Chat:
Suraje Dessai: I am a student at the university of East Anglia, Norwich, UK. I have worked with climate models and I am interested in both the science and policy aspects of this.

Moderator: Professor Lindzen is professor of Meteorology at the Massachusetts Institute of Technology. Welcome, Dr. Lindzen.

Suraje Dessai: Hello Dr. Lindzen, greetings from Norwich, UK

Lindzen: Good to here.

YMP130: Hello Dr. Lindzen. I am an undergraduate "global environmental problems" student, from the University of Jyvaskyla, Finland)

Moderator: Hello, Dr. Lindzen. The subject of today's chat is What if science begins to show the problem is of diminishing importance. Let me ask you if you're following the negotiations in Buenos Aires.

Lindzen: I'm afraid not. The coverage is minimal here.

Suraje Dessai: I was wondering what you mean by "diminishing importance" in the topic?

Lindzen: Let me say that although IPCC estimates for 2100 are diminishing, and the evidence in the data remains ambiguous, what I really was concerned with was the possibility that future evidence would show the problem to be negligible and how this would impact policy?

Suraje Dessai: Do you think there are signs of this?

Lindzen: Yes. For example, increasing CO2 alone causes very little warming. Predictions of a lot of warming depend on water vapour feedbacks, and several recent papers suggest that models have the wrong sign for this feedback. I am not really referring to anthropogenic gases, but rather internally determined gases like water vapour.

Suraje Dessai: I agree. Non-CO2 GHGs are becoming more and more important. You are basically saying CO2 forcing has been exaggerated?

Lindzen:. Not really. I am saying that the CO2 forcing was always small. Its importance depended on amplification by water vapour.

Suraje Dessai: How does that connect with the hydrological cycle?

Lindzen: The hydrological cycle says that increased evaporation leads to increased precipitation. It has no direct implication for water vapour.

YMP130: Dr Lindzen: Do you think the Gulf stream might shut down?

Lindzen: No.

YMP130: Why not?

Lindzen: At present, it is totally unclear whether warming would make such an unlikely occurrence more or less likely.

Moderator: Dr. Lindzen, the NYT in an article on you said that you had identified 5 effects that should be considered by the IPCC (including one you yourself found to be insignificant). Which are these effects?

Lindzen: Frankly there are more than 5 effects. However, positive water vapour feedback is essential to predictions of significant warming, and data fails to support models.

Suraje Dessai: Dr. Lindzen, what if science really shows that CC is of no importance, what implications might you think it could have on policy?

Lindzen: The attempt to couple ocean and atmosphere models reveals large errors in the energy budget. As concerns ENSO there appears to be no clear link. As concerns policy, I was hoping that others might have some thoughts. My impression is that current negotiations allow for no possibility of the problem proving to be non-serious.

Suraje Dessai: Agreed. If science would prove such a thing FCCC and the KP could be thrown out!

Moderator: So, water vapour feedback is one effect, what about the others?

Lindzen: I have already mentioned the overall budget problems. There are also large errors in transports, and there are severe numerical problems in integrating the model equations.

Kaplan: Like what?

Lindzen: Science rarely proves anything. The present procedures count on uncertainty to project bad scenarios.

Suraje Dessai: Besides that, we are basing all our policies on the precautionary principle.

Lindzen: The difficulty with the precautionary principle is that it encourages the purchase of insurance policies that cost more than the anticipated damage, while promising to cover only a small part of the damage.

Suraje Dessai: I agree that current IPCC scenarios are out-of-date but do you think the new generations of scenarios will not prove useful?

Lindzen: Not for quite a while. Our predictive capacity has always been limited. Consider predictions of oil prices in the 70s.

Suraje Dessai: Robert Watson (talking at 21:30) might enlighten us on IPCC scenarios.

Moderator: What are the current bounds on our predictive capacity, in your opinion?

Lindzen: What do you mean?

Moderator: With regard to climate models, where and when does their predictive capacity reach its limit?

Lindzen: At the moment this ranges from 5 days to (for very specific phenomena) 6 months.

Moderator: What about coarse-grained (averaged) quantities? Are these also so limited?

Lindzen: It is possible that for long term globally averaged temperature one might do better, but that depends on the physics being correct.

Christian Marquardt: One might argue that our predictive capacity is limited in both directions - what if the prediction of CC not being an issue should turn out to be wrong?

Lindzen: Well, at present nothing would happen. Kyoto will have little impact regardless of what one believes. Everything is possible, but for such things we don't even know if what we are doing is going to help or hurt.

Staffan: Dr Lindzen: Big ecological turnovers are, by definition, rare events. Might the risks not be underestimated in models?

Pablo: This limitation is clearly from the perspective of models. However what would you say frrom the data currently available?

Lindzen: Currently, major modelling groups are admitting that past data shows nothing about predictions.

Pablo: What do you mean by 'predictions'. There is an increase in mean temperature over this century. On the one hand the argument is that that is a trend, on the other that the increase is part of a long-term cycle.

Lindzen: Yes, the past temperature record has to be distinguished from natural variability. That hasn't been done yet. About 4 Watt per square meter for a doubling.

Christian Marquardt: Do you think this will be possible at some point in the future (distinguishing trend and natural variability, I mean)? How?

Lindzen: Remember, climate changes all the time regardless of human activity.

Pablo: Is there evidence in past records of such an abrupt change as registered in some locations?

Lindzen: Climate changes on the order of 1-4C would probably be distinguishable. Certainly. Local changes are much larger than global changes, and generally uncorrelated with global change.

Christian Marquardt: I wonder - if the climate system reacts to any kind of forcing in similar modes of variability, it will be hard to find a reasonable criterion to distinguish between anthropogenic and natural...

Lindzen: That's true. The question is what does this lead to for policy and its evaluation.

Christian Marquardt: So doesn't that mean that we will never be entirely certain if some change in the atmospheric circulation is due to natural variability or GHG increases?

Suraje Dessai: What is your opinion on that?

Lindzen: Personally, I'm uncomfortable with major policies that can't be assessed.

Suraje Dessai: What do you mean by "can't be assessed"?

Lindzen: There is an expectation of mean increase apart from patterns of variability.

Pablo: If from your point of view, the situation is that current models and current data cannot give us a definite answer, would you not consider it best to promote both the modeling field and enhanced monitoring activities rather than denying the possibility of CC?

Lindzen: I mean that there won't be a criterion for establishing whether there is a problem or whether it is being mitigated. I also think that it would be worth assessing the model representation of important physical processes.

Pablo: In other words, according to you we are in a no-win situation.

Lindzen: It depends on what role you are playing.

Suraje Dessai: You're basically saying that we should sit tight and see what happens!

Modulator: I would argue that Dr. Lindzen is saying that we need to have more science before we can base policy on it.

Pablo: From the point of view of science, as a source of information for policy makers, what do you think should be done then, both with models and with data and monitoring?

Modulator: But when will we have enough science?

Lindzen: We have already decided that. As I mentioned Kyoto won't have much impact on climate.

Suraje Dessai: What about the Montreal Protocol?

Christian Marquardt: Is your opinion that we should put any political action on hold until CC can be "proven"?

Lindzen: At present we are so far from proof, that the question is irrelevant. What about the Montreal Convention?

Pablo: Montreal is a different issue. To a certain extent the role of CFCs has been confirmed. However other sources of change in the ozone content yet remain to be tested.

Modulator: Well, would you think that the Montreal Protocol and the action that ensued has helped reduce the Ozone problem?

Lindzen: It is too soon to tell.

Pablo: The impact of the ozone change on CC has still to be assessed. Some model results do suggest that ozone depletion might have mitigated temperature increases by as much as 10%.

Christian Marquardt: If CC happens - should we not act as early as possible? And can you really exclude that possibility?

Lindzen: There is a general tendency to look for reasons why so little warming has occurred so far. It depends on what action consists of. Kyoto, if followed by everyone would do almost nothing, while doing anything significant is unaffordable.

Christian Marquardt: Little warming occurred could mean that CC is not a mean increase of temperature, but rather a complicated change in circulation...

Pablo: I must say that the issue is not only temperature increase. We need to consider changes in weather patterns and the occurrence of extreme events.

Lindzen: That may be true, but we are even less capable of saying anything about such matters.

Pablo: For example there is evidence of significant changes in stratospheric ozone distribution due to ten year changes in tropospheric circulation in the northern hemisphere (Hood and Zaff, 1995)

Lindzen: At present we are taking ignorance to mean that anything is possible. However, in many instances we know that there is no relation to mean temperature, and in others we know that variability should diminish in a warmer world, and yes, Pablo, circulation is a major determinant of ozone.

Modulator: Could you give specific examples of that?

Lindzen: For example ozone column densities change about 30% with the passage of storms.

Pablo: Hence would you not agree that we need to have a broader approach to the issue of CC taking into account other variables that could provide early signals of variability or change?

Christian Marquardt: In a later paper, Hood and Labitzke and McCormack (I think) argued that as much as 50 % of ozone decrease in the NH are due to circulation changes, mainly the NAO.

Pablo: That is correct Christian.

Lindzen: Pablo, how do you justify broader policy as ignorance increases?

Christian Marquardt: What ignorance?

Pablo: I am talking of the scientific perspective where we need to confirm or deny the existence of a signal of CC in the observations and modelling.

Lindzen: Ignorance concerning connections of CC to local behaviour. I fear that this usually means that when warming fails to meet one criterion, one makes up another criterion.

Pablo: I can't agree with you. I have always thought that warming was but one possible indicator.

Lindzen: However, no other criterion exists for which we even know the sign.

Christian Marquardt: And if we learn that the first criteria were too simplistic? I find it very naive to assume that a complex non linear system can be understood in terms of means.

Lindzen: My main question is: Is anything built into the negotiations that allows us to back off.

Pablo: What about the increase in the occurrence of extreme events? I agree with Christian that the system is too complex to understand with only means.

Lindzen: That may be true, but other criteria simply don't exist at the moment.

Christian Marquardt: Well - if there is a proof - a generally accepted by scientists - can't negotiations be stopped?

Lindzen: In a world with reduced equator to pole temperature difference we expect less variance. I doubt it.

Pablo: However, others say that because of the increase in water vapour and possible changes in SST the extremes could occur more frequently.

Lindzen: They say that, but the experts here disagree.

Modulator: Pablo, and others, could you please spell out acronyms...

Pablo: Sorry, SST is sea surface temperature. Now, which experts are you referring to?

Lindzen: The group of IPCC authors dealing with tropical cyclones.

Pablo: OK!

Kim: I think that Dr Lindzen is quite right to point to the uncertainties behind the science of global warming and the risk is somewhat exaggerated. But isn't it true that many of the IPCC scientists also accept the presence of uncertainties? I mean, aren't we talking about the precautionary principle?

Christian Marquardt: I think we are....

Lindzen: Of course. The question is what use is being made of this uncertainty.

Suraje Dessai: (I just had to share this one with you because it made me laugh! I was reading the BBC news and saw John Prescptt saying "Nobody doubts science anymore"!)

Lindzen: That is an easier position to adopt when negotiating.

Modulator: John Prescott being the head of the UK delegation to COP4.

Suraje Dessai: Do you think that's wrong?

Lindzen: Exactly what is the science that no one doubts?

Christian Marquardt: What kind of data/modelling is needed to decide the issue "natural" vs. anthropogenic.

Lindzen: That isn't an easy question. It will be easier to determine whether model physics is correct. This question becomes less germane if the model physics is wrong.

Modulator: How can we improve/test the model physics? Better data? Better algorithms? Better computers?

Pablo: Clearly there is much science still to be done (both models and monitoring) in order to get a better idea of the problem. On the other hand the precautionary approach could help determine better ways to use the limited natural resources available.

Lindzen: Pablo, for that to be true, we would have to have policies that are relevant. As concerns improvements, we need more specificity and focus.

Suraje Dessai: The Kyoto Protocol is relevant

Christian Marquardt: International politics is slow (as the FCCC shows) - should we wait even longer?

Lindzen: We might as well, if we are simply acting for the sake of acting.

Pablo: I agree. But even just the discussion of this issue has led to development of much more efficient engines which have doubled the mileage per gallon!

Kim: I wonder how the scientific practices based on General Circulation Models has come to dominate the study of climate change. Surely, if the credibility of model physics were not that solid, such methodology would not have become so prevalent today.

Christian Marquardt: Another point of view concerning GCMs is that some scientists promised too much in the beginning, but are busy with understanding the basic physical mechanisms and their parameterisations.

Lindzen: That is hopefully true, but current negotiations are following the earlier work.

Suraje Dessai: I guess you first need the science then the policy.

Modulator: Dr. Lindzen, if you were able to set the priorities for funding the science that is set to support these negotiations, where would you put your emphasis?

Pablo: Good question!

Lindzen: Physics, and numerical methods.

Christian Marquardt: What about the need of a better communication between scientists and policy makers?

Kim: So, you do also value the use of computer modelling in the study of climate systems, then.

Pablo: Would you not say atmospheric sciences which also include the chemical aspects of the problem? Also oceanography which is highly relevant?

Lindzen: As far communications goes, I'm not sure that politicians can avoid getting ahead of the science. As far as broadening the scope of research goes, I agree, but there is the danger of lack of prioritisation.

Christian Marquardt: What should be prioritised?

Lindzen: At present, there is a little too much of everyone wanting a piece of the action.

Modulator: In support of the negotiations, there are a number of efforts that deal with improving the flow of information to decision-makers and there will be a chat session devoted to that later in the week.

Pablo: The problem is complex. The chemistry involved in tropospheric and upper tropospheric processes could be significant. Oceans play a key role in the distribution of heat.

Lindzen: Frankly, the first priority would be to determine exactly how the greenhouse effect is functioning.

Staffan: So you want more focused resources?

Christian Marquardt: Clouds - Dr. Lindzen mentioned the water vapor problem. Also transport in the tropopause region.

Lindzen: I didn't mention transport in the tropopause region.

Pablo: The ozone problem was at least partially solved thanks to a broad frontal attack on the problem.

Christian Marquardt: Ooops - forgive me. I wondered if it could be an important point.

Lindzen: How so?

Pablo: Well, you need to understand the chemistry involved on one hand, but to explain the chemistry you also needed the dynamics

Moderator: I think we should be wrapping up fairly soon.

Christian Marquardt: Which is a pity!

Moderator: We cannot answer all the scientific questions.

Suraje Dessai: or the policy ones!

Moderator: But at least we agree that we need more science.

Christian Marquardt: and more policy?

Lindzen: Better, if not more.

Moderator: Well, I want to thank you all for participating. And in particular, Dr. Lindzen.

Lindzen: Enjoy your stay in BA.

Pablo: Though I cannot agree with you in many points, thanks Dr. Lindzen.

Suraje Dessai: Thank you for the chat

Moderator: Thank you all. Please check our scheduled future events.