The Global Cooling Bet - Part 2
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) Last week we proposed a bet against the "pause in global warming" forecast in Nature by Keenlyside et al. and we promised to present our scientific case later - so here it is.
This is why we do not think that the forecast is robust:
Figure 4 from Keenlyside et al '08. The red line shows the observations (HadCRU3 data), the black line a standard IPCC-type scenario (driven by observed forcing up to the year 2000, and by the A1B emission scenario thereafter), and the green dots with bars show individual forecasts with initialised sea surface temperatures. All are given as 10-year averages.
- Their figure 4 shows that a standard IPCC-type global warming scenario performs slightly better for global mean temperature for the past 50 years than their new method with initialised sea surface temperatures (see also the correlation numbers given at the top of the panel). That the standard warming scenario performs better is highly remarkable since it has no observed data included. The green curve, which presents a set of individual 10-year forecasts and is not a time series, each time starts again close to the observed climate, because it is initialised with observed sea surface temperatures. So by construction it cannot get too far away, in contrast to the "free" black scenario. Thus you'd expect the green forecasts to perform better than the black scenario. The fact that this is not the case shows that their initialisation technique does not improve the model forecast for global temperature.
- Their 'cooling forecasts' have not passed a the test for their hindcast period. Global 10-year average temperatures have increased monotonically during the entire time they consider - see their red line. But the method seems to have produced already two false cooling forecasts: one for the decade centered on 1970, and one for the decade centered on 1999.
- Their forecast was not only too cold for 1994-2004, but it also looks almost certain to be too cold for 2000-2010. For their forecast for 2000-2010 to be correct, all the remaining months of this period would have to be as cold as January 2008 - which was by far the coldest month in that decade thus far. It would thus require an extreme cooling for the next two-and-a-half years.
- Even for European temperatures (their Fig. 3c, not part of our proposed bet), the forecast skill of their method is not impressive. Their method has predicted cooling several times since 1970, yet the European temperatures have increased monotonically since then. Remember the forecasts always start near the red line; almost every single prediction for Europe has turned out to be too cold compared to what actually happened. There therefore appears to be a systematic bias in the forecasts.
- One of the key claims of the paper is that the method allows forecasting the behaviour of the meridional overturning circulation (MOC) in the Atlantic. We do not know what the MOC has actually been doing for lack of data, so the authors diagnose the state of the MOC from the sea surface temperatures - to put it simply: a warm northern Atlantic suggests strong MOC, a cool one suggests weak MOC (though it is of course a little more complex). Their method nudges the model's sea surface temperatures towards the observed ones before the forecast starts. But can this induce the correct MOC response? Suppose the model surface Atlantic is too cold, so this would suggest the MOC is too weak. The model surface temperatures are then nudged warmer. But if you do that, you are making surface waters more buoyant, which tends to weaken the MOC instead of enhancing it! So with this method it seems unlikely to us that one could get the MOC response right. We would be happy to see this tested in a 'perfect model' set up, where the SST-restoring was applied to try and get the model forecasts to match a previous simulation (where you know much more information). If it doesn't work for that case, it won't work in the real world.
- When models are switched over from being driven by observed sea surface temperatures to freely calculating their own sea surface temperatures, they suffer from something called a "coupling shock". This is extremely hard, perhaps even impossible, to avoid as "perfect model" experiments have shown (e.g. Rahmstorf, Climate Dynamics 1995). This problem presents a formidable challenge for the type of forecast attempted by Keenlyside et al., where just such a "switching over" to free sea surface temperatures occurs at the start of the forecast. In response to the "coupling shock", a model typically goes through an oscillation of the meridional overturning circulation over the next decades, of the magnitude similar to that seen in the Keenlyside et al simulations. We suspect that this "coupling shock", which is not a realistic climate variability but a model artifact, could have played an important role in those simulations. One test would be the perfect model set up we mentioned above, or an analysis of the net radiation budget in the restored and free runs - a significant difference there could explain a lot.
- To check how the Keenlyside et al. model performs for the MOC, we can look at their skill map in Fig. 1a. This shows blue areas in the Labrador Sea, Greenland-Iceland-Norwegian Sea and in the Gulf Stream region. These blue areas indicate "negative skill" - that means, their data assimilation method makes things worse rather than improving the forecast. These are the critical regions for the MOC, and it indicates that for either of the two reasons 5 and 6, their method is not able to correctly predict the MOC variations. Their method does show skill in some regions though - this is important and useful. However, it might be that this skill comes from the advection of surface temperature anomalies by the mean ocean circulation rather than from variations of the MOC. That would also be a an interesting issue to research in the future.
- All climate models used by IPCC, publicly available in the CMIP3 model archive, include intrinsic variability of the MOC as well as tropical Pacific variability or the North Atlantic Oscillation. Some of them also include an estimate of solar variability in the forcing. So in principle, all of these models should show the kind of cooling found by Keenlyside et al. - except these models should show it at a random point in time, not at a specific time. The latter is the innovation sought after by this study. The problem is that the other models show that a cooling of one decadal mean to the next in a reasonable global warming scenario is extremely unlikely and almost never occurs - see yesterday's post. This suggests that the global cooling forecast by Keenlyside et al. is outside the range of natural variability found in climate models (and probably in the real world, too), and is perhaps an artifact of the initialisation method.
Our assessment could of course be wrong - we had to rely on the published material, while Keenlyside et al. have access to the full model data and have worked with it for months. But the nice thing about this forecast is that within a few years we will know the answer, because these are testable short term predictions which we are happy to see more of.
Why did we propose a bet on this forecast? Mainly because we were concerned by the global media coverage which made it appear as if a coming pause in global warming was almost a given fact, rather than an experimental forecast. This could backfire against the whole climate science community if the forecast turns out to be wrong. Even today, the fact that a few scientists predicted a global cooling in the 1970s is still used to undermine the credibility of climate science, even though at the time it was just a small minority of scientists making such claims and they never convinced many of their peers. If different groups of scientists have a public bet running on this, this will signal to the public that this forecast is not a widely supported consensus of the climate science community, in contrast to the IPCC reports (about which we are in complete agreement with Keenlyside and his colleagues). Some media reports even suggested that the IPCC scenarios were now superseded by this "improved" forecast.
Framing this in the form of a bet also helps to clarify what exactly was forecast and what data would falsify this forecast. This was not entirely clear to us just from the paper and it took us some correspondence with the authors to find out. It also allows the authors to say: wait, this is not how we meant the forecast, but we would bet on a modified forecast as follows… By the way, we are happy to negotiate what to bet about - we're not doing this to make money. We'd be happy to bet about, say, a donation to a project to preserve the rain forest, or retiring a hundred tons of CO2 from the European emissions trading market.
We thus hope that this discussion will help to clarify the issues, and we invite Keenlyside et al. to a guest post here (and at KlimaLounge) to give their view of the matter.
13 mai 2008 at 4:30 PM
And let’s not forget that the media largely misreported the results of this study because the authors use a very strained definition of the term “next decade.”
http://climateprogress.org/2008/05/02/nature-article-on-cooling-confuses-revkin-media-deniers-next-decade-may-see-rapid-warming/
As I explain, the Nature study is consistent with the following statements:
* The “coming decade” (2010 to 2020) is poised to be the warmest on record, globally.
* The coming decade is poised to see faster temperature rise than any decade since the authors’ calculations began in 1960.
* The fast warming would likely begin early in the next decade — similar to the 2007 prediction by the Hadley Center in Science (see http://climateprogress.org/2007/08/15/climate-forecast-hot-and-then-very-hot/).
* The mean North American temperature for the decade from 2005 to 2015 is projected to be slightly warmer than the actual average temperature of the decade from 1993 to 2003
13 mai 2008 at 4:32 PM
I just heard the Keenlyside cooling prediction used on the radio to argue that
there is no such thing as a climate crisis (by a guy from the office of Sen.
James Inhofe, he of the hoax comment). Thanks for making this a betting matter,
RC. It gives the question a higher profile. Scientific American says that ice
sheets are sliding faster toward the sea. I’d say that’s a crisis .
13 mai 2008 at 4:34 PM
So the Chaiten eruption isn’t going to get big enough to call off the bet?
[Response: Doesn’t look like it. Not enough SO2. - gavin]
[Response: And as I pointed out in response to an earlier similar comment, extratropical eruptions like this rarely give rise to a significant global mean cooling. - mike]
13 mai 2008 at 5:10 PM
Re the Chaiten eruption, from what I’ve read, a volcano needs to emit at least 1 million tons of sulfur dioxide into the stratosphere to have an effect on global temperature. Chaiten has only emitted an estimated few thousand tons of sulfur dioxide:
http://ap.google.com/article/ALeqM5h6XCGT4X37OvMVvC6CA6UaDMeriAD90GHEFO0
13 mai 2008 at 5:46 PM
Very interesting thanks.
Recent evidence suggests that CO2 has now reached the level of 387 parts per million - what is the total figure for CO2 equivalents - probably more significant?
Are we yet at a tipping point?
13 mai 2008 at 6:40 PM
Thank you very much for these 2 articles. I used the first 4000 characters of the first one on alternet.org/environment already.
All bachelors level degrees, including journalism and English, should require the engineering and science core curriculum. Journalists do the journalism thing to sell papers. The journalism thing is exactly the wrong thing to do when reporting science. RealClimate needs to be read by the whole world. You are often too mathematical for almost everybody. Your concepts are mathematical. Nonetheless, RealClimate should be what everybody reads directly for themselves, if they can. A wager is a good idea and I think it is working for those who come in contact with your story in some way.
13 mai 2008 at 7:51 PM
Last week I criticised your bet as I thought it trivialised the issues involved but I understand your rationale better now.
This post is exactly why this site is so popular for lay-people: it provides a clear explanation of climate change science and informed debate on current topics. Your best posts, like this one, allow lay-people to “see inside the heads” of how climate scientists think. For any objective, critical thinker reading your work the explanations of the assumptions you are making and the sources of error you identify both explain the issues involved and build confidence to accept your conclusions.
As you say, your “assessment could of course be wrong” but a critical thinker reading your work is looking for the evidence and reasons you present to support your argument.
Well done and thanks.
13 mai 2008 at 8:04 PM
Dear group,
It seems a pity that you have had to use this hammer to crack a nut; but it works!!!
If only… If only they had let their paper speak for itself and had left out the big claim. The sadness is that if we bury this and I suspect you, others and simply the passage of time will. The interesting part (can and how oscillations be predicticted) will be buried alongside the headline result.
To me it seems such a pity for them and all of us.
Best Wishes
Alex Harvey
13 mai 2008 at 8:06 PM
Why not propose your bet to Inhofe? The guy is utterly shameless.
13 mai 2008 at 9:13 PM
RE:#6,
I have a journalism degree technically, but I have three times as many science credits in environmental biology, physical science, and work as an endangered species biologist for the US Forest Service and others. It’s a good point though since most top reporters come from Ivy league schools where no such requirement exists. Not so at public universities. Since graduating a couple of years ago, (non-traditional) I’ve not landed so much as an interview for a reporting job. Editors are science averse like that guy in Ely, Nevada! It’s a real problem.
13 mai 2008 at 10:35 PM
Evidence shows that CO2 is going up at over 3% per year…Faster than in the highest IPCC scenario. Interesting to see if it continues at this rate…and what is causing it…drought?
Good thing for the bet that there is a lag time.
[Response: Emissions are rising 3% a year, concentrations at just over 0.5% a year (~2ppm). - gavin]
13 mai 2008 at 10:52 PM
Two excellent posts regarding Keenlyside, et al. As others have said, the paper is already being used to excuse denialists’ delusions despite the fact that the authors, themselves, say clearly that their paper does not contradict AGW and should not be used to assert it does. Rapid Climate Change is a real and present danger that short-sighted denialists/industrialists pay scant attention to. The delays in action created by the lies, distortions and muzzling done by Exxon and the Bush administration have already put the world into a percarious position given that climate changes are happening all over at far faster rates than ever considered possible just a year ago. Too many of the citizens of the US and Britain still believe there is substantive scientific uncertainty about climate change - even as George Bush lives in a “green,” off-grid home and now says climate change is real.
One change I’m sure the Keenlyside authors couldn’t have considered is the much-more-rapid-than-expected release of methane in the Arctic that was reported in the last week or so. (Can’t find link now, but the results will do: http://www.csmonitor.com/2008/0428/p01s04-wogi.html )
Keep up the good fight with good science.
Cheers
13 mai 2008 at 11:05 PM
“Thanks for making this a betting matter, RC. It gives the question a higher profile.” I agree, but I wonder why RC does, as the higher profile gives the lie to the notion that there is universal scientific consensus on AGW. Granted Keenlyside predicts only a temporary reprieve before AGW predominates again, I doubt that nuance will make to the coverage of a Warming vs. Not Warming bet. RC fears the media is making an issue of Keenlyside temperature flattening — I see the media in comfortable lockstep with AGW proponents regardless of an occasional Keenlyside blip on the screen. AGW sells more papers, so to speak, than its absence. I admire the courage of RC’s convictions, then, because it has nothing to gain if the bet is won and everything to lose if the bet is lost.
14 mai 2008 at 1:05 AM
#13, wmanny that is such an disingenious, inaccurate, and lazy post.
There is broad scientific consensus on the reality of anthropogenic climate change but there still a huge amount of ongoing research into many of the details. Keenlyside and his colleagues deal with some of the details but expressly state they not doubt the broad consensus view on the reality of anthropogenic climate change.
Your suggestion that the bet offered by RealClimate “gives the lie to the notion that there is universal scientific consensus on AGW” is just plain wrong.
Your comments about RealClimate’s motives and your suggestion that they are driven by “convictions” rather than good science indicate you are too lazy to engage them in a debate based on science and evidence.
If you want to do some background reading on the scientific consensus statements (you seem in real need of it), there is a good compilation of them (with links) at http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change .
14 mai 2008 at 1:42 AM
Re #13 “media in comfortable lockstep with AGW proponents” might have less to do with comfort and more to do with honest reporting. After all, they spent 20 years “comfortably” reporting the debate about AGW, but that debate is finally over, so the media have simply moved with the news. Can’t expect anything less, nor anything more, than that from the media.
I guess I’m of two minds about this whole affair. Sure, let’s not let the “debate” thing derail us again just because a couple guys with a model think there might be a flat spot in the warming trend, if you hold the chart up to the light just so and squint.
On the other hand… who gives a poop anymore? Seriously, it’s getting to the point where anyone who stands up in a crowd and says “my dog knows more about climate than Jim Hansen” is not going to like the reaction he gets. People in the streets are reading the reports carefully now, and what they are finding there gives little comfort. Setting aside the price of oil and its immediate impact on food, there is still enough going on with climate change and related water and agriculture issues to cause a prudent soul to glance around for an exit.
Well we’re 7 billion prudent folk all glancing around nervous, and I’m not the first to point this out. And going forward, anyone says all this is just smoke and mirrors to get grants to study tree rings is advised not be standing under a sturdy limb and holding a rope when he’s saying it. If you follow my meaning.
14 mai 2008 at 1:50 AM
I love that “monotonously”! Maybe monotonically? Or is this another example of the transAtlantic divide in language?
John
[Response: Thanks John, fixed that. Not transAtlantic, but we’re not all born native speakers of the global language of science. -stefan]
[Response: Actually, I almost changed that when were editing, but I thought monotonously was a little more apt…. - gavin]
14 mai 2008 at 2:20 AM
Latif’s group does not have much experience in modelling the MOC. But how could they (and the Nature reviewers) have overlooked so many obvious red flags? The fact that the hindcasts with their method perform worse than a standard IPCC scenario, the number of failed previous cooling predictions, the negative skill in the Gulf Stream and deep-water formation regions… should these not have cautioned them against going to the media to forecast a pause in global warming? Your bet does a good service, but I fear that it cannot undo the damage that they have already done in confusing the media public about global warming.
14 mai 2008 at 2:56 AM
Gavin, you responded at #11 that emissions are rising at 3% per year while concentrations only rise at 0.5% per year. That is somewhat logical because there was already some concentration before we started any emissions. However there is another phenomenon that I have been unable to understand, and I would like to know if there is any theory that explains it.
Between the 80’s and the 90’s, man-made emissions of carbon from fosil fuels increased from about 5 billion tons per year to about 6.5 billion tons per year, which means a 30% increase in how much CO2 we put into the atmosphere yearly. However, the ratio at which CO2 concentration increases in the atmosphere slowed down between the 80’s and the 90’s, from 1.6 ppm/year to 1.5 ppm/year. Is there an explanation for that? Do you think it could be related to the rising temperatures and how it affects the Earth’s capability to sequester atmospheric CO2 by natural processes like the photosintesis of the plants? Or is there something else? And whatever the cause may be, is it predicted in the models?
Thanks.
14 mai 2008 at 3:04 AM
“Even today, the fact that a few scientists predicted a global cooling in the 1970s is still used to undermine the credibility of climate science”
Why does the HadCRU3 temperature data not show the cooling in the 1970s? Does the forecast of Keenlyside et al for this period, of a cooling, reflect the cooling in the 70s from other datasets?
14 mai 2008 at 3:13 AM
Re: coupling shock
Nice summary. I read the paper as saying that they are restoring to SST anomalies rather than the raw SSTs themselves - does this make a difference?
[Response: Not to the coupling shock problem. -stefan]
14 mai 2008 at 3:24 AM
There is no need to bet when you stick to the science (and measured data and observations as much as possible). The green line “forecast” for the period 1995-2000 in the graph above is well below actual observations for the same period. This speaks for itself.
Also, evidence of the affects of global warming from many parts of the world speaks for itself - melting ice, droughts, increasing water supply problems in big cities like Barcelona etc.
What causes doubt and confusion is that the effects of global warming are not uniform around the globe and there are always weather fluctuations (that may even increase in scale and predictability) as global warming progresses. Global circulation patterns are very complex and the effects of any changes are so difficult to predict on a local, regional level. This is why we need a focus on regional and local studies, observations, and assessment that do not depend so heavily on models.
Professor Molina, Nobel Prize (chemistry) issued a stark warning recently (April, 2008) by suggesting that, “…long before we run out of oil, we will run out of atmosphere”. Professor Santilli (nominationed for the Nobel Prize in chemistry and physics) has raised the issue of atmospheric oxygen depletion - particularly in some of our largest cities around the world. The Chinese, for example, have planted a forest twice the size of New York’s Central Park on a 1,750-acre site north of the Olympic village in Beijing, to raise oxygen levels. Nearly a dozen factories are also closing or relocating outside Beijing, and factories hundreds of kilometres away will suspend operations for the duration of the olympics.
Our emissions to the atmosphere impact on natural processes, the environment, and health in very many ways - the ozone hole was the first big warning. It is so important that we learn, inform and educate on the basis of the best known science - illiminating guesswork (and certainly no bets)!
14 mai 2008 at 3:38 AM
Re: RMS error and correlation skill
The supplementary information to the paper has an interesting figure - Supp. Fig. 2c shows the difference in RMS (root mean square) error (as compared to the correlation maps shown in the main paper) between the hindcasts and non-initialised cases. There it demonstrates that the RMS error in the Atlantic is worse in the forecast cases compared to the non-initialised cases. There are a few regions where the forecast appears more skillful in this metric of skill, which could be viewed as more relevant when making forecasts.
14 mai 2008 at 4:34 AM
You are always very polite and diplomatic. The guts of this story is really quite funny: a group of climate scientists manages to sell a weird model result, most likely an artifact due to an inadequate modeling technique, as a sensational forecast to Nature and the world media…
I think the lesson of this story is that it is rather problematic that new climate science papers are now all over the media within hours of appearing in a journal, with political implications being discussed before the scientific community had time to properly assess and discuss the new study.
14 mai 2008 at 7:00 AM
Brilliant article review, I hope I can capture some of the magic in the paper I am reviewing today. I understand the gist of coupling shock, but can you provide an example of how it would play out, and what can be done to identify and quantify this result.
14 mai 2008 at 7:10 AM
Re #22, yes the media has to learn that peer review is not the end of the scientific process but part of an ongoing process of validation and verification before it is allowed into the hallowed halls of scientific truths.
14 mai 2008 at 7:12 AM
Whilst bets are of no use in determining the underlying physical reality, they are very useful in sorting out people’s real level of confidence in their predictions. This can be a useful indicator how strongly we lay-people should factor them into out considerations.
I do hope Keenlyside’s team post here, their take would be interesting. From a policy and adaptation point of view such efforts to make more accurate short-term predictions could be valuable, if time bears out their predictions.
#5 Martin Pierard,
I wouldn’t think of a single global tipping point as such, what’s important in this respect are the different climate subsystems. In that respect you may find this page interesting:
http://www.pik-potsdam.de/infodesk/tipping-points
#17 Nylo,
Those CO2 increments seem all over the place to me, when viewed on a short term basis:
http://www.esrl.noaa.gov/gmd/ccgg/trends/ scroll down to global average.
1998 is interesting, but without looking at what’s happening regionally I wouldn’t read too much into most of the year-to year variance. What is apparent is that on a multi-year basis the ppm/year increase is going up, try something like a 5 year moving average to filter inter-annual difference for the full record.
With regards CO2 emissions uptake, have you read David Archer’s post on this? http://www.realclimate.org/index.php/archives/2007/11/is-the-ocean-carbon-sink-sinking/
#19 Gareth John Evans,
Out of interest, the Arctic Oscillation/North Atlantic Oscillation (which are intrinsically linked) seem to have a key role in both the Arctic ice loss (outflushing through the Fram Strait) - Rigor/Wallace) and the Mediterranean drying e.g. Figen Mekik’s post at RC http://www.realclimate.org/index.php/archives/2007/10/sweatin-the-mediterranean-heat/
Mmmmm, I’m far from convinced.
14 mai 2008 at 7:59 AM
wmanny #13–Let’s get one thing straight. The consensus of scientists on climate change is that humans, by releasing massive amounts of the greenhouse gas, CO2, into the atmosphere, are largely responsible for the current epoch of warming. Keenlyside et al. is part of that consensus, not a challenge to it.
You say, “I see the media in comfortable lockstep with AGW proponents… ”
Well, I’ve always found the truth to be more comfortable than any lie. Actually, the media lag far behind the scientists in terms of the level of consensus. If they really understood the science, then the occasional outbursts by denialists would generate no more notice than a fart in polite company–a little embarassment for the offender, but no overt comment.
14 mai 2008 at 8:11 AM
Re #10
” It’s a good point though since most top reporters come from Ivy league schools where no such requirement exists.”
That’s certainly not true of the one where I teach.
14 mai 2008 at 8:49 AM
It is true that old fears of a new ice age did not originate with climate scientists [edit - no nonsense please] and I confess to being someone who worried about such things at that time. But was I wrong? When estimates of a possible return of an ice age still vary between this week and 50,000 years why should I be confident that the guys with tenure and titles have a handle on it?
In that large, mysterious (to me, anyway) context, listening to climate scientists boldly predict changes or non-changes in the range of tenths of degrees over a mere 10 or 20 years strikes me as more than just a tad beyond hubris and more like a standard deviation or two into the delusional range. One volcanic burp, one solar belch, a passing cosmic cloud or some butterfly flapping its wings in New Jersey and entire models can become just really bad computer games.
I admire the creativity and genius in climate modeling and the insights it can provide but when you guys start thinking it’s real, maybe it’s time to back away from the keyboard for a bit.
Without the ugly constraints of the overarching politicized death struggle, there is a beauty even in the uncertainties of this pursuit. To minimize or even fail to investigate uncertainties lest it give comfort to the denialist foe is no way to live.
14 mai 2008 at 9:23 AM
#29 - the phenomenon of greenhouse gases retaining heat at the surface of the earth operates on decadal scales, and the orbital variations (Milankovitch cycles) which cause the waxing and waning of the ice ages operate on millennial scales, and both are fundamental physical processes, and are not elucidated by computer models. Nothing is going to change those results, short of a complete refutation of fundamental physics - unlikely.
The computer models deal with the actual energy and matter flows within, and in and out of the system, and do not account for random geological or cosmological events, such as volcanic eruptions or asteroid impacts, solar disturbances, etc. However, these computer models are also based in fundamental physics, and the random events can be modelled as well, if not predicted in advance.
14 mai 2008 at 9:23 AM
This begs a question. Should you lose the bet, what ramifications does that have for AGW theory? How many years of cooling will it take before AGW theory is debunked? Let’s see a commitment from RC staff on this. How many years of continued cooling will it take for AGW theory to be rejected? You like bets, then place one on that.
[Response: None. About 20. Like I said. Lot’s of bets have been offered - few taken. - gavin]
14 mai 2008 at 9:40 AM
CarbonSink51, Spoken like a man who doesn’t understand the science. Look, the GCMs are complicated, and yes there are uncertainties, but the fundamental reality, the 800 pound gorilla in the room is the fact that CO2 traps outgoing infrared radiation. Since such radiation is the only way energy escapes the climate system, that has to heat things up. Since the only escape clause is some magical negative feedback that kicks in to keep climate from warming above its current level, and since there is no such mechanism known and further since climate has warmed above this level in the distant past, I’d say this is pretty darned unlikely. Those who look to such a mechanism are appealing to Disney’s first law–Wishing will make it so.
14 mai 2008 at 9:46 AM
Sad to say, I keep hearing people — and these are bright people — say “I don’t believe in global warming.” I don’t know how to get away from paralyzing fear that must be the driver of this sort of comment — they don’t want to believe it.
I’m writing a novel with a denier in it, and tried to come up with a carp about the GW science that hasn’t been used. Just my luck, I decide the denier announces that global cooling has begun! reality imitating art…
14 mai 2008 at 9:52 AM
> 21, Gareth
Molina was talking about climate change.
Santilli? Look him up. Utterly off topic.
14 mai 2008 at 10:05 AM
You don’t have permission to access /~stefan/Publications/Journals/rahmstorf_climdyn95.pdf on this server.
[Response: I made a local version you shouldn’t have a problem with (link above). - gavin]
14 mai 2008 at 10:54 AM
[Response: Emissions are rising 3% a year, concentrations at just over 0.5% a year (~2ppm). - gavin]
Hi Gavin,
I clearly heard the exact phrase “over 3%” deliberately and clearly stated yesterday at a government-funded research institute in Boulder at a presentation by a visiting publishing scientist using the latest sources who is researching the latest CO2 trend anomalies.
Of course, this is my own personal opinion, the researcher might have been exagerating (I doubt it..the researcher would have been crucified by other publishing experts present..not to mention their reputation) and my statement is not in any way connected to any single institution.
14 mai 2008 at 11:26 AM
This is nice, that climate scientists have reached consensus. If you want to convice the general public to the “tipping point” that we actually as a society begin to do something about it. You must preserve your credibility, and resist the temptation to say, every time that there is a hot day or a hurricane “see-it is global warming”. Because surely then when there is a cold day or a calm season, you have taught the deniers.
And when the arctic ice melts - faster than the models predict - who can say this is AGW?
Alien (Only art, no science)
[Response: If you care to look, we have been remarkably consistent on that point. - gavin]
14 mai 2008 at 12:07 PM
Re #36: Possibly a reference to the increase in the rate?
14 mai 2008 at 12:35 PM
Why do you think it’s melting? Global cooling?
14 mai 2008 at 12:36 PM
You know, when somebody introduces themselves as “veritas” or Mr. Friendly the used automobile salesman, I reflexively reach for my wallet.
14 mai 2008 at 2:07 PM
RE#38 I think that we are in deep doo doo a’la AGW. I am just pointing out that if the speed of arctic ice melting is outside the parameters that are predicted by the model, then the model might be wrong.
Alien
14 mai 2008 at 2:20 PM
As one that repeatedly asked that you rescind your bet in favor of a gentleman’s bet, I commend you for agreeing to a non-financial bet. I still believe that the wager is too high but it will be interesting if Keenlyside et. al. will respond with terms that are more fitting with science and its discussion - perhaps a year’s subscription to Nature magazine for the inner city high school of the winner’s choice.
One question on your logic that I don’t quite understand (and perhaps I am misinterpreting the chart at the top of the article). You state in point 2 that since there are two false cooling forecasts that the model is suspect. While I grant you that the large gap in the late 90s is of huge concern, isn’t that same concern warranted with the large continuous gap from actual in the IPCC hindcast from 1965 to 1985?
14 mai 2008 at 2:37 PM
“You know, when somebody introduces themselves as “veritas” or Mr. Friendly the used automobile salesman, I reflexively reach for my wallet.”
No biggie, but Gavin I’m sure has my two IP addresses. One of them is rather blatent and has been so for the two years or so that I’ve been posting on this blog.
14 mai 2008 at 3:21 PM
Re #42 Sean O,
No there isn’t a concern about the IPCC model and the small deviations from the measured temperature evolution during the period around 1970-1985. The IPCC models make no claim to reproduce every variation in the temperature evolution in response to enhanced greenhouse forcing. That’s the whole point, of course. Everyone recognises that the Earth undergoes a warming response to enhanced greenhouse forcing. In general it’s recognised that prediction of the so far unpredictable phenomena (El Nino’s, La Nina’s, the fine details of ocean circulation oscillations, volcanos and any solar variation outwith the 11 year solar cycle) that provide short term modulation of any trend is likley to be unfruitful at present.
However Keenleyside et al are claiming to be able to predict the trend incorporating these short term modulations. Therefore Keenleyside’s assertions concerning the short term should be subject to the degree of scrutiny commensurate with their particular claim. That doesn’t apply to the IPCC simulations since they make no such claim of being able to predict short term modulations of the long term trend. That’s obvious isn’t it?
14 mai 2008 at 3:51 PM
Re #18: Nylo says “Gavin, you responded at #11 that emissions are rising at 3% per year while concentrations only rise at 0.5% per year. That is somewhat logical because there was already some concentration before we started any emissions.” Actually, you are trying to compare two numbers that have completely different meanings…It is an apples-to-oranges comparison. The 3% per year is the amount by which the emissions are increasing…and (assuming that the fraction of this that stays in the atmosphere is constant) this would then be essentially proportional to the second derivative of the concentration of CO2 in the atmosphere with respect to time. However, the 0.5% per year is the rate at which the concentration of CO2 in the atmosphere is increasing…i.e., it is essentially the first derivative of the concentration of CO2 in the atmosphere with respect to time.
Thus, whether this 0.5% value is less than, greater than, or equal to the 3% value is irrelevant. It is sort of like trying to figure out if my weight in pounds is less than my height in centimeters and attaching some deep meaning to it.
14 mai 2008 at 4:19 PM
#1
“As I explain, the Nature study is consistent with the following statements:
* The “coming decade” (2010 to 2020) is poised to be the warmest on record, globally.
* The coming decade is poised to see faster temperature rise than any decade since the authors’ calculations began in 1960.
* The fast warming would likely begin early in the next decade — similar to the 2007 prediction by the Hadley Center in Science”
If 2005-2015 turns out to be cooler than 1995-2005, do you think that would be cause to question the projected warming for 2010 to 2020? What about longer projections? I guess my main question is: what projections of warming can be accurately assessed for their true accuracy in the short term (next ten years or so)?
14 mai 2008 at 4:24 PM
#44
“Everyone recognises that the Earth undergoes a warming response to enhanced greenhouse forcing.”
But what is debatable is the degree of that warming response, and what amount of forcing correlates into how much warming. And how much of the warming seen in the past century is conclusively due to GHG.
14 mai 2008 at 4:49 PM
> debatable
Wrong concept, for scientific work.
Try for publishable. It’s harder, but it’s useful.
14 mai 2008 at 6:47 PM
Re: 27
“Actually, the media lag far behind the scientists in terms of the level of consensus.”
No doubt. Generally, the public forms views by what it sees in the media and internet (not peer-reviewed journals, academia, scientific conferences, or the consensus from the major science academies) and what I see in the general media a pretty even mix, with many outlets covering contrarians exclusively (such as the WSJ op-ed columns to name one of many). The result is that the same handful of contrarian names get constantly recycled to the point where they have long reached virtual celebrity status. It’s a little disconcerting.
RC is an outstanding site and I’m amazed at the patience the scientists express here, but for every site of this quality there seem to be several junkscience.coms.
15 mai 2008 at 1:27 AM
Why did GISSTEMP for March fall from 0.81 deg to 0.68 deg?
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
This makes the first 4 months of 2008 the coolest since 2000.
PJ
15 mai 2008 at 4:50 AM
I’ve just finished reading an article in a popular Italian newspaper titled “The catastrophe of the catastrophists” in which the “pause in global warming” forecast in Nature is deliberately depicted as a terrible debacle for the community of climate scientists.
Unfortunately we don’t have resources like Real Climate in our own language to question such silly arguments and a lot of people will just believe what they read in the newspaper. Quite sad..
15 mai 2008 at 8:40 AM
Ref 50 Peter Johns asks “Why did GISSTEMP for March fall from 0.81 deg to 0.68 deg?
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
This makes the first 4 months of 2008 the coolest since 2000.” Presumably because that is what actually happened; the “measured” temperature for April 2008 was 0.68 C. If the satellite data reported daily for May is representative of GISTEMP, then the May figure will be around the same number.
15 mai 2008 at 9:07 AM
Actually it rose from 0.33C the month before to 0.68C.
Is there any particular reason why you think comparing Feb ‘07 with Mar ‘08 is more valid than comparing Feb ‘08 with Mar ‘08?
Is there any particular reason why you think such month-to-month comparisons are meaningful in the first place?
Oh, and the question, Alex, is “What is La Niña”.
15 mai 2008 at 9:38 AM
I never believed there would be a pause in global warming, thanks for your article about it.
I have a nephew who is a student at Princeton University and he is pursuing a degree and career regarding how to save the planet from global warming problems. I’m going to email him the link to this blog. He might already have it, but I’m going to email it to him anyway.
I just read a magazine article about how we could be getting fuel from algae, and be able to get rid of our dependence on fossil fuel. Wouldn’t that help to slow down the global warming?
Thanks for the good work and the good fight!
15 mai 2008 at 10:02 AM
Re #45 Joel Shore: You are completely right. But that was not the point I was trying to make. As you say, the 3% should be, if anything, proportional to the second derivate of the concentration of CO2 in time. And that is what I addresed next. How could it be, that during the eighties and the nineties the emissions were growing at about a full 3% per year, and yet the second derivate of the concentration was 0 or slightly negative?
My guess was that the rising temperatures did the miracle, and because they stopped rising in 2000, now the second derivate is positive. But in the eighties and the nineties, an improved response by the photosintesis of plant life due to increased temperatures would have been able to neutralise all of the extra emissions we were sending to the atmosphere with respect to the emissions of 1980, and becaue of that the increase in the concentration of CO2 (the first derivate) became constant (i.e. the second derivate was 0).
Cobblyworlds in #26 suggested that the fact that we have more CO2 in the atmosphere has made the oceans be able to also keep more CO2, taking it from the atmosphere. He is right about the physics of the process. However I doubt that that is the real reason, for 2 things: first, the absolute change in concentration of CO2 was very little as to absorb that much; second, the ocean temperatures were increasing at the same time, which means they can absorb less CO2, because of another phenomenom called outgassing, which may well cancel or even override the first one. And third, we are still rising our emissions, the conentrations are still increasing, and it is like the ocean stopped absorbing CO2. Why? It makes no sense. The photosintesis hypothesis looks better correlated with the known events we are experimenting, and also has a well known physical process to support it.
[Response: This is all very well, but wrong. You have to explain the O2 change (Keeling et al) and the d13C changes as well. They clearly point to the fact that the ocean has been the net sink for almost all the carbon (uptake by land in some areas is mainly balanced y deforestation in others). Plus we have direct inventories of ocean carbon that confirm the rise (see IPCC AR4 2.3.1). - gavin]
15 mai 2008 at 11:07 AM
re 32
We could deal with one 800 pound Silverback in the room. The problem is that there are two big gorillas in the room - the other one is the ice sheets. Together, They are likely to cause quite a ruckus.
15 mai 2008 at 1:11 PM
I know climate science is complex but thinking about warming of a block of ice in a glass, the temperature increase will stall for a while at 0deg.C while the ice melts before taking off again. It could just be that the same thing is happening on a global scale.
15 mai 2008 at 1:44 PM
Mark Sharkey–Yes, the temperature IN THE VICINITY OF THE ICE stops rising. However, I would be reluctant to attribute a cold winter in Baghdad to melting ice at the poles. This is weather. The skeptics will continue to crow that warming stopped in 1998, just like they did in 1996 and 1993 and 1991… They will do so until the next big El Nino knocks us up to another record year, and when the following year is cooler than the record, they’ll say global warming stopped them. Hell, I’m surprized they don’t claim warming stops every winter just for the practice!
15 mai 2008 at 2:17 PM
#36, #11 etc. I’m not sure what your point is. Hearing the phrase “over 3%” in Boulder yesterday doesn’t contradict Gavin’s assertion: [Response: Emissions are rising 3% a year, concentrations at just over 0.5% a year (~2ppm). - gavin]
You can easily discern the correct numbers with google.
These numbers confirm that Gavin’s 3% for the emissions rate is correct.
http://www.earth-policy.org/Indicators/CO2/2006_data2.htm
This site gives the growth rate in ppm:
http://www.esrl.noaa.gov/gmd/ccgg/trends/
Typical annual increase is about 2 ppm/year.
The CO2 concentration is about 380ppm. Thus the fractional increase is 2/380 = .005 = .5% as Gavin stated.
15 mai 2008 at 3:41 PM
The April numbers are in from GISS and HadCRU.
GISS: .51 anomaly. Dropped .17 from March. 2008 so far the coolest year globally since 2001.
HadCRU: .25 anomaly. Dropped .18 from March. 2008 so far the coolest year globally since 1997.
In addition, 2008 has been the coldest year in the U.S. since 1993.
15 mai 2008 at 4:00 PM
> 3%, Richard Ordway
It’d be interesting to know what source you were relying on when you wrote “evidence shows” — where did you get that? Link or cite? If it’s an error somewhere it’s worth correcting. If it was misread, that’d be useful to know.
15 mai 2008 at 4:09 PM
I am an amateur at this subject but I keep up with this website and I admit I’m a partisan pro-climate changer. But I wanted to bring up a previous bet by a few russian scientists a few years ago claiming that there will be a pause as well (global cooling briefly) and then roaring back heating. Whatever happened to that bet ?
Thanks
15 mai 2008 at 6:18 PM
Sir Gilbert Walker’s (”discoverer” of the Southern Oscillation) words seem apposite here with respect to short term predictions of “climate” and their value and the dangers of making predictions on unsubstantial grounds:
Speaking (of the monsoon) at the 1930 meeting of the Royal Meteorological Society, Walker stated:
“In general the object of prediction is to assist the layman, and it is the opinion formed by him that decides whether they will suceed or fail. Hence I regard it foolish to issue a prediction except in years when the indication for an excess or deficit [of rainfall] are so strongly marked as to give a 4:1 chance of success….and as the claim to “forecast” the seasons arouses the expectation of an annual precipitation, I advocate the word “foreshadow” as expressing a smaller ambition”
Do Keenlyside consider their prediction to be a “forecast”….. or a “foreshadow”….?
[Walker quotation from J. Madeleine Nash “El Nino: Unlocking the Secrets of the Master Weather-Maker” AOL-Time Warner 2002, p 45…..which is a very good read]
15 mai 2008 at 6:30 PM
Gosh, Jared has discovered weather. Next think you’ll know, he’ll discover climate.
15 mai 2008 at 7:03 PM
Nick:
http://julesandjames.blogspot.com/2005/08/bet.html
(I Googled: climate Russian scientists bet cooling
and it popped right up.)
15 mai 2008 at 8:05 PM
#60. Golly, Jared, thanks for the weather report. Maybe there’s a domain name “realweather” and somebody will care there.
15 mai 2008 at 10:56 PM
Hank Roberts Says:
15 May 2008 at 4:00 PM
> 3%, Richard Ordway
[[It’d be interesting to know what source you were relying on when you wrote “evidence shows” — where did you get that? Link or cite? If it’s an error somewhere it’s worth correcting. If it was misread, that’d be useful to know.]]
Hank, I’ll get their source…I need to know myself. I was out of the office today. It was from an in house presentation from a visiting scientist. Thank’s for reminding me.
If I mistated it, I will gladly post that too. Like I said, any of the moderators can look up one of my two IP addresses and know where the source was. Speaking of which, finding out where I heard the original presenter speak, would probably take you about two minutes if you really wanted to.
15 mai 2008 at 11:12 PM
Hank Roberts wrote:
“where did you get that?”
You could also look at the acknowlegements section of the book “Climate Change” by Bob Henson
15 mai 2008 at 11:40 PM
Unless I missed something, I’m not seeing anything as to whether your bet has been accepted. What’s the status?
If nothing else, it would be nice if Keenlyside et al would come by here and post a response - I hope they are taking this in good spirit.
This is turning into a nice demonstration of how blogs like this one can supplement comments and replies in the published literature - it’s fast, informal and more public.
16 mai 2008 at 12:01 AM
Ray:
You know, when somebody introduces themselves as “veritas” or Mr. Friendly the used automobile salesman, I reflexively reach for my wallet.
Reach for a bat instead.
Responding to gavin’s response:
This begs a question. Should you lose the bet, what ramifications does that have for AGW theory? How many years of cooling will it take before AGW theory is debunked? Let’s see a commitment from RC staff on this. How many years of continued cooling will it take for AGW theory to be rejected? You like bets, then place one on that.
[Response: None. About 20. Like I said. Lot’s of bets have been offered - few taken. - gavin]
Respectfully, I disagree. If we see — call it 3 to 5 years — a period of cooling that isn’t predicted by the same people predicting warming, any progress on reducing emissions will be lost and the consequences will be worse. After several warm winters and summers, most people I know that I talk to causally about global warming were “convinced”. Now, with two regular winters, a mild summer, and what looks to be another mild summer, the “it was a scam” drumbeat is growing.
It’s like the stupid “Gasoline Tax Holiday” ideas being floated here in the States. The most direct measure we have of scarcity is cost, and cost needs to accurately reflect scarcity or people will forget it is “scarce”. Dropping the tax will increase consumption, and then when the poop really hits the propeller, things will be even worse.
16 mai 2008 at 2:00 AM
dhogdzha - March was initially 0.81 when first added 4 weeks ago but the Mrch figure decreased to 0.68 when the April data was added. I was talking March only, not the change from Feb to March.
16 mai 2008 at 2:15 AM
#55 (Gavin response): If photosinthesis is not the cause, why does it happen that the years in which CO2 concentration increases the most are years which are colder than the year before, independently of the changes in emissions? Also, why do you think that the ocean’s absorption of CO2 has reduced so much? We didn’t change too much the rate of increased emissions, but the rate of increase of CO2 concentration has raised a full 25% from the 90’s. Another thing, you make reference to O2 changes and d13C published somewhere. Is there a link I can follow to read that information?
Thanks a lot.
16 mai 2008 at 10:10 AM
Furrycatherder, While a few years of cooling might change the urgency in the collective mind of the great unwashed, it will not change the science. Hell, the public mind changes with the weather–literally. Ultimately, it will come down to education. I am hoping that as climate models improve we’ll have a better fix on the realistic risks. I really believe that one of the things driving opposition to the science is uncertainty over what actions will be required to limit damage from climate change. Most people envision going back to the horse and buggy days, and they are understandably loathe to do that. I think that if we can come up with a concrete plan of action and show that it does not destroy the economy, we will win a lot more converts.
16 mai 2008 at 11:33 AM
Ray #73, I agree with your post and the need to act without destroying the economy. One of the problems is that there are proposals from various state legislatures (US)and other organizations to reduce emissions by 80 percent by 2050 to stabilize CO2 levels. If you account for population growth between the baseline year of 1990 and 2050, you end up in 2050 with a per capita carbon footprint that gets us back to where we were in colonial times. So the horse and buggy days fear is not unfounded.
16 mai 2008 at 1:21 PM
B. Buckner, To claim that because we cannot burn fossil fuels, we cannot consume energy is a fallacy. With oil becoming ever more scarce, our energy consumption will have to change in any case. Adding climate to the equation eliminates coal as an option, but that is about all. I would claim that this is a problem that could have a technical solution–and technical solutions often have a way of finding applications that make the economy grow.
The main problem is that we don’t know how close we are to various tipping points, so it makes sense to try to conserve as much as possible in order to buy time. The goal has to be sustainability, and sustainability is not incompatible with growth, as long as the growth comes via technological advance.
16 mai 2008 at 1:42 PM
#72 Nylo,
If photoynthesis is the cause then why the change in isotope composition?
A large part of the CO2 we emit is absorbed by the ocean and land biological processes. Any changes in either ocean (Weather/El Nino’s, circulation changes, etc) or land, (warmer/cooler or wetter/dryer years) will impact how much is taken up. That means the amount added to the atmosphere would vary even if we were emitting a constant amount each year. Actually we’re rapidly increasing emissions on a global basis.
And on the subject of warm/cool or wet/dry years: The article by David Archer that I linked to discusses cases where average wind conditions have changed and this, not primarily temperature, has reduced CO2 uptake by the oceans.
With regards an explanation of isotopes and how we know the CO2 increase is down to humans: Just click on Index at the top of this page, and scroll down to “Greenhouse gases:”, you need the second link down, entitled “How do we know that recent CO2 increases are due to human activities?”. It is not a coincidence that the article explains how we know the CO2 increase is due to human activity.
#74 B Buckner,
I think it is unfounded, personally I consider it a straw man.
Based on those I know at work and socially, I consider it inherently improbable that you could get people to vote for a government that proposes such austerity. There are 2 reasons I have reduced my emissions: Because it’s the right thing to do and because it saves me money.
16 mai 2008 at 1:46 PM
> finding out where I heard the original presenter speak
Richard, that doesn’t matter, I’m just asking for a source for the number — ‘reference librarian’ not ‘private investigator’ question.
Next time I see the number in someone’s blog, I’d like to point to a cite for it, not trying to blame it on anyone (grin).
16 mai 2008 at 3:17 PM
Hi Hank,
Here is the peer-reviewed reference from the National Academy (PNAS) on CO2 rising more than 3% per year:
“CO2 emissions from fossil-fuel burning and industrial processes
have been accelerating at a global scale, with their growth rate
increasing from 1.1%/y for 1990–1999 to >3%/y for 2000–
2004.
The emissions growth rate since 2000 was greater than for
the most fossil-fuel intensive of the Intergovernmental Panel on
Climate Change emissions scenarios developed in the late 1990s.
‡‡CO2 data are available at www.cmdl.noaa.gov/gmd/ccgg/trends.”
Raupauch et al. PNAS 2007. “Global and regional drivers of accelerating
CO2 emissions”
http://www.pnas.org/cgi/reprint/0700609104v1
16 mai 2008 at 3:26 PM
77 Ordway’s original comment was bizarre: “Evidence shows that CO2 is going up at over 3% per year”
since he doesn’t actually say what it is that he’s talking about. “CO2 is going up”? What is that supposed to mean? Up into the sky? Up in concentration? Up in rate of emission? In none of his subsequent remarks did he acknowledge that his original post was incoherent.
if you want a source for Gavin’s numbers you can click on the links that I posted in 59 and you’ll find all the numbers you need to get an estimate that is in accord with Gavin’s claim of emissions rate increasing at 3%/year and concentration increasing at 0.5%/year.
16 mai 2008 at 4:47 PM
There we go, it’s _emissions_ not _atmospheric_level_ going up at three percent, which does make sense.
Illustrating why to state units when quoting digits (grin).
16 mai 2008 at 6:50 PM
Hi,
Re #6,
‘RealClimate needs to be read by the whole world. You are often too mathematical for almost everybody. Your concepts are mathematical. Nonetheless, RealClimate should be what everybody reads directly for themselves, if they can.’
I am about to set up a web site that, amongst other things, will report such things as Realclimate articles (with citation). The idea is that it will be aimed at a slightly less educated audience
than this site. The web site exists but is currently private.
17 mai 2008 at 7:46 AM
Re 31: I assume that 20 years includes the previous 10 that has shown a flat temperature change, so on Jan 1, 2019 and the world has not heated up you will declare AGW theory false, right?
Ok, so let’s add others to the mix. How many years of there not being any acceleration in the rate of sea level rise would it take to declare AGW theory false? To accommodate the IPCC the rate would have to increase 3-5 times the current 1.33mm/yr, the same rate it’s been for at least the last 110 years. Some of the more extreme increases would call for a rate increase of 30 to 40 TIMES the current rate. So, how many more years of flat rate will it take to abandon AGW theory?
17 mai 2008 at 9:29 AM
Richard Wakefield, What is it with the anti-science crowd and “falsification”? A failure of models to predict correctly does not necessarily mean the model is completely wrong. More likely, the model is incomplete. It neglects a factor that is important during the period under question. This factor may counter the anthropogenic hypothesis, or it may merely mask it for awhile. A Grand Solar Minimum, as many in the denialosphere are blogviating (btw, thanks to the RC folks for this term), does not mean that CO2 is unimportant, as it will kick in with a vengeance when the minimum ends. You guys really need to look into how science actually is done. There’s more to it than Karl Popper.
17 mai 2008 at 10:53 AM
Assuming, for the purposes of this question, that the Keenlyside et al paper is right so that there will be a pause in the rise of land and sea surface temperatures, am I right in thinking that this does not indicate a pause in global warming in that, during the pause in the rise in surface temperatures, the temperatures in the ocean below the surface layers would be increasing?
If so, would such rises be very small compared with surface temperature rises? I’m thinking that they would be because of the huge thermal capacity of the ocean.
Again if so, are ocean temperature measurements made with sufficient accuracy that such rises could be detected reliably?
17 mai 2008 at 11:13 AM
Re Richard Wakefield @82: What 10 year flat temperature change?
http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/
I don’t see a ten year flat temperature change anywhere on that graph.
Nor on this one
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
As for your 1.33 mm/yr rate of sea level rise, you are woefully behind in your reading:
http://www.sciencemag.org/cgi/content/abstract/sci;294/5543/840
Even if entirely due to thermal expansion the current rate is almost double that.
Not only do you guys really need to look into how science is actually done, you need to look into what the science actually says.
17 mai 2008 at 12:24 PM
Ed Davies, I think you are basically correct. The heat does not leave the system. However, the extent of the warming in the ocean depends on how much mixing (e.g. to what depth) occurs.
17 mai 2008 at 1:05 PM
> falsification
The physical theory and data collection can be falsified — that’s the individual pieces.
A whole model can’t be falsified. Willy Ley once famously remarked that analysis is all very well, but you can’t figure out how a steam locomotive works by melting it down and analyzing the mess. You have to look at the pieces and test each one.
Same thing when airplanes fall out of the sky. That doesn’t falsify aviation, or the particular airplane design, or flight in general.
A repeated problem can falsify one component:
http://www.promotex.ca/articles/cawthon/2005/2005-06-15_article.html
“… The testing took months but finally identified the problem. The stresses caused by thousands of takeoffs and landings were causing the plane’s aluminum skin … to crack …. Eventually the metal would completely fail, causing immediate depressurization of the cabin and catastrophic structure failure….”
That falsifies one design element, not the whole idea of flight.
If a problem once identified fails to be understood, yes, later designs will have the same kind of failure:
http://www.ec.erau.edu/cce/centers/edwards/SF335/CaseStudy1Pres.htm
“… As the airplane leveled at 24,000 feet, both pilots heard a loud “clap” or “whooshing” sound followed by a wind noise behind them. The first officer’s head was jerked backward, and she stated that debris, including pieces of gray insulation, was floating in the cockpit. The captain observed that the cockpit entry door was missing and that there was blue sky where the first-class ceiling had been….”
There is no such thing as a fail-safe design:
http://peanuts.aero/low_cost_airline_news/airline/8661//Southwest+Airlines+provides+Testimony+to+US+House+of+Representatives+Committee+on+Transportation+and+Infrastructure
“The Boeing 737 Classic was designed with a ‘fail-safe structure’…”
Current aircraft use far more modeling in the design than the older ones. No one claims to be able to “falsify” computer models per se, or even individual models at a particular point in time.
Well, no one who uses or understands them.
So, see someone claiming some one fact can falsify a model, or modeling?
Check their cites.
17 mai 2008 at 1:58 PM
Re: 74
To add to the other comments, the “horse and buggy” logic seems to go like this:
1. Before fossil fuels, quality of life was lower (horse and buggy).
2. Fossil fuels increased quality of life.
3. Therefore, a strong move away from fossil fuels will return us close to (1).
Problem is, in the horse and buggy days, we didn’t really have a great ability to capture wind and solar energy, among other things. There wasn’t the option of nuclear power. There was no such thing as EV or plug-in hybrids. Carbon sequestration wasn’t a possibility in the near future. There wasn’t a range of other options to make us more energy-efficient.
Some technologies are already economically viable:
http://news.yahoo.com/s/ap/20080512/ap_on_go_ca_st_pe/wind_energy
17 mai 2008 at 8:06 PM
#83 “A failure of models to predict correctly does not necessarily mean the model is completely wrong.”
That’s the best you got? Kidding aside, I know it’s not your best, but you have to admit that statement is a fair distance removed from “an overwhelming scientific consensus has determined humans are responsible for most of the global warming in the last xx years.” I appreciate the honesty, and it’s good to see some healthy scientific caveats emanating from the insistosphere.
18 mai 2008 at 2:21 AM
#32 Ray Ladbury,
The 500 kg CO2 gorilla’s dad in the room is the 4000 kg H20 that also slows the rate of heat loss from the surface to space. (In and of themselves, the gorilla family would block about 1% of out-going infra-red radiation. Feedbacks, both positive and negative, are well known to climate science - much of the uncertainty revolves around the net effects of clouds which exhibit both forms). A slowing rate of heat loss means cooling more slowly than before, not warming. Surface temperature equilibrium is reached when the sum of the energy absorbed by the surface from the sun and the from atmosphere equals the energy it radiates to space. At equilibrium, changes to either the sun’s or the atmosphere’s radiation fluxes would determine whether the surface begins to warm or continues to cool. The changes need be only small to switch the temperature from equilibrium. We know from geology that the surface temperature periodically reaches equilibrium, switching between ice ages and inter-glacial warm periods. We know from the laws of physics and astronomy about the cyclical fluctuations on an increasing trend in the sun’s radiation. We know, from the same laws, about cyclical fluctuations in the sun’s magnetic field and, consequently, in the entry into the atmosphere of cosmic rays, a form of energy. We know from ice-core analysis about the cyclical variability in atmospheric concentration of CO2. We can find correlations between temperature on the one hand and both sun’s radiation and atmospheric concentration of CO2 on the other. We know that the latter correlation is time-shifted, temperature leading CO2 concentration. We ought, therefore, to agree that pre-human, or more precisely, pre-industrial climate change was caused by changes in solar activity; that these effects continue today; and that past changes in the atmospheric concentration of CO2 remain to be explained. We ought also to agree that fossil fuel burning industrialisation pumps increasing quantities of CO2 (plus water vapour and sensible heat - I wonder whether the models include these?) directly into the atmosphere. This is where questions and disagreements begin. The IPCC argues that these effects completely swamp solar ones, on two main grounds: first, the rate of warming in the latter half of the 20th century exceeds all previous experience; and second, otherwise their models don’t make sense. Well, the latter sounds a bit chicken and egg-ish to this layman. As to the former, the Central England temperature record contains a period of warming three times as much in two- thirds of the time. On the other side of the Atlantic, unpublicised revisions to the US temperature record reveal that six of the hottest ten years occurred in the first half of the 20th century. What I would like the climate models to tell me is when, in the absence of AGW, average global surface temperature would reach its zenith before beginning descent into the next ice age. I would also like a climate scientist to confirm that, in and of itself, CO2 would block no more than 0.04% of out-going infra-red radiation. A supplementary question: Would the absorbed energy raise the molecule’s temperature or increase its velocity or are these one and the same thing?
18 mai 2008 at 7:40 AM
Re 85:
James, did you not read that abstract on sea level change?
Science 26 October 2001:
Vol. 294. no. 5543, pp. 840 - 842
DOI: 10.1126/science.1063556
Prev | Table of Contents | Next
Reports
Sea Level Rise During Past 40 Years Determined from Satellite and in Situ Observations
Cecile Cabanes, Anny Cazenave, Christian Le Provost
The 3.2 ± 0.2 millimeter per year global mean sea level rise observed by the Topex/Poseidon satellite over 1993-98 is fully explained by thermal expansion of the oceans. For the period 1955-96, sea level rise derived from tide gauge data agrees well with thermal expansion computed at the same locations. However, we find that subsampling the thermosteric sea level at usual tide gauge positions leads to a thermosteric sea level rise twice as large as the “true” global mean. As a possible consequence, the 20th century sea level rise estimated from tide gauge records may have been overestimated.
Twice 3.2 is 1.7 mm/y.
As for your ref http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/. Nice try, but do you not see the downward last 10 years? Best to see it in a tighter perspective:
http://atmoz.org/blog/2007/10/22/no-global-warming-signal-in-sea-surface-temperature-data/
[edit]
[Response: You need to look at the same groups updates ie. Lombard A, Cazenave A, DoMinh K, Cabanes C, Nerem RS, GLOBAL AND PLANETARY CHANGE 48 (4): 303-312 OCT 2005. And please stay on topic. - gavin]
18 mai 2008 at 8:49 AM
” I would also like a climate scientist to confirm that, in and of itself, CO2 would block no more than 0.04% of out-going infra-red radiation. A supplementary question: Would the absorbed energy raise the molecule’s temperature or increase its velocity or are these one and the same thing?”
I’m able to confirm that CO2 will absorb far more than 0.04% of the IR emitted from the surface, more like 10%.
The absorbed energy will initially raise the rotational and vibrational temperature of the CO2 molecules which within less than a microsecond will raise the temperature of the surrounding molecules.
18 mai 2008 at 9:20 AM
Re John Millett @90: “We ought, therefore, to agree that pre-human, or more precisely, pre-industrial climate change was caused by changes in solar activity”
Sorry, John, but changes in solar activity has never been the only and not always the dominant driver of climate change. Google “Milankovic cycles”, “Paleocene-Eocene Thermal Maximum”, “Permian-Triassic”, and “snowball Earth”, for example.
John: “We ought also to agree that fossil fuel burning industrialisation pumps increasing quantities of CO2 (plus water vapour and sensible heat - I wonder whether the models include these?) directly into the atmosphere.”
Water vapour from direct human activity does not need to be included–google “relative humidity.” Atmospheric water vapour content can not be permanently increased unless either atmospheric temperature or pressure is increased first, otherwise the addition simply rains or snows out in a matter of days. That said, increased water vapour as the atmosphere warms is included in the models. Sensible heat from human activity has been discussed and quantified here repeatedly, it is negligible.
John: “The IPCC argues that these effects completely swamp solar ones, on two main grounds: first, the rate of warming in the latter half of the 20th century exceeds all previous experience; and second, otherwise their models don’t make sense. Well, the latter sounds a bit chicken and egg-ish to this layman.”
It’s not only the models that do not make sense without including the effect of increasing CO2, John, observed reality doesn’t make sense without including it either.
John: “On the other side of the Atlantic, unpublicised revisions to the US temperature record reveal that six of the hottest ten years occurred in the first half of the 20th century.”
You’re falling prey to deliberate disinformation here, John.
See: http://data.giss.nasa.gov/gistemp/graphs/Fig.D.txt
You have to go to the hundredth of a °C to break the tie between 1934 and 1998 for highest annual mean temperature anomaly (1.25 vs 1.23), and the following 23 ranked years, all above .50, are: 2006 (1.15), 1931 (1.00), 2005 (.99), 1999 (.94), 1953 (.90), 2001(.89), 1990 (.88), 2007 (.84), 1987 (.84), 1954 (.84), 1939 (.80), 1938 (.78), 1986 (.74), 1946 (.71), 1991 (.69), 2002 (.67), 1933 (.66), 2000 (.65), 2003 (.65), 1981 (.65), 1941 (.61), 2004 (.54), 1900 (.52).
That’s only two years from the first half of the century in the top 10, not six, and 15 of the above 25 are since 1980.
You might want to double check stuff like this that is easy enough to look up before you post next time.
18 mai 2008 at 10:28 AM
#93
CO2 in the 1930’s was ~303 ppm.
CO2 in the 90’s and 00’s is ~370 (currently ~380).
Yet temperatures are only slightly higher now than 1930’s.
Why?
18 mai 2008 at 10:52 AM
1. An alternative approach. (Not really serious). One bet based on probability may not be decisive in determining the superior type of model. The trouble is that each model is consistent with a range of outcomes with different probabilities. Just for the sake of argument consider instead a couple of betting shops using different advisors to offer the public a range of bets with different odds. One shop would base its offers on the set of IPCC models and the other would use Keenlyside et al (perhaps supplemented by some more runs). The better modelling would be converted into a profit.
2. Does the proposed bet suggest that the group are betting against the relevance of Schlesinger and Ramankutty ,1994. Nature,367,723 who looked at unforced oscillations of period 65-70 years period? They ended with the warning:
“Accordingly, it is prudent not to expect continued year-after-year warming in the near future and, in so doing, diminish concern about global warming should global cooling instead manifest itself again.”
Perhaps they really meant decade on decade. (Incidentally the German defeat in the 2nd world war has been partially attributed to the prolonged cold about 65 years ago). Its difficult for a non expert to judge the importance of individual papers.
3. Coupling shocks. I suspect I have missed something. The green curve appears to have unphysical looking kinks at about 2000 and 2010; are these symptoms of coupling shocks? If so, what about the kink in the black curve at about 2010?
18 mai 2008 at 11:24 AM
Re 84. In regard to Ed’s comment, I want to follow up with a related question.
If there is a pause in surface warming because of cooler water being brought to the surface of the oceans, would this not lead to an increase in the energy imbalance, and thereby increase the rate of heat accumulation at the earth’s surface? The cooler ocean surface would radiate less IR back to space. Maybe the effect is negligible, or maybe there would be an offsetting negative feedback due to changes in clouds. I am asking.
18 mai 2008 at 11:47 AM
> Jim Cross, temperatures
Which ones, Jim?
http://cdiac.ornl.gov/trends/temp/jonescru/graphics/nhshgl.jpg
PS, I really appreciate your blog post on “How To Create a Major Software Outage”
18 mai 2008 at 1:41 PM
wmanny, “insistosphere” good! we need a screech name to counter all the labels laid on us skeptics. Makes the debate healthy.
18 mai 2008 at 2:25 PM
Re: Several comments on falsification.
Just as current models can be verified by successfully reproducing the observed climate of the recent past century or so( the ones that include anthropogenic effects anyway), so can models be falsified by say, using orbital parameters such as the tilt of the Earth’s axis, and not being able to reproduce seasonal variations. Such a model would wrong.
If a models have successfully shown the effects of sizable volcanic eruptions, as a number have, they’ve been verified, if a model could not, it’s been falsified. At least that’s my take on it.
If this were not true, science counterparts of Elmer Gantry, could spout all kinds of nonsense, which may happen anyway, but it could not be shown to be wrong.
18 mai 2008 at 3:41 PM
John Millett, You make a lot of assertions with zero attribution. Some are true, some half true and some blatantly false.
To correct the most blatant false notions:
Each warming and cooling epoch in the paleoclimate has its own causes. In some cases these were based on solar variations, but in others volcanism, greenhouse warming and other factors were dominant.
Then you say: “I would also like a climate scientist to confirm that, in and of itself, CO2 would block no more than 0.04% of out-going infra-red radiation.”
Where the heck does that come from? Are we talking IR energy or IR photons?
and
“A supplementary question: Would the absorbed energy raise the molecule’s temperature or increase its velocity or are these one and the same thing?”
This sort of thing has been discussed repeatedly. First, how do you get a temperature for a single molecule? Second,
Read:
http://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/langswitch_lang/sp
and
http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument/langswitch_lang/sp
18 mai 2008 at 4:34 PM
First post on Realclimate from me. Very good site. Thank you for helping me form opinions on the science (I’m a lapsed Geologist/Biologist so i can follow a lot of it, but have not kept up to date since the early 90’s)
you are right to be concerned about media coverage of this. The New Scientist in the UK is reporting this in a misleading way:
“The controversy is unlikely to go away. A study in Nature this month (vol 453, p 84) led by Noel Keenlyside of the Leibniz Institute of Marine Sciences in Kiel, Germany, forecasts that this cyclical warming would soon abate. “There could be some cooling in Europe and North America over the coming decade as the natural cooling offsets the warming from human activities,” Keenlyside says.”
– that’s at the end of an article on the Rosenzweig et al study published recently in Nature on the impact of climate change on plants and animals. Presumably New Scientist have put this in as a counterpoint. It is very misleading though. No “this is only an experiment” or “not everyone agrees with this result” etc.
and i always thought New Scientist was a good magazine. just goes to show how messages can get distorted very easily.
http://environment.newscientist.com/channel/earth/mg19826564.400-life-feels-the-effects-of-a-changing-climate.html
18 mai 2008 at 6:43 PM
I like to think for myself and hypothesize what would the Earths climate be like if Mankind did not exist.
Assuming that was so. :-
We are in a warmer interglacial period would I therefore expect the climate to be warming, to be stable, or to be cooling?
Would I expect Glaciers and ice coverage to be reducing, to be stable, or to be increasing?
The information I would really need to know, I think, is whether, the non mankind influenced, inter glacial period had reached its maximum or not and was now in decline.
Does anyone know for certain?
Therefore, when you put mankind back into the equation how can anyone postulate that mankind is having any influence either way?
18 mai 2008 at 7:05 PM
Alan, if you want “for certain” you need either the mathematics department or a religion — they’re the ones who can prove statements beyond any doubt, as long as you accept their basic assumptions.
Science doesn’t offer that kind of certainty.
Do you ever gamble? Fly on an airplane? Use a device with a semiconductor in it, like a laser, CD player, phone, or computer?
Those are all matters of probability, not certainty.
If you’ll accept the level of likelihood we use day to day in using science and what’s developed from it, you can have a very good likelihood of an accurate answer.
Interested? Read more. Try the “Start Here” link at the top of the page. Put any term or name you read about elsewhere into the Search box.
Oh, and consider just looking at the pictures.
Here’s one:
http://svs.gsfc.nasa.gov/stories/greenhouse_20020103/images/figure1m.gif
Remember chlorofluorocarbons? hair spray? refrigerants? the ozone hole? Those also are greenhouse gases.
So, yes, it IS possible to do what you ask, figure out what difference human contribution makes.
And, yes, it IS possible to do something about it. We already have.
18 mai 2008 at 7:56 PM
Hi Hank
So what would your guesses be for the Earths current climate if Mankind didn’t exist?
18 mai 2008 at 8:59 PM
103. Careful. Paradigm shifting. Dichlorine peroxide break-down rates not as previously understood. Science consensus being called into question, as invariably happens throughout the history of science. TBD whether Montreal has proven to have changed much.
[Response: The recently reported revisions to the rate constants are inconsistent with clearly observed shorter time variability. Many people more directly involved in ozone chemistry than I do not expect them to stand up. - gavin]
18 mai 2008 at 9:40 PM
Hank, the relative/historical forcings set me back abit. A question out of right field: what happened to the 30-50years it takes (took?) for a CFC moleculae to make it to the stratosphere?
18 mai 2008 at 10:44 PM
Rod, if you would check your own beliefs before posting them as assumed truths, it would save me a lot of unnecessary typing. I’m trying to teach you how to be a good skeptic, you know. Trust me on this. You -can- get there. I’ve got to go spend time helping inlaws with a sick kid for a few weeks starting soon.
You’re ready to solo. Go for it. Last time, let’s do the exercise:
Standard question — what’s your source? Why do you believe the number? Where did you get it?
I did a Google search for “30-50 year” and — lo, are we surprised? — find that in posts from the people still claiming “the ozone hole is a fiction” on blogs.
Nothing in any science sites I found — got any other source for the notion you have?
Let’s try Google Scholar:
http://www.sciencemag.org/cgi/content/abstract/272/5266/1318
That suggests five to seven years would be about right, though it’s an early and optimistic post, things didn’t work out that well.
A little more searching (you can figure out the terms, the minus sign rules out terms you don’t want, like “ocean” in searching).
“… stable and reach the stratosphere unchanged over a five to seven year period following release into the atmosphere. CFC and HCFC. molecules are then …”
www.uneptie.org/outreach/wssd/docs/sectors/final/refrigeration.pdf
OK? Three minutes. You _can_ do this.
Now, the thinking part. Dang “wisdom” button still not programmed.
What was that graphing? Global warming potential. How big is the GHG potential of chlorofluorocarbons?
You can look it up. I trust you.
Thinking it through, where do greenhouse gases operate? “Whevever they want to sit.” As they say about the 800 pound gorilla. The time lag getting to the stratosphere has no relation to the greenhouse warming potential of the chlorofluorocarbons.
Yes, they persist, they do over time (not that long either) reach the stratosphere where they also catalyze ozone breakdown, that changes ozone levels, and that has a greenhouse forcing effect — but that’s a different aspect of their chemistry/physics than greenhouse gas-ing.
18 mai 2008 at 10:52 PM
Alan, if mankind didn’t exist — or if we’d invented something better than burning coal and hadn’t started the current experiment? Well, look at the past.
This may help, look at the cited papers and the citing (subsequent) papers with the links in the sidebar:
http://www.sciencemag.org/cgi/content/abstract/240/4850/293
This may help; the black line goes vertical at the right margin, note the arrow labeled “2004″ pointing to where it was at that time. The last 200 years are in the tiny little bit of the chart right of the tickmark.
http://www.globalwarmingart.com/images/b/bb/Holocene_Temperature_Variations_Rev.png
19 mai 2008 at 12:04 AM
What kind of function line (equations) are they using that is rendering their probability outcomes within their programming that is being used in their varying computer models
and what did they base that, or those, functions and or equations on?
All computers,computer modeling included, are subject and constrained to the limits of programmer and program itself. The math go to string inputs contained within the programming.
19 mai 2008 at 1:42 AM
Hi
I’m new here. Have only been folowing the AGW debate for a little while so please excuse me if my question has been answered already. I’m definitely on the fence. It sure is fasinating!
My question: Does RC believe that increases in C02 leads or follows increased temps?
Thanks.
[Response: The carbon cycle is both affected by climate and, through the greenhouse effect, affects climate. Therefore the answer is both. If climate changes through some other factor (say Milankovitch forcing), the carbon cycle will follow and amplify the change. If you add carbon to the system (i.e right now or at the Paleocene-Eocene Thermal Maximum), climate will follow. You might as well ask whether chickens or eggs lead or follow. - gavin]
19 mai 2008 at 5:47 AM
re 97
http://en.wikipedia.org/wiki/Image:Instrumental_Temperature_Record.png
The five year average at the end of the 1930’s and the five year average in the mid 1990’s is only around .2 degrees different but CO2 is up over 20% between those times.
I’m not saying it was as warm as it is now in the 1930’s and I’m not denying that the difference right now is closer to .4 degrees from the 1930’s. I am just asking for an explanation of why raising CO2 over 20% didn’t create more warming than it did.
19 mai 2008 at 5:56 AM
re #93
Google and climate change. You have done a good job replying to #90. Just one comment. You have advised John to use Google and your examples may have been good ones for doing that. The trouble is that he may have started with Google as his main source anyway. He might come back at you with ‘Google solar changes’ or some such. Using Google with discrimination is a skill which needs to be learned and is perhaps hard to teach. I am beginning to despair about Google when it comes to this subject. When Channel 4’s Great Global Warming Swindle came out in the UK I was surprised to receive enquiries from graduates who decided to check up on the programme by using Google and immediately found it to be confirmed. This is of course one of the arguments for the existence of Realclimate but some people (especially those who don’t like authority) end up by being completely confused.
Whereas the world wide web used to be mainly a means of sharing science and other academic material it has become joined at the hip with the media in general and is now open to purchase by those with money to spend. Since Google Scholar may be too technical it might be possible to use more specific suggestions like giving the whole link,Googling for the subject + Wikipedia,or + the Met Office etc. or Googling for a named person or group. If this sounds like censorship I would argue that I am not arguing for anything as absurd as a ban, just a bit of guidance. No one would recommend say the UK’s Telegraphs (Daily and Sunday) as sources for information about climate even though the Telegraphs do report on the subject in between articles by Christopher Monckton. No criticism of #93 intended.
19 mai 2008 at 6:40 AM
John Millett writes:
Of course they do.
The second “argument” is something you made up. The IPCC doesn’t say anything of the sort. Have you actually read the AR4 report? Why don’t you do that before telling us what it says?
What “unpublicized revisions?” Are you making stuff up again? And what makes you think US continental temperature records, or central England temperature records, reflect what’s true for the whole world? Do you understand what an ‘average’ is?
No climate scientist in his right mind is going to “confirm” something that just isn’t true. CO2 accounts for 26% of the clear-sky greenhouse effect according to Kiehl and Trenber