This month’s open thread…
…at least North Carolina relied on a scientific assessment for their legislation.
I’m sure Dan H is well aware that this legislation was passed in order to block adoption of an *actual* scientific assessment in coastal development/regulatory planning.
It seems to me that weather forecasting in Virginia should probably be similarly improved.
June 14th, for example, can be forecast by consulting the records for all the previous June 14ths and simply publishing the statistically normal highs and lows along with one days’ share of June’s monthy precipitation.
Imagine the savings!
Yes, I am well aware that this bill was a refinement of the original “scintific” assessment (which was anything but). The final version relies on much more scientific research than the original, which relied on one report, and much speculation. The bill even includes arrangements for further research into local SLR to amend future regulations.
[Response: "Much more scientific research" - perhaps you mean "Much more wishful thinking and closing ones eyes to scientific reasearch"? The idea that you can, with an apparently straight face, endorse this neo-Canutism is a marvel to behold. - gavin]
I’m looking forward to the day that Dan H. reaches the tipping point that allows him to start accepting reality as it relates to Climate Change. What will that tipping point be for you Dan H.?
Dan H wrote: “At least the legislation says that scientific (and statistical) methods shall be used.”
No, in fact the legislation specifically PROHIBITS the use of scientific methods, and mandates an unscientific method that the authors of the legislation are well aware is guaranteed to produce misleading results.
Your deliberate, blatant, sneering dishonesty is disgusting.
Did I hear that little squeaking noise again?
I could swear I heard somebody suggesting that the governor of North Carolina should veto stupid legislation that seeks to interfere with rational planning and instead leave coastal development policy to be guided by engineers and scientists, as it is now.
Status quo sounds like a great idea. Outlawing scientific progress and better engineering really does seem extraordinarily idiotic.
So, a century worth of data is now considered “unscientific” and misleading? Do you feel the same way about temperature data? Your snide remoarks only serve to hinder your argument.
[Response: I wasn't aware I was arguing with you. But since you ask, 'data' is neither scientific nor unscientific. Those adjectives apply to how one treats the data and the conclusions one draws. The mandate to only use extrapolation is unscientific since there any number of easily plausible circumstances in which that will patently fail to properly assess the risks. The only 'get-out' clause allowed by the legislation is if "scenarios of accelerated rates of sea-level rise" have rates "from statistically significant, peer-reviewed data" which I'm sure sounded wonderfully sciencey to whoever drafted this, but is actually completely meaningless. If you want to hold this up as a paragon of science-based policymaking, you have more problems than I can possibly address in blog comment. I might add that your argument (whatever it is) is greatly hindered by your posting of poorly digested talking points. - gavin]
gavin wrote: “with an apparently straight face”
Oh, I don’t think so. I think that Dan H is probably grinning ear-to-ear if not laughing out loud at just how much of intelligent people’s valuable time he wastes with his transparent nonsense.
“Extreme weather events are still uncertain, as higher water vapor leads to greater precipitation events, but the lessened temperature gradient is expect to lead to a reduction. ” Dan H.
That’s not my understanding.
“Because atmospheric circulation largely is generated by the gradients resulting from heat gain at low latitudes and heat loss at high latitudes, the approximate 6×106 km2 perennial ice cover of the Arctic Ocean has a profound effect on modern world climate. Flohn (1978) described details of this pattern for polar regions. Because it is more than twice as large, the Antarctic is a more significant climate modifier. In both areas, the ice cover restricts heat exchange between the atmosphere and the ocean. Heat loss by the ocean is suppressed in winter as is heat gain in summer. This results in at least three times as much atmospheric cooling with the ice as there would be without it (Fletcher and Kelley, 1978).” http://www.nap.edu/openbook.php?record_id=11798&page=133
“The consequences of increased September open water in the western Arctic and increased 1000–500 hPa thickness is an anomalous late autumn easterly zonal wind component, especially north of Alaska and Canada on the order of 40%. This could be interpreted as a diminished contribution to the large scale wind pattern from the positive AO, and support for the AD and more regional variability.” http://tellusa.net/index.php/tellusa/article/download/15661/17553 – Large-scale atmospheric circulation changes are associated with the recent loss of Arctic sea ice, JAMES E. OVERLAND and MUYIN WANG
“In addition to affecting general atmospheric circulation, short-term weather modifications caused by changes in extent of the ice cover illustrate direct effects. A decrease in area of Arctic ice correlates with a northward shift of storm tracks and a shift of mid-latitude rainfall patterns eastward (Fletcher, 1972; Fletcher and Kelley, 1978). A dramatic example of weather modification is based on satellite data that showed that the ice cover was 12 percent greater in 1971 than in 1970. This produced a surface-heat-exchange deficit for the Arctic that was correlated with anomalous weather patterns in lower latitudes during 1972 and 1973 (Kukla and Kukla, 1974).
“Since the level of Arctic sea ice set a new record low in 2007, significantly above-normal winter snow cover has been seen in large parts of the northern United States, northwestern and central Europe, and northern and central China. During the winters of 2009-2010 and 2010-2011, the Northern Hemisphere measured its second and third largest snow cover levels on record.
“Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation,” said Judith Curry (the uncertainly skeptical darling of climate change denialists), chair of the School of Earth and Atmospheric Sciences at Georgia Tech. “The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents.” http://www.sciencedaily.com/releases/2012/02/120227111052.htm (And it was atmospheric blocking which led to the recent European heatwave which killed 30,000 people)
“The prediction, one season ahead, of summer heat waves in Europe remains a challenge. A new study led by a French-Swiss team shows that summer heat in Europe rarely develops after rainy winter and spring seasons over Southern Europe. Conversely dry seasons are either followed by hot or cold summers. The predictability of summer heat is therefore asymmetric. Climate projections indicate a drying of Southern Europe. The study suggests that this asymmetry should create a favorable situation for the development of more summer heat waves with however a modified seasonal predictability from winter and spring rainfall.” http://www.sciencedaily.com/releases/2012/05/120527153720.htm
Experiments by J.J. Thomson in 1897 led to the discovery of the electron, one year after Arrhenius predicted that adding CO2 to the atmosphere would decrease the temperature gradient between the equator and the poles.
Thomson’s discovery ultimately led to the intertubes which allow you to read this, (and learn lots of nifty science if you are so inclined.)
The decline in latitudinal gradient resulting from global warming is resulting in more extreme weather events, but because the chaotic nature of atmospheric fluid flow and the butterfly effect, ““Attribution of single extreme events to anthropogenic climate change is challenging.” http://ipcc-wg2.gov/SREX/images/uploads/SREX-SPMbrochure_FINAL.pdf
Ray, if we passed a law that limited corporate profits to historical norms, that might actually work. Legislating physics will never work.
Yet again Dan H. comments are completely the oppoosite of reality. North Carolina paid for a scientific report, and then disregarded it because the scientific reality didn’t fit with their conservative ideals. So they decided to make a law specifically against the scientific assessment that Dan H. pretends the law is based on.
>Would you prefer no legislation on coastal building restrictions?
Yes. Yes, I would. That would be far more honest than asking scientists to put together an assessment, and then when you are unhappy with the results to change them and pretend it is scientific. Go ahead and write the legislation however you like, such that it fits with your preconceived ideals. But lawmakers changing the results given by scientists and calling it scientific is as dishonest as claiming they did “more science”. Yet another false claim from Dan H. lacking a source.
Dan H. serves as a good source of bad information for us to continuously debunk, and provides me with an insight into the kinds of misinformation I may encounter in the real world.
Where are you getting the idea that the legislature changed the results? The original assessment was based on one report, and neglected others (maybe it fit your own preconceived ideals). Just because further study determined that the first assessment was high, based on the available science , is no reason to call it dishonest. Apparently, everything that is in agreement with your own preconceived ideals must be good science, while anything that does not must be pretend. It must be nice in your own little bubble.
The only thing on which we agree, is that this legislation was unnecessary. However, it was better than the original legislation, which was based on questionable values.
1)Are there long term measurements of OH- radical concentrations over the arctic ? I ask because news of large methane releases coupled with small change in methane concentrations suggest that methane is being efficiently oxidised, so I would expect to see drawdown in OH- concentration.
2)the new Rignot paper suggests that basal sliding is dominant mode of GRIS mass waste. This is surprising to me, could someone knowledgeable comment on the paper ? Is a comparable study of WAIS or EAIS available ?
3)We are wasting time addressing Mr. Dan H. Suggest, as on Usenet, heavy handed moderation, coupled with a request to the commentariat, please do not feed the troll.
In case others are similarly interested, I was looking for sea ice data and I notice that the SEARCH sea ice outlook has been released:
As I write this Dan H. occupies all five of the listed in-line responses. Just sayin’.
Claiming that North Carolina’s legislation requires scientific study is pretty much like having a contract that says “you must take me to the prom in a brand new Porsche” but at the same time says the the “Porsche” must be at least 30 years old and have “Volkswagen Golf” printed on the owners manual. You can call it anything you want, but that won’t change what it is. If your date is blind and deaf (or desperately wants to believe that you’re in a Porsche), you might get away with it.
A nice little climate outlier…
‘… the conditions that killed the cows were unlike anything local farmers had experienced before.’
‘He says it was a very isolated case of a weather bomb and it wasn’t rain or sleet, but frozen ice going sideways.
“It happened so quickly that these animals, and the herd was on the move, it literally stopped them in their tracks and the ones that stopped couldn’t be encouraged to move again and the situation escalated from there. And a number of the stock remained where they were and subsequently died”.’
Last time I heard of something like that it involved woolly mammoths being snap-frozen into tundra; quite a while back.
Brian Dodge @159
That unsupported assertion that a reduced latitudinal temperature gradient is expected to lead to a reduction in extreme weather is one of the pieces of simplistic nonsense that Lindzen spouts. Like most else in Lindzen’s clownish speechifying, it is entirely contrary to the science as is borne out within the IPCC reports.
However, what is missing is a straightforward reply to Lindzen’s nonsense. The IPCC reports are not appropriate in such a role & I have never come across any good succinct reference that would be. Does anyone know of such a reference?
In the absence of a good reference, rather than resort to AR4.1 ch10, I fight ‘simple’ with ‘simple’.
Linzden insists that, as the temperature difference between tropics and the poles decreases due to AGW, extreme weather will also diminsh. But the temperature difference we see is not what drives weather. Rather, it is what is left after the weather has been driven.
The warming of the poles resulting from AGW requires (& will require) tons more weather to drive polewards from the tropics, more weather not less.
As with so much, on extreme weather Lindzen spouts nonsense.
I’m embroiled in an argument with a co-worker about the impact of CO2 emissions reductions on the planet. Since neither of us really knows anything about the subject, I’d like to solicit at least one professional opinion to help put this to rest.
The line of argument is this:
If a climate treaty can achieve cumulative global CO2 emissions reductions of “X” tons by the year 2100 compared to “business-as-usual”, then the amount of CO2 in the atmosphere at the end of the century should be lower by “Y” ppm. And if CO2 is “Y” ppm lower at the end of the century, then global average temperature should be lower by “Z” degrees.
Can anyone here offer a simple way (using no more than a pocket calculator) to estimate how much X is required to achieve a given Z?
Our biggest area of disagreement involves how much of the incremental X tons of CO2 actually remains in the atmosphere vs. being absorbed by plants and oceans.
Thanks in advance.
Unsettled Scientist, the laws of economics are no less laws than those of physics, at least in the domain where they apply (human commercial interactions). You can no more legislate profits than sea level rise. That is always a red flag when I look at a company’s balance sheet–if things are too regular, something isn’t kosher.
Need@167, I don’t think there is a simple argument, but it is true that decreasing carbon emissions by X tons for n years will decrease the ultimate amount of carbon in the atmosphere by an amount greater than nX tons, as sinks will take up more of the carbon. And if you know the difference in the carbon in the atmosphere, you can estimate the difference in global temperature from the CO2 sensitivity–~3 degrees per doubling.
@”Would you prefer no legislation on coastal building restrictions?”
I would certainly prefer no govt subsidized insurance on coastal areas and in flood plains subject to increased flooding.
As some are wont to say: Let the market decide. Insurance companies are quite aware of the increased risk. It is only govt–i.e., taxpayer–subsidized insurance that allows people who want to build there to ignore what the private market is clearly signalling.
Unfortunately, it is not so easy. Slight reductions in CO2 emissions (low X) would still result in increased atmospheric CO2 (negative Y). Estimates are that CO2 reductions need to be reduced 25% just to achieve stable atmospheric CO2 concentrations (albeit, at a level higher than todays), or 60% to 80% to stabilize CO2 at todays levels (0 Y).
Then, there is the whole issue of Y influencing Z.
Currently, about half the emitted CO2 is being absorbed by plants and oceans. The higher the atmospheric concentration, the greater the absorption. If emissions were to suddenly stop tomorrow, The atmospheric level of CO2 would begin to decline immediately. Higher at first, and then tapering off to reach equilibrium.
Yeah, you’re right, I was thinking more along the lines of legislating prices or salaries. It is possible for governments to freeze prices, but not oceans. Of course corporations will always seek to reduce costs and thus increase profits. Certain jobs can be subjected fixed salary structures that are negotiated, but you can’t negotiate with the Sun or glaciers. That was a sloppy comment by me. My apologies.
> So, a century worth of data is now considered “unscientific” and misleading?
With this comment Dan H. is implying that NC legislators have taken more data into account than the scientists who were commissioned to provide the assessment for North Carolina. Yet again, he either failed to read and understand the material on which he is commenting, or he is deliberately trying to confuse RealClimate readers.
“The longest record of direct measurement of sea level comes from tide gauges. A drawback to tide gauges in North Carolina, in addition to their small number, is that most of them don’t extend back in time more than 50 years, making it difficult to resolve changes in the rate of rise over the decades.
The RSL rise record for northern North Carolina was recently extended back in time to AD 1500 using organisms, which are sensitive to the level of the sea and preserved in thick peat deposits, as a proxy for sea level (Kemp et al., 2009).
Four studies provide data on rates of RSL rise in North Carolina. Each covers a different time period, but the studies that cover shorter time intervals are nested within those that cover longer time intervals (12,000 year ago to present, 2,000 years ago to present, 400 years ago to present, and ca. 70 years ago to present. The first three studies utilize geological data whereas the study covering the shortest time interval utilizes instrumental data.”
So the scientific assessment actually used data going back 12 millennia! According to Dan H.’s measuring stick, this perhaps would be 120 times “more scientific” than the legislators mere century of data. That of course means nothing, the scientific assessment was science… the NC legislation is not.
My recommendation to readers of Real Climate is to only pay attention to Dan H. when there is an inline comment from one of the working scientists to run this site. Every so often Dan H. mixes in some real information, so you might see something by him and want to blow it off, but it could be right. It is best to skip over his comments unless they are directly addressed by professionals to avoid being misled.
>The original assessment was based on one report, and neglected others
Flat out wrong! Please, just go read it and stop lying. There are numerous studies cited in the assessment…
Dan H wrote: “… further study determined that the first assessment was high, based on the available science …”
That’s a blatant falsehood.
Dan H does one thing and one thing only on this site, and does it again and again and again:
He wastes people’s time with deliberately dishonest bullshit. He doesn’t “argue”. He doesn’t “debate”. He doesn’t “discuss”. He just lies.
Blatantly. Repeatedly. Lies.
Why is this tolerated? Because it’s easier and more comforting to play whack-a-mole with clownishly dishonest deniers than to confront the very harsh realities of AGW?
Need… — have you considered looking for an online model the two of you can agree on and playing with that a bit? If the person you’re arguing with is of the “anything but the IPCC” persuasion that may not be workable — but if you can agree that there are people who understand the basics, then you can use something like
or this: http://www.climate.unibe.ch/jcm/
or this: http://climateinteractive.org/simulations/bathtub
(others may have better suggestions, those are from quick searching)
Need to settle… @169
If by 2100 the cumulative global emissions were “X” billion tonnes CO2 lower than otherwise, atmospheric CO2 would be lower by about 0.45 “X” Gt CO2 (assuming present levels for carbon sinks. From memory, the proportion of CO2 released from burning fossil fuels, cement production & land use changes that remains in the atmosphere since atmospheric CO2 has been measured average out at 43% and that proportion is pretty constant over the period.). Divide by 2.13 x 3.67 to convert to atmospheric ppm(v) = “Y”.
Converting “Y” ppm into “Z” deg C requires more assumptions. Let “Z” be the eventual resultant (equilibrium) reduction in global temperature rise (thus the timing of the reduction relative to 2100 is not a concern). Also assume climate sensitivity as say 3 deg C per 2xCO2 and assume this 2100 CO2 level is not wildly far from the mid-range of 275-550ppm (as, for instance, the same drop in CO2 level at today’s 397ppm would have twice the effect that it would have at 794ppm). Given the above, the estimated reduced temperature “Z” = (3/275) “Y” deg C.
PS This is an entirely amateur answer. If you insist on being provided with a professional opinion, do say and I’ll provide an address for you to send the cheque.
Need to settle an argument says: Can anyone here offer a simple way (using no more than a pocket calculator) to estimate how much X is required to achieve a given Z?
No. As a guide to whether or not you’re wasting your time, I’d suggest that an ingenuous and competent interlocutor in a discussion over the topic won’t insist on such an impossibility.
Ask yourself whether monumental amounts of supercomputer time would be devoted to the topic, if a pocket calculator could produce a useful result?
The good news is that the output of all those calculations can be presented in a fairly accessible way. That leaves the question of whether your discussant is accessible, something with which not even a supercomputer can help.
> a simple way (using no more than a pocket calculator)
> to estimate how much X is required to achieve a given Z?
> Our biggest area of disagreement involves how much of
> the incremental X tons of CO2 actually remains in the
> atmosphere vs. being absorbed by plants and oceans.
You’re probably disagreeing on some underlying assumptions there.
First, do you agree on where you’d look up what’s known?
Do you agree on what you consider facts?
Do you have a library near you?
And a reference librarian you both trust to help you find facts?
DP@50 – Sea ice extent is diving too.
Re- Comment by SecularAnimist — 14 Jun 2012 @ 9:47 AM:
Specifically your statement about Dan H behavior-
“Why is this tolerated? Because it’s easier and more comforting to play whack-a-mole with clownishly dishonest deniers than to confront the very harsh realities of AGW?”
I think another way to look at this situation is that, in light of the fact that the primary problem with advancing the realities of AGW is the denialist agenda of creating doubt, Dan H provides an excellent bad example of denialist strategies. His behaviors include misstatements of fact, unsupported allegations, blatant misinterpretations of citations, bad reasoning skills, and very impolite actions with regard to common rules of conversation, especially scientific dialog. One might suspect that he is working on a profitable Moncton act.
So, my point is that whacking this mole provides a relatively easy model for demonstrating to the general public who come here for answers how simple and dumb much of the information provided by the denialist enterprise is. Just keep your answers to Dan H short and to the point. Whenever you write an essay you are making a troll happy. Steve
Of course you can legislate limits on corporate profits. Just change tax rates.
Steve Fish wrote: “Dan H provides an excellent bad example of denialist strategies”
Every blog in the universe that discusses anthropogenic global warming is already overwhelmed with virtually identical bad examples.
Dishonest, deliberately time-wasting deniers like Dan H are a dime a dozen.
> impolite actions with regard to common rules of conversation,
> especially scientific dialog
Anyone know if there’s a variety of Turing Test meant for scientists?
That would be a simulation of a scientist good enough to would fool people familiar with a scientific subject into continuing a ‘dialog’ about it.
I see a remarkable feature amongst NOAA authority being very conservative with prognostications, which is not necessarily a bad thing,
but El-Nino seems to be coming back
Likely they will announce a mild el-nino in the middle of summer having the usual suspected implications. But in the Arctic it should mean clouds, already the sea ice is at or very near rock bottom extent, more clouds up there is again not so much a bad thing. The #1 player at this time is the high 20 degree sun at the Pole. But even with cloud shade me thinks the extent will beat 2007 come mid-september.
Now I also know, schools like Harvard get involve in controversies, I cite as an example the Dershowitz–Finkelstein affair; http://en.wikipedia.org/wiki/Dershowitz–Finkelstein_affair .
I can easily say that Lindzen, Steve McIntyre and others have used their tenure to bash Climate science and scientists way out of line. I am a bit puzzled why their respective faculties were not complained to. Often I read statements echoing Chomsky defending the most ardent lies as freedom of speech. And that Universities are islands of free speech. Finkelstein colleagues complained to Harvard about Dershowitz asking for his dismissal with respect to a claimed book plagiarism, an academic no no, much unlike climate guys taking punches continuously and their colleagues claiming freedom of speech at schools is paramount. I would say that not punching a complaint back to the schools of origin is denial of freedom of speech, a further self inflicted wound during a boxing match is no good. It does not make sense to allow bad science or behavior go unchecked from institutes flunking students who would write the same thing an exam or act the same way towards professors.
Here comes El Niño. Land + ocean combined anomaly for May just published:
Here is the trend so far this year, starting in January:
2012: 34 41 47 55 65 (< May)
Yeah, early days yet, but if the El Niño conditions persist into 2013, it will make 1998 look relatively frigid by comparison :-\
I assumed we hit near record temperatures in May because ENSO neutral is back. Lately it doesn’t seem like El Nino is required for that.
More importantly (or, maybe not. TBD) over on CA, Steve McIntyre has lobbed another spitball (as he would describe it) at paleoclimatology in the form of a 2 millennia reconstruction of the O18/O16 ratio – better known as ‘delta O18′, or ‘dO18′ for short – from the Law Dome ice core in Antarctica, which purports to show a prominent MWP, with temperatures today lower than that.
Of course, WTFUWT has unconditionally reported this as the 57th final nail in the coffin of AGW. But Watts made an assumption about McI’s killer graph that threw most of the thread readers off track. He assumed that the units for the Y axis were in deg C, when in fact they were supposed to be in ‘dO18′, and were indeed labelled as such on the graph, which was a direct copy from the one on CA. Anyway, here is a link to the post on WTFUWT:
The longest, most high resolution, most inconvenient paleoclimate data that hasn’t been published
Well, Nick stokes roped into the comments, with the observation that it was his understanding that there was a negative correlation between dO18 and temps. As it turns out, this is normally true (as demonstrated by the 2nd graph in the same post). This type of calculation is normally performed by comparing the O18/O16 ratio in calcite-shelled creatures (from ocean sediments) with the O18/O16 ratio in typical seawater. But when we are talking about just precipitation, as is the case with ice core data, then the dO18/temp correlation is indeed reversed, and occurs on a different scale. This fact is driven home by a graph provided by one of the commenters responding to Nick, vis:
June 13, 2012 at 2:37 am
“Not so clear to me. As I recall, d18O correlates negatively with temperature.”
June 13, 2012 at 2:37 am
“Not so clear to me. As I recall, d18O correlates negatively with temperature.”
Now… Nick did apologise for his mistake on the thread, but of course, his apology was ignored by all the WTFUWT regulars, because that’s the way they roll. However, this is where it gets interesting, and where I, as a layperson, am a little bit out of my depth…
You can see from the graph that Jerold posted that there is a linear relationship between dO18 and temperature, according to latitude, at any given point in time (and this particular point in time was 1964). So questions arising from all the above for people who have a clue (like the RC team and other regulars here):
1. This linear relationship between dO18 and temps is valid only for locations at >45 deg latitudes, but it obviously flips at some stage, because it gets progressively more negative in ppt (parts per thousand) and correspondingly colder the further you go *south*.
2. Law Dome would appear to be nearly at the South Pole to the casual observer, but it is actually only ~67 deg south. So if you extrapolate from Jerold’s graph, then the dO18 should be ~-33ppt at Law Dome, whereas McI’s graph has it at around -22.25ppt. So there is a disconnect somewhere.
$64000 question: why the disconnect? Is Law Dome an outlier for some reason? Or, is there a big enough difference between now and 1964 to invalidate Jerold’s graph? Or… is this armchair scientist (moi) barking up the wrong tree?
Back to recent research…
Ocean acidification during Permian period may have caused the Great Dying
Carbon dioxide belched out by volcanic eruptions during the Permian period could have caused the oceans’ chemistry to change. That’s worrisome because CO2 levels are rising today — thanks to the burning of fossil fuels — and pushing down seawater pH, researchers report online June 8 in Geology.
“The worst biodiversity catastrophe we’ve had in the history of animal life appears to have been associated with ocean acidification and other kinds of environmental changes we anticipate in the coming centuries,” says Jonathan Payne, a paleobiologist at Stanford University.
Evidence for end-Permian ocean acidification from calcium isotopes in biogenic apatite
End-Permian (ca. 252 Ma) carbon isotope, paleobiological, and sedimentary data suggest that changes in ocean carbonate chemistry were directly linked to the mass extinction of marine organisms. Calcium isotopes provide a geochemical means to constrain the nature of these changes. The δ44/40Ca of carbonate rocks from southern China exhibits a negative excursion across the end-Permian extinction horizon, consistent with either a negative shift in the δ44/40Ca of seawater or a change in the calcite/aragonite ratio of carbonate sediments at the time of deposition. To test between these possibilities, we measured the δ44/40Ca of hydroxyapatite conodont microfossils from the global stratotype section and point (GSSP) for the Permian-Triassic boundary at Meishan, China. The conodont δ44/40Ca record shows a negative excursion similar in stratigraphic position and magnitude to that previously observed in carbonate rocks. Parallel negative excursions in the δ44/40Ca of carbonate rocks and conodont microfossils cannot be accounted for by a change in carbonate mineralogy, but are consistent with a negative shift in the δ44/40Ca of seawater. Such a shift is best accounted for by an episode of ocean acidification, pointing toward strong similarities between the greatest catastrophe in the history of animal life and anticipated global change during the twenty-first century.
JCH, you might look into whether that ratio varies with elevation as well as with latitude. Just speculating but Law Dome may be subject to several influences that might affect that ratio besides latitude.
“Law Dome, East Antarctica (66°44′S, 112°50′E, 1390 meters above mean sea level)….. negligible melting of the ice sheet surface, low concentrations of impurities, regular stratigraphic layering undisturbed by wind stress at the surface or differential ice flow at depth, and a high snow accumulation rate.”
HAnk asked Anyone know if there’s a variety of Turing Test meant for scientists?
Feynmann said that if you talk to any honest scientist for a short period of time you’ll ask a question the scientist admits not knowing the answer to.
Please note that I have followed virtually nothing of what SteveM or WUWT have written about this (though I do agree concerning the availability of data)…
… but in general, the d18O of precipitation is not just a function of temperature. This is certainly not the case in the tropics, where you get big “chunks” of convection, and the relationship to temperature becomes spurious. Indeed, d18O left in ice core records or speleothems at low latitudes seems to be much more indicative of rainout upstream (e.g., in the case of South America, rainout over the Amazon basin) or of the Asian monsoon. They are tracers of the hydrological cycle from source to sink, and are affected by fractionation processes along a transit from evaporation to precipitation. This includes evaporation of ‘new water’ along the transit of the air mass, transport from oceanic to continental regions, the exchange of different air masses, orographic lifting, etc. In some cases, the record is seasonally biased to just a few wet months and annual mean information is not retained. It’s a very poor temperature signal in fact (though Lonnie Thompson might disagree) but has been demonstrated in a number of papers (see several of the publications by Mathias Vuille for S. America for example, with whom I’m doing my PhD work, but independent analyses from Kanner et al., 2012, Science, or Pausata et al., 2011, Nat. Geo, and many others). Explanations are often regional rather than local, and are site-specific (see e.g., LeGrande and Schmidt 2009).
At mid to high latitudes, the isotope relationship to temperature (or better yet, precipitation-weighted temperature) seem to be much more robust than in the tropical case, but it is not free from the obvious demand that the isotopes will be modified with changes in the circulation. The temperature relationship has been known since the 1950s, though there are similar issues as above that arise on a region-by-region basis (e.g., whether you are talking about an inland or coastal Antarctic site, there are different moisture transport pathways); moreover, the spatial variation between d18O/dD-temp is not necessarily indicative of the temporal variation (see e.g., Jouzel et al., 1997, JGR; Masson-Delmotte et al., 2008, Journal of Climate). The spatial variation is also location-dependent and can vary with longitude in addition to latitude. The Masson-Delmotte paper is a good review highlighting the importance of both condensation temperature and moisture source in Antarctica (see also Sturm et al 2010, Climate of the Past). There is in fact a lot of literature on this.
For high-accumulation sites (largely in Greenland), independent information can be gathered from inverse borehole thermometry, as well as comparisons as from deep-sea records, but it is now becoming necessary to use isotope-enabled GCMs as a supplement to proxies in order to guide their interpretation. The tropical oxygen isotope relation is what I’m doing my research work on now (Gavin has been very active in this area), and I’m not really familiar with the Law Dome site specifically, though I believe some have interpreted it in terms of circulation variability (e.g., Souney et al 2002) though someone with more experience with that record might have something to add.
A quick summary is that isotopes are just that…isotopes. They aren’t intrinsically “temperature” anymore than the outgoing radiation seen from a satellite is a “temperature,” but it can be a useful and physically-based proxy. There are confounding variables however, and as is the case with science, different scientists are interested in different components of those multiple influences. For isotopes, the extent to which a useful climate record may be extracted, and what climate variable is represented in a record (if any), is not a universal rule of physics. The Deuterium-to-hydrogen isotopic signal on Venus, for example, is a proxy for its atmospheric evolution and slow “evaporation” of atmosphere into outer space.
Hope that is useful. I tried to be a bit more general even though I don’t think I directly answered your question. But, I am a little tired of the blogosphere potshots being thrown around by people with no desire to learn anything about atmospheric physics, and only know how to do statistics on data they don’t understand. It ends up as a usual routine in making unfounded statements concerning proxy interpretation/selection, conspiracy theories to maximize modern warming, and the like.
Thanks for the detailed explanation, Chris. I do grok some of that. Hank’s observation above, about dO18 also being dependent on elevation (and coastal vs. inland, longitude, et. al. as you point out) are also factors that could explain why the dO18 ice core data from Law Dome may not be a good indicator of temperature.
This seems to be a pattern of McIntyre’s over the years: take an isolated data series and run statistical analysis on it with complete (one might even dare say willful!) ignorance of whether or not the data has a scientific basis for being valid. Then jump up and down when there is no hockey stick ensuing from that data, and accuse climatologists of hiding ‘bad results’. Rinse and repeat, yamal, yamal, yamal :-)
Thanks to all who offered their guidance (Ray Ladbury, Hank Roberts, Dan H., MARodger & dbostrom).
MARodger’s approach was the closest to what I was hoping for. (Yes it’s an oversimplification and ignores uncertainties, but for a back-of-the envelope estimate, it’s good enough for amateurs like me.)
So, any serious objections to using the following “back-of-the-envelope” approach, adapted from what MARodger wrote above:
Δ”X” GtCO2 emitted * (40% remaining in atmosphere) / (3.67 tC02/tC) * (2.13 ppm CO2 / GtC) = Δ”Y” ppm CO2
Δ”Z” deg C = [ln((550 ppmv + Δ"Y" ppmv)/550 ppmv) / ln(2)] doublings * 3.0 deg C/doubling
Hypothetical example: Assume by 2100 humanity reduces cumulative CO2 emissions vs. “business as usual” by 500 GtCO2, then:
Δ”X” = -500 GtCO2
Δ”Y” = -500 * (40%) / (3.67) * (2.13) = -116 ppm(v)
Δ”Z” = [ln((550-116)/550) / ln(2)] * 3.0) = -1.03 deg C.
1)It isn’t clear that 40% of CO2 will continue to stay in the atmosphere–it could vary as we stop overwhelming the natural sinks
2)The changes in CO2 emissions will not occur in isolation. For instance, if it is accompanied by a significant decrease in sulfate aerosols (from burning less coal and dirty oil), that could lead to more warming.
> John E Pearson says: 14 Jun 2012 at 10:53 PM
> Feynmann said that if you talk to any honest scientist
> for a short period of time you’ll ask a question
> the scientist admits not knowing the answer to.
But alas, by now, that’s probably been
put into the Turing script. I’ll watch for it though. Thanks.
@Steve Metzler — 14 Jun 2012 @ 8:16 PM regarding the Law Dome WUWT “nail in the coffin of global warming” -
Did McIntyre compensate for changes in accumulation rates? see http://www.slideserve.com/hung/the-study-of-the-d18o-temperature-relationship-at-an-antarctic-coastal-station, particularly slides 22-26. The image from Jerold represents climatological smoothing, which will remove short term noise in the correlation between delta 18-O and Temperature.
It might be informative for you to download the delta 18-O dataset from ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gispd18o.txt, and plot out the data for the last 2k years; I see a similar curve to what McIntyre produced, but with a much less pronounced “MWP” and rising temperatures at the end – and the data cuts off at 1986, so doesn’t show the additional arctic amplification warming since then.
Another interesting graphic that perhaps McIntyre doesn’t want you to see is that the Law Dome delta 18-O(a somewhat noisy and accumulation rate dependent proxy for temperature) diverges from its bore hole temperature record. http://climateaudit.files.wordpress.com/2010/04/lawdome.gif
Borehole temperatures aren’t a proxy, but an actual record of temperature, but with a variable integration time(smoothing) that is depth/age dependent. Which is more trustworthy, borehole temperatures or delta 18-O proxies?
Another source for learning about oxygen isotope thermometry is “High variability of Greenland surface temperature over the past 4000 years estimated from trapped air in an ice core”, Kobashi et.al. http://www.leif.org/EOS/2011GL049444.pdf – especially section four, Comparison With Oxygen Isotopes of Ice, “However, this measure[d18O in ice] is also affected by changes in moisture source regions, moisture transport pathways and precipitation seasonality such that the application of this metric to temporal variation is more difficult…”
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