Ocean Cooling. Not.
A lot has been made of a paper (Lyman et al, 2006) that appeared last year that claimed that the oceans had, contrary to expectation, cooled over the period 2003-2005. At the time, we (correctly) pointed out that this result was going to be hard to reconcile with continued increases in sea level rise (driven in large part by thermal expansion effects), and that there may still be issues with way that the new ARGO floats were being incorporated into the ocean measurement network. Now it seems as if there is a problem in the data and in the latest analysis, the cooling has disappeared.
Ocean heat content changes are potentially a great way to evaluate climate model results that suggest that the planet is currently significantly out of equilibrium (i.e. it is absorbing more energy than it is emitting). However, the ocean is a very big place and the historical measurement networks are plagued with sampling issues in space and time. Large scale, long term compilations globally (such as by Levitus et al, 2001; Willis et al, 2004) and regionally (i.e. North Atlantic) have indicated that the oceans have warmed in recent decades at pretty much the rate the models expected.
Since 2000, though, ARGO - which is a network of floats that move up and down in the ocean and follow the currents - has offered the potential to dramatically increase the sampling density in the ocean and provide, pretty much for the first time, continuous, well spaced data from the least visited, but important parts of the world (such as the Southern Oceans). Data on ocean heat content from these floats had been therefore eagerly anticipated.
Initial ARGO measurements were incorporated into the Willis et al, 2004 analysis, but as the ARGO data started to dominate the data sources from around 2003, Lyman et al reported that the ocean seemed to be cooling. These were only short term changes, and while few would confuse one or two anomalous years with a long term trend, they were a little surprising, even if they didn't change the long term picture very much.
The news this week though is that all of that 'cooling' was actually due to combination of a faulty pressure reading on a subset of the floats and a switch between differently-biased observing systems (Update: slight change in wording to better reflect the paper). The pressure error meant that the temperatures were being associated with a point higher in the ocean column than they should have been, and this (given that the ocean cools with depth) introduced a spurious cooling trend when compared to earlier data. This error may be fixable in some cases, but for the time being the suspect data has simply been removed from the analysis. The new results don't show any cooling at all.
Are we done then? Unfortunately no. Because of the paucity of measurements, assessments of ocean heat content need to use a wide variety of sensors, each with their own quirks and problems. Combined with switches in data sources over the years, there is a significant potential for non-climatic trends to creep in. In particular, the eXpendable BathyThermographs (XBTs - sensors that are essentially just thrown off the side of the ship) have a known problem in that they didn't fall as quickly as they were originally assumed to. This gives a warm bias (see this summary from Ingleby and Palmer or the paper by Gouretski and Koltermann) , particularly in data from the 1970s before corrections were fully implemented. We are still going to have to wait for the 'definitive' ocean heat content numbers, however, it is important to note that all analyses give long term increases in ocean heat content - particularly in the 1990s - whether they include the good ARGO data or exclude the XBTs or not).
There are a number of wider lessons here:
- New papers need to stand the test of time before they are uncritically accepted.
- The ARGO float data are available in near real-time, and while that is very useful, any such data stream is always preliminary.
- The actual problem with these data was completely unknowable when Lyman et al wrote their paper. This is in fact very common given the number of steps required to create global data sets. Whether it's an adjustment of the orbit of a satellite, a mis-calibration of a sensor, an unrecorded shift in station location, a corruption of the data logger or a human error, these problems often only get fixed after a lot of work.
- Anomalous results are often the driver of fundamental shifts in scientific thinking. However, most anomalous results end up being resolved much more straightforwardly (as in the case, or the MSU satellite issue a couple of years back).
Scientists working in a field build up a certain intuition about how things 'work'. This intuition can come from a gut instinct, deep theoretical understanding, robust model results, long experience with observations etc. New results that fall outside of that framework often have a tough time getting accepted, but if they are solid and get subsequent support they will generally be incorporated. But that intuition is also very good at detecting results that just don't fit. When that happens, scientists spend a lot of time thinking about what might be wrong - with the data, the analysis, the model or the interpretation. It generally pays to withhold judgment until that process is finished.
18 April 2007 at 2:43 PM
Nice post, Gavin. I had not heard of this issue before. It does seem to be very similar to the MSU satellite data issue. I still run into people who argue that satellite data shows no warming, at which point I have to go into my monologue about the corrections to Christy’s data. Was the Lyman paper a deliberate attempt to discredit AGW like M&M, or honest research that was subsequently pounced on by skeptics like Caillon’s ice core paper?
[Response: Definitely the latter. As I stated above, they couldn’t have been aware of the sensor problem and they updated their analysis as soon as it was discovered. -gavin]
18 April 2007 at 2:58 PM
This is great news Gavin. The Lyman et al paper has been a bit of a stumbling block, something that flew in the face of what we would expect to happen, and I’m glad that it has turned out to be something as simple as faulty equipment. With this one now sorted, the contrarians will have to find something else to hang their hat on.
18 April 2007 at 3:29 PM
How likely is it that we’ll be able to correct for the mistaken depth estimates?
When the Hipparcos satellite was launched, it had severe orbit problems, and this was big trouble for its onboard photometers. But by comparing the satellite photometry to ground-based observations, it was possible to “calibrate” the satellite photometers, finally yielding very high-quality results (I was part of that effort). Any chance a similar strategy might recover good data from Argo?
18 April 2007 at 3:30 PM
Thanks for the quick posting of this. I’ve been waiting for a simple explanation to Lyman’s report (something zealously promoted by some skeptics) for a while. Instrumentation (especially new equipment) should always be suspect when results seem counterintuitive.
18 April 2007 at 3:44 PM
More info available; first hit is from the Argo site on this subject.
I wonder who else may have bought from the bad batch and installed them in even less accessible or more life-critical equipment.
Posting just the Google search since many hits are PDFs; people may prefer to look at Google’s HTML versions.
http://www.google.com/search?q=Argo+float+pressure+transducer+error&start=0
18 April 2007 at 4:00 PM
Thanks gavin,
When I started to look at the global warming issue my initial inclination was to look at Ocean data, since it’s such a huge heat sink, relatively constant backscatter, and potentially the source one would want to measure with as much accuracy as possible.,Also, Seemed to me like it was a “natural” filter of noisy data.( does that make sense?).
The sea level response to heating looks nearly linear over the past century . The air/land temp record looked to be rather noisy. Having both signals is nice, but from one perspective focusing on the sea level/temp metrics is much less susceptible to local chaotic distruptions ( hey it was cold this month in New york).
Compared to air temps. the signal from the ocean appears to be much cleaner. Although, from a publicity standpoint, it air temp that gets people interested.
I read about the Laymen report on Pielke’s site. The simultaneous cooling and sea level increase made no sense, from a physics standpoint, prima facia. So one would expect some kind of instrumentation correction. ( no hypothesis faces disconfirmintion in isolation).
Anyways, if you had a $1 dollar to spend on instrumentation. would you spend it on an ocean temp sensor, sea level sensor? or air temp sensor?
18 April 2007 at 4:07 PM
Gavin
You fail to mention that the corrected data show no temperature increase, still a problem for the models, no?
[Response: Not really, having flat trends for a couple of years at a time is neither unprecedented nor unusual. Natural variability hasn’t been banished after all. But, I think it’s better to wait for the definitive time series (which we don’t yet have). Right now all analyses show significant long term warming, just like the models suggested they would. -gavin]
18 April 2007 at 4:10 PM
Gavin, I think it would be worth adding to the post 1) the main reason why there was so much doubt about the Lyman et al results (the unphysical melt amounts for 2003-5), 2) the expected role of GRACE in obtaining a reliable result, 3) the fact that the ARGOs don’t measure the deep oceans, and 4) that it’s inappropriate to take the remaining ARGO data (shown in the Lyman et al correction to be essentially flat for the last two years) and draw any conclusions about ocean heat content trends for that period. This latter point is especially important since the usual suspects are already spreading the idea that the correction is somehow additional confirmation of lack of warming.
18 April 2007 at 4:23 PM
Should not the climatologist’s (and RC’s) response to the question, “Are the oceans warming?” be: “Likely, but we don’t know for sure.” Or, “maybe; maybe not.”?
[Response: No. There is good evidence that the oceans warming on the long term. Look at the Ingleby and Palmer presentation linked to above - it doesn’t matter if don’t use the XBTs or the ARGO data. I would say that it’s ‘very likely’ (on the IPCC scale) the oceans are warming. - gavin]
18 April 2007 at 4:33 PM
Re #3: Tamino, let me first state how excited I am to find a climate subject about which I know more than you, however temporary past experience would seem to indicate that condition is likely to be.
The ARGO folks seem to think their data is correctable, but according to the Lyman et al correction the XBTs (which are needed for any sort of long-term trend analysis) are a different story. Even the corrected ARGO data will have potential remaining problems, the obvious one being the lack of coverage of the deep oceans, plus of course additional calibration problems may remain. It appears that any definitive results will have to rely on GRACE (which as I understand it, being a new instrument itself will require another couple of years of data in order to make sure its results are self-consistent).
Re #6: There was a reconciling hypothesis. The problem was that it called for an “unphysical” amount of recent melt (in direct conflict with other obs). To be fair, Lyman et al did note that this was a shaky idea, and looked forward to GRACE resolving all in a couple of years.
Re #7: Et voila.
[Response: I’m not sure about your statements re: GRACE. Those instruments measure gravity anomalies (and hence mass) and so are will be great at measuring the loss of ice from the ice sheets etc. Combined with the altimeter data you should be able to back out the component of sea level rise associated with thermal expansion. However, while this is an important check on the ocean heat content data, it isn’t a substitute for it and GRACE will not ‘resolve it all’ in a couple of years time. -gavin]
18 April 2007 at 4:52 PM
RE 2
You wrote:
“This is great news Gavin. The Lyman et al paper has been a bit of a stumbling block, something that flew in the face of what we would expect to happen, and I’m glad that it has turned out to be something as simple as faulty equipment. With this one now sorted, the contrarians will have to find something else to hang their hat on. ”
When people write things like this I think of two words: confirmation bias.
” The Lyman et al paper has been a bit of a stumbling block, something that flew in the face of what we would expect to happen”
An observation is NOT a stumbling block unless you have an agenda. A scientist puts up a hypothesis. The task is then to CONFIRM/DISCONFIRM the hypothesis. One does not profess an interest in certain outcomes. It’s
objective. It’s science. Not religion. not politics. Just the facts maam. From one perspective( popper, you can wiki him) Science seeks observations to prove theories wrong. theories are made STRONGER by facing tough tests. I’ll explain a bit more..
2+2=4 is not a scientific hypothesis. Do any experiement you like, I won’t give up that knowledge/power. This sentence is observationally vacant. Let’s take another extreme.
For the religious, “god created the world” cannot be disconfirmed. Everything tells them their belief is true. Evidence to the contrary is a test of faith. stumbling block.
So the scientist is not interesting in things that are observationally vacant ( 3+3 =6) or in things that cannot be DISCONFIRMED by observation ( an invisible non measureable force made the world). They are intersted in things that can be Proven wrong. They are intersted in things that fly in the face of expectation.
Then you wrote:
“and I’m glad that it has turned out to be something as simple as faulty equipment.”
Well, you cannot be glad of that. Let me reframe this. These scientists spend millions of dollars to take the temp of the ocean. And look. THEY SCREWED UP. Now, they ask me to trust the temp from land systems?
Now they ask me to trust computer models. The scientist must master the job of being the fallible priest.
Pointing out the errors of another scientist, while claiming infallibility for yourself, does not work from a rhetorical standpoint.
See how that works. The issue is science progresses by continual failure. by a belief in the falibility of human intellegence. Retest, duplicate the results, open source, don’t pre judge, be willing to throw your theory to the winds. If you are not open to being wrong, then you are wrong.
Finally:
“With this one now sorted, the contrarians will have to find something else to hang their hat on”
Yes, this is a GOOD THING. You want them pounding and questioning and improving the grounding of the belief. The contrarians are GOOD for the theory, good for the science.
So the sceptics will pound on ocean temp and then that will drive a better understanding of that area. And they will pound on land use,and that will drive a better understanding of that. And they will pound on the lack of understanding clouds, and that will drive…..
YOU SEE? the DISBELIEVER drives the science. Science needs the disbeleivers. Otherwise it’s just scholasticism.
[Response: It’s generally not the contrarians who drive better understandings of the science, because most of the contrarian points are completely irrelevant and are used as rhetorical, not scientific, points. If, however, you go to scientific meetings like AGU and you sit in on a session where there is some conflict (real or apparent), what you’ll see is not contrarians vs establishment, but a whole bunch of skeptical individuals trying all sorts of ways to reconcile the different data. This is certainly the case for the ocean heat content discussion, and the GW/hurricane links, the aerosol issues etc. The ‘contrarians’ as you see them generally play the role of Greek chorus - just adding to the background noise. They are (with a couple of exceptions, Lindzen having been one in the past) completely irrelevant to the actual practice of science. - gavin]
18 April 2007 at 5:52 PM
hi gavin
you wrote:
“It’s generally not the contrarians who drive better understandings of the science, because most of the contrarian points are completely irrelevant and are used as rhetorical, not scientific, points. If, however, you go to scientific meetings like AGU and you sit in on a session where there is some conflict (real or apparent), what you’ll see is not contrarians vs establishment, but a whole bunch of skeptical individuals trying all sorts of ways to reconcile the different data. ”
I think you misunderstood. we are talking about the same thing. Scepticism has always been percieved in these two modes. one mode is merely rhetorical. the other pragmatic. I’m talking about the pragmatic mode. Namely, people looking at ARGO data. characterizing them as contraians ( the polite version of denier) isn’t really factual now.
you go on:
“This is certainly the case for the ocean heat content discussion, and the GW/hurricane links, the aerosol issues etc. The ‘contrarians’ as you see them generally play the role of Greek chorus - just adding to the background noise. ”
Is there some new issue on GW and huricanes? Is somebody somewhere claiming that GW will lead to fewer or less strong hurricanes? WHAT? Utter nonsense! It is not logicaly possible. the link between GW and hurricanes is settled science. it’s like the laws of newton, it’s like F=ma. Nobody could argue that GW leads to fewer hurricanes. don’t they know that 2+2 =4? these sceptical greek chorus idiots; are they talking about wind shear, or long term cycles. Hmm is there a test we could set up.. maybe a hypothesis.. a prediction.. and then test, yes test the theory?
Dang, they should shut up and get on with the program. ( called normal science). We have code to write.
You went on:
“They are (with a couple of exceptions, Lindzen having been one in the past) completely irrelevant to the actual practice of science.”
The great OZ would not appreciate the irony of the following.
“Thomas Kuhn is most famous for his book The Structure of Scientific Revolutions (SSR) (1962) wherein he argued that science does not progress via a linear accumulation of new knowledge, but undergoes periodic revolutions that he called “paradigm shifts”, in which the nature of scientific inquiry within a particular field is abruptly transformed. In general, science is broken up into three distinct stages. Prescience, which lacks a central paradigm, comes first. This is followed by “normal science”, when scientists attempt to enlarge the central paradigm by “puzzle-solving”. Thus, the failure of a result to conform to the paradigm is seen not as refuting the paradigm, but as the mistake of the researcher, contra Popper’s refutability criterion. As anomalous results build up, science reaches a crisis, at which point a new paradigm, which subsumes the old results along with the anomalous results into one framework, is accepted. This is termed revolutionary science. In SSR, Kuhn also argues that rival paradigms are incommensurableâ??that is, it is not possible to understand one paradigm through the conceptual framework and terminology of another rival paradigm. For many critics, this thesis seemed to entail that theory choice is fundamentally irrational: if rival theories cannot be directly compared, then one cannot make a rational choice as to which one is better.”
RELEVANCE is a social/politocal determination. Predictive power is what matters. So when you say irrelevant that merely recapitulates a social structure
[Response: I specifically make a distinction between skepticism - which every good scientist has in spades, and contrarianism which has been the mainstay of people like Singer, Crichton, Carter, and now Lindzen. The former is vital to the scientific enterprise, the latter is about as useful as promoters of perpetual motion machines to the understanding of particle physics. Who ever called the people looking at the ARGO data contrarians? We’re not talking about paradigms here, we’re talking about rhetorical devices. With respect to GW and hurricanes, I’d ask you to point out anything I’ve ever written that said that that issue was settled. If you want to converse seriously here, drop the snark. -gavin]
18 April 2007 at 5:54 PM
This is not just a lesson about changes in ocean temperature. It is also about the scientific process and how well it is working.
1) A paper was published in a peer reviewed journal with data that was viewed by AGW denialists as proof of their viewpoint.
Data contrary to the consensus does make it to print. AGW denialists, please, stop arguing it doesn’t.
2) The self correcting nature of scientific research is apparent in this story. The process works and it is not corrupt as the denialists falsely report.
Thanks for a great post.
18 April 2007 at 7:12 PM
http://oceans.pmel.noaa.gov/Pdf/heat_2006.pdf
“The OCHA estimate made using all data (thick solid line), including spurious float profiles, shows an apparent cooling of about 48 Ã� 10^21
J (48 zeta joules) from 2004 through 2006. This erroneous cooling arises because of the increasing fraction of spurious profiles in the Argo data stream produced by the WHOI SOLO floats. Another estimate using all data except the spurious float data (thick dashed line) suggests much less cooling, only about 25 zeta joules.”
Much less cooling, but cooling none the less.
Also, how does this new information change the point made in the discussion from the original paper?
“This work has several implications. First, the updated time series of ocean heat content presented here (Figure 1) and the newly estimated confidence limits (Figure 3) support the significance of previously reported large inter annual variability in globally integrated upper-ocean heat content [Levitus et al., 2005]. However, the physical causes
for this type of variability are not yet well understood. Furthermore, this variability is not adequately simulated in the current generation of coupled climate models used to study the impact of anthropogenic influences on climate [Gregory et al., 2004; Barnett et al.
2005; Church et al. 2005; and Hansen et al., 2005]. Although these models do simulate the long-term rates of ocean warming, this lack of inter annual variability represents a shortcoming that may complicate detection and attribution of human-induced climate influences.”
18 April 2007 at 7:24 PM
Re #13 — definitely agree. Although it clearly shows that the study of global climate is a very young science. Given the data failures in both the satellite and now oceanic data, I would not trust any predictions at this time. Need a lot more of (2) “correcting nature of scientific research.” This “oceans cooling - not” is terrible news for the credibility of AGW.
It’s great that this work is being done, but it’s going to be years (if not a decade or two) before definitive conclusions can be made.
18 April 2007 at 7:33 PM
I’d like to extend Steven Mosher’s point, but goes further. When looking at data phenominologists are at a severe disadvantage because they only look at the numbers. Scientist, on the other hand, compare the data to their theoretical model. When there are major differences, before shooting wildly, we (yes, even the fuzzy took classes) look for consistency. A good scientist is extremely reluctant to accept data that does not conform to her understanding of reality and will test such non-conforming information because the alternative is that the model, built and tested on a large body of data has much more support than a single set of measurements.
18 April 2007 at 8:00 PM
gavin> “But that intuition is also very good at detecting results that just don’t fit. When that happens, scientists spend a lot of time thinking about what might be wrong - with the data, the analysis, the model or the interpretation.”
That implies that ’scientists _do not_ spend a lot of time thinking about what might be wrong - with the data, the analysis, the model or the interpretation’ if those fit their intuition. While that is probably natural, it seems like a potential trap to avoid.
Is anyone looking for what might be wrong with the data that does fit the current model?
18 April 2007 at 8:26 PM
re 14:
Eli it’s actually a bit more complicated than that. because science is not math, because it is not true by definition, there is ALWAYS some tension between “theory” ( a dubious term) and observation. In the face of this tension humans have several coping mechanisms.
1. Accept the prevailing socially accepted norms, follow current theory and engage in behavior to make the non conforming data go away.
2. Accept the data, but work to make it consistent with accepted theory by introucing ancillary hypotheses.
3. Accept the data, reject the theory and suggest a replacement paradigm.
4. Withhold judgement and do so more study.
Throughout the history of science one could probably find examples of each of these behaviors being successful. None is inherently more rational than another. But you could submit a proof.
18 April 2007 at 8:37 PM
Since this paper was heavily trumpeted by Pielke et al as ‘proof’ of the failings of climate models, it’s worth reviewing their comments:
“The recent dramatic cooling of the average heat content of the upper oceans, and thus a significant negative radiative imbalance of the climate system for at least a two year period, that was mentioned in the Climate Science weblog posting of July 27, 2006, should be a wake-up call to the climate community that the focus on predictive modeling as the framework to communicate to policymakers on climate policy has serious issues as to its ability to accurately predict the behavior of the climate system.
“ No climate model that we are aware of has anticipated such a significant cooling, nor is able to reproduce such a significant negative radiative imbalance. “Meaningless distinctions between “projections” and “predictions” will be unlikely to convince consumers of climate models to overlook experience that does not jibe with modeled output.”
Roger Pielke also claimed that the IPCC should have modified their report to include the results.
The list of ‘climate skeptics’ who widely claimed that the paper was proof that the models were wrong is long: Patrick J. Michaels (American Spectator), Dennis Avery (Orange County Register). The conclusion so far? Despite long searches for ‘fatal flaws’ in modern climate models, a handful of contrarians still have no supporting evidence.
Will Pielke&Pielke now write an article about the success of climate models in predicting ocean warming over the past few decades? Will they even write a retraction of their previous claims?
18 April 2007 at 9:23 PM
“There is good evidence that the oceans warming on the long term. ….. I would say that it’s ‘very likely’ (on the IPCC scale) the oceans are warming. - gavin]”
Well, that’s pretty much what I said, with a little wiggle with emphasis. My point is that all of the anamolies with measurements showing an increase are all rationalized away with almost a wave of the hand. The anamolies with measurements showing cooling are highlighted and patently justified. Maybe in reality it all might be true. But on the surface it sounds way too pat, and borders on incredulous — at least in scientific circles. (Might work just fine in political circles.)
18 April 2007 at 10:03 PM
I blogged on this here. My main point is similar to yours about how new papers must stand the test of time. I said that one must view “revolutionary” results suspiciously, esp. if they overturn a claim that is accepted with high confidence by the scientific community. Such results will be retested by the scientific community, and if they are right, such retests will verify the results.
18 April 2007 at 11:22 PM
Re: Steve Reynolds,
You remarked that “Is anyone looking for what might be wrong with the data that does fit the current model?”
Clearly many are, as there is a damn good paper (and reputation) in store for the individual(s) who brings the AGW house of cards crashing down. However, I imagine you will find its foundations are a tad stronger than you seem to think.
19 April 2007 at 12:11 AM
Gavin, thanks for this post, it is really helpful in understanding this specific point.
I’m sure it’s not lost on you that you are describing here a textbook example of a paradigm leading scientists to the rejection and reinterpretation of an anomaly that appears to contradict the paradigm.
I am reminded very strongly of the first scientific paper I ever wrote while a UROP student at MIT on “apparent super-luminal motion”, which is to say astronomical observations that seemed to indicate that two celestial objects were moving apart faster than the speed of light. The astrophysics community was loath to accept this result, since overturning Special Relativity would have required either going back to the Newtonian mechanics that had many unexplained anomalies that led to relativity theory in the first place or else developing a better framework than Einstein had (not real likely).
Eventually, of course, the mystery was solved and the observations were reconciled with the paradigm - rest assured relativity is safe. The big difference (admittedly of degree) is that Special Relativity had already passed many rigorous falsification tests of a kind that climate models have not (readers of my prior posts will know this is a monomaniacal obsession of mine)
The practical question that I think this leads to is how do we develop confidence that we have found all of the material measurement error and properly eliminated it? If a measurement error of this severity has escaped notice up until now, how do we know that there are not other undiscovered errors of similar or greater import? If our stopping condition is conformance with the model-driven paradigm, and the models have not been subject to sufficiently rigorous falsification tests, this becomes circular.
Clearly there is no absolute answer to this question - there is always some philosophical possibility of error in any measurement - but I’m asking it in a spirit of practicality. That is, this seems like a pretty huge set of adjustments that in retrospect look kind of obvious, and we are conforming to a set of models that I think any fair-minded observer would agree are not at the stage of maturity of, say, Special Relativity.
Thanks,
Dana
[Response: As you say, there always remains the possibility that any and all measurements are contaminated in some way. So you need to look at a wide range of indicators all of which have independent sources of error (for instance, errors in satellites are not likely to be correlated with errors in weather stations or ocean buoys) and see if your understanding matches all of the different aspects that you expect from the theory (stratospheric cooling, ocean warming, Arctic melt, poleward and upward expansion of biomes etc…). There is never going to be an absolute proof in the mathematical sense, and frankly we are never going to get to the confidence that we have in QED for instance. But the level of confidence we do have (having passed a whole bunch of tests) is enough to allow to project pretty confidently a lot of what’s going to happen. - gavin]
19 April 2007 at 12:28 AM
re: #15
“Given the data failures in both the satellite and now oceanic data, I would not trust any predictions at this time…. This “oceans cooling - not” is terrible news for the credibility of AGW…..but it’s going to be years (if not a decade or two) before definitive conclusions can be made.”
This is throwing out the baby with the (ocean) water.
1) Science doesn’t instantly discard huge masses of data, just because a few new results (especially new types of measurements):
- disagree
- disagree, then get changed, and converge into consistency with older data
2) Surely, anyone who reads RC understands that it is easy to have jiggles in climate time series, and not just measurement errors, and it takes more than 3 years to yield a strong long-term conclusion in any direction.
It is *really* exciting when new data contradicts older data, and turns out to be right, and leads to radical new hypotheses that evolve into strong theories (i.e., like Michaelson-Morley … Special Relativity). That’s a dream case!
But it just happens far less than when new data that confirms old data, maybe filling in holes, or getting another decimal point. Most science works by successive approximations, not flying leaps.
19 April 2007 at 3:16 AM
Re #2. I don’t understand why one should one be glad about this correction - why should warming of the oceans be something to celebrate? Apparently, your Schadenfreude towards the contrarians is stronger than your concern about global warming. Wouldn’t it be best to keep your emotions out of the debate and try to avoid liking some results and disliking others? Like Gavin explained, it is very likely that science will correct itself.
19 April 2007 at 4:35 AM
Gavin, I know this is only tangential to this thread but do you have any comment on the new paper by Vecchi and Soden in GRL, which Chris Landsea is promoting as evidence both that the recent increase in Atlantic hurricane activity is due to the AMO, and that global warming should reduce activity (because it increases windshear)?
[Response: I have no knowledge of (or frankly, interest in) what Chris Landsea may be saying about the paper, but I don’t see this paper as changing the picture significantly. Two points are relevant here, (1) our modeling of future changes in TC remains an uncertain area of the science. Nonetheless, predictions of increased potential intensity due to rising SST which rest on fairly fundamental thermodynamic arguments, remain robust, and I would refer you back to our discussion of this previously. Climate model predictions of changes in ENSO and the Walker circulation, upon which the conclusions of this paper with regard to possible changes in wind shear rest, remain far from robust for reasons we discussed here previously. In short, the Emanuel (2005) study continues to stand on its merit, and I don’t see where this paper puts even a dent in it. We may have more to say about this paper in the near future. -mike]
19 April 2007 at 5:32 AM
Great news this, eh! Another rotten apple thrown out of the barrel. As the satellite data’s errors get sorted, as the Argo float’s errors get sorted, as we recognise with increasing clarity the changes happening underfoot on the Antarctic ice sheets and elsewhere the picture does become clearer.
I think (unlike some here) that we ARE able to place increasing trust in the models. Finding an error means it can be allowed for. It’s knowing nothing, or denying everything that are the dangerous positions to assume. It’s sad (but I guess inevitable) to see those with their heads in the sand (or in this case in a thermos flask!) using this correction as a reason to toss the baby out with the bath water. But I guess when they assume that posture they do make a nice target for the rest of us to expend our ammunition upon, eh!
19 April 2007 at 5:41 AM
I think it is a bit premature to hope that GRACE will help solve this issue; I have written about this here: http://fergusbrown.wordpress.com/
and am taking the opportunity to shamelessly promote my own new blog on climate and similar matters.
Sorry. *blush*
I’d also be very interested to know what proper scientists think about the material on ocean circulation in the same article.
Regards,
19 April 2007 at 6:56 AM
Why? In both cases, the predictions (models) were claimed to be shown to be bogus, while in reality it was the instrumentation that was broken.
This makes me tend to be skeptical of new data which contradicts our current understanding of how climate works, rather than make me question that understanding.
19 April 2007 at 9:11 AM
Re #25. Matti, the celebration is not that the oceans are warming, but that the models are working. The models and paleoclimate data are the only handles we have on the potential effects of climate change–and the models are much better understood than paleoclimate. Thus, we may be able to bound risk at some reasonable level and that will be invaluable in deciding how we allocate resources toward mitigating the effects of warming. The contrarians may be objects of wrath from climate scientists, but they are also increasingly irrelevant. Does this make sense to you?
19 April 2007 at 10:00 AM
re: #25
No offense, but I find your comment somewhat counter-intuitive, a bit of a disconnect, if you will.
The inference you seem to be making is that someone is happy data points to reinforcing the body of evidence regarding Global Warming. I would be willing to wager hard cash that there are few, if any, people that are concerned about Global Warming and the potential for harm it presents who would like nothing better than to have solid, irrefutable evidence it won’t be a problem.
19 April 2007 at 10:08 AM
Re # 17 Is anyone looking for what might be wrong with the data that does fit the current model?
They should be. Competent, credible scientists are usually very self-critical, and always scrutinizing their data. And even if they aren’t as self-critical as they should be, their collaborators, post docs, graduate students, and technicians will likely also be scrutining the data - they all know that experimental results should be repeatable, both internally (in the lab that generated them) and externally (in labs that try to replicate them). And even if no one actually replicates the original experiment (which may be too costly or expensive), predictions generated from those results will likely be tested (esp. if the original results are important) and the new results should be consistent with the original results.
And any scientist who works with electronic instruments knows that spurious results often arise (due to electronic noise, baseline drift, etc), so careful calibration and close analysis of the data is crucial. This point was driven home to me as a graduate student using a data recorder powered by rechargeable batteries. Half way through the experiment I kept getting a sudden sharp deflection of the recorder thermal pen, suggesting some previously unknown and dramatic physiological response by my experimental animals. My excitement was tempered by my skeptical graduate advisor who assured me that my results were “very unlikely.” Sure enough, the batteries in the recorder were not holding a full charge, and were dying in the middle of my experiment.
19 April 2007 at 10:39 AM
Re: data reliability
Even statistical analysts like me have to be constantly alert to this. I can often prove that a statistically significant change has occured in the data. But this doesn’t mean there’s a significant change in the physical signal — it could be, or there may be a significant deviation between reality and measurement. This emphasizes the need to take a long, hard look at the data to establish its reliability and consistency.
19 April 2007 at 10:54 AM
Re # 9 Should not the climatologist’s (and RC’s) response to the question, “Are the oceans warming?” be: “Likely, but we don’t know for sure.” Or, “maybe; maybe not.”?
For an issue of such importance, do you really think that response would be accepted by the press, or politicians, or the general public? I seem to recall a controversy in California years ago dealing with an earthquake prediction; if I remember correctly, seismologists predicted an earthquake that never occurred, and were severly chastized for being alarmist and scaring the public. Surely, any seismologist who detects rumblings deep in the earth and refuses to speculate on the likelihood of an earthquake in the very near futue would be severely criticized, as well?
So, what ethical obligation do scientists have when it comes to informing the public (or not) about a possible natural disaster, be it global warming, an earthquake, flood, hurricane, disease outbreak, etc? Should they maintain a conservative, scientific skepticism and just shrug their shoulders and say, “We don’t know for sure if the disaster will strike…any prediction is just a guess…we’ll just have to wait and see”? Or should they give their best professional assessment, describing the threat and assigning a degree of confidence in their prediction?
It seems to me the climatologist community has adopted the latter position.
19 April 2007 at 12:09 PM
“But that intuition is also very good at detecting results that just don’t fit. When that happens, scientists spend a lot of time thinking about what might be wrong - with the data, the analysis, the model or the interpretation. It generally pays to withhold judgment until that process is finished.”
I think -just my opinion, no pun intended- that’s a very simplistic approach to scientists work. Sometimes, the results that do not fit are discarded, because they are not considered representative, because they do not follow other data collection standards, because they provide from other sources, etc. Sometimes, new hypothesis and conditions are added to the original theory to make that results fit. And sometimes, the results are just ignored because they don’t fit.
Scientists are people, they make mistakes and sometimes, it’s hard to recognize your work might be walking on the wrong direction. And usually theere is a mass of followers that are ready to deny any objection made to the theory. There are indeed plenty of examples in Philosophy and History of Science.
Not that this applies to GW research -or the rest of the psot-, but I don’t think reflects exactly how scientists work.
19 April 2007 at 12:13 PM
Chuck:
http://eqint.cr.usgs.gov/eq/html/eqprob.html
19 April 2007 at 12:25 PM
Something like that happen to me yesterday when I figured grades. I was multiplying .9 x total points for the A cut-off, etc., & came up with a odd-looking cut-off for the Bs. It caught my eye, and I redid the calc & got a number that looked right. Then I turned to my students and said, it’s very important to eyeball results to see if they look right, and also recalculate to see if they jive.
The point is (Re #11), nn observation is NOT a stumbling block unless it looks wrong, based on what you know and expect. It has nothing to do with an agenda.
GW believers would love nothing more than to find out they are entirely wrong. I keep thinking, when will I wake up from this unpleasant dream (made more unpleasant by GW-deniers — that really demoralizes me), and find out GW is not at all an issue in the real world.
The people with an agenda are those who would deny facts and probabilities of harm from GW. But I have a hard time understanding that agenda. ? They want the world to be destroyed & want people to do nothing to reduce the harm ? That doesn’t make sense. They desire to live in pleasant dreamland. They want to stay hooked up to the matrix? Doesn’t make sense either.
Bottom line, THEY DON’T WANT AGW TO BE TRUE. But that’s just how the believers in AGW feel. No one wants it to be true.
19 April 2007 at 1:29 PM
Re: #24 “(especially new types of measurements)”
Exactly. No one (on either side of the debate) should be making hay (let alone predictions) off such new information. As Gavin said, ARGO “has offered the potential to dramatically increase the sampling density in the ocean and provide, pretty much for the first time” data. As just happened, the initial version of the information was somewhat incorrect.
Question: The CO2-T lag suggests that it takes hundreds of years for the ocean mass to warm. Does that mean we need to wait a long time (say 25 years) to see non-surface heating?
19 April 2007 at 1:34 PM
There was an article in the recent issue of Spektrum der Wissenschaft, the German version of Scientific American, about shortcomings of climate models. It says that the study of Gouretski and Koltermann (2007, GRL 34) has reduced the 1957-1997 increase in ocean heat content (0-3000m) by about 38% and that this would be a big problem for climate models. Looking at the paper of Levitus et al. (2005, GRL 32) I find that the 1955 to 1998 ocean heat increase was 14.5*10^22 J. The corresponding value from the paper of Gouretski and Koltermann is 12.8*10^22 J for a slightly shorter interval (1957-1966 to 1987-1996). Considering the different time periods the two values are in fact identical within error. So where is the 38% reduction? Why should there be a problem for climate model verification? Can anybody explain that to me?
19 April 2007 at 1:40 PM
I am very curious about another glaring error in the making, which is the continuance of MSU graphs not showing 2005 as the warmest year in history at all, if there is a scandal in atmospheric science that’s the biggest one I know of at this time. Rather you have to read the fine print that MSU mixes lower stratospheric temperatures (usually quite cold) with the mid troposphere.
Has there been a theory , from proponents confident in MSU data, which limits the warming of the atmosphere strictly near the surface? No, not like a Chrichton Urban warming error proposal blunder, the world is not one paved big city yet.
19 April 2007 at 2:14 PM
re 34: As I mentioned in a follow-up post my suggestion might not be good for political situations. In the dilemmas you present there is no best answer: there is exactly a 50% chance the person will be hailed and a 50% chance of being creamed. The response should be “we don’t know for sure” but also include a learned opinion with a degree of certainty. I had a minor concern in how, in scientific circles like RC, the level of confidence is drawn, like (exaggerating a bit): “Bad measurements that show warming? NO PROBLEM! Bad measurements that show cooling? SEE? NO GOOD!”
19 April 2007 at 2:30 PM
Lynn (37): If AGW proves to be wrong, some of the proponents will be apoplectic, some angry, some depressed and some disappointed — for a while. This does not make them nefarious (except maybe the first two groups who probably do have strong secondary agendas.) To presume they’d be happy is naive; maybe accepting and redirecting a year or two down the road, but not happy
19 April 2007 at 2:42 PM
Guys (re: #26),
Emanuel (2005) finds that the increase in potential intensity during his study period (~10%) far exceeds the increase in potential intensity resulting from rising SST (that he estimates as ~2-3%). So thermodynamical goings-on besides SST can (and apparently do) have a large impact on the potential intensity. Emanuel explains, the observed atmospheric temperature does not keep pace with SST which leads to a decrease in vertical stability and an increase in potential intensity. This result, decreasing atmospheric stability, is confirmed by Hoyos et al. (2006). Knutson and Tuleya (2004) show that climate models run with increasing CO2 project that in the tropics the atmosphere should become more stable as there is more warming aloft than at the surface. Thus, I think we all should be able to agree, that unless the upper-air observations are wrong, the observed trend in atmospheric stability over the tropical Atlantic is in a sense opposite to direction that models suggest it will be, at least into the future. As Gavin pointed out over at ClimateScience, perhaps it is not so much that the observations are wrong, just that the observed forcings over the past 30 years or so, have been different from the simplified set of forcings used by Knutson and Tuleya, and that when the observed forcings are used as input, climate models do a better job at handling the evolution of the Atlantic tropical atmosphere. I would be very interested in seeing climate model simulations of the evolution of the atmospheric stability in the Atlantic (both with and without CO2 changes) during the past 30 years to see if they do indeed replicate the observed trend and to what degree CO2 increases were involved in the match.
The same goes for vertical wind shear trends. As Vecchi and Soden report, there is a robust increase in vertical wind shear over a good deal of the tropical Atlantic in the collection of the 18 climate model results they examined (running SRES A1B). Again, there is a good deal of evidence that vertical wind shear has generally declined over the past 30 years in the Atlantic (e.g. Hoyos et a., 2006). Again, I think we can agree that the trend in observed vertical wind shear is opposite that projected to occur under SRES A1B. Agreeing with Gavin, A1B is not what happened during the past 30 years. If someone actually does know how the models simulated the evolution of vertical wind shear over the Atlantic during the past 30 years, it would be very worthwhile to share that information.
However, even without the actual results from the models for the past 30 years, I think we can surmise that driven by changes in anthropogenic forcings alone, the models simulations of the past 30 years would be trending in a similar direction as the model projections for the future, that is, vertical stability and wind shear should be increasing, at least over the tropical Atlantic. Adding non-anthropogenic forcings to the mix may, or may not, overwhelm these trends (they will if the models are getting things right, they wont if things in the models are still amiss). But assuming the case that the models aren’t horribly wrong, non-anthropogenic influences must be largely responsible for the observed trends being in the direction that they area which is towards producing a more hospitable environment (that works along with SST increases) for tropical cyclone development and intensification.
The only problem I have with Emanuel (2005) is that his results are overplayed to infer that the observed trend in tropical cyclone activity is largely anthropogenic in nature. The results in his paper, coupled with the results of Knutson and Tuleya (2004) and Vecchi and Soden (2007) argue otherwise. So [edited] I think that the results of Vecchi and Soden do put a dent in the hypothesis that human industrial emissions are largely responsible for the observed increase in Atlantic tropical cyclones and that they will have a larger impact into the future [edited]
-Chip Knappenberger
to some degree, funded by the fossil fuels industry since 1992
[Response: Chip, we’ll permit this one comment, but since this is obviously not supposed to be the topic of this thread, we’ll limit it at that. You seem to have missed the central point here. Emanuel (2005) shows that the warming SSTs are behind the increased TC intensity in the Atlantic. No impartial reading of that paper could come to any other conclusion. Independent studies, such as the Santer et al PNAS paper, show that this warming is inconsistent with natural variability, i.e. it is likely only explainable in terms of anthropogenic forcing. That basically closes the loop on the argument that anthropogenic forcing is likely behind increased tropical Atlantic Hurricane intensity. Future predictions of shear changes are interesting, but they have no bearing on this fairly simple logic. -mike]
19 April 2007 at 3:02 PM
Joe White: “This is great news Gavin. The Lyman et al paper…”
Yes! Great news. Now the prediction still is that the world goes into the global warming inferno! Good news. You CO2 devoted are so funny.
19 April 2007 at 3:17 PM
Let me be blunter: Without a theoretical framework one wanders in ignorance. The more quantitative and basic the framework the better (Gray vs. Trenberth).
Models (aka theory) provide a bullsh*t test for observations as much as data is a bullsh*t test for observations.
You ain’t Einstein and you ain’t Gallileo either.
19 April 2007 at 3:23 PM
Re: #41
No, it’s not great news because the world is going into inferno. It’s great news because our understanding of climate, and therefore our ability to deal with the problems it presents, is more likely to be sound.
The objection you raise was already raised on this thread, and already addressed.
You delusionists are most definitely not funny.
19 April 2007 at 3:37 PM
[[Joe White: “This is great news Gavin. The Lyman et al paper…”
Yes! Great news. Now the prediction still is that the world goes into the global warming inferno! Good news. You CO2 devoted are so funny.]]
Obviously it’s bad news for human well-being. But it’s good news in cutting the feet out from under the deniers who are trying to stop us from doing anything about the problem.
19 April 2007 at 4:29 PM
Re: 41.
1. There won’t be a global warming inferno if people finally start to react (and start quickly because some may need a little longer to realize they have to act). 2. It definitely is good news for those people who try to understand how climate works. It is probably bad news for those who try to make people think it is impossible to understand how climate works. 3. Three years of ocean cooling would certainly not have saved the world from warming.
19 April 2007 at 4:51 PM
Environmentalism is no longer a popular movement like it was at the time of the first Earth Day in 1971. It’s become a very esoteric academic discipline that only a few select “experts” in an elite priesthood can understand and participate in. Much like in the humanities and literary studies. And the inferior common folk are to be derided and excluded for their gauche taste in reading Michael Crichton and so on. The result of one is “reading at risk” and the dissolution of the American publishing industry, the result of the other is slow but steady enviromental degradation.
19 April 2007 at 5:55 PM
Re 45.
Yes, that’s what I meant with my comment. Thanks to all the others, special mentions to 44 & 46, who have gone in to bat on my behalf.
http://joewhiteleftfield.blogspot.com/
19 April 2007 at 7:03 PM
Mike-
You are simply incorrect when you assert: “Emanuel (2005) shows that the warming SSTs are behind the increased TC intensity in the Atlantic. No impartial reading of that paper could come to any other conclusion.”
[edited]
[Response: Roger, we’re not about cherry-picking sentences and out of context quotations here at RC, so you should take that somewhere else. Anybody who has studied the scientific issues involved well knows that SSTs in this context are a proxy for a more complex set of interconnected atmospheric environmental variables which tend to covary with it. We hardly need you to quote Emanuel for us. Figure 1 in Emanuel (2005) comparing SST and TC Power Dissipation in the tropical Atlantic speaks for itself, you might want to take another look. If we do an article on Hurricanes in the near future, you’re free to engage in the discussion. But that’s not the topic of this post, so we’re going to close it out with this. -mike]
19 April 2007 at 7:04 PM
Re: Kuhn, paradigms, and the neutrality of scientists. Yes, I also see this as an example of paradigm-driven revolutionary science, and gavin (and co.) shouldn’t apologize for it. As he says, scientists are skeptics trying to make sense out of data. It is eminently satisfying when they do! That is an intellectual and emotional attachment to what they do. Scientists are not robots: they *enjoy it* when they solve a problem. They don’t simply spit out “fits theory” “doesn’t fit theory”. No scientist should apologize for this commitment. Just so, when a scientist or group of scientists think they have solved a problem, and then new data suggests they were wrong, there is nothing wrong with feeling frustrated about it! (In fact, there’s really nothing wrong with favoring one theory over another for whatever reason one wants; as long as you follow the data, you can think whatever you want about the theory.)
Also I want to comment on this snippet from one of gavin’s replies to a comment on this thread:
“But the level of confidence we do have (having passed a whole bunch of tests) is enough to allow to project pretty confidently a lot of what’s going to happen.”
Yes–in fact I’m about to post on ClimateAudit on this very point to see how they react. This gets to the heart of the debate about “consensus”–Kuhn even writes on this subject in SSR (I forget exactly where: it’s at the very end of one of the middle chapters…I can look it up). When two paradigms are competing–or simply during a revolutionary period when one paradigm is supplanting an earlier normal science tradition (I get the sense that all this HPS/STS talk makes gavin a little nervous…) then it eventually becomes clear when one paradigm is becoming ascendant. You can almost always bet that it will ultimately be triumphant, i.e. its theory will eventually become accepted as fact, *without* appeal to consensus at all (because everyone will think that way; no proofs will be necessary, though there will be plenty on hand). The alternative paradigm (that anthro ggs play no significant role in current warming) is currently losing the battle; although they are still alive and kicking (and will probably continue to score points here and there) they are not making progress towards convincing the relevant community. It would take a seriously revolutionary set of data (a “counter-revolutionary” set of data?) to put a halt to agw theory right now–undeniable proof that cosmic rays are behind everything, for example, or maybe evidence that an immense cloud feedback is kicking in as we speak (though that latter might not really count as evidence against agw theory…hard to say). And, of course, it remains possible that even if agw theory ultimately triumphs and becomes accepted as fact, it could still be *wrong*–but again, it would take another revolutionary finding to show that.
If agw is wrong, why does it keep succeeding among the scientific community? (As measured, for example, by the number of scientific organizations that support it:
http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change
I also bet that the citation index shows similiar levels of support, though to my knowledge no one has investigated this in detail.)
Sorry for the windy lecture; I just wanted to weigh in. And of course, this could all be totally wrong
But regardless, scientists still don’t need to apologize for having strong feelings about being wedded to one theory or another.
19 April 2007 at 9:08 PM
I think it is now clear (after the warming of the oceans has now been proven) that if we do not stop adding GHGs to the atmosphere, the entire human race might go extinct along with thousands of other species wihtin a few decades.
We must stop this catastophe from happening as soon as possible.
19 April 2007 at 9:34 PM
I’d like to comment simply that I agree with the first part of #11 (Mosher) — it is important to be unbiased in our interrogation of observational data. Yes, data that don’t fit the common theory should be scrutized. Data that do fit should be scrutinized equally. Probably everyone could agree with that.
On another matter, what have the ATOC results contributed to understanding oceanic heat content? http://en.wikipedia.org/wiki/Acoustic_Thermometry_of_Ocean_Climate
It looks like “nothing” is the answer, but given a decade of data I’m surprised not to see a graph of some sort.
19 April 2007 at 9:51 PM
And since the new analysis agrees with you, it should be taken the final word and not subjected to the same skepticism with which the previous study was treated, as per usual.
19 April 2007 at 10:30 PM
RE #53, “entire human race might go extinct along with thousands of other species wihtin a few decades”
I think the possible danger is not so much that the worst will happen in a few decades or even in a hundred years, but that what we’re doing now may cause the earth system to rearch a point (maybe in years or decades, or we may have passed it already) at which it may be nearly impossible to slow or halt dangerous warming & great future harms, which could go on for hundreds, thousands, even hundreds of thousands, of years.
And re #42, I can’t imagine anyone who would want AGW to happen (except some suicidal mass murders). That’s why so many good people are becoming climate scientists and environmentalists. Because they want to warn people and help us solve this problem.
Seriously, are there GW believers on this site, who would be unhappy if tomorrow we found out that, oops, we forgot to square-root some calculation (or something) and GW is not happening afterall? Some may be red as beets for having claimed it was happening, they may be jumping hoops to show how any reasonable & smart scientist could have made that mistake, but surely their ecstasy in knowing it wasn’t happening, would far outweigh any embarrasment or even temporary unemployment (the guys here are smart, they’d get some other job; in fact I’ve read the many climate scientists started out in other fields). Many people have children and love them. Don’t you think they would be happy to know their children will have a good, sustainable world? Again, it is the denialists who are truly perplexing in their thinking and motives.
And as for the environmentalists and do-gooders, there’s no shortage of other harms & evils in the world to combat, or one could just stop and smell the flowers along the way. Plenty of other things to do.
19 April 2007 at 11:56 PM
Measurement error, calculation error and reporting errors occur in every field - not just climate science. A significant portion of every professional’s time is spent investigating or fixing problems resulting from these kinds of errors. This is particularly painful in areas such as this - where decisions affecting potentially millions of lives is based on what can turn out to be faulty data or misapplication of data to theory. If it turns out that we can avoid the coming AGW disaster but we failed to act quickly enough because of faulty data - life in fubar. [NOTE: I think we’re fubar already, but I’m hoping I’m really wrong about that.]
Often I believe this drives the deniers - everyone knows that data is wrong, theories are wrong, etc and so they insist that its a data problem or theory problem. As long as the possibility exists that the data or theories are wrong - they reach for the elixir of “it could be bad data/theory” to avoid changing their reality. It’s natural. Human nature basically. In stable times, a high quality survival strategy. In unstable times, not so good.
20 April 2007 at 2:52 AM
DaveS the denialist says:
The original post says:
Seems that DaveS didn’t bother to read the post, which goes on to say:
In other words, that bias due to sensor problems has in one case been shown to run in the direction of warming.
Gosh. Maybe it’s just about getting more accurate data and understanding the science after all, DaveS.
20 April 2007 at 4:45 AM
Can anyboy here please show me someone explaining the 800 year lag of co2? Any place where I can read about it?
The explanation given on this site is not very intelligent.
Thank you.
20 April 2007 at 5:12 AM
Re #56, As we came out of the last Ice Age there was a large amount of warming and as the oceans warmed there was a net large release of CO2 from them, however the warming attributed to this period lagged some 800 years behind the initial warming and did not cause it but it was responsible for its own warming and that is the point. It was not a driver for this ending of the ice age but it is a driver for warming as we are experiencing it today.
I believe that some climate denialists have used the CO2 is not a driver for past climate argument which is incorrect.
20 April 2007 at 5:55 AM
Re 56: explaining the 800 year lag of CO2
There is a good explanation here. In a nutshell: 1) wobbles in the Earth’s orbit (the Milankovich cycles) have a warming and cooling effect. 2) Warming causes CO2 to be released - e.g. by thawing the permafrost and drying wetlands, soils and forests thereby allowing organic matter to breakdown, and warming the oceans which causes dissolved CO2 to outgas and methane (which breaks down to CO2) to be liberated from clathrates etc. 3) the extra CO2 (and methane) causes warming that is significantly greater than would otherwise result from the wobbles alone. 4) There is a delay because the various processes such as thawing of permafrost and breakdown of organic matter, warming of the oceans etc. take a certain amount of time to kick in after the wobble mediated warming starts.
This time around we are not see a warming kick-started by a Milankovich wobble. Instead we are in an already warm period and are initiating extra warming by injecting even more CO2 into the atmosphere. The 64 million dollar question is: how much extra CO2 will now be liberated by those various CO2 liberating processes. And given that we seem to be kick-starting it all much faster than a wobble would, and are doing it on top of an already warm interglacial climate; how fast will that liberation occur, and how much CO2 will it add?.
20 April 2007 at 6:29 AM
Re: 85
Thank you Dr. Schmidt. Both links were very helpful. I also read some of Hansen’s work on the subject.
A few more questions for the forum on climate sensitivity to greenhouse gases:
1. Doesn’t measurement of climate sensitivity rely on historic data?
2. Are ice core temperature and gas composition data applicable to the entire globe or just Antartica?
3. Hasn’t the climate changed dramatically over the last 400k years and thus how can we know how the earth will respond to forcings today if there are different processes at work?
4. Hansen believes we can avert certain disaster if we keep warming under 1 degrees celsius. Isn’t this hypothesis built on the assumption that the earth will respond in a similar fashion to forcings that occured tens of thousand of years ago?
Thanks again for taking the time to explain this to a non-scientist.
20 April 2007 at 7:10 AM
[[I think it is now clear (after the warming of the oceans has now been proven) that if we do not stop adding GHGs to the atmosphere, the entire human race might go extinct along with thousands of other species wihtin a few decades.]]
I doubt that. There will be great economic disruption and many people will suffer, but I don’t think the species is in danger of extinction. Let’s try to keep some perspective here.
20 April 2007 at 7:33 AM
So you say that the sun coming in at a different angle due to wobble of the earth is what previously caused global warming? But now it is the increase by 80 ppmv of CO2 that is the cause? Where in the Milankovic cycle are we now? Will that (M-cycle) have any effect on global warming this time?
Trying my best to understand.
Thanks for replying
20 April 2007 at 8:35 AM
Re #64
See Present Conditions on this linked page. You might well like to read the whole page, too.
20 April 2007 at 8:58 AM
Can anyboy here please show me someone explaining the 800 year lag of co2?
A natural 800-year lagging increase in atmospheric CO2 in response to rising temperatures does not somehow preclude an increase due to anthropogenic emissions… what’s to explain?
20 April 2007 at 9:12 AM
Ha, I love that I’m a “denialist” because I point out the somewhat immature tone with which Gavin consistently addresses these things…. he’s made up his mind and has his biases as much as the “deniers” he derides. Even in this post, he said “[sea surface cooling] was going to be hard to reconcile with continued increases in sea level rise (driven in large part by thermal expansion effects)”. That’s called “begging the question”… if you presuppose that increases in measured sea-levels are due in large part to thermal expansion and that there is no “inertia” involved–whereby sea-level rise due to 350 years of warming may not necessarily stop on a dime with sea surface warming–then of course it’s difficult to reconcile. To a more objective observer, thermal expansion might be equally hard to reconcile with cooling waters.
I’m no climate scientist, but I have a decent science background and I’m something of a lurker here… I’m just saying that it has been obvious to me from day one that Gavin is not exactly an objective source of information… he provides very good information from a perspective, and he does it in an intelligent–but slightly snarky–way. I like this blog and find it informative.
Don’t project your biased, politicized view of this onto me, please.
20 April 2007 at 9:16 AM
#66, “Can anyboy here please show me someone explaining the 800 year lag of co2?
A natural 800-year lagging increase in atmospheric CO2 in response to rising temperatures does not somehow preclude an increase due to anthropogenic emissions… what’s to explain?
When you put these together, it’s a really bad scenario…much worse than simply CO2 causes warming.
Watch out, world, for CO2 causes warming, which causes more CO2, which causes more warming, which causes more CO2, which cause a hellava lot more warming, which causes a hellava lot more CO2, which causes….(no one left to write about it).
20 April 2007 at 9:30 AM
Re #67: On ‘Gavin is not exactly an objective source of information’…
On the list of people who I would trust to be a straight as possible on the subject and likely to know WTF they were talking about, Gavin is near the top of my list. Maybe this is because I, too, am prejudiced, or maybe it’s because I like the fact that he’s taking time , along with all the other experts here, to educate the likes of us.
I like to pretend my judgement of other’s reliability is based on an assessment of their rationality and fairness, but who gives a damn about such archaic notions these days? I think there’s an important distinction to be made between being biased and having a clear point of view based on substantial knowledge and experience. But hey, that’s just me…
20 April 2007 at 9:56 AM
I think you make an important point regarding the “test of time” for research papers. In my studies I have found a number of papers which become widely accepted in a short period of time and shortly after we find stronger studies rebutting these initial findings. This applies to both sides of the controversy. After all, this is what science is all about, the problem is that some researchers, journalists and even the public get deeply attached to the first set of data they encounter and disregard subsequent arguments against those claims. That is why we should keep a critical eye on research papers concerning climate change, whether they support our personal beliefs or not.
It is important to recognize that some data sources, such as the ARGO floats, can provide instantaneous data, but the overall trends may require more time to be determined. Some of the arguments I have encountered against global warming are based on a quick glance at these data, which may be displaying only short term trends, rather than continuous global cooling patterns. At the same time we also have some researchers supporting their claims on global warming in a similar fashion. This calls for caution on the part of the audience to which these claims may be directed. Neither proponents nor opponents should knowingly make strong claims based on faulty, incomplete or adjusted data due to the implications these factors may have on their conclusions.
It is also alarming the fact that some of the probes may be producing anomalous data, and some researchers may be using it to back up previously construed arguments, instead of analyzing it, taking into consideration its flaws, to provide an objective study of climatic trends. With the increasing number of debates over this issue, my personal recommendation for the public is to understand data sources presented by both proponents and opponents before following either sideâ??s conclusion.
20 April 2007 at 9:59 AM
I am so happy that finally oceans get the attention they diserve, as I have strongly stated in varoius ways that we should consider more that the oceans are linked to the climate and influence the climate almos as much as the son does.
20 April 2007 at 10:00 AM
Don’t project your biased, politicized view of this onto me, please
Is anybody forcing you to participate here? Nobody is projecting anything on you here, if anything, by choosing to participate, you are projecting yourself onto us.
This website belongs to its creators. They are free to project anything they want here, and you are free to ‘turn the channel’.
20 April 2007 at 10:33 AM
DaveS:
As the Buddha said in a different context, “The pollution is in your mind.”
Gavin’s statement that ocean cooling was going to be hard to reconcile with rising sea levels is simply fact, not attitude. Given that we know that sea level is rising several millimeters per year, the observed net contribution of melting glaciers and ice caps is not enough to explain current sea level rise, and water shrinks as it cools, how would you explain the current rate of sea level rise? You have to come up with a completely new source of water, a source of heat in the deap ocean, or show that water expands as it cools.
If you don’t have an answer handy, then I submit that you demonstrate the simple truth of Gavin’s statement that such a reconciliation is hard.
20 April 2007 at 10:38 AM
Dave S., Gavin does indeed have a perspective. We all do. The difference is that Gavin’s perspective is supported by the evidence and so reflects the scientific consensus on matters of climate. And lo and behold, because his perspective is consistent with the scientific consensus, he is, far more often than not, right.
A scientist may support the scientific consensus. A scientist may be skeptical of the scientific consensus. In either case, they must do so based on the evidence. As soon as they lose sight of this fact, they leave the realm of science and, if they are experts, become contrarians (e.g. Lindzen), or if they are not experts, denialists, (e.g. you). In either case, you make yourself irrelevant to the process of science–quite unlike the true skeptic.
Look, we know the climate is changing–that is beyond question. We have a very probable mechanism–anthropogenic greenhouse gas emissions. Those who say, “It’s natural” have absolutely no mechanism to propose to explain the changes we are seeing. As a physicist, I get uncomfortable when people seem to suggest that the energy in a system (e.g. the climate) can just increase with no cause. So until you have a mechanism to suggest, you are not part of the scientific process–skeptical or otherwise.
20 April 2007 at 11:56 AM
RE# 68
On the good side, we have 800 years to prepare before this supercharged co2 feedback begins?
20 April 2007 at 12:24 PM
Re: #75
Not necessarily. One of the reasons the lag of CO2 behind temperature in deglaciations is so long is that warming during deglaciations is so slow. The rate of warming during a reasonably rapid deglaciation is about 0.1 deg.C/century, the rate today is about 1.8 deg.C/century.
Also, the ice core records from Antarctica give a good measure of global CO2 concentration (it’s a well-mixed gas), but give a more local measure of temperature. Milankovitch cycles don’t actually cause warming globally, they redistribute incoming solar energy to more polar latitudes, so that they trigger ice melt. This causes the temperature in polar regions to warm even before the global temperature warms, but it’s the global warming that triggers CO2 release from the oceans. But the modern warming is global, so we can expect ocean-solubility influence to happen sooner.
There is, however, the factor of CO2 released from melting ice masses, which one would expect to be “prompt” in relation to ice mass wasting. Anybody know the relative contribution to CO2 increase from oceans versus ice melt, during a deglaciation?
20 April 2007 at 12:29 PM
Hmm, for whatever reason, my reply hasn’t showed up after two postings over the course of a couple of hours.
I guess I’ll ask again and hope for the best…
Gavin’s statement that ocean cooling was going to be hard to reconcile with rising sea levels is simply fact
Since we know that the oceans expand and release CO2 over hundreds of years in response to surface warming, how is a few years of surface cooling hard to reconcile with continuing thermal expansion? The expansion is occurring in the depths of the oceans, in response to ongoing warming that has been occurring going back 300+ years, is it not?
The “irreconcilability” seems to be an unfounded assertion. It seems to me that the thermal expansion wouldn’t stop on a dime in response to what amounts at this point to an insignificant blip of a few years of recent cooling (assuming, for the sake of argument, that cooling has occurred). If you take a longer-term moving average, any recent cooling wouldn’t even show up.
20 April 2007 at 12:34 PM
Re 75. Actually, no. The feedback is temperature, rather than time dependent, so once we reach the temperature where the feedback kicks in, it will be too late–be that in 800 years or next year.
That is one of the reasons why having working models is so important–it allows us to explore feedback mechanisms under various scenarios. This post is neither crowing over success, nor rejoicing at the demise of yet another denialist argument. Rather, it is saying that the models are working well, and that means that we will not be flying blind as we confront the likely effects of climate change.
20 April 2007 at 12:40 PM
Look, we know the climate is changing–that is beyond question. We have a very probable mechanism–anthropogenic greenhouse gas emissions. Those who say, “It’s natural” have absolutely no mechanism to propose to explain the changes we are seeing. As a physicist, I get uncomfortable when people seem to suggest that the energy in a system (e.g. the climate) can just increase with no cause. So until you have a mechanism to suggest, you are not part of the scientific process–skeptical or otherwise.
You are arguing with a straw man. You also seem to be unaware, incredibly, that noone denies that the climate varies naturally and always has… in other words, it is certainly true that “the energy in a system (e.g. the climate) can just increase with no cause”–of course, noone is arguing that there is “no cause” aside from your straw man. To claim such is nothing less than an intentional misrepresentation of people with whom you disagree.
The difference is that Gavin’s perspective is supported by the evidence…
What evidence is there that a few years of surface cooling would immediately stop the thermal expansion that is occurring in response to 300-400 years of warming? That was the statement I originally inquired about. There may be an answer, and that’s why I asked.
I’m not a climate scientist, but common sense tells me that his assertion there was 100% unfounded. I’m simply asking, for the 4th time now, for someone to explain to me why it is founded. That’s all. What’s with the super-defensive reaction to a simple question?
[Response: You are confusing surface warming (which can be checked directly with satellites) and upper ocean heat content (top 700m). Both the sea level change and the numbers reported here are sensitive to the latter, not the former. - gavin]
20 April 2007 at 12:52 PM
So you’re saying that warming causes CO2 increases, which causes warming, which causes CO2 increases, etc? Why has this perpetual feedback cycle not caused our planet to be uninhabitable prior to this point?
Once again, asking because I want an answer, not to be contrarian.
20 April 2007 at 1:01 PM
It seems to me that the thermal expansion wouldn’t stop on a dime in response to what amounts at this point to an insignificant blip of a few years of recent cooling (assuming, for the sake of argument, that cooling has occurred)
That just the point. Since sea level continues to rise, any observed cooling is likely to be insignificant in the long run. There are clear mechanisms for observed local cooling, which are not incompatible with local warming. A large volume of ocean is very cool. The ice sheets are melting into the oceans. Get the picture now?
As long as sea level continues to rise, then there is no way to repudiate global warming. Sea level rise is clear evidence that warming is continuing, and there is no evidence to date to indicate that trend is reversing, or likely to reverse. Everything we see is in accord with our expectations. When the paper indicated anomalous cooling, we fully expected to see correction to the data to appear, because we understand sea level is rising via thermal expansion, and thermal expansion is nearly instantaneous on geological timescales. The analogy is neutrinos from the solar interior, they give us a nearly instantaneous picture of stellar processes which are otherwise obscured from our direct view.
20 April 2007 at 1:02 PM
Re: 77: DaveS: Why wouldn’t thermal expansion stop on a dime? If there is no additional heat going into the ocean (and it is hard to imagine a way that additional heat could enter while the surface is cooling), then we are just moving heat around in the deep. And if we’re doing that… any increase of temperature and therefore expansion in one place will be balanced by a cooling and therefore contraction in another… There isn’t (as far as I understand it) “inertia” in thermal expansion: the water molecules respond pretty much instantly to the new temperature. The inertia comes in with the transfer of heat from atmosphere to ocean, and that’s why it takes hundreds of years to cause the expansion.
20 April 2007 at 1:12 PM
Re: the continuing saga of CO2-lagging indicator
Going back 400,000 years, the maximum CO2 concentrations surrounding the warming and cooling pulses are all lower than current levels. (And the heating associated with those spikes is around +4C. )
20 April 2007 at 1:29 PM
There isn’t (as far as I understand it) “inertia” in thermal expansion: the water molecules respond pretty much instantly to the new temperature.
Hmm, that makes sense to me. However, the amount of expansion in response to new energy wouldn’t be uniform. That heat near the surface will move deeper over time, which will certainly have some sort of “lagging” effect. The density of the water is a function of temperature and pressure, right?
Admittedly–off the top of my head–I suspect that this would actually exaggerate short-term sea-level changes, since the response would probably be smaller in colder, deeper waters under higher pressure. In other words, a complete halt in surface warming would probably cause a slow decline in sea levels, as surface heat mixed downward.
That assumes, of course, that I’m remembering my physics correctly.
20 April 2007 at 2:41 PM
Re #76: tamino — While but an amateur, it seems that the oceans store vast quantities of carbon in various forms and are much more extensive than the LGM ice sheets were. So I’ll hazard the guess that the contribution of carbon dioxide stored in the ice is negligible…
20 April 2007 at 3:16 PM
>thermal expansion
I have no idea how pressure depth relates to thermal expansion — anyone got a pointer? I’m sure the submariners have charts for how density changes with temperature and with depth.
20 April 2007 at 4:12 PM
Re: #83, DaveS: Huh. Yeah. The differences in density between deep water and surface water might mean that moving heat around could cause changes in sea level without new heat inputs. Also, the density to heat content relationship is probably non-linear, so that could also cause discrepancies.
I’d still think that these would be 2nd order effects, and not large enough to account for the sea level changes being observed… but I acknowledge that I could be wrong.
20 April 2007 at 4:30 PM
RE: 62
Still struggling with the concept of climate sensitivity. Questions above. Can anybody summarize the fundamental assumptions being made to estimate current climate sensitivity. I cannot seem to get past the idea that we can only make assumptions about today’s climate’s reaction to forcings based on the earth’s reaction to forcings from tens of thousands of years ago. Is it not reasonable to assume that many climate systems (ocean circulation patterns, cloud dynamics, etc.) are likely very different and thus past behavior cannot really give us an accurate sense of climate sensitivity today?
Sorry if I am overlooking something obvious.
20 April 2007 at 5:14 PM
Lyman’s assert on observed ocean cooling last year was an interesting attempt on understanding ocean changes. Discussing therefore whether the ocean heat contents changes is a quiet sensible consequence. But wondering should be permitted. The oceans water masses are quite a massive body, with 1000 times the “heat capacity” of the entire atmosphere, and last not least are only +3,5 degree Celsius warm. Who will be able to tell that the ocean heat content has changed?
20 April 2007 at 5:23 PM
Responding to 14 (I know this was a long way back, but I haven’t seen a specific response): “Also, how does this new information change the point made in the discussion from the original paper? This work has several implications. First, the updated time series of ocean heat content presented here (Figure 1) and the newly estimated confidence limits (Figure 3) support the significance of previously reported large inter annual variability in globally integrated upper-ocean heat content [Levitus et al., 2005]…”
You’ve got to understand that none of the numbers here is known with a high degree of confidence, because the ocean is very poorly sampled. (Until ARGO, that is, but unfortunately that data is still new.) There have been suggestions for a while that the global ocean heat content has higher interannual variability than simulated by the models (ie by the ocean component of coupled climate models). With the latest revision the evidence for *really* high interannual variability has melted away. Still, it’s an interesting subject and one that should be revisited when we have, say, a decade of ARGO data.
I wouldn’t be at all surprised if the ocean component of coupled climate models *did* show lower than observed levels of interannual heat flux variability. For one thing, the models in question have rather coarse spatial resolution and so the flow in them is very “syrupy”. (How that would affect interannual variability in heat content I don’t know, but you’ve got to wonder.) For another, there could be greater interannual variability in the radiative forcing at the ocean surface than we know about. But I don’t think any of this provides evidence of serious problems with the climate models, ones that would make their projections invalid.
20 April 2007 at 5:39 PM
re 69: I’m a skeptic and on opposite sides of the table from Gavin. I think he sometimes goes over the top and sometimes shows his bias too much (though bias is kinda O.K as opposed to prejudice). But, IMO, I’m very impressed with his efforts and scientific demeanor and consider him extremely reliable. I’ve critized him sometimes and questioned him a number of times but think he is top-notch and does a helluva job.
20 April 2007 at 5:57 PM
re 73 et al: This is a latent sandbox1 concern that’s been bugging me for some time. Beyond the spin and assertions of the sensor designers (designers always contend their design works exactly) how can we tell if ocean(s) rise a couple of millimeters? All the oceans? An average of all of the oceans? Particular oceanic “hot spots”? El Niño changes the surface about 500 mm; can we detect a variation of 1-2 mm “because of AGW”???
20 April 2007 at 9:00 PM
No-one has answered 79 from DaveS yet: “So you’re saying that warming causes CO2 increases, which causes warming, which causes CO2 increases, etc? Why has this perpetual feedback cycle not caused our planet to be uninhabitable prior to this point?”
I haven’t been able to found any good answers elsewhere yet. I assume that during the interglacials, various carbon sequestration processes kick in or are enhanced, and that these lower the CO2 concentration enough to bring the temperature back down. Does anyone have information on the specifics of this? What are the candidate processes and how well do we understand them? This explanation prompts the opposite question though. What prevents the CO2 concentration from continuing to drop until we freeze over?
20 April 2007 at 10:44 PM
Re 85 Hank,
If I understood your question correctly:
Water is nearly incompressible, so its density doesn’t change significantly with depth - any density differences are almost entirely due to differences in temperature and salinity. Any good oceanography textbook (e.g., Sverdrup, Johnson, and Fleming,1942, The Oceans Their Physics, Chemistry, and General Biology; see Chapter IV, http://ark.cdlib.org/ark:/13030/kt167nb66r/) have tables or nomagrams relating temperature/salinty/density, and tables or figures showing temperature and salinity as a function of depth. Another, more recent, source is:
Emery, W.J. and L.J. Dewar, 1982: Mean temperature-salinity, salinity-depth and temperature-depth curves in the North Atlantic and North Pacific. Pergamon Press, Oxford, England, 91 pp.
20 April 2007 at 11:01 PM
Re #92 Sea level changes
Basically, tide gauges and satellite altimetry:
http://sealevel.colorado.edu/
http://www.pol.ac.uk/psmsl/manuals/
http://www.csr.utexas.edu/gmsl/main.html
http://science.howstuffworks.com/question356.htm
21 April 2007 at 1:02 AM
This was a very informative post. The details of the ocean temperature data are important.The wider lessons at the end are even more important. One of the things that the general public needs to know when they are trying to understanding global warming is how science works.
It also shows how politics have become a part of the public debate of the science. If someone submits a paper, like Lyman et al, that might cast doubt on AGW people wonder if there is a contrarian/political motive involved. In my own idealistic way, I think its unfortunate that that the clean scientific method is being drawn into the dirty world of politics.
21 April 2007 at 6:28 AM
re 92
I agree that we seem to be extrapolating global trends from a limited number of data sets and therefore these global sea level rise figures have to be viewed with a healthy dose of skepticism. I think the same can be said of Antartic ice core data and their utility for determining temperature for the rest of the planet.
Still learning a lot reading the contributions at this exceptional site, but it is my impression that the scientists still lack sufficient knowledge to be able to categorically state that the earth is on the verge of catatrophe.
21 April 2007 at 8:22 AM
Re: #87: Marcus-*The differences in density between deep water and surface water might mean that moving heat around could cause changes in sea level without new heat inputs. Also, the density to heat content relationship is probably non-linear, so that could also cause discrepancies.*
When a water molecule warms it vibrates more. This causes it to occupy more space amongst the molecules surrounding it. As it mixes with cooler molecules it warms them and they cool it, causing the extra space that it occupied on warming to diminish; however, the original extra space is not lost but merely acquired by the molecules that it warmed.
The net effect is no additional thermal expansion or contraction due to mixing with other molecules. Additional heat must be added to the water molecules to cause more expansion.
21 April 2007 at 8:35 AM
Re: #92, #97 (sea level trend)
Indeed the rate of sea level rise is slow by comparison to changes brought about by tide and wind. I don’t know whether or not there is a limited number of data sets, but let’s assume, for the sake of argument, that indeed it’s true.
The limited amount of data does not invalidate in any way the detection of a trend. When we study data looking for a trend, we apply statistical tests which are tried-and-true, confirmed by literally millions of cases, and more important, can be *proved* in the only way that true proof exists: mathematically. If the statistical test shows overwhelming likelihood of a trend, then it’s overwhelmingly likely to be there — regardless of whether we have a limited number of data sets.
Of course, more data sets are better, because that increases the sensitivity of the trend analysis; it enables us to separate ever-smaller trends from the noise with statistical confidence. So, more is better.
The “catch” is that statistical tests can detect and quantify trends in the data. But if the data don’t match the physical system, as is the case for the Argo floats, then we’ve only detected a trend in a bunch of numbers, not in the physical quantity we tried — and failed — to measure.
Therefore a larger number of data sets is doubly helpful: not only does it increase the sensitivity of statistical tests, to identify even smaller trends if present, it also decreases the likelihood that we’ll be fooled by bad data, since it’s unlikely that multiple data sets will all be affected by errors that go in the same direction, giving false detection of a trend (opposite errors will cancel in a trend analysis, and give the false impression of the absence of a trend).
21 April 2007 at 9:45 AM
[[if you presuppose that increases in measured sea-levels are due in large part to thermal expansion and that there is no “inertia” involvedR