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 247
A ‘clear and present danger’ IS seen by many, but human nature and the political leadership do not have the will to step up to the plate and do the right thing, and… global warming is on an entirely different playing field.
Re #249 (Sashka): The scenario of fossil fuel shortages forcing us to reform our carbon-emitting ways before anything really horrible happens to climate is an optimistic one, but I don’t think it’s right. A more likely scenario if we do nothing is that emissions will continue at a rapid pace as oil from sand and shale plus coal substantially replace oil and natural gas, with the consequence that we will have dug ourselves into a deeper hole in terms of having sufficient resources to reduce emissions sufficiently without major disruption to our society. If we start now, the transition will be far less painful. Unfortunately, our society can’t even get it together to overcome the resistance of the fossil fuel industry to minimal changes like switching to CF light bulbs.
Regarding using free markets as a tool to protect the environment, the record isn’t good. Free markets may from time to time benefit the environment, but such effects are incidental and are the consequence of actions taken for reasons related to profit. Even where market mechanisms have had some success, it has been under a government-enforced scheme.
re 249 and 252:
Shaska,
here are my two cents on this off-topic:
Not all problems are solvable by the free market. Consider pollutant A, which everyone expends into the environment. Each person’s contribution to overall A pollution is so slight – given that there are 6 billion others out there – that, guided purely by informed self-interest of the sort the market is based upon, he has no incentive to reduce his emission of pollutant A. In fact, it is *against* his own informed self-interest to reduce his own A emissions, even if he is highly concerned about the environment. So even if private companies were to produce more-expensive products that did not use A, a traditional economist would conclude that no right-minded person would choose to buy such a product.
In this respect, pollution-control has a game-theory-like aspect.
The rational actor is only interested in reducing his own pollution if he knows others will be required to do so as well, i.e., if there is a law that requires it. Without such a law, there is no reason to believe A emissions would ever be controlled.
Folks, I hope you are all enjoying the conversation. Isn’t it fun when you can say all you want but your counterparty cannot respond?
Re: 253.
Without much hope to see it posted, I’ll still say that your logic, Dann, is flawed. Just look at Europe and observe that they drive much smaller cars than us. Guess why.
[Guys, this is getting way off topic. No more posts on this please! -moderator]
Now, class, just to prove to the moderator that we can stay on topic, let’s all repeat after that nice Dr. Gray (paraphrasing here but I think accurately): “All this hurricane activity is part of a natural cycle. It has nothing to do with global warming. Even if there is some global warming effect, and believe me there isn’t, no particular hurricane can be shown to be affected by it anyway. So you’d all better just stop thinking about any hurricane – global warming connection.” To which Fred would add (exact quote): “Wiilllmmaaa!!!”
Wilma has blown up from a tropical storm into a very strong Category Five hurricane faster than you can say “Andrew.” I understand it has some other unique characteristics (e.g., the tightest eye ever for a cat 5) that make its behavior a little hard to predict. Key West’s long run of luck may be about to end, with heavily populated areas of south Florida nearly certain to be struck. It might weaken a bit (hard to say with that weird eye) and/or it might manage to stay in the Florida straits and miss a landfall altogether. Maybe. Evacuation in the time available will be problematic.
MIAMI, Florida (CNN) — Hurricane Wilma has strengthened into an “extremely dangerous” Category 5 hurricane, with sustained maximum winds of 175 mph, the National Hurricane Center said Wednesday.
The hurricane’s minimum pressure is 892 millibars — the lowest pressure observed in 2005.
Forecasters warn that the storm could possibly slam into southwestern Florida by this weekend.
At 2:30 a.m. EDT, the National Hurricane Center reported an Air Force plane had found 175 mph winds with higher gusts in Wilma.
Wilma “has become an extremely dangerous Category Five hurricane on the Saffir-Simpson scale,” the center said in an advisory.
The storm’s minimum pressure of 892 millibars “is equivalent to the minimum pressure of the 1935 Labor Day hurricane in the Florida Keys,” the advisory added.
The storm has already left seven to 10 people dead in Haitian mudslides caused by heavy rains, government officials told Reuters news agency.
The latest in a slew of devastating storms to sock the Gulf region, Wilma became a hurricane Tuesday — tying the record for both most hurricanes in a season with 12 and most named storms at 21.
Just nine hours after becoming a hurricane, Wilma’s wind speeds had jumped from 75 mph to 100 mph. Then, within two hours, the winds intensified from 110 to 150 mph. A short time later, its winds had increased to 175 mph.
At 2 a.m. EDT, the center of the storm was located 170 miles south-southwest of Grand Cayman Island and about 400 miles southeast of Cozumel, Mexico. It was moving west-northwest at nearly 8 mph and is expected to turn to the northwest over the next 24 hours, the hurricane center said.
A Category 5 hurricane can cause a storm surge of more than 18 feet above normal.
Projections for Wilma’s path suggest the storm may skirt the western tip of Cuba on Friday, possibly as a Category 4 storm with winds of greater than 130 mph, before curving eastward and barreling toward the southwestern Florida coast.
“All interests in the Florida Keys and the Florida peninsula should closely monitor the progress of Wilma,” the NHC said.
Hurricane-force winds extend outward about 15 miles from the eye, and tropical-storm-force winds stretch up to 155 miles from the center.
Cuba has issued a hurricane watch for the provinces of Matanzas westward through Pinar del Rio and for the Isle of Youth, according to the hurricane center. Late Tuesday, Mexico extended a hurricane watch for the Yucatan Peninsula. The watch area now stretches from Punta Gruesa to Cabo Catoche. A hurricane watch means hurricane conditions, including winds of at least 74 mph, are possible within 36 hours.
A 150-mile stretch of the Honduran coast is under a tropical storm warning, and the Cayman Islands are under tropical storm warning and a hurricane watch.
The hurricane center said Cuba could get anywhere from 10 to 15 inches of rain in Wilma’s wake, with some areas getting socked with as much as 25 inches. Additional rainfall accumulations of of up to 10 inches, with up to 15 inches possible in some areas, was possible across the Cayman Islands and Jamaica through Thursday. Across the Yucatan Peninsula, rainfall of up to 6 inches was possible, with up to 12 inches in some areas.
Wilma is the 21st named storm of the 2005 hurricane season and the 12th to reach hurricane status. Of those, five have developed into major hurricanes.
The only other time 12 hurricanes have been recorded in the Atlantic was in 1969, according to the hurricane center. The most major hurricanes in a year was eight, in 1950.
Wilma is also the final name on the 2005 list. The hurricane center does not use certain letters of the alphabet, including X, Y and Z, because there are so few names begin with those letters.
If any tropical storms and subsequent hurricanes form before the season ends on Nov. 30, they will be classified using the Greek alphabet, beginning with Alpha.
If that happens, it would be the first time since the naming of storms began in 1953, according to the hurricane center.
Reuters contributed to this report.
Wilma update: As of 5:00 AM EST, Wilma is the strongest Atlantic hurricane on record. Still no global warming anywhere around those parts, no sirree Bob.
Re: 255, 256
To paraphrase the old proverb, no matter how many times you repeat “GW”, it doesn’t make a hurricane. By the end of the day, these are just words that are worth nil. There is no connection between the individual weather events and GW. The unusually strong hurricane season is explained by the huge local SST anomaly in the Western Tropical Atlantic. The possible connection to of this SST anomaly to GW is purely speculative.
Re 257
Clearly individual weather events are not unconnected with global climate (perform an extreme conditions thought experiment: are weather events somehow invariant to snowball earth or runaway GW conditions)?
If you think that the cause of the SST anomaly is unknown, then you can’t disprove a GW link any more than you can prove cyclical behavior.
Re: 258
This is the case when extreme conditions thought experiment is not helpful. The reason is that the amplitude of the SST anomaly is huge compared to global trend. Consider: the world ocean warmed up by about 0.5 C over hundred years (that’s, roughly, GW signal). The local SST anomaly is about 4 C over one year. To deduce that the latter is caused by the former requires more than handwaving. Just saying “clearly” doesn’t make it any more clear.
The cause of the SST anomaly may not be entirely unknown. Local currents and/or cloud cover patterns must have contributed. I can’t disprove a GW link other than by pointing out that from a physical point of view this claim is as nonsensical as the groundhog routine. However, I’m not in the business of disproving everything than can ever be claimed without a reason. In science, the party that makes a statement is supposed to prove it. Otherwise it’s just hot air.
Re 259
In science, the party that makes a statement is supposed to prove it. Otherwise it’s just hot air.
Right. You said, “There is no connection between the individual weather events and GW.” Absent proof, that’s hot air. Had you said, “Wilma is just one more data point that doesn’t prove a connection by itself” I wouldn’t have argued.
I didn’t deduce that this particular SST anomaly was caused by GW. My thought experiment was intended as a counterexample to restrict the idea that there’s no connection between GW and SST anomalies. I agree that the signal hasn’t clearly emerged from the noise, but that’s not the same as no relationship. It strikes me as odd to posit a dead spot in the transfer function between GW and weather around current conditions simply because stochastic variation is hiding the real relationship.
Stepping back from SST to currents or clouds doesn’t change anything. If some cause of the SST anomaly is known, it would be interesting to see some citations. If it really is a mystery, then I don’t see how GW is more nonsensical than other hypotheses. If I take your meaning correctly, the groundhog routine is nonsense because accumulated evidence makes it easy to reject the notion that rodent shadows are predictive of spring. That’s not a good analogy for this case.
I have an impression that we are sort of splitting hair. If we agree that Wilma has nothing to do with GW, that’s pretty good already.
If I’ll be allowed a word on philosophy of science, I’ll add that it doesn’t matter who said it first. For lack of knowledge (or at least suggested mechanisms) to the contrary, the default is “no connection”.
The groundhog routine is nonsense not only for lack of evidence which is sometimes imagined by biased observers. It is nonsense because there is physics behind it. Likeweise, we don’t know physics that explains how a super-strong SST anomaly can be born out of tiny backround global trend.
[Response: Everything we said about Katrina goes for Wilma as well. -gavin]
Shashka,
Maybe I’m misunderstanding, but it seems to me your own data run somewhat counter to your argument. The ocean warmed by .5c over the last 100 years, presumably due primarily or entirely to AGW. The SST anomaly is 4c on top of the .5c. So, of the total anomaly, AGW represents roughly 1/9th contribution. Still smaller, to be sure, than natural variability, but certainly not nothing, when once considers that that each degree c represents a 15-20 mph increase in potential hurricane strength.
I apologize for failing to read the prior discussion – thanks, Gavin. If you guys don’t want to listen to me nor my reasoning, read what the founders have to say:
there is no way to prove that Katrina either was, or was not, affected by global warming. For a single event, regardless of how extreme, such attribution is fundamentally impossible.
Re: 262
Dahn,
Even if the GW trend is additive to local SST event, it doesn’t necessarily translate to proportional increase in wind speed. However, this is not the point. The point is that is impossible to link the origin of the SST anomaly to GW.
Well, we almost agree. But the hair we’re splitting is rather important. First, I wouldn’t say that Wilma has nothing to do with GW; I’d say that Wilma increases our knowledge of hurricane-GW links by some small fraction (the share of Wilma data among all data on the topic). The RC Katrina quote doesn’t say “nothing to do” either; it says “no way to prove”. Second, I think Occam’s Razor actually selects Dan’s contribution (1/9, or 1/8 if the anomalies aren’t additive), not 0. To presume 0 d(local SST anomaly)/d(global anomaly) requires an extra assumption that the Atlantic is somehow special, such that all the effects of global radiative imbalance wind up elsewhere in the ocean. Even if currents are chaotic, so anything goes at a particular point in time, you’d expect the local statistics to follow the global, absent some theory about why it should be otherwise.
At least you’re in good company with William Gray. I found his written testimony rather puzzling. It refers to a Figure 5 showing SST anomalies with a forecast to 2020. Yet elsewhere he argues that climate models “have no damn skill” and that oceans are poorly modeled. So, where does the 15-year SST forecast come from, if not an ocean model? Just a strong presumption of mean-reversion or oscillation?
“No way to prove” means the issue is not in the realm of science. Let liberal arts majors talk about it and save these pages for rational discussion.
I’m afraid you misunderstand the meaning of the SST anomaly. Should the same thing happen 100 years ago, it would be, roughly, 29 C SST over average of 25 C (an average for a previous long term observation period for the same location and season). Today we have 29.5 vs. 25.5. You need to make a case that extra 0.5 C in the background state somehow enabled 4 C anomaly. Just noting that 1/9 is greater than 0 doesn’t do the trick.
I skimped through Dr. Gray’s testimony. Regrettably, I have to decline the honor of being in his company. While he is not entirely unreasonable, especially when he is talking about hurricanes, I cannot share company with someone who is convinced that in 15-20 years, we will look back on this period of global warming hysteria as we now look back on so many other popular, and trendy, scientific ideas — such as the generally accepted Eugenic theories of the 1920s and 1930s that have now been discredited. It’s OK to be a skeptic but there is nothing out there to be firmly convinced about.
Re: Fig 5, my (possibly wrong) interpretation is that he is simply extrapolating the observed fluctuating pattern into the future. It has nothing to do with models’ skills. The exercise doesn’t prove anything but it’s no worse (probably better) than projecting current warming trends 50-100 years into the future.
Re 265
I’m afraid you misunderstand the meaning of the SST anomaly…
Not at all. As pointed out in the Katrina thread, it’s the absolute temperature that matters. Moving the basis period for the anomaly around is irrelevant, and isn’t normally done as far as I know (most data I’ve seen is based on 1961-1990). If, as you say, today we have 29.5, and would have had 29.0 with no GW, there’s your contribution of GW to SST.
Tom,
Well said.
Sashka, regarding your post 263. You write:
Even if the GW trend is additive to local SST event, it doesn’t necessarily translate to proportional increase in wind speed.
True. But we have all been busy attributing the busy hurricane season (and strong hurricanes) to high SSTs. You and me and Dr. Gray and, I think, Gavin, have all accepted this highly reasonable assumption. So if we accept that the active season is due to high SSTs, and accept that roughly 1/8th or 1/9th of the high SSTs is due to AGW, then it is reasonably to infer, that overall AGW is having some slight-to-moderate contribution to the activeness of the season. It would be odd indeed if the first 4c caused more hurricanes but the last .5c did not.
BTW, I know I’m not supposed to follow up on your latest pollution post…rrrr….it’s not easy. Suffice it to say that I am hording my ammunition.
– Dan
These hearings show the importance of experts. When dealing with a complex topic like climate change science people with training and experience in the field are necessary. Not everyone has this type of knowledge (although I suppose I could have gone to grad school and not law school, biogeological cycles would have been an interesting area to get into) so we do need experts to explain complicated topics.
The use of experts can have positive results. Largely from reading RealClimate I think I have a basic handle on the science of climate change. I recently saw an interview with Dr.s Landsea and Curry about hurricanes and global warming and the discussion was complex but I was able to understand it because of what I have learned from RealClimate.
Reliance on experts also makes us vulnerable because we can be misled if the experts are incorrect. Crichton’s testifying is similar to how experts are used in legal proceedings. In a lawsuit you are not trying to find the facts you are trying to win a conflict. The objective truth is secondary to your side winning (Steven Schneider has a good section on this on his site). The most important ability an expert witness can have in a trial is not proving that something is factually correct, it’s convincing people to support your side. This leads to the use of experts who are not giving accurate testimony because of political or philosophical reasons (IMO Crichton) or economic reasons.
Experience with experts in the courts has helped me to understand the use of science in the climate change debate. IMO when someone hears or reads something about climate science they should be careful about taking things at face value, consider that climate change science does have major regulatory/economic/environmental repercussions, realize that the source may be motivated by these potential repercussions, and look at the past behavior of the source (have they usually said accurate statements?).
That being said I would characterize Sashka as a sophisticated skeptic. As with many skeptics Sashka is economically/politically motivated. Sashka’s main goal seems to be convincing us about the uncertainty in climate science, then to use this uncertainty to argue against regulatory action. Sashka is careful not to openly reject the scientific consensus on AGW, but Saska does touch on the skeptic’s talking points that AGW is synonymous with extremist claims, is a belief, models aren’t reliable, GW is a natural cycle etc. Finally Sashka complains about not being listened to e.g. #209. I hope Sashka doesn’t start comparing himself to Galileo ;)
United States has the most extensive system of environmental regulation and has the largest and strongest economy in the world. Environmental protection and economic prosperity are not exclusionary. More importantly if GW regulations are created it will mean more work for lawyers! This is the most important reason for passing laws that address global warming! Don’t you want those kids in law schools to get good jobs?
Re: 267
I don’t think I’m making a very complicated point but you and Tom repeatedly miss it. I’m not saying that background SST trend contributed nothing to hurricane stregth. I’m saying that we can’t link the current anomaly to GW.
[inflammatory remarks deleted. -moderator]
Re: 268
[inflammatory remarks deleted. -moderator]
As with many skeptics Sashka is economically/politically motivated.
Same thing. I am not allowed to make this sort of statements here. Let’s migrate to an unmoderated environment and I’ll
[inflammatory remarks deleted. -moderator]
Sashka is careful not to openly reject the scientific consensus on AGW, but Saska does touch on the skeptic’s talking points uch on the skeptic’s talking points that AGW is synonymous with extremist claims, is a belief, … GW is a natural cycle etc.
Examples please?
[inflammatory remarks deleted. -moderator]
Not that I have much hope that mods will let it through but you never know.
[we rarely admit a posting with so many instances of inflammatory language; it is much easier to simply screen those out than go through, as we have done in this case, and carefully edit out the inflammatory remarks. Please be more careful in the future–just make your points objectively. We have no problem with that. However, if the post is filled with ad hominem remarks, vituperative language, or otherwise inflammatory content, we will most likely just screen it out as per our comment policy. -moderator]
I don’t think we’re missing the point; we just disagree – perhaps only on definitions. Here’s an trial balloon. Suppose that SSTs consist of two separable components – a mean with a long run trend, and an oscillation:
SST[t] = SST[1961-1990] + a*(t-1976) + b*sin(w*t-p)
You seem to be arguing that GW has no effect (or at least no provable effect) on the amplitude of the oscillation, b. I think there’s general agreement that that’s a reasonable null hypothesis. But today’s anomaly, SST[2005] – SST[1961-1990], depends on both the GW trend in the mean a and the oscillation, in which case the current anomaly is influenced by GW. If you redefine “anomaly” as SST[t] – SST[1961-1990] – a*(t-1976), then the anomaly is independent of GW, but has little physical meaning w.r.t. hurricanes and is impractical to implement. Same applies if you change the reference period to a sliding window or define the anomaly as SST[local]-SST[global].
No redefinition supports the statement that “There is no connection between the individual weather events and GW.”
The anomaly is a singular event, so your equation is inapplicable. At the very least, the argument of your oscillating term must be multiplied by the indicator function of this summer-fall seasons.
As for he last sentence, I cannot argue this point better than the founders did before.
Re 271
If the anomaly is a singular event then the 2nd term gets replaced by something else (an impulse function or …) but that doesn’t change the argument. What equation would you propose?
As for the last sentence, the RC position that there is no way to prove that Katrina either was, or was not, affected by global warming contradicts your assertion that there is no connection, unless by “no connection” you mean only “no inference from an event to GW is possible.” I had the impression that you meant that there was no causal influence of GW on events.
SST[t] = SST_mean + a*(t-t0) + b(t)*indicator_function(2005)
You need to show that b(t) isn’t zero due to background state (first 2 terms) reaching a threshold.
Most people are sure, without a reason, that Katrina, Rita, Wilma etc are due to GW. or was not is irrelevant to the point.
Shaska,
re post 267:
If I’m missing your point, I assure you it is not deliberate. Maybe your wording is ambiguous or maybe I’m being slow on the uptake or maybe both. But I have tried to keep this in the spirit of friendly, if frank, debate.
you said “I’m not saying that background SST trend contributed nothing to hurricane strength. I’m saying that we can’t link the current anomaly to GW.”
Would you accept that current SST (not current anomaly, but current local SST) is the result of a combination of cyclical variation plus GW?
Re: #273, “Most people are sure, without a reason, that Katrina, Rita, Wilma etc are due to GW. or was not is irrelevant to the point.”
This is incorrect. Most people are sure, with plausible reasons, that Katrina’s, Rita’s, and Wilma’s severity are, at least in part, due to human-induced climate change. Most people do not say that these storms are entirely (or entirely not) due to GW.
Re: 274
Dan,
Since your tone have drastically changed after your dramatic #154, I no longer have any personal issues with you. Even if it doesn’t come across that way, I’m actually being friendly, despite your misspelling my name. :)
Would you accept that current SST (not current anomaly, but current local SST) is the result of a combination of cyclical variation plus GW?
Yes, I accept it. What I’m saying, though, is that the cyclical part, for all we know, is independent of the trend and dominates it by 3 orders of magnitude. (I am referring to the partial derivative of temperature with respect to time.)
Re: 275
Most people are sure, with plausible reasons, that Katrina’s, Rita’s, and Wilma’s severity are, at least in part, due to human-induced climate change. Most people do not say that these storms are entirely (or entirely not) due to GW.
Most people (including yourself, on many occasions) don’t tend to make well-hedged statements like yours above. Laymen conversation typically doesn’t include caveats in each sentence. I hear what I said I hear: “This is GW! Let’s do something! NOW!”
Earlier (222), I linked an article by Robert Korty where he explains why GW contribution is small.