concern about stratospheric ozone decline (the US has joined the other Montreal Protocol members in trying to speed up the phaseout of the HCFC chemistry). China appears to have discovered the Protocol’s original grant of a long slow phaseout as a way to increase revenue by maximizing production of the stuff so they get paid more to stop producing it —- realpolitik from the “mutually assured destruction” school of international politics, I guess.

    Lots of links mentioning upcoming seminars like this:
    CSD Seminar Schedule
    May 9, Insights into future ozone depletion and climate forcing attributed to ozone-depleting substances (ODSs) John Daniel, NOAA ESRL CSD …

  3. 103
    ghost says:

    Frank Luntz had a lot to do with the change in the U.S.

    “Can somebody explain how global warming morphed into ‘climate change’?”

  4. 104
  5. 105
    Joseph O'Sullivan says:

    Tom (#99)

    In the scientific circles it always has been climate change. The press started with global warming. The press has to some degree started going back to the term climate change due to the influence of public relations people (eg Luntz) who want to influence the language of the debate to sway the political outcome.

  6. 106
    nicolas L. says:

    RE: 77, 92

    Ozone is a GHG. To make it very short, less ozone means less GH effect, means negative forcing on the atmosphere.
    But ozone depletion shouldnâ??t be considered as a good thing for GW problem, as far as Ozone Depleting Substances (like CFCs) are also GHG, and have an effect of positive forcing much more important that the negative forcing due to the ozone depletion itself
    Very short answer, if some want to develop it, theyâ??re very welcomed :)

  7. 107

    Re #94

    Paul Barton,
    Stomata index proxy of past CO2 levels is a relative newcomer in the proxy world. As every proxy (or even direct measurements), it has its own problems in contamination and accuracy.
    One problem with the stomata index is that stomata density is fixed when leaves start to grow. At that moment, CO2 levels are at their highest level, due to decay of previous years leaves, especially in forested areas and more at ground level (moss) than at the canopea of trees. This gives some positive bias compared to ice cores CO2.
    At the other side, ice cores only give smoothed data, the fastest accumulation cores still need some 60 years before the ice is closed. Stomata index is fixed the year they grow, so in theory, the resolution is 1 year. Practically, one can’t distinguish individual layers with such a resolution, but averages of less than a decade are possible.

    In fact, the difference between stomata data and ice core data is smaller than you may think, see the abstract of the work of T. van Hoof ea.:
    Where the larger variations of CO2 levels in the 13th century for stomata were smoothed in ice cores:

    A period where both methods consistently provide evidence for natural CO2 changes is the 13th century.The results of the two independent methods differ significantly in the amplitude of the estimated CO2 changes (10 ppmv ice, versus 34 ppmv stomatal frequency). Here, we compare stomatal frequency and ice core results by using a firn-diffusion model in order to assess the potential influence of smoothing during enclosure on the temporal resolution as well as the CO2 mixing ratios. The seemingly large discrepancies between the CO2 levels estimated by the contrasting methods, diminish when effects of natural smoothing of the ice-core record is simulated for the raw data of the stomatal frequency record.

  8. 108
    tamino says:

    Re: #197 (Ferdinand Engelbeen)

    No, there were not “larger variations of CO2 levels in the 13th century.” The large, ubiquitous, decadal-timescale fluctuations in van Hoof et al.’s analysis are just not realistic, given the incredible smoothness of the CO2 fluctuations seen over the last 50 years. Nor do very-high-snowfall sites (like Law Dome) smooth the CO2 signal so much that we can’t discern changes on sub-decadal timescales. See my blog for details.

    I’m quite familiar with the van Hoof et al. paper, and they do not “assess the potential influence of smoothing during enclosure on the temporal resolution as well as the CO2 mixing ratios.” They simply assume smoothing, and assert assessment.

    You’re just attempting to revive the ideas of Wagner (who is a co-author on the van Hoof paper) and colleagues, which frankly don’t make sense.

  9. 109
    Chris says:

    Re: #73 and #84

    William Astley, you state:

    “Continuing from “Paleoclimatology”, Second Edition: “Pore close-off varies with accumulation rate, ranging from approx. 100 yr at high accumulation sites such as Dye-3 in Greenland� to as much as 2600 yr at very low accumulation sites such as East Antarctic.”

    However, the high resolution data from Law Dome has far lower differences between ice age and trapped air age than your excerpt indicates (around 30 years in the DE08 cores) and the air-age spread (around 10-15 years) is much, much smaller than 100 years:

    Natural and anthropogenic changes in atmospheric CO2 over the last 1000 years from air in Antarctic ice and firn Etheridge et al (1996) J. Geophys. Res. 101, 4115-4128 [This has recently been extended to 2000 years: Geophys. Res. Lett. 33, L14810 (2006)]

    Thus one would have to propose some extraordinary upwards driving (sources) and downwards driving (sinks) of atmospheric CO2 during the last 2000 years to accommodate the possibility that sharp spikes of atmospheric CO2 were “hidden” in the ice core record of the last 2000 years.

    Might these occur in the ice core records covering the early Holocene some 8000 years ago? Of course it’s possible, but not that likely.

    Far more likely is the possibility that the problems that others have noted with Betula as a stomatal frequency proxy for atmospheric CO2 is causing a misinterpretation in the data of Wagner et al.

    For example the since qua non of proxy measurements is that the proxy is reliably calibrated with respect to independent measures of the parameter being “proxied” (temperature in this case). This seems to be problematic for Betula:

    Stomatal frequency of Betula pubescens and Pinus sylvestris shows no proportional relationship with atmospheric CO2 concentration, Eide W & Birks HH (2006) Nord. J. Bot. 24 327-339

    And Jessen et al, who also looked at Holocene (later) CO2 estimations using both Betula and Quercas, and found CO2 levels rather more in line with those from ice cores. Referring to their Betula data, they say:

    â??For the purposes of comparison with other data, the longer Quercas reconstruction is considered in the following discussion, but the inconsistencies with the Betula record ensure that it must be considered tenuous.â??

    Abrupt climatic changes and an unstable transition into a late Holocene Thermal Decline: a multiproxy lacustrine record from southern Sweden Jessen CA (2005) J. Quart. Sci. 20 349-362

    The practitioners of the fascinating method of fossil stomatal frequency indices as a proxy for atmospheric CO2 need to agree themselves on the methodologies of their technique before the rest of us can be confident of its merits.

  10. 110
    Timothy Chase says:

    Lynn Vincentnathan (#98) wrote:

    Luckily I don’t have cable and no time to read other blogs, so I just check in here now & then. Unfortunately an influential person I know seems to be checking in somewhere else, where all they do is complain that their (denialist) theories are not given fair coverage and consideration in the media, and he thinks that’s unfair, that all ideas should be given a fair chance. I think I’ll send him this entry.

    He believes there ought to be checks and balances.

    Seems reasonable enough on the face of it. If two people have different opinions, both should be heard and others can decide for themselves what is reasonable – given all the available evidence and the relative strength of the arguments.

    The only problem is that when you are dealing with science, not all opinions are equal and the opinion of someone who has not devoted years to the study of a given discipline matters a great deal more. The “common man” doesn’t have time to familiarize himself with all of the evidence or to follow through the arguments step by step.

    Nevertheless, there are checks and balances. One of the most important is “peer review.” Journals don’t want to publish articles which will be judged poorly reasoned or as being the result of so much arm-chair theorizing entirely divorced by reality, so they will have experts in a given field judge articles as being worthy of publication or not. Of course, the experts doing the peer review for a given article at a given journal may be biased. But then there are other journals.

    Now one can imagine that there is some sort of dominant paradigm that becomes entrenched. People in the discipline become used to viewing the world through that paradigm – and they might see some new theory which nevertheless better accounts for new evidence (and accounts just as well for older evidence) as a threat of some sort. However, it should also be recognized that scientists do not earn a reputation or go down in the history books simply by means of supporting an old paradigm. The best way to earn a reputation and a place in the history books is by overturning an paradigm whose time has come and gone. This, too, is one of the checks and balances in science.

    Then there are checks and balances associated with the science itself. Some of these are fairly basic. The mathematics, for example, which for a disciplined mind acts as a form of checks and balances upon the conclusions the individual arrives at before even sharing his results with others. Another form checks and balances are general physical principles which are so well established they are considered basic to science as a whole. For example, the conservation of energy, the second law of thermodynamics, or the conservation of momentum.

    Then there are the results of independent lines of investigation. New evidence is constantly being acquired. And while a given piece of evidence may offer only a limited amount of support for a given conclusion, when there are multiple independent lines of investigation which support the same conclusion, the justification which that conclusion receives is far greater than it would receive from any given line of investigation in isolation from the rest.

    Now when a given individual within a given discipline decides to bipass the checks and balances which are at the heart of the scientific endeavor and instead attempts to have his case tried in the courtroom of public opinion, one should immediately consider this highly suspect, for it suggests that they realise they could never win their case in the courtroom of science itself. It suggests that they believe they can have their views judged reasonable only by those who are unfamiliar with the subject, unfamiliar with the evidence, unfamiliar with the fundamental principles, and who are not as disciplined or rigorous in their reasoning – within the context of that subject. People who are more likely to be swayed by appeal to emotion, appeal to the majority, appeal to tradition, or the all-too-common ad hominem attack.

  11. 111
    pat n says:

    Re: 105, 99

    At least one scientist used global warming in talking about a past episode of global climate change (Paleocene Eocene Thermal Maximum 55 million years ago).

    The emissions that caused this past episode of global warming probably lasted 10,000 years. By burning fossil fuels, we are likely to emit the same amount over the next three centuries,

    James Zachos, professor of Earth sciences at the University of California, Santa Cruz
    Santa Cruz CA (SPX) Feb 16, 2006

  12. 112
    Bob Cousins says:

    [Response:There’s still plenty of coal, even if oil becomes scarce. David]

    Unfortunately, if you are not familiar with the Peak Oil problem, this might seem true, but is not. Coal is only plentiful now because we don’t use it much. Coal use is about 25% of total global energy use, oil and gas over 60%. Coal is not a good substitute for liquid fuels. If coal to liquids (CTL) was used to make up for declining oil supplies, the hundreds of years of coal [presumed] reserves suddenly become 30 years, or less. CTL is not very efficient either.

    As oil and gas supplies decrease, coal prices will increase, as energy is largely fungible. Therefore, for various reasons, coal will not remain cheap nor plentiful.

    While a few countries have large coal reserves, notably USA and China, these countries have voracious domestic demand for energy. Increased coal production in those countries would likely be swallowed up by domestic demand, leaving the rest of the world, like Europe, with little coal reserves.

    I don’t wish to be rude, but dismissing Peak Oil by saying “there is plenty of coal” does not do the topic justice, it’s like dismissing AGW by saying “climate variation is natural”.

    I am not saying that PO will prevent damaging climate change, I think it is already too late to prevent that. The point is, that the solutions to PO and GCC are the same – reduction of use in fossil fuels, increase of carbon neutral, sustainable alternatives. However, other people might use PO as an excuse to avoid action on AGW, and it would help the credibility of the IPCC reports if they took better account of likely future energy reserves. If we are not prepared for PO, there is a real danger that people will turn to dirtier fuels, like coal, in desparation.

    The conclusion from Kharecha and Hansen, that coal use should be phased out or have mandatory carbon sequestration, is something I think we can all agree on.

    [Response:Oil and gas reserves are measured in hundreds of gigatons, maybe 200-300 each, while of coal there is 5000 gigatons. I don’t think coal is usually included in the peak oil predictions, I think that’s generally just oil. David]

  13. 113

    Re #108

    Tamino, I have no stake in stomata data, and indeed this rather new method has its own problems, including calibration problems, bias to higher values and overestimate of the accuracy in the first publications. But you have to be careful for the smoothing problem in ice cores too. Law Dome today shows sub-decadal resolution with the South Pole CO2 measurements, because the trend is going up continuously. If there was bidirectional variability, the smoothing would be more visible…

  14. 114
    richard ordway says:

    re. 99 Tom stated: [Can somebody explain how global warming morphed into ‘climate change’?

    Climate change seems to me a useless term as: A> the climate always changes and B> ‘change’ implies that the globe could be cooling.]

    I have to deal with these terms every day and how I use them in presentations.

    Global warming means only part of the problem. There is also colder areas, more rain and snow in some areas in greater amounts and more desertification in other areas. The troposphere is wetter. The oceans are rising, glaciers are melting, whole animal species are disapearing or are already permanently gone (Golden Toad).

    The Stratosphere and Mesosphere are cooling and getting wetter. Storms are getting bigger in at least some areas.
    The oceans are becoming too acidic for sea life to function normally.

    Reefs are dying and could mostly go extinct.

    Human migrations are already taking place.

    Our entire civilzation could go extinct (wars, water, stress, etc.).

    The melting permafrost is destroying infrastructure. Whole cultures are disapearing and will be exterminated at this rate (Inuits).

    The changes are very long term in set areas. Some scientists call the current geological period, the “Anthropocene” because of all the changes CO2 is doing.

    Now how to relay this concept to the public that it is bigger than just “warming” and to be more scientifically accurate for long term changes…so use the term “climate change.”

    I have also heard the phrases, global change, climate distortion, global distortion, climate catastrophe and such to explain global warming.

    Others will have other explanations, but that is mine after being in it for 11 years.

  15. 115
    egbooth says:

    Realclimate folks –

    With Dr. Reid Bryson coming up in the blogosphere and other places recently, I decided to take a further look into his work. What are your general thoughts about him? It seems like he really advanced climatology and meteorology throughout his long career but his stubborn dismissal of increasing CO2 as a climate problem is rather confusing to me.

    Also, what do you think of his Macrophysical Climate Modeling (MCM) methodology? More info can be found here:

    Thanks for any info.

  16. 116
    tom says:


    “our entire civilzation could go extinct”


    That’s rhetorical.
    I’d counsel against using such bombastic language.

    but the answers are what I suspected. The term is being played as if the climate in year 1995 < or thereabouts > was in a state of perfect equilibrium and man’s influence is knocking the whole perfect system out of kilter.

  17. 117
    Hank Roberts says:

    Just noticed this in something Google News pulled up; seems like an ‘oops’ moment for the sensitivity calculations. Has anyone got a better pointer to real information?

    Grabbed in passing from an article Google found via ‘Hindu News’:

    “‘We found that the region affected by this cloud field ‘twilight zone’ extends to tens of kilometers beyond the identified cloud edge,’ said Koren. ‘This suggests that 30 to 60 percent of the atmosphere previously labeled as ‘cloud-free’ is actually affected by cloud-aerosol processes that reflect solar energy back into space.’
    “… ‘Current estimates of the effect of aerosols on global temperatures, which is primarily cooling, may be too small because the large contribution from this transition zone has been overlooked,’ Remer said. ‘If aerosols are offsetting warming more than we thought, it’s possible that warming could increase more than expected in the future if aerosols continue to decline, as has been reported recently.'”

  18. 118
    Ray Ladbury says:

    Tom, I find it rather amazing that you can chastise someone else for bombastic language and in the next paragraph claim that “The term is being played as if the climate in year 1995 was in a state of perfect equilibrium and man’s influence is knocking the whole perfect system out of kilter.”

    How much credibility do you think that leaves you with? The term climate change “is being played” as if human beings had developed an infrastructure during a 10000 year period of exceptional climatic stability and then started perturbing the system to the point where it cannot be predicted whether that infrastructure will still be functional. There is nothing magic about 1995, or any other year. Rather what is amazing is the stability of the past 10000 years relative to just about any other period in geologic history and certainly in human history.

  19. 119
    DaveS says:

    My comment hasn’t showed up yet, so I guess I’ll ask again. I followed the “feedback not a forcing” link above, and I have a question.

    I don’t disagree, of course, with the conclusion–the water vapor is obviously a feedback. But, at the link, you appear to address the question of whether computer models correctly handle water vapor by… wait for it… asking a computer model if computer models correctly handle water vapor.

    [edit – word to the wise, don’t insult those who you wish to respond]

    [Response: You conflate two issues. The first is why water vapour is a feedback and not a forcing and the second is how well do models treat water vapour. The first was a the subject of the post, the second was not. If I were addressing the second, I would compare water vapour changes that have been measured with those that have been observed (see Soden et al (2001 etc.) for examples). Instead, I gave an explanation of what goes on in the models, backed up by line-by-line calculations and heuristic arguments for why the results are likely to be correct. This would appear appropriate for a blog post that isn’t part of the technical literature. If you have a good reason why the calculations are wrong, let me know. -gavin]

  20. 120
    Ray Ladbury says:

    Hank, here’s a link to a press item from NASA that seems to be related–it points to an 18 April GRL publication.

  21. 121
    Richard Ordway says:

    Richard: “our entire civilzation could go extinct”

    Tom replied: “[edited, ‘bleep, bleep, bleep, bleep’.]”

    Tom, I did not say that humans would go extinct….or that it was probable that our civilization would go extinct.

    I said that it is a “possiblity”. Your saying, “bleep, bleep, bleep, bleep” to me is rather naive, in my opinion. The Pentagon and military is studying this very possibliity.

    Let’s run though some possible percentages and scenarios to investigate why the pentagon and others are taking this seriously.

    Yes, I’ll be “handwaving” a little…but not too far off what I understand peer reviewed studies are indicating for current and possible future climatic

    Okay, let’s say that abrupt climate change occurs in the next 50 years (15-25% possibility? might be a good guess.)

    We know from paleoclimate evidence that our climate system historically works by tipping from one state to another in as little as ten years, is unstable, chaotic and most likely being forced closer to a tipping point by extra human CO2 forcing.

    This CO2 forcing is expected to increase almost exponentially in the next 200 years.

    So we can say with a 95% probability, that abrupt climate change *will* happen in the future (it always has)…the question is when?

    Okay, if this happens, could it alone (without even other GW forces alone) cause the possible end of our civilization…that is a possible question that the Pentagon and others are investigating.

    The scientific communtity is conservative, and treats this, correctly, as an extreme scenario (but so was the ozone hole which proved to be a near-worse-case scenario).

    All right, so we get abrupt climate change (We know its going to happen sometime).

    Now let’s look at possible scenarios. “Permanent” droughts might result over the Amazon, Australia, Africa, US west and Indonesia by altering the Pacific warm pool and associated pressure systems and oceanic systems. The asian monsoon could be “permanently” derailed or interrupted.

    Now, melt the polar ice cap during the summer (70-80%? possiblity at this rate in 100 years) and there goes a permanent stablizing high pressure system…this could screw up rain patterns at least in the US.

    Rain-carrying jet streams are moving rain farther poleward of where they usually go (70%?).

    Hmmm, now you have “a billion +” angry starving people in near proximity to unstable atomic bomb states of Pakistan and China, Russia and perhaps India. Secondly, you have several hundred million desperate terrorist candidates at least. It is when conditions get bad historically, that despots often rise to power.

    Hmmm, that could result in martial law in the USA, as we have to close our borders to trade and start a police state as A-bombs or other scintilating treats cook off in US cities. That might be just one pressure on Western civilization. The world economy could collapse as all freight, airplane cargo, ships, etc. have to be inspected crate by crate.

    Hmmm, when do you historically get disease pandemics…when people are really stressed out and starved…this scenario certainly fits…Whoops, there goes all international and local trade and cross border movement that could be added simultaneously to this witches stew. Pandemics often recircle the world over a period of years…so how do you get help to a billion people with diseases and save your country?

    Now, Da immigrants, man. Historically, ancient peoples could just move to better areas…now there is a little thing called borders. Imagine, people with no reefs to fish (50%?) in developing countries, hard to get food, if at all due to GW, rising sea levels (95%), flooding and drought (95%) and lots of people (hmmm, tens of millions flood US and European borders.

    Let’s add the possibility of what we know to a (70%+? confidence level) that sea levels have risen easily eighteen meters in 100 years in the past. This can happen by the collapse/disintigration of Greenland ice shelves/glaciers and the west Antarctic ice sheet or portions thereof (10-20% possiblility in 50 years?)

    Guess what if this happens…it most likely (90+%) means the permanent evacuation (or extreme decadal damage) of New York City, Boston, Washington DC, Seattle, Miami, London. How is the USA going to handle tens of millions of USA refugees, at this point not to mention from the USA’s south, not to mention millions of blood-thirsty terrorists all over the world?

    I have only gone lightly into some of many *possible* GW risk scenarios. The bottom line is…that these extreme scenarios are possible…and must be, and arebeing, taken seriously.

    [Response: Frankly, I mostly agree with Tom, exaggeration of even worst case effects is not particularly helpful – it generates a backlash and makes any proposed action seem pointless. However, I ‘m not going to get involved in this other than to insist that all such discussions remain polite at all times. – gavin]

  22. 122
    Michael Gell says:

    Re 121. Richard, what is (are) the source(s) for “the possibility of what we know to a (70%+? confidence level) that sea levels have risen easily eighteen meters in 100 years in the past.”

    I am aware of James Hansen’s suggestion that a reasonably good estimate of sea level rise by 2100 would be 5 metres.

    [Response: Sea level rise during meltwater pulse 1A (during the last deglaciation) was on the order of meters per century. Hansen has not suggested that 5 m is a “reasonably good estimate” for 2100 – instead, he has stated that the sea level rises on the order of a meter may occur by 2100 (and with larger changes over time) if current forcing trends are maintained and the ice sheets are less stable than often thought. ‘5m’ is very much a worst case scenario, not a likely estimate: – gavin]

  23. 123
    David B. Benson says:

    I’ll simply encourage tom and Richard Ordway to read Jared Diamond’s Collapse (if they haven’t already) and leave it at that.

    Doesn’t seem that directly related to climatology. Well, maybe land use change…

  24. 124
    Michael Gell says:

    Re 122. Gavin, what I was referring to was the paragraph by Hansen in his Scientific Reticence paper (which you linked) in which he wrote “Under BAU forcing in the 21century, sea level rise undoubtedly will be dominated by a third term (3) ice sheet disintegration. This third term was small until the past few years, but it is has at least doubled in the past decade and is now close to 1 mm/year, based on gravity satellite measurements discussed above. As a quantitative example, let us say that the ice sheet contribution is 1 cm for the decade 2005-2015 and that it doubles each decade until the West Antarctic ice sheet is largely depleted. That time constant yields sea level rise of the order of 5 m this century. Of course I can not prove that my choice of a 10 year doubling time for non -linear response is accurate, but I am confident that it provides a far better estimate than a linear response for the ice sheet component of sea level rise.”

    How do I reconcile this with your edit comment?

    [Response: It’s quite clearly a worst case scenario – not a likely estimate. I’m not as confident that a 10 year doubling time for the ice sheet disintegration is accurate, but I would agree that the response is very unlikely to be linear. His later comment is clearer: “The nonlinearity of the ice sheet problem makes it impossible to accurately predict sea level change on a specific date. However, as a physicist, I find it almost inconceivable that BAU climate change would not yield a sea level change measured in meters on the century time scale.” Note however, this is if we stick to business as usual – it is therefore a cautionary warning, not a prediction. – gavin]

  25. 125
    Richard Ordway says:

    Gavin wrote: [Frankly, I mostly agree with Tom, exaggeration of even worst case effects is not particularly helpful – it generates a backlash and makes any proposed action seem pointless]

    Thanks Gavin. I needed and appreciated your thoughts on this.

  26. 126
    Nigel Williams says:

    We’ve had World War 1 and WW2. In the face of the apparent inability of the world’s political processes to get their heads around the war on climate change (WWC) shouldn’t we be slapping ourselves around the face a bit with a dead fish with a few home truths written on it?

    As far as I understand it, roughly, the IPCC’s Business as Usual position is a view of the future assuming we hold emissions at around present day levels.

    Can you please point me to a source that gives an idea of a true Keep Doing What We Are Going To Do future that entails elements such as:

    *Fossil fuel use in western world increasing at population growth plus 10percent pa,

    *Asian fossil fuel use increasing at population growth plus 20 percent pa, including (and if appropriate adding) about 150 coal-fired power stations a year.

    *Artic summer ice cover running down to 5% of present over the next 20 years.

    *Permafrost GHG emissions doing what they do in response to temperature increases

    *… and any other obvious realities that reflect a view of a likely world over the next 10 to 20 years, in the absence of any practical change in direction…

    I know this is not a politically correct view, but from my perspective this is a realistic view of the near future. For some perverse reason, (because it will not be a nice picture) I would like to know what impact that truth will have on emissions and GHG and hence temperature over the next 50 years.

  27. 127
    Paul M says:

    Is there a website I can go to to discuss the disappearance of the bees? I am scared to death because there is no way we will be able to feed 300 million plus people without bees. Isn’t anyone else scared? This is the real deal folks. Forget about the climate, it’s not going to be a good year for humankind. Is this the beginning of the end? Is this what they were talking about?

  28. 128
    Mark A. York says:

    “Can somebody explain how global warming morphed into ‘climate change’?”

    Yes and a key line from my novel on this subject. It’s a political euphamism that equates change with: may be good, whereas warming means a negative conotation even thoug that’s where the evidence leads. It’s pure politics.

  29. 129
    Steve Bloom says:

    Re #124: A minimum “far better estimate” that the AR4 would be on the order of 2 meters this century, still rather a lot. I assume it’s probably the case that human society would respond to such a change by taking very sharp action, but will that necessarily be the case in 2050 when that pace of rise has only resulted in on the order of 25 centimeters of SLR? I’m not so sure. The problem is that waiting too long will subject our immediate descendants to something much worse. As Jim says, we are seeing the early signs now.

  30. 130
    Timothy Chase says:


    Gavin points out the Hansen paper in #122. And I thought that I might earn some credit bringing it up first.

    Quite readable, incidently. Prior to reading it, I didn’t realize that melting would cause the snow or ice to be darker and absorb more sunlight that without melting. Puddles being darker, sure, but not this.

    I should have remembered this much from my childhood.

  31. 131
    SCM says:

    I’d be interested to know what the climatologists here think of Hansen’s “scientific reticence” paper. He makes a worst case scenario suggestion of metres per century sea level rise. What he is doing seems reasonable in terms of risk analysis in bringing attention to a low (but not negligible) probability risk because its consequences are so severe. Yet it does go against the scientific grain a bit (which is the point of the paper i guess) – do other scientists feel he is sticking his neck out?

  32. 132
    Nick Gotts says:

    Re #112 “Coal is not a good substitute for liquid fuels…

    As oil and gas supplies decrease, coal prices will increase, as energy is largely fungible.”

    Those two statements are surely inconsistent with each other.

  33. 133
    pat n says:

    I think a 5 meter rise in sea level will occur this century.

  34. 134

    [[ I am scared to death because there is no way we will be able to feed 300 million plus people without bees. ]]

    I was under the impression that cereal crops didn’t need insect pollination, but maybe that’s wrong. Does anyone here know?

  35. 135
    Paul Dietz says:

    Cereal crops are mostly wind pollinated. Notice they don’t have showy, insect-attracting flowers.

  36. 136
    FurryCatHerder says:

    Re #132:

    Re #112 “Coal is not a good substitute for liquid fuels…

    As oil and gas supplies decrease, coal prices will increase, as energy is largely fungible.”

    Those two statements are surely inconsistent with each other.

    Energy being fungible doesn’t mean the price is constant. If CTL was cost-competitive with oil, it would already have taken place to large extents. Economic markets generally work fairly well and there’s no large scale (that I’m aware of) coal-to-gasoline or coal-to-diesel project in the works.

    The most likely post Peak Oil scenario, if people don’t move from fossil fuels, is escalating coal prices as coal is used as feedstock. Further increases will occur as infrastructure to liquify or gasify coal is produced. That assumes that waste stream biomass (which is a “free”) is piled into landfills and methane capture ignored. It’s the fact that waste stream biomass is “free” that will move the market away from coal as the feedstock.

    Using coal as an oil substitute isn’t just environmentally stupid, it’s also economically stupid.

  37. 137
    pete best says:

    Re #136. On CTL I believe that the USA have recently announced a large scale project in Virginia.

    There is also gas to consider and it will peak too not long after oil it has been suggested. if that happens then unless we have a lot of alternative vehicular and heat around we are all going to suffer economically.

    It is imperative that alternatives to Oil, Gas and coal are found and brought online very quickly. But do not hold your breath, alternatives for the masses are years off.

  38. 138
    Vicky says:

    Re: Nature’s new blog – I will be having a look at it I suppose, but you guys are the original and best!

  39. 139
    Timothy Chase says:

    My view (as someone who is by no means an expert) is that it is likely we will see an acceleration in the rate of decline of the cryosphere within the next decades, and that given runoff, it will not simply overtake the thermal expansion of the ocean as a cause of sealevel rise, but that it will be several meters. Numerous feedbacks – of the sort that Hansen suggests. Likewise, given the droughts and human migration, politics will most certainly be a problem.

    I would expect new totalitarian ideologies and wars – before the end of the century. Likewise, I would expect significant feedbacks from the ocean as it becomes a source rather than a sink, from permafrost and from shallow methane hydrates near the coastlines. Exceeding 1000 ppm of CO2 and equivilents is a real possibility some time next century – largely due to feedbacks.

    However, technological investment may lead to breakthroughs, first in energy – within the next several decades. Commercial solar energy currently stands at 20% efficiency. We may be able to achieve the efficiency of photosynthesis at 95%. The first nuclear fusion commercial prototype is due to start construction by about 2050 – but this could be accelerated.

    Then there is the possibility of genetic engineering, archaea or prokaryotes perhaps, so as to create additional carbon sinks. We have already genetically engineered mosquitos which are immune to malaria and which do better than their non-immune counterparts only in regions where the rate of infection is high.

    However, all of this will require investments in science. With some luck, we might avoid sustained levels of greater than 1000 ppm and non-H2O equivilents.

    In the meantime, I agree with Gavin that we need to avoid worst-case scenarios or even reasonable scenarios – assuming they can’t be quantified and substantiated by reference to available evidence. What I have suggested above seems reasonable – but it clearly doesn’t fall into this category.

  40. 140
    Paul Dietz says:

    If CTL was cost-competitive with oil, it would already have taken place to large extents.

    The estimates I’ve seen for mine-mouth CTL using Wyoming Powder River Basin coal have it competitive with oil in the mid $40/barrel range (+- 25%). At today’s oil prices, the internal rate of return is estimated to be around 100%/year. Sequestration of the extra CO2 produced would add a few dollars per barrel equivalent (CO2 from combustion of the synfuel itself would still be released, of course.)

    So why hasn’t it been built? These are large facilities (economies of scale are needed to reach that cost figure), very capital intensive, and take years to plan, permit, and build. Billion-dollar investments are very risk intolerant, and there’s not yet confidence that oil will remain at current prices. Give it a few more years, and some smaller efforts to reduce technical and cost estimation risks, and you’ll see more of this.

  41. 141
    Eli Rabett says:

    #140, which is, of course, the point of a carbon tax to put a floor under fossil fuel prices that reflects the actual cost and will encourage new developments.

  42. 142

    Is it possible to see a link showing GCM model projections 20 years from now? Particularly the period betweem 2027 to 2037 map animations including ice coverage and temperature anomalies. 2007 is on its way to shatter all records, but perhaps 2007 was already mapped by models but only for 2027?

  43. 143
    Steve Bloom says:

    Re #131 (SCM): “Low probability” assumes some ability to model the course of events, which we don’t presently have. Another difficulty is that the Pleistocene deglaciations are imperfect analogies for what’s happening now, although some things can be postulated (e.g. Hansen’s observation that slightly higher temps during the last interglacial correlated with somewhat higher sea levels). In any case, “unknown probability” is a better term to use for the moment. I would add that the recent discovery of all that mobile subglacial water in Antarctica is cause for great nervousness since it presents the possibility of very rapid movement of the ice.

  44. 144
    Hank Roberts says:

    I was collecting some links on news about discoveries of the water moving under the Antarctic ice (rapid drumlin formation for example). I put them in the comments under “why do science in Antarctica” thread over at Stoat, in hopes more of the researchers would find them and comment when they can:

  45. 145
    Jim Frank says:

    re:#127 Disappearing bees

    The disappearances are mainly reported by commercial honeybee keepers, who transport large hives of bees via truck. Some beekeepers state that these ‘die offs’ have been happening regularly all along, and have received press attention that is unwarranted.

    There are a great many species of bees that also pollinate crops, so there is not a famine situation in the works. At least, not from the decline of honeybees.

    I want to say how much I enjoy the discussion at this website. Even though I’m politically far to the right end of the spectrum, I loathe the subjugation of science by politicians and lawyers. This includes both fringes, liberal and consevative. It’s nice to find some place where science is the yardstick. I was leaning pretty heavily toward the “there’s little evidence that global warming is anthropogenic” side of the debate, until I found this site and followed the math through CO2’s contribution to warming, and the isotopic evidence of fossil carbon’s contribution to global CO2 levels.

    A special thanks to all the climate scientists who post here for their temperance around politcs, and their adamance about accurate and peer reviewed science.

    Great resource.

  46. 146
    John L. McCormick says:

    RE # 9, SecularAlarmist, you asked:

    “No later than 2015” means we have no more than eight years in which to slow, stop and then reverse the present accelerating growth in emissions. Is that likely?

    Despite the reassuring words of the renewables and efficiency advocates, Americans are nowhere near even contemplating – much less accepting – the massive rehab of consumer habits to which we have ascribed an inalienable right.

    Higher gasoline prices appear to have no impact on consumption.

    ……………………………………..Av. Reg.
    ……………………….MMBPD ……$/gal.
    Mar 05, 2004 … 8,968 … $1.74
    Aug 13, 2004 … 9,521 … $1.88
    Mar 04, 2005 … 9,014 … $2.00
    Aug 12, 2005 … 9,408 … $2.55
    Mar 03, 2006 … 9,057 … $2.33
    Aug 11, 2006 … 9,530 … $3.00
    Mar 02, 2007 … 9,191 … $2.51
    Mar 09, 2007 … 9,158 … $2.56
    Mar 16, 2007 … 9,240 … $2.58
    Mar 23, 2007 … 9,250 … $2.61
    Mar 30, 2007 … 9,491 … $2.71
    Apr 06, 2007 … 9,472 … $2.80
    Apr 13, 2007 … 9,247 … $2.88
    Apr 20, 2007 … 9,163 … $2.87
    Apr 27, 2007 … 9,260 … $2.97

    That answers a part of your question.

  47. 147
    William Astley says:

    The attached prediction for Solar Cycle 24 is of interest. Solar cycle 23 is dragging out and is not following normal solar cycle behavior. As noted in the attached news bulletin, the predictions for Solar cycle 24 are split between a weak and strong solar cycle.

    A weak or very weak solar cycle should provide data to resolve the question how much of the 20th century warming was due to increased solar activity.

    April 26, 2007- The next 11-year cycle – (Solar cycle 24) – will start, March,2007 and peak in late 2011 or mid-2012 – up to a year later than expected – according to a forecast issued by the NOAA Space Environment Center in coordination with an international panel of solar experts. NASA sponsored the panel. Expected to start last fall (Solar Cycle 24), the delayed onset of Solar Cycle 24 stymied the panel and left them evenly split on whether a weak or strong period of solar storms lies ahead, but neither group predicts a record-breaker. â?¦
    In the cycle forecast issued Wednesday, half of the panel predicts a moderately strong cycle of 140 sunspots, plus or minus 20, expected to peak in October 2011. The other half predicts a moderately weak cycle of 90 sunspots, plus or minus 10, peaking in August 2012. An average solar cycle ranges from 75 to 155 sunspots. The late decline of Cycle 23 has helped shift the panel away from its earlier leaning toward a strong Cycle 24. Now the group is evenly split between strong and weak.

  48. 148
    John L. McCormick says:

    RE # 146

    Any suggestions on how to copy an otherwise legible xcel sheet into the commnets box. Apologies for my pitiful attempt.

  49. 149
    Richard Ordway says:

    [do other scientists feel he (Hansen-RO) is sticking his neck out?]

    This is a very instructive case study, I think, on how peer-review-type science sometimes works, in my opinion.

    To my knowlege and talking with peer-review research scientists who know him, Hansen has had quite a reputation for sticking his (and climate science’s) neck out since his first big AGW (human warming) declaration in Congress in 1985.

    As I understand it, in 1985, he was really pushing the science to its limits in stating that GW was happening and humans were likely causing it (this was too strong a statement for the peer-review review community as a whole at the time…

    …ie. the peer-review evidence was not strong enough yet for most peer-review scientists to feel comfortable with his statements.)

    The science community in its own ways, put pressure on him…{not to mention the fossil fuel industry} to be “more conservative.”)

    The good? Yes, he did turn heads and help to start some serious debate and start more serious investigations on GW.

    Yes, he was sometimes a maverick… but who knows? Science sometimes needs people to shake things up…

    …and in this case at least, his GW reasoning came to be backed up by hard evidence ten years later by the 1995 IPCC report at least and until today.

    Now on to Hansen’s current research. Firstly, it was accepted for publishing by the peer-review process- so he is not saying things wildly without evidence.

    Secondly, I hear at where I am (no where near a comprehensive report though) that some research scientists are keeping their ears to the ground with his current work and not dismissing his recent report as “irresponsible”…but perhaps his recent work leans to more of the “extreme scenario situation” rather than the most likely one.

    In fact, his report adds to a growing body of evidence, I understand, that “ice sheet disintigration” is something that needs to be further researched with regards to Earth’s future- instead of his recent paper pioneering this concept.

  50. 150
    Hank Roberts says:

    John, the forum software won’t do tabs and doesn’t like repeated spaces, I’ve had the same trouble trying format as columns. I think
    dots might work; is the above in three columns? (“Preview” lies)

    Anything but plain text ASCII (like Microsoft curly quote marks and dashes) gets mangled if “character encoding” settings don’t match.

    Copying and pasting is the problem. Try “paste special unformatted” — even between Word docs, doing that causes less corruption than their standard paste.

    I often move text via a text editor to clean up garbage. More often I forget (sigh).

    A link to the source could be better.

    Jim Frank, thanks! good info. Though the beekeepers I’ve talked to say this is a dramatic loss; seems scary.