Gavin Schmidt and Michael Mann
Today we witnessed a rather curious event in the US Senate. Possibly for the first time ever, a chair of a Senate committee, one Senator James Inhofe (R-Oklahoma), invited a science fiction writer to advise the committee (Environment and Public Works), on science facts–in this case, the facts behind climate change. The author in question? None other than our old friend, Michael Crichton whom we’ve had reason to mention before (see here and here). The committee’s ranking member, Senator James Jeffords (I) of Vermont, was clearly not impressed. Joining Crichton on climate change issues was William Gray of hurricane forecasting fame, Richard Benedick (a negotiator on the Montreal Protocol on ozone-depleting chemicals), and David Sandalow (Brookings Institution). As might be expected, we paid a fair bit of attention to the scientific (and not-so-scientific) points made.
Many of the ‘usual suspects’ of half-truths and red herrings were put forth variously by Crichton, Gray, and Inhofe over the course of the hearing:
- the claim that scientists were proclaiming an imminent ice age in the 1970s (no, they weren’t),
- the claim that the 1940s to 1970s cooling in the northern hemisphere disproves global warming (no, it doesn’t),
- the claim that important pieces of the science have not been independently reproduced (yes, they have),
- the claim that global climate models can’t reproduce past climate change (yes, they can)
- the claim that climate can’t be predicted because weather is chaotic (wrong…)
and so on.
We won’t dwell on the testimony that involved us personally since the underlying issues have been discussed and dealt with here before, though we will note that comments from both of us pointing out errors in the testimony were entered into the Senate record by Sen. Barbara Boxer (D-California). Instead, we will focus on the bigger picture.
First, let’s be clear where there is agreement. Climate science doesn’t deal in certainties – it deals in probablities and the balance of evidence. We agree with Crichton’s statement that ‘Prediction is not fact’. That certainly doesn’t mean, however, that projections of possible future climate changes are not meaningful or useful, as Crichton claims.
Crichton seemed to imply that “prediction” (such as that provided by weather or climate models) is useless in the decision making process. (As an aside, we wonder how Gray, who is largely known for prediction of hurricane behavior based on (statistical) modeling, felt about this?). We fundamentally disagree. All science is about observation, understanding and prediction. When those predictions work, you make new predictions. When they don’t, you revisit the observations, attempt to improve your understanding of the underlying processes, and make a new prediction. And so on. In the case of climate models, this is complicated by the fact that the time scales involved need to be long enough to average out the short-term noise, i.e. the chaotic sequences of ‘weather’ events. Luckily, we have past climate changes to test the models against. Even more to the point, successful climate predictions have actually been made in past Senate hearings. The figure at the end of this comment by Jim Hansen demonstrates that projections of global mean climate presented in a 1988 senate hearing (17 years ago) have actually been right on the money
Others panelists attempted to combat the onslaught of disinformation. Sandalow sensibly suggested that the National Academy of Sciences be used to inform the Senate on where the consensus of the science is, and Benedick made some excellent points about how legislation can be successful in the face of scientific controversy and uncertain predictions. However, none of that provided as good theater as the other witnesses.
A highlight of the session was Gray making one particular statement that he may be asked to defend (at least financially): “I’ll take on any scientist in this field …. I predict that in 5 to 8 years the globe will begin to cool” (1:10:00 on the video). This would appear to be a direct call to those “global warmers” (see also here, here and here) who are trying to get contrarians to put their money where their mouths are (with very limited success). We eagerly await developments!
Inhofe ended the hearing by declaring his desire to ‘sit back and look at [this] in a non-scientific way’. We think he already has.
Re: #198, “And so are the yeah-sayers. I didn’t really utter much of “nay” before I was accused of being a McCarthyst, no less.”
I never accused you of being a McCarthyist. What I said was:
“Your sentiments of the Sierra Club smacks of McCarthyism…”
That is a bit different. If you took it the wrong way, I apologise, but I was trying to say something to the effect that it was silly for you to criticise me for reading a SC interview, which you made sound like something to the effect that I was drabbling in some sort of environmental “Communist Manifesto.”
If you read some SC material, you would see that there is some sound science in there, rather than the junk science that exists on the Marshall Institute site (and others).
There is a real problem that certain segments of the population (those on the conservative right) blame environmentalists for the problems of the world, such as those associated with the Katrina disaster. They say that enviros are to blame because they blocked improvements on levees. What is really to blame is poor land management and building infrastructure on land which was not meant for human inhabitation, as well as increasing the amount of toxins that are present (leading to what resulted from Katrina, the toxic soup that remained on the streets of New Orleans).
Re: 200
But I don’t see how this effect is of the slightest consequence, ultimately.
The trouble is that chaotic noise coming from the unpredictable weather could (doesn’t have to) accumulate and pull the solution trajectory to a different part of the attractor. I intentionally speak very loosely here.
I know that you will dispute my interpretation of this graph, and claim that the models were built by a sort of trial-and-error to fit the historical forcings / temperatures. But we will have to disagree on that point.
The parameter fitting is is not a subject of an argument, it’s a fact and there is nothing wrong about it. The interpretation of the graph is indeed subjective. In addition to what I said before, reproducing past climate pretty darn well must include reproducing regional climate change, not only global mean T.
Yet now you have, apparently, *proven* that it is chaotic in spite of this.
Not true. I never said or implied that I have a proof. I certainly have an opinion that climate is chaotic and unpredictable on sufficiently long time scales. But this is no different qualitatively from what most climate scientists would tell you. We can only differ in the subjective estimates of the predictability limit.
Now I’ll go out on a limb to make a claim that I won’t be able to prove. Any state of the art climate model (CGCM) under stationary forcing (plus annual cycle) will eventually demonstrate some sort of chaotic behavior and/or will drift away from the realistic description of the actual atmosphere. Corrections with references to the published research are gratefully accepted.
Re: 199 (Steve Bloom)
Thus we get to the crux of the problem: How much are we willing to pay now to avoid these future problems? The response implicit in your answer seems to be “not much” absent a degree of certainty that science probably can’t provide for the simple reason that we haven’t been able to observe such events before; i.e., we’re running the experiment now.
This is not what I asked (and, BTW, I didn’t give any answer). The question that William allowed was How do we know that we can substantially delay or stop them {catastrophic melting events)? Curiously, your version is a mixture of my questions.
Some of these changes are a bit more prone to prediction than others, but there will still be some uncertainty about the exact amount of GHGs over what period of time will be needed to make them happen and about the implications of each change. The problem is that by the time uncertainty is eliminated we will have very few options. But just out of curiosity, how much certainty would it take to convince you?
I cannot even begin answering this question without building a certain framework. Unfortunately, the moderator believes it’s off-topic.
I don’t know what will happen by the time uncertainty is eliminated. The question is whether we can significantly change the outcome.
Re # 198
Lorenz derived a simplified system from Navier-Stokes equations and showed it to be chaotic. Therefore climate does have attributes of chaotic system, contrary to what Dan Allan claimed. Q.E.D.
This is incorrect.
That the Lorenz system’s trajectory, i.e., its weather, is chaotic is clear. That its statistics, i.e., its climate are chaotic, is clearly false.
That weather is chaotic is probably true. That climate is chaotic is undetermined and plausibly indeterminate.
The only bearing the Lorenz system has on the matter is to show that nonchaotic climate is not trivially excluded by chaotic weather. The Lorenz system’s relevance to the point at issue therefore wieghs in only in the opposite direction that Sashka alleges.
It’s also still indeterminate whether Sashka is obfuscating or confused, but those appear to be the only alternatives.
Re: 204
The only bearing the Lorenz system has on the matter is to show that nonchaotic climate is not trivially excluded by chaotic weather. The Lorenz system’s relevance to the point at issue therefore wieghs in only in the opposite direction that Sashka alleges.
This doesn’t make any sense. You don’t need Lorenz to see that chaotic weather doesn’t exclude anything about climate.
[ad homs removed – gavin]
Sashka,
Stop me if I’m nitpicking.
You said, in post 198: “Therefore climate does have attributes of chaotic system, contrary to what Dan Allan claimed. Q.E.D.”
In post 202 you wrote: “I never said or implied that I have a proof. I certainly have an opinion that climate is chaotic and unpredictable on sufficiently long time scales.”
Don’t you think Q.E.D. implies, in fact says, that you have proven the assertion therein?
Re: 197
I meant catastrophic as widespread destruction and death.
That is why I think it is irresponsible to re-post old ideas and articles about global warming which no reasonable scientist would support in 2005.
Global warming is not a debate game. Global warming is a serious wrong which we are doing to life on this planet. New information on global warming is coming in by the minute. That is why I said in a previous post to my yahoo group members: Old articles and arguments which are obviously not valid now should not be posted to these groups.
[odd circular reference deleted- gavin]
Re: 207
Right. The odd circular reference deleted by gavin in 207 was my reference to a commentary at: http://www.earthinstitute.columbia.edu/index.html
Perhaps the following excerpt and reference may be of interest.
The Lost City – Was It Global Warming?
Oct 6, 2005, Rolling Stone magazine.
Excerpt: “Katrina should cure us of the happy delusion that we can easily adapt to global warming”.
Re: 206
IMO, nitpicking is exactly what you are doing now.
Climate is an average of weather over “long” term. The climat’s underlying quantity (weather) is chaotic and there is no reason to believe that chaotic component would average out to zero without impacting the mean. It may or it may not. This means that the climate has attributes of chaotic system but cannot be proven to be actually chaotic.
It is probably not the most important issue relevant to climate projections and policy making. But I feel cheated when it is simply ignored or laughed at.
re: 204 et al,
Sashka,
per your statement: “In addition to what I said before, reproducing past climate pretty darn well must include reproducing regional climate change, not only global mean T.”
I would like to clarify that, in speaking about climate as generally non-chaotic I have been focussed specifically on global mean T. If I were to think about it as looking at regional as well as global climate, I would probably alter much of what I said previously in this post. I do see the possibility (again, as a non-scientist) of considerably more chaos arising at a regional level, particularly due to possibly chaotic changes in ocean currents.
I’m not aware that climate scientists even claim that they are in a position to predict specific regional climate changes to a high degree of accuracy. Perhaps one of the moderators can chime in on this point. If this is so, then we are not really in that wide a disagreement about how much we think we know, just about whether what we do know is sufficient to be meaningful, useful, etc.. In this regard, I would observe that at least one important AGW effect, rising sea level, does not depend on a specific regional outcome so much as on global mean T. (At least, I think this is so (because my understanding is that most of the rise comes from lower density of warmer water, not from melting ice sheets – though again, not 100% sure on this point)).
Finally, I would say, generally, that I feel that I am somewhat shooting at a moving target. Perhaps this is just due to miscommunication. First you challenge graph c on grounds that it does not show a correlation. Then the issue is that the correlation, which perhaps does exist, was backed-into by arbitrary adjustment of parameters. Then, in post 204, that is okay. The issue has become that global mean T correlation is not enough, because it does not help with regional climate changes.
Re: 207
I meant catastrophic as widespread destruction and death.
Sorry that I misunderstood you. In this case you need to demonstrate that destruction and death will be significantly more widespread under business as usual scenario compared to mitigated.
Re: 208
Katrina should cure us of the happy delusion that we can easily adapt to global warming.
It is a delusion to link an individual weather event to GW. No such connection was or can be scientifically established.
Re: 210
1-st paragraph: progress!
2-nd paragraph: Note that rising sea level depends on melting at very specific locations of which by far the most important is Antarctica. Not only we have no ability to make a reliable regional forecast, but the current thinking suggests that Antartcica is net-net accumulating ice due to increased precipitation. As per IPCC (all caveats apply), thermal expansion is expected to be between 11 and 43 Cm. Unpleasant perhaps but hardly catastrophic.
[Response: I’m baffled by what you write here. As you clearly state, the bulk of SLR is expected to come from thermal expansion; and Ant is expected to be a net contributor to fall. So why say “rising sea level depends on melting at very specific locations of which by far the most important is Antarctica”. Do you mean, that getting SLR in xs of the std IPCC prediction means this? Then you are likely wrong, since Greenland is more probable. If you mean WAIS, then… maybe – William]
3-rd paragraph: Please understand that I couldn’t say everything I have to say in my first post. There are multiple issues that I wish to address. I had to start somewhere. So I chose a couple of points that I considered least controvercial. Little that I knew … So, I’m not moving the target. Everything I said stands. Effectively, I’m making the target bigger and easier to shoot at by including additional concerns.
re 212:
well, in that case I appreciate your expanding your target.
Best.
Dan
Well, this post is potentially off-topic. But I have a minute here and feel like writing it, and it will make a nice threshhold-test for our moderators, who will hopefully let is slip through (You guys are doing a great job by the way. Have I mentioned that?).
One thing that is surprising, given the level of vitriol on both sides, is that when you come down to it, the skeptics and the believers are not as far apart as it might seem. We apparently agree that cimate is warming due to increased CO2, and only disagree on the magnitude of the effect. We apparently agree that climate could respond chaotically to forcings, but again, apparently disagree on the magnitude of the effect. We apparently agree that predictions about regional climate are not yet that reliable (again, moderators, correct me if I’m mistaken), but disagree here on how to weigh this in terms of where the science is.
What becomes apparent, then, is that the vitriol is coming from the what is underlying, the subtext: “i don’t want to pay for your dumb mitigation costs” versus “you myopic fool, we need to spend now to avoid spending later.”
In fact, some of the comments here that are ostensibly about pure science – that it is “unscientific” to not include likelihoods of different outcomes within the ipcc 1.4c to 5.8c range, or that you cannot predict climate well until you can predict regional climate well -show that the two issues, the scientific one and the cost one, are so inextricably wound together that even thoughtful people have trouble separating them. After all from a purely scientific point of view, predicting global mean T (if we are successful at it)is quite a triumph, just like predicting the acceleration of a falling body was a triumph. Whether it has application or not. Why complain about it? The complaint implies that underlying debate about “what does this mean for me?”
As I have said before, I am a skeptic regarding all statements of cost, on either side of the debate. Because if we really want to see free parameters at work, we should take a look at how economic models are constructed. (They also have they unfortunate habit of being wrong pretty frequently).
I am therefore pretty centrist on the subject of mitigation. But I do (no surprise here) tilt a shade to the left, out of a simple, fundamental view that the planet that we have inherited is pretty darn great, beautiful and life-sustaining, and the less we muck with it the better.
Do I know of specific outcomes that will be catastrophic? No. I don’t even really buy the argument that AGW will trigger mass extinctions – partly because we have already bent the environment to our will so completely that this is just one more challenge among a great many that species will have to adapt to. Many specialist species are already on their way out. Most large mammals are already hemmed into cages and electrified fences of game parks. The battle has been lost and won (to paraphrase MacBeth). And we are the winners. And the losers.
How much am I willing to lower my standard of living, if that is necessary, to avert AGW? Hard to say. There are some trapping of fossil-fuel based affluence I would not want to part with. But there is also plenty I can live without.
[Response: I’m happy with that. Especially the bit about is doing a great job! para 3 (vitriol) is perceptive – William]
Re: 215
More progress! Just two minor points:
1. Don’t judge skeptics based on my example because my comments are not accepted any more warmly among real skeptics than here. Similarly, note that most of the true believers fell out of this discussion long ago. They either lost interest, or ran out of depth or lacked time. Either way, I’m sure that most of them feel as far apart from me as 2 weeks ago.
2. As for moderation, I don’t entirely agree. In a some cases, I wasn’t able to post succinct messages that were IMHO closer to the subject than some of the allowed page-long posts from the “believers”.
I have a question:
You say above: “Even more to the point, successful climate predictions have actually been made in past Senate hearings. The figure at the end of this comment by Jim Hansen demonstrates that projections of global mean climate presented in a 1988 senate hearing (17 years ago) have actually been right on the money.”
The graph certainly is convincing.
However, although I am no expert in these things, I am under the impression that GCMs have come a long way since 1988, incorporating important new revelations about the climate and related systems. If so, then how were models in 1988 (which incorrectly left out these phenomena) able to make such accurate predictions?
Thanks!
Ryan
[Response: An excellent question! It is true that GCMs have got better over the years and now include more processes, better resolution and more sophisticated forcings. These extras have enabled us to understand and model more and more diverse aspects of the climate and climate change. However, the dominant forcing today is from CO2, and so it was 30 years ago as well. The physics of the greenhouse effect has been well known for a hundred years, and our best bet for the climate sensitivity (how much the climate warms for a doubling of CO2) is still around 3 deg C. The models in 1987 contained that physics, as do models today. The one slightly fortuitous aspect to this is that the forcing from CO2 alone is around 1.5 W/m2, while if you add up all of the forcings, including warming factors (like CO2 and CH4) and cooling factors (like aerosols), you end up with a total around 1.6 W/m2 – i.e. all of the extra stuff we’ve put in over the years pretty much cancels out in the global mean. So just using CO2 gives you a good estimate of what has been happening (though of course you need all the other forcings to properly get the full 20th century variability and some of the key regional changes.) – gavin]
Ok, that is very helpful, but leads me to some other questions:
I do not know exactly how much money has been spent in the US on developing our scientific understanding of the climate system since 1987, but I believe it is many billions of dollars, yes?
Given that our best bet of climate sensitivity has remained the same (1.5 – 4.5 C) for over 30 years with all new information “pretty much cancelling out”, at one point do we begin to focus this investment more on mitigation or another approaches to climate change in general? at one point do we have enough information, and who makes that decision?
I am not suggesting that research on longterm climate should be discontinued, but with no change in consensus after 20 years of modeling, maybe it is time for a new approach?
i feel that sometimes there is confusion between “climate science” and “the issue of climate change” (a much broader concept that includes climate science, societal values, international AND domestic policy, economics, etc. etc.). Simply spending billions of dollars on honing our seemingly immovable estimates addresses only one tiny aspect of the latter.
Thanks again
Ryan
Re #217:
> Simply spending billions of dollars on honing our seemingly immovable estimates addresses only one tiny aspect of the latter.
I think the misapprehension that this is all there is to climate science is all too common. Certainly it’s all most people hear about. I would hope that broadening that perspective is part of what this site is for.
The lion’s share of the two billion often quoted goes to NASA for deploying and supporting earth observation satellites. I believe that observing the earth is a good use of funds regardless of the climate change issue, but somehow it gets charged to us.
There are many other issues that the remainder funds, including short-term climate prediction, theoretical meteorology, interactions between atmosphere and soil, hydrology, etc. Certainly, the field that is lumped in under the 2 billion is much broader than the climate model development community and its policy-driven experiments, which I would guess amounts to less than 5% of the total.
Climate science is an extremely valuable pursuit in itself. It lies at the cutting edge of what humans and their machines can manage. It is paradigmatic (sorry, I don’t care for that word but it really is) of multidisciplinary science. As such, it has a lot to offer the development of science as a whole. Remember that “chaos” thing, for instance?
Certainly the fact that it has policy implications shouldn’t count *against* climate science in funding, should it?
Sashka:
Re: 211. The reason why AGW should be a concern on destruction grounds is that the current pattern of development worldwide – i.e. where our cities are, where we farm, the types of building constructed – are adapted to local sea level and climate conditions. Some dramatic cases will involve the swamping of entire cities, but more subtle effects include cities losing their water supply. This is a highly destructive process. Even though adaptation is possible – for example farmers changing their crop mix – whilst the climate is changing, there is great uncertainty as to exactly what they should plant. To summarise; any given constant climate is fine; change is bad. Rapid change – which is something that is observed in the climate record – would be catastrophic.
With regard to linking extreme events to AGW, see other discussions; it would be fair to link a proportion of hurrricane damage to AGW. This is not an all or nothing proposition.
Re: 215. I judge skeptics (or, indeed, any participant in the climate debates) according to their willingness to admit error, willingness to learn, and quality of argument. I try and apply this to both sides; climate scientists are usually fine, but the more committed environmentalists frequently appear to hear only what they want to.
Re 211
My point (in 196) was that not acting to reduce GHG emissions will bring on the catastrophe sooner, impacting more people here today, and those not yet born. Young married couples are planning to have families right now. They should be considering global warming. Most are not because they continue to be mislead by others. If they had the latest information, I think most would limit their family size, or not have children. If I were one of them, I would consider it my responsibility to not have children who will likely have to live in an environment with horrific conditions, made worse by those who don’t care enough to change their excessive burning of fossil fuels in any way.
Your comment about the excerpt from Rolling Stone tells me that you misunderstood. I suggest you review the entire article before making additional remarks on that.
The Lost City – Was It Global Warming? (Rolling Stone)
http://www.rollingstone.com/politics/story/_/id/7661162?pageid=rs.Politics&pager
egion=single1&rnd=1129096734590&has-player=unknown
re 218
“Certainly the fact that it has policy implications shouldn’t count *against* climate science in funding, should it?”
I completely agree. There are many good reasons to fund climate science.
But the need for a policy outcome is not one of them. Given the last 30 years there is no reason to believe, from a policy perspective, that spending more money on climate change will lead to any more certainty about climate sensitivity. Nor is there any reason to believe that such certainty (were it achieved) would somehow answer the question of what we should do about it. The nature of the debate might change, but it would be no less polarized.
Does climate science get funded at $2 billion a year because of its valuable contributions to concepts like chaos theory, or because politicians think (or like to tell us) that it will solve the problem of climate change? In the case of the latter, only a shift in thinking (and funding?) will lead to new approaches to that particular problem.
i suppose we are fairly off topic now…
Re: 219
95% of the problem is overdevelopment and overbuilding in places where nothing should have been built in the first place (IMHO). GW is almost irrelevant. See Robert Korty’s article for more:
http://grist.org/comments/soapbox/2005/09/07/korty/index.html
Last sentence is 100% on the money.
Re: 220
How much sooner? A week? A year? 100 years?
I’ve read the whole RS article. Science-wise it is content-free.
Re: 212 (Response to William)
Maybe I wasn’t very clear. I’ll try to clarify what I meant. The context is the possibility of the catastrophic SLR due to GW. The last sentence was to note that catastrophic SLR won’t come from thermal expansion (per IPCC). Therefore if catastrophic SLR is to occur it will come from melting. But where? First of all, we can’t predict regionally so we can’t really say. Antarctica is by far the most dangerous but it goes the opposite way for now. So the likeliest source is Greenland (you are right) but it doesn’t have enough ice to enable catastrophic SLR. Does it make more sense?
[Response: [NB. SLR= Sea level rise] – Two things, IPCC discussed both the (rather predictiable) thermal exapansion and also the (more uncertain) issue of ice sheet melting. It makes sense to separate out the two components given the different degrees of uncertainty. That doesn’t mean that the IPCC thinks the possibility of ice sheet melt is small, just that there is a large uncertainty in how likely it is. Secondly, there is plenty of ice available to cause significant (which could be catastrophic) sea level rise. Only the central East Antarctic ice sheet is accumulating (which is expected). The margins of all ice sheets (including Greenland) are in retreat, and accumulation is negative over almost the whole of the West Antarctic sheet. At the last interglacial, there was probably 5 to 6 meters higher sea level, of which most came from Greenland, but a significant chunk from Antartica as well. It was not that much warmer then than now, and so continued warming is likely to put us in a similar position. The actual mechanics of the whole thing are a hot topic (basal lubrication effects, ice shelve supports, ice stream variability etc.) and so actual predictions are in short supply. But don’t conclude from that that there is no potential problem. -gavin]
Re: #224, “So the likeliest source is Greenland (you are right) but it doesn’t have enough ice to enable catastrophic SLR. Does it make more sense?”
No, it doesn’t make sense. It is incorrect, as well.
From: http://www.earth-policy.org/Books/PlanB_ch4_climatechange.pdf
That would certainly be a catastrophic result of climate warming.
Re #221
In my opinion, climate should be studied because it’s intrinsically valuable to study it. Climate should be modeled because it’s intrinsically useful to model it.
Whether it’s possible or not to get good regional climate predictions is an open question. This is a legitimate utilitarian policy-driven application of contemporary climate science, and is a major focus of ongoing effort. It is not clear whether it will work out or not, but the question is still open enough to pursue.
If we can understand regional impacts we can go a long way toward reducing the impact of the climate change we are already committed to. Regional climate prediction can contribute directly to mitigation. Who needs to worry about drought? About floods? About storms? About floods? Different regions will face different problems, and will require different civil engineering strategies.
Also, we do need as many people as possible who understand the state of the art as thoroughly as possible, so that in forums like this one information isn’t drowned out by misinformation (not to mention deliberate disinformation). This is an important role of the climate science community.
These are among the reasons to continue funding climate science. I suggest it should not be funded *less* than it would have been in the absence of policy controversy, nor *less* than the amount spent studying the atmosphere of other planets.
However, I agree that justifying a big budget line item on the grounds that “further research is needed” to drive greenhouse gas emissions policy is not justifiable.
The global temperature sensitivity to anthropogenic forcings is probably known about as well as it will be known for the next few decades. It’s unlikely that further research will narrow or change it enough to make a huge difference to the policy picture. I think that’s a sound observation.
As I see it we already have a clear picture that the Kyoto protocol is inadequate as a final policy, that it is useful only as a first step toward very serious changes that will be necessary. We are so far from that sort of a sensible emissions policy that fine tuning the science is not relevant to that question in the short run. Maybe in some happy future, once we get the costs and risks into a reasonable balance, fine tuned science will be needed to fine tune the policy, but at present there is little that “further research” can offer in that regard.
“Further research on this controversial question is being generously funded” is used as an excuse to avoid coping with the emissions side of the problem. Among other unfortunate consequences, this results in institutional pressure to be as inconclusive as possible in public communications. The scientific community ought to have the spine to avoid complicity in this, but it does not always manage it.
Re #223
The Rolling Stone article is not totally content free. It has this nice observation.
That analogy is both memorable and worth remembering.
Re: 224, 225
I stand corrected on the size of the Greenland ice sheet, thanks to Gavin and Steven. (For some reason, a number an order of magnitude maller stuck in my head.) It would indeed be a catastrophic result of climate warming.
My other points remain:
1. We cannot yet make a regional forecast, especially for the centuries that it would take the Greenland ice sheet to melt.
2. Major part of Greenland ice sheet melted in the past without any help from humans. (Actually, this is Gavin’s remark.) Obviously, this is a part of glacial-interglacial cycle. While GHW probably will accelerate the process, we don’t know by how much.
3. It is not clear what can we do about it (how much the proposed mitigation will help).
Re 217, 218 funding for climatology etc.
NSF reports federal funding for all environmental science (earth/ocean/atmosphere) at about $3.5 billion/year – up from about $2 billion/year in real terms in the 70s and 80s. It’s not clear to me how the budgets really add up (because they are reported by different sources) but the USGCRP spends about $2b/yr, of which satellites consume about half.
The Earth Observing System is regarded with some consternation – NASA wants to slash it to fund Mars exploration and it’s eating up a huge chunk of climatology budgets. On the other hand, the cost of a more comprehensive system could be much greater (see Stormy Forecast for Climate Science in Science).
In addition to satellites, the money supports about 750 phd degrees/year and there are about 20,000 phds in the workforce (only a fraction of those are doing climate work) vs. about 100,000 physicists.
To put the $ in perspective, remember that damage estimates and mitigation cost estimates are both at least an order of magnitude greater.
Given that our best bet of climate sensitivity has remained the same (1.5 – 4.5 C) for over 30 years with all new information “pretty much cancelling out”, at one point do we begin to focus this investment more on mitigation or another approaches to climate change in general? at one point do we have enough information, and who makes that decision?
That new information has been cancelling out could be taken as a sign that the original theory was basically right. Otherwise it’s likely that some major negative feedback, like Lindzen’s adaptive iris, or natural forcing, like solar output, would have turned up by now.
I think the reason that focus hasn’t shifted to mitigation or other options is that skeptics (including the current administration) have set the bar impossibly high, requiring total scientific certainty on impacts in order to justify costly action. This is a parlor trick because the mitigation cost estimates are at least as uncertain (last time I checked, economics still wasn’t a hard science) and because emissions are more irreversible than mitigation costs.
Crichton uses the same parlor trick in his description of arsenic policy:
My point here is that based on the current data on arsenic, a good case could be made for 50, 20, 10 or 5 parts per billion. We don’t have decisive data telling us what to do. We know the cost differential between setting a level at 20 ppb and 3 ppb is about three quarters of a billion dollars.
The argument that I would make is that simply because we don’t have the information is not a reason for us to think we can’t get it. We might reduce contentiousness if we set a policy and simultaneously initiated an epidemiological study to tell us if the policy was correct.
Now, in the case of arsenic, this is going to be a long-term study. Arsenic cancers develop late in life; many are not fatal, so we’re talking about a hundred year study. But so what? And if it costs you a million dollars, it’s still a bargain. Because it’s a lot better to spend a million and set your level at a certain higher point and review it again in 20 or 30 years, than it is to commit to 750 million dollars now. …”
It’s not easy to dismiss 20 or 30 years of sunk health effects, ignore asymmetries in cost and benefit assessment, neglect cost-reducing learning curves, etc. with just a wave of the hands, but Crichton pulls it off. There’s no doubt that he is adept at making technical subjects sound good to the layman; too bad he wastes his efforts on making a bunch of hooey sound good.
If we really want to pursue a learning strategy for climate, as Crichton seems to suggest, we should be doing more climate research and nontrivial mitigation experiments at the same time.
Re: 227
Climate was left alone (by humans) for millions of years yet it fluctuated widely.
[Response:Trees fall down all the time too. It doesn’t imply that clear cutting doesn’t exist. -gavin]
[Response:Despite the evidence for rapid regional climate changes during certain past transitional periods (e.g. the Younger Dryas), there is no evidence that global mean temperature changes of the amplitude seen in the past century have occured on centennial or shorter timescales in the past. Moreover, greenhouse gas concentration increases of the magnitude observed over the past two centuries have in the past occured only taken place on timescales of millions of years. -mike]
227, 230:
If we treat the atmosphere/hydrosphere as the climate system, do we know of any wide climate fluctuation that was unforced?
The Younger Dryas was forced by the undamming of Lake Aggasiz. The glacial cycle of the past million years was forced by long-term orbital variations. The K-T boundary was (almost certainly according to my most informed source on the matter) caused by an asteroid impact. Most of the other long-term fluctuations are apparently connected to (tectonically forced) greenhouse gas variations and continental configurations.
Climate was surely unforced by humans until recently. Even so, most of its changes appear to have been forced by natural events extrinsic to the climate system.
Re: 230
Gavin: I agree with you but not with Richard Alley.
Mike: I agree with you too but with the caveat. We don’t know everything about past climate variability on centenntial or shorter timescales. Moreover, I’m not sure how much is knowable about past climates on short timescales. Therefore, while your “no evidence” statement is probably (a caveat reflecting my incomplete knowledge) correct, it doesn’t follow that the current rate of change is actually unique.
Re: #230, “Climate was left alone (by humans) for millions of years yet it fluctuated widely.”
And now that our activities are directly affecting the world’s climate, this fluctuation will exacerbate, and not just on a million-year time scale, but on a century- and decadal-scale (and if things go really badly, possibly on an annual-scale).
Re: 231
Not necessarily. If we were in the cooling phase then it will be moderated or reversed. If we were in the warming phase then the trend will be exacerbated. The scale is likely to be closer to centennial because it takes us over 100 years to double CO2. In any event, Richard Alley’s statement is indefensible.
[Response: Not so. As a surrogate for the real world in the absence of forcings, climate models do tend to a stable quasi-equilibria (with some intrinsic variability of course, but with a stable climate). Since we cannot examine the real world in the absence of forcings (there is always solar variability, volcanic eruptions, orbital forcing and random events like asteriod impacts), it is a valid working hypothesis to assume the models are reasonable. Whether this will remain so as more and more geo-biochemical/vegetation feedbacks are included remains to be seen, but my forecast is that it will. Whether ice dam breaks or ice sheets are forcings or feedbacks is more of a semantic issue than a real one. If your model doesn’t include the physics of ice sheets (i.e. they are fixed), than changes need to be imposed as a forcing. If your model simulates the growth of ice sheets, then they will be a feedback. Since we are talking about the models that are being used today to model the next 50 or so years and that those models don’t generally include ice sheet models, it is correct to describe ice sheet changes as forcings in this case. It is not worth making a federal case out of though. -gavin]
re funding global warming science:
Seems like we have two contrasting views here. Ryan, in 217 and 221, is suggesting we may not need to fund it at currently levels because it already so good, so predictive, it doesn’t really need to improve (from a policy point of view). Whereas many skeptics consider it so bad as to be useless (from a policy point of view). Guess there’s no winning.
One point I would at to responses to 217: just because the CO2 forcing alone came close to predicting the temperature anomaly for 1998 (the other, smaller forcings apparently cancelling each other out), that doesn’t mean this will be the case for all years. For example, without understanding impacts of other forcings, predicting the effects of large volcanic eruption would not be possible. Etc.
re AGW costs versus mitigation costs: i hope realclimate will reconsider its policy of limiting discussion on this topic. I realize you are not experts in this, but perhaps you could have a separate post written / moderated by someone expert in this. There certainly is a dearth of decent information on this topic, and it is plenty interesting – not to mention important – in its own right. Moreover, we can have lots of good fun applying our understanding (in my case limited) of feedbacks and chaos to economic modelling.
Re: 231
The Younger Dryas was forced by the undamming of Lake Aggasiz.
In my book, it’s not forcing per se, it’s an intrinsic source of variability; I can call it intrinsic forcing for brevity. What caused Little Ice Age and Medeival Warming? Whatever it was, it’s most likely to be intrinsic.
[Response:With regard to the LIA and MWP, this is clearly not correct. As we have discussed several times elsewhere on this site, studies employing model simulations of the past millennium have been extremely successful in reproducing many of the details evident in paleoclimate reconstructions of this interval as a forced response of the climate to natural (primarly volcanic and solar) and in more recent centuries, anthropogenic, radiative changes. This is true both with respect to hemispheric-mean temperature changes and spatial patterns of climate change (see our previous discussions of this precise point here (see 4th paragraph and figure 2), here (see 8th paragraph), and here (see final paragraph). -mike]
The glacial cycle of the past million years was forced by long-term orbital variations.
Why not before that? What’s so special about last 5 million years?
Even so, most of its changes appear to have been forced by natural events extrinsic to the climate system.
I’ll agree to accept Milankovich and even plate tectonics as extrinsic. But not the ice sheets freezing/melting.
Excerpt from Rolling Stone (208)
————————————-
Katrina should cure us of the happy delusion that we can easily adapt to global warming.
Comments by Sashka (211)
It is a delusion to link an individual weather event to GW. No such connection was or can be scientifically established.
Comments by Sashka (223)
I’ve read the whole RS article. Science-wise it is content-free.
My reply to Sashka:
You seem to be having a debate with yourself. Rolling Stone has a wide audience of non-scientists. The author of the RS article did not make the connection which you implied (211), nor did anyone besides you imply that the article was scientific.
The Rolling Stone article concludes:
—————————————
The real message of Katrina is not that big winds blow down houses. It’s that on the Greenhouse Planet, we all live in New Orleans.
Re #236 (Sashka): Consider the implications of this latest research just published in Science. If CO2 changes drive both ice ages and SSTs, and we are pumping CO2 into the air at a faster rate than naturally possible, don’t you think there’s cause for alarm?
Link Between Tropical Warming and Greenhouse Gases Stronger Than Ever, Say Scientists
October 13, 2005
(Santa Barbara, Calif.) – New evidence from climate records of the past provides some of the strongest indications yet of a direct link between tropical warmth and higher greenhouse gas levels, say scientists at the University of California, Santa Barbara. The present steady rise in tropical temperatures due to global warming will have a major impact on global climate and could intensify destructive hurricanes like Katrina and Rita.
The new evidence linking past tropical ocean temperatures to levels of atmospheric greenhouse gases is published in this week’s Science Express, the on-line publication of the journal Science. The authors are Martin Medina-Elizalde, graduate student in the Department of Earth Science and the Interdepartmental Program in Marine Science at UC Santa Barbara, and David Lea, professor in UCSB’s Department of Earth Science and the Marine Science Institute.
The link between increased atmospheric greenhouse gas and global temperatures underlies the theory of global warming, explained the authors. This link can be established by computer climate models or modern observations. Another way to study the link is through paleoclimate observations where past climate is reconstructed through natural archives. This latest study is based on such paleoclimate observations; the scientists analyzed the chemical composition of fossil plankton shells from a deep sea core in the equatorial Pacific.
“The relationship between tropical climate and greenhouse gases is particularly critical because tropical regions receive the highest proportion of solar output and act as a heat engine for the rest of the earth,” said Lea.
Modern observations of tropical sea surface temperature indicate a rise of one to two degrees Fahrenheit over the last 50 years, a trend consistent with rising carbon dioxide in the atmosphere due to fossil fuel combustion, according to the authors. The paleoclimate evidence from this new study supports the attribution of the tropical temperature trend to the ever-increasing greenhouse gas burden in the atmosphere.
The research described in this week’s article demonstrates that over the last 1.3 million years, sea surface temperatures in the heart of the western tropical Pacific were controlled by the waxing and waning of the atmospheric greenhouse effect. The largest climate mode shift over this time interval, occurring ~950,000 years before the present (the mid-Pleistocene transition), has previously been attributed to changes in the pattern and frequency of ice sheets.
The new research suggests instead that this shift is due to a change in the oscillation frequency of atmospheric carbon dioxide abundances, a hypothesis that can be directly tested by deep drilling on the Antarctic Ice Cap. If proved correct, this theory would suggest that relatively small, naturally occurring fluctuations in greenhouse gases are the master variable that has driven global climate change on time scales of ten thousand to one million years.
Re: 236
Mike: Correct me if I’m wrong, but it was my impression that the scientists haven’t entirely settled all issues regarding solar forcing in the last century. First we read about modest increase in irradiation, then about solar dimming. Given that, I’m rather skeptical regarding what we really know about solar irradiation 800 years ago. You could possibly explain LIA by abnormal volcanic activity, I’d buy that. But if you want to explain MW by cranking up solar forcing, you need solid reasons. BTW, I wasn’t able to download the review paper (Schmidt et al, 2004) as Acrobat dies immediately on both of my computers.
Gavin: Currently, your comment appears in 234 but it is clearly meant for 236. It’s true that we can’t observe real world in the absense of variable forcings. Therefore it’s best (especially for a scientist) not to say what you can’t prove. Are models reasonable? “Reasonable” is not a quantitative statement. The answer is not “yes” or “no”, but “to an extent”. But you can’t say that the Earth’s climate would hang around in a stable quasi-equilibrium for a million years if variable forcings would suddenly disappear because that’s how the models behave. The models need a lot more validation before you could claim things like that.
WRT ice sheets, it’s more about time scales than about semantics. If you are making a 50 years forecast then of course ice sheets can be considered as forcings. If you are talking about climate variability on the scale of 100,000 years then it’s clearly a feedback.
Re: 238
First of all, I never said that there is no reason to be alarmed. There is. It doesn’t follow that current mitigation ideas are any good.
As for the Science paper, I’m confused. I thought we know already from ice cores that CO2 at times lags behind the T. For example, https://www.realclimate.org/index.php?p=13
>> The glacial cycle of the past million years was forced by long-term orbital variations.
> Why not before that? What’s so special about last 5 million years?
I don’t know the latest thinking on this.
As far as I know, the leading theory is that the long-term decline of CO2 since the Eocene might have crossed a threshhold where perennial glaciers become stable. (This would seem to be consistent with Alley’s analogy.)
My thinking regarding climate changes (500 ma to present) has been that whenever greenhouse gas (GHG) concentrations were high, GHGs drove climate changes. Whenever GHGs were low, other factors may have triggered climate changes. (High GHGs assumed when CO2 above 350 ppm.)
Re: 237
RC also has mostly the audience of non-scientists. The content, however, is scientific.
re 239:
Sashka,
Not sure why I go on, but here goes:
It seems to me that idea that climate would likely hold steady were there no change in forcings could be reasonably inferred from climate data even in the absence of a long period of steady forcings.
Let’s say a period exists where, for example, three variables are holding steady and one is changing, and the climate change appears to have, in that period, a fairly direct relationship to the one changing variable, it would surely lead one to suggest that, had this variable not moved, the climate probably would have remained steady. One instance of this wouldn’t prove much. But if the data repeatedly showed proportional changes in climate associated with specific changes in forcings – which I believe is what the data do show – then it seems to me that a reasonable inference can be drawn.
Re: 244
I don’t believe we can always reliably differentiate between forcings and responses. CO2 is the best example.
Re: #245, “I don’t believe we can always reliably differentiate between forcings and responses. CO2 is the best example.”
This statement is without any merit, whatsoever. The Keeling Curve shows a steady increase in CO2 content, which correlates with the global temperature increase very well.
How could a CO2 increase be a response and not a forcing? About the only way it could be is if ocean temperatures rose to the point where the waters could not absorb any more CO2, but actually began to emit CO2. Also, dealing with the forests as a “carbon sink,” deforestation and other factors may have rendered trees as a net carbon emitter, rather than a sink.
Where did you get that one, Sashka?
[Response: To pre-empt some mutual incomprehension, note that industrial CO2 rises are certainly an anthropgenic forcing and not a response (see here and here), but clearly CO2 changes over glacial-interglacial cycles is both a response (to Milankovitch-driven changes) and a forcing (since the additional radiative forcing from CO2 is about a third of that needed to keep the ice ages as cold as they are – see here). Therefore there is no contradiction with something being both a forcing and a response – though in different periods the balance may well be different. -gavin]
I spent two or three hours yesterday evening reading my way down this entire thread. Even for a crass layman, it’s been an interesting dialogue. The conversation seems to have progressed constructively from what was, at the start, a standard believers vs. sceptics stand-off to something more useful. If I can presumptively precis where the discussion stands now, it seems to me we have something like:
“Okay, something supra-natural clearly IS happening to Earth’s climate. The question is what – if anything – we can or even should try to do about it.”
The moderators have already let some fairly wildly off-topic diversions pass (a critique on the intellectual capacity of actors?), so let me try another:
Our ancestors became bipedal perhaps five million years ago, but it took them the next four million years to master fire. 300,000 or so years ago they came up with stone-tipped spears. It’s been just 5,000 years since homo sapiens figured out the wheel, two or three hundred since we invented useful engines. A little over 100 years ago we finally came up with a practical lightbulb and started to utilise radio waves. Then, 60 years ago our greatest brains ‘mastered’ nuclear fission and 25 years later they put us on the moon. Today, global diffusion of the internet and of optical fibre have made possible this discourse.
So, two conclusions suggest themselves. Either Outcome A; our exponentially growing rate of technological change will quickly lead us to exert such devastating impact on our planet that we’ll be extinct within a few generations (apologies to the guy who thought his kids would live 10,000 years), or Outcome B; our exponentially growing rate of technological change will quickly lead us to effective measures to control the global climate.
Nothing new there of course. But which is it to be? Is a choice even necessary? The collapse of numerous pre-industrial civilisations suggests we could fail (or perhaps are even bound to). But since we ‘got’ technology we’ve actually done pretty well. Look at disasters we’ve averted or overcome: the Dust Bowl; the threat of Silent Spring; nuclear Armageddon; the population explosion in China (even globally?); and on a far smaller scale, I’d argue also Chernobyl and New Orleans. Not without losses, of course. But it seems to be human nature and hence also the nature of our political leadership to step up to the plate and do the right thing when the ‘clear and present danger’ is finally seen.
Kyoto was a first step, and many more will be needed before consensus is achieved. No doubt more drastic ‘incidents’ will occur, and many more people will die. But the first juddering signs of a direction change in the global juggernaut can already be seen. Pollution emissions have been vastly reduced in the most advanced nations since the 1970s. Japan may serve as a perfect example. No doubt China and other developing countries will follow as their economies advance, their citizens’ voices grow and they become better able to afford the ‘luxury’ of environmental controls. As noted elsewhere in this thread, rising oil prices are already spurring the development of alternative energy technologies – even (some of) the oil companies have seen the light. For all the angst devoted to the perceived obtuseness or even perfidy of the USA’s current administration, I’d say fear not – they just need a little more prodding from Mother Nature and/or their citizens, and if that doesn’t work, don’t worry, a new bunch will be along soon anyway.
As a layman, I’m not qualified to even participate in this discussion. I am permitted to read your exchanges, however, and what I’d like to read is your thoughts on some of the above. In particular, from your eye-of-the-storm point of view, do you see the inevitable, inexorable process evolving that I do, or am I being a complete Pollyanna?
Well, the whole question is one of time scales. If the time scale necessary for us to get kicked hard enough to take action to prevent the death of our civilization is longer than the time scale on which we have to take action, then we can’t wait for the prodding from Mother Nature. Or, at least, we need to pay close enough attention and make enough noise that the prodding happens when the effects are still subtle. But the tendency to discount subtle-seeming effects works against us. E.g. “Two degrees Celsius? What’s that to us?”
Industrial civilization hasn’t been around for all that long, and there’s not really a lot of data to go on. I hope that the corrective effects you’ve mentioned are enough but I am not entirely sanguine.
Re: 247
The question is what – if anything – we can or even should try to do about it
This is my question indeed. The trouble is that for most people here there is no question. They see the problem and the want to act now in hope (e.g. 248) to fix it.
My immediate objections are not as much about the uncertainty of the climate forecast but mostly about the economic uncertainty and attainability of the stated goals.
[Response: Then you’re at the wrong blog. This one is about climate science – William]
On a “macro” level, the consequences of CO2 build-up will not, in my view, be the principal challenge for the humanity in this century. The principal challenge will be posed by the upcoming energy crisis. My hope is that we’ll learn to reduce emissions in the process of dealing with the scarcity of fossil fuels. I believe the economics of the energy-starved world won’t leave us any choices other than to become more efficient. A market-based solution is likely to be better than whatever the bureacrats can concieve.
Re: #249, “I believe the economics of the energy-starved world won’t leave us any choices other than to become more efficient.”
Shouldn’t that be “energy-wasteful world” instead of “energy-starved world?”
We have easily the technology to make our machines and lifestyles far more energy-efficient, but political pressure (mainly from the energy industries) prevent governments (at least in North America) from actually setting targets which will make meaningful progress (i.e. mass-hybridisation of vehicles, increasing mass transit, ridding the world of gas-guzzlers, and greatly increasing mass wind and solar electricity generation) and helping to minimise the effects of the 21st century’s greatest problems, climate change.
By making these changes, perhaps there will be enough energy for developing nations, as well as ourselves. Without it, we’ll all be in for more than just an energy pinch.