UK Parliamentary Hearing on the IPCC

curryja

10 years ago

by Judith Curry

A fascinating hearing on the IPCC was held today by the UK Parliament Energy and Climate Climate Change Committee.

The link to hearing video is [here]. The witnesses:

Professor Sir Brian Hoskins, Grantham Institute, Imperial College London, Professor Myles Allen, University of Oxford University, and Dr Peter Stott, Met Office
Professor Richard Lindzen, Massachusetts Institute of Technology, Nicholas Lewis, Climate researcher, and Donna Laframboise, Author

I listened to the entire hearing this morning, I really didn’t have 3 hours to spare in today’s schedule, but I couldn’t resist. It was definitely worth listening to.

A quick reaction to the form (rather than the substance). I found this format to be much more illuminating and informative than the typical Congressional hearing in the U.S., where the members posture and pontificate and try to catch out the witnesses with ‘gotcha’ questions. By contrast the UK MP’s had really done their homework and asked very good questions, with a minimum of ‘gotcha’ type questions.

Blog articles are starting to appear on the Hearing:

Bob Ward
Paul Matthews
RTCC
Bishop Hill (mainly the comments)

The most extensive discussion is on RTCC which also includes tweets; the RTCC assesses the hearing from the ‘warm’ perspective. The best summary of the hearing I’ve seen so far is this comment from John Shade posted at Bishop Hill:

There was no knock-out punch from either ‘side’, so the contest has to be decided on points. Points may to some extent be in the eye of the beholder, but to my eyes, the 3Ls made at least a couple of dozen good ones, while the ASH team were largely, and not very convincingly, on the defensive. If the committee is a rational one, I think this hearing today will serve to have broadened and deepened their grasp of key issues, and to have shifted them away from the sort of dumb deference to the IPCC that has so disfigured such as the Royal Society in its political posturings for example. Both panels deserve our admiration for remaining courteous and to the point throughout. I think the hearing did credit to Parliament, and to the panelists.

I append below the notes I took during the Hearing, paraphrasing the questions and responses (I found it difficult to hear/understand many of the questions), and this pseudo transcript is not complete as I had so step away a few times, but it provides the gist of the hearing. To get the exact statements, you will need to listen the video, or look at some of the transcripts in the other blog posts. I have tried to represent the comments faithfully (but I am not a court reporter).

My quick summary of most significant statements from the witnesses (not necessarily ones that I agree with, but ones that I think defined the Hearing):

Allen: Nothing is ever completely settled, on the other hand disagreements are on the level of 20-30% or so, doesn’t make all that much difference to kinds of decisions we need to make

Allen: Climate sensitivity is difficult to resolve. ECS is much less significant to the argument than TCR. A lot of the controversy revolves around ECS, a parameter that doesn’t matter very much. Sort of the Katie Price of climate, every body talks about it but no one can remember why they are talking about it. A certain inertia in the climate community re ECS.

Hoskins: Its not all natural and not all anthropogenic, which makes it difficult to understand. If I have a criticism of IPCC, it is the tendency to think that everything is forcing, perhaps an understimate of natural variability. Probably in the 1990’s natural variability enhanced the warming. Untangling these is the challenge.

Allen: An enormous amount of judgment goes into the climate models themselves. Some things I would rely on these models and for other things I wouldn’t. This is where expert judgment comes in. Climate models are useful for big picture estimates of warming over the coming century.

Hoskins: Among thousands of scientists you will get a range of views. For the vast majority of scientists, they are within the range of the IPCC assessments and projections. The climate system is very complex, and getting a consensus is not a natural thing for scientists. The policy makers want a consensus. The IPCC has done a remarkable job.

Hoskins: What we’ve seen from the models is circulation remains the same, but overall things get warmer. The challenge is now to understand the interaction of warming with circulations so that we can get regional climate change right, which is key for adaptation decisions

Hoskins: Science is full of probing and discussion, sometimes that gets into the media. There is general agreement on science, the question is what actions we should take. The IPCC gives a range, we don’t know all the details, lets move on to the next stage

Hoskins: there have been huge swings in climate in the past, but we were not around with our socioeconomic system, and the recent extremes are exposing our vulnerability to the environment. Keeping the environment within these bounds will allow us to continue our activities; exceeding these bounds will put major stresses on societies

Lewis: Observations point in one direction, model simulations point in a different direction towards substantially higher warming. Policies are based on projections of models. Models don’t reflect the current evidence including the reduction in aerosol cooling effect strength. If aerosol cooling is lower, then it follows that the warming is less from carbon dioxide. The model simulations used in AR5 predate this particular finding.

Lewis: The issue is how much warming to expect from the different scenarios. From my point of view, those projections are about 60% higher than they would be if they had sensitivity consistent with observations.

Lindzen: Previous panel says you can trace statements in the SPM to main report. That is probably true, although they allow the SPM to change the main document. 31 pages leaves a lot out. The issue is selection of statements. The omissions are significant.

Lindzen: You are asking a policy question and most scientists would like to avoid it. The range of uncertainties include the possibility that warming of 2C is a net benefit.

Lindzen: Whatever the UK decides to do will have no impact on your climate, but will have a profound impact on your economy. Trying to solve a problem that may not be a problem by taking actions that you know will hurt your economy

Lindzen: I think the IPCC assessment of natural variability is not adequate and there is not much argument about that. No models at present do an acceptable job on ENSO and the multidecadal oscillations. And also not the longer timescale circulations of the oceans on timescales of thousands of years. The fact that the system can change on its own is an important development in public understanding of climate change.

Laframboise: If you want the public to have confidence in a public body, the body should do its best to be objective

Lindzen: At this point, we don’t know what to do about it. We have certainty about adverse consequences of the policy options on the economy, but uncertainty about the impact of the policy options on the environment

JC’s pseudo transcript of the Hearing

Below is the complete set of written notes I took during the Hearing.

Question: what are the new things in AR5 relative to AR4

Hoskins: Better understanding of glacier mass balance, contributions to sea level rise

Stott: Further evidence that warming is unequivocal, and more evidence of the human impact, new evidence about the future, limiting warming requires substantial reduction in emissions

Allen: Focus on what we agree on. High level of agreement on the big picture. Skeptics are merely at the bottom of the range of projections (which is an improvement over previous skeptical situation say a decade ago).

Question: What is settled?

Allen: Nothing is ever completely settled, on the other hand disagreements are on the level of 20-30% or so, doesn’t make all that much difference to kinds of decisions we need to make

Hoskins: Mistakes will be made, we are always skeptical, IPCC not to be taken as the bible but it is the consensus view of a large number of scientists

Allen: The strength of the evidence lies not in the process of the report, but rests in the fact that results are reproducible. All the climate models show this, very difficult to construct a climate model that doesn’t show the anthropogenic impact. The data speaks for itself.

Stott: The controversy surrounding the paleo reconstructions plays a relatively small part in the overall assessment

Question: Policy makers don’t get beyond reading the summary for policy makers, are there any concerns about relying on the summary?

Stott: Statements in SPM are traceable back to the report, supported by a wealth of evidence.

Allen: Regarding lowering the lower bound of ECS. Scientists have pushed back aginst this, that is part of the process of scrutiny by scientists

Question: Scientists come across like politicians; some of this arguing seems to be for the sake of the argument.

Question???

Allen: There is no clear pattern of papers after the assessment that are in net higher or lower in terms of ECS

Hoskins: This is living science

Question: Related to aerosol forcing

Stott: The assessment takes into account our uncertainty in aerosol forcing.

Net cooling effect from aerosols.

Hoskins: Understanding the impacts from different aerosol types is an area of living science.

Question: Mentions stadium wave theory!!!!

Stott: Natural internal variability describes ENSO, multi-decadal variability. Investigated the null hypothesis that we can explain the warming by natural variability – we can’t. Timescales are important here. Natural variability does not provide the very long-term trends. Also patterns of warming low lat, high lat, allows us to distinguish between natural variability and anthropogenic forcing. Natural variations have always happened and will continue.

Allen: The uncertainty in natural variability is reflected in the range of uncertainty in future projections.

Hoskins: Climate change could cause a change in the natural variability. One can’t separate natural variability from climate change

Question: IPCC scales down future projection by 40% for 2016-2035, and why didn’t this make the SPM?

Stott: Scaling of 10%, related to comparison between model and current observations. All of this is fully described in the text of the Report.

Allen: Expert judgement summarized what they thought was most important.

Initialization is a key factor to better represent natural variability, which is constrained by observations. Expert judgment is based on a range of lines of evidence

Stott: Bringing models, observations and understanding together to interpret all this

Question: implications of using expert judgment vs models

Allen: An enormous amount of judgment goes into the climate models themselves.

Some things I would rely on these models and for other things I wouldn’t. This is where expert judgment comes in. Climate models are useful for big picture estimates of warming over the coming century.

Question: On longer timescales, the IPCC reverts to the model estimates.

Allen. The models are not assumed to be right; there is no particular evidence that models are too warm or too long on these timescales. IPCC gives likely confidence level for these long term projections; one in 3 chance that reality lies outside the model range.

Question: Swanson et al. finds greater convergence of models, but they agree less with observations. Natural tendency for models to agree with each other.

Stott: If you compare CMIP3 to CMIP5, more account for aerosol forcing in CMIP5 increases the spread. Comparison with surface temperatures is imperfect, since we are really concerned about imbalances in the energy balance over longer terms.

Allen: You have to choose which aspect of reality to compare the models with. Cites the recent Sherwood et al. paper. Elements of judgment in assessing which is most relevant parameter to compare with.

Question: Models that compared best with clouds (reference to Sherwood et al) compared worst with temperatures. Lower sensitivity to aerosols. If aerosols are less powerful than we thought, then CO2 sensitivity must be less powerful than we thought.

Stott: Models have a whole range of aerosol forcing,

Allen: Some of them match observations, others don’t.

Question: You have a new generation of models, why don’t they get aerosol forcing right?

Allen: the long time scale for climate model development and computer simulatiosn precludes the latest developments being incorporated into them on a short time scale. Allen has provided them with the climateprediction.net model to play with.

Question: The language of uncertainty concerns that the IPCC is confusing for the media and policy makers.

Hoskins: The IPCC tries to quantify the uncertainty.

Stott: summarizes the formal methods of uncertainty assessment in the report. States that the IPCC provides very clear guidance for characterizing uncertainty.

Allen: Its an assessment made on the lines of evidence on the probability of it occurring. It’s a reasonable effort at communication.

Question: Interacademy Council criticisms of the IPCC

Allen: IAC reinforced a direction that the IPCC was already going in

Question: which are main areas of uncertainty increase/decrease?

Stott: more evidence so ‘extremely likely’ more confidence that humans have caused the warming since 1950. Observational evidence for changes in temperature extremes and links to greenhouse gases

Allen: lower confidence on climate sensitivity, although it doesn’t make much difference for the futureprojections. The uncertainty ranges don’t always get smaller in the short term.

Hoskins: ECS estimates has stayed the same for decades. Provided the history of the more sophisticated models whereby uncertainty models could increase

Allen: discusses objective Bayesian methods; IPCC looks at all the published literature on sensitivity

Question: why increased confidence in attribution in light of the hiatus?

Stott: Oceans are warming

Question: Oceans are a symptom of warming; how does it increase confidence in the cause:

Stott: (describes the general attribution process)

Allen: Increased confidence in aerosol forcing increases our confidence in the total anthropogenic warming. We are more confident humans are not cooling the climate

Questions: Lower aerosol forcing implies smaller greenhouse effect

(not sure who?) By ruling out something that might compensate for the warming effect, you increase your confidence in the CO2 forcing

Question: If there is less human input to cooling, then less human input to warming

Allen: That uncertainty contributes to the uncertainty in future projections.

Question: given the increased confidence and consensus in the conclusion, is the economic case for mitigation stronger or weaker in AR5 relative to AR4?

Hoskins: Nothing has been found in the AR5 that goes against previous conclusions, we are conducting a very dangerous experiment

Allen: as long as emissions continue to increase, we are committing to future warming.

Question: even if the rate of emission stopped increasing, concentration would continue to increase.

Allen: until we bring carbon emissions to zero we will continue warming

Hoskins: Confirms that our target is well based

Question: to what extent does AR5 represent a consensus among scientists.

Allen: The IPCC discusses the range of opinions. The argument is where in the range of uncertainty does reality lie.

Questions: criticisms of IPCC in terms of it being political and overly burdensome for scientists. How has the IPCC responded to the IAC recommendations

Hoskins: Re the 26 IAC recommendations, 20 of them have been given a tick. As a result, the process is even more burdensome than before for the scientists. IAC criticisms of IPCC ‘head office’ have not yet been implemented.

Stott: It is hard work for sure. Some of the recommendations have been helpful. Re politicization: the SPM process the scientists have the final world, it is a very clear process to clarify the language for policy makers. It is not a political process it is a scientific process.

Allen: In the big picture the key thing to recognize that the strength of the evidence stands alone, it does not rely on the IPCC. IPCC process is so elaborate, it can detract from the evidence

Allen: strongly supports the Netherlands proposal for annual assessments on special topics. Finds this would much better reflect the progress of science.

(Question)

Allen: If we are at the low end of the range versus the high range, we still need to reduce emissions by a challenging amount, so these uncertainties don’t matter for policy

Question: IPCC inaccuracies and exaggerations, e.g. Himalayan glaciers

Hoskins: The problems aren’t in WGI, but were in WG2 owing to the unavoidable use of grey literature for that subject area.

Allen: The error was pointed out by scientists, scientists are their own best policemen

Question: The IPCC makes a political not a scientific statement?

Stott: Describes the extensive review process, and the care taken to insure that the summary document represents the science. Scientists have the final word

Allen: You need that dialogue with the policy makers to make sure that the scientists that are correctly understood

Hoskins: The IPCC is for governments, there is a tightrope that needs to be walked. But as a lead author,he did not feel the weight of governments telling him what to say

Allen: at the level of individual chapters, there is no involvement of the governments at all

Question: Concerns that many of the authors are activists. Do you see this as a problem

Stott: There is a conflict of interest statement that we sign. We are first and foremost scientists, skeptical scientists. Our positions are based purely on the science.

Question: How to you insure that all perspectives are represented in the report

Allen: You draft the chapter, you send it out for review, then we go through all those review comments and make sure they are adequately addressed. This draws in comments from directions that we might not have otherwise considered.

Question: Hiatus in temperature, in conflict with the increase in confidence in attribution?

Hoskins: The models are not in the position to predict the hiatus, because of lack of initial conditions. You would not expect them to predict that behavior. You would hope that in long runs of the model they would show this, but models do not have enough of that kind of variability. That is a decadal prediction problem for which adequate initial conditions are not available

Stott: Not a huge amount of literature on the hiatus but that literature was assessed. We discussed possible contribution of internal variability, and the Pacific Decadal Oscillation.

Hoskins: In the late 1980’s, I said that we could see a decade of cooling, this is not unexpected, but climate models should not be expected to predict this.

Question: Climategate, Jones et al. not prepared to share their data

Allen: IPCC encourages sharing of information between groups, thanks to the IPCC there is a lot of sharing, which is unusual relative to some other fields. Climate science is remarkably collegial in this way.

Question: Why are we here? In previous epochs that has been large climate variability

Allen: Makes economic sense to contain it.

Panel II:

Question: Which conclusions from AR5 give you greatest cause for concern?

Lindzen: I don’t find much of concern about the content of the report, but I’m concerned about the translation. I don’t disagree with the argument for attribution. If man is responsible for 50% of the warming, that in itself doesn’t tell you the sensitivity is high. I find this finding inconsistent with catastrophe is around the corner. I don’t think the IPCC itself says that.

Lindzen: States his own experience with the ipcc in the TAR the pressures were never political, if there were any pressures it was against criticizing models. In the U.S. the reward for solving a problem is to have your funding disappear.

Lindzen: The hiatus is completely consistent with nothing to worry about. Re sea level rise. My colleague Carol Wunsch feels you can’t say anything about that, since you have two different measurement systems that haven’t been fully reconciled, so we are not sure what is going with sea level. I don’t see much evidence that points to man doing something extraordinary.

Question: Are there any areas of climate science that are settled?

Lindzen: We understand that man should have some effect. We agree that climate changes. None of this tells you that there’s a problem. Sea level rise is not something we agree on.

Question: Turning to SPM, can policy makers rely on this?

Lindzen: How would you propose to use it? How would you translate it to policy? What in the present summary could you use for what policy?

LaFramboise: Concerns about condensing so much material into a 30 page summary, a lot of room for human judgment which is not science. More like a summary BY policy makers, the 4 day meeting with policy makers ‘behind closed doors’. So are we just to take their word for it that this is not influenced by politics? Potential for politics to influence the contents of SPM.

Question: Are scientists protesting this?

Donna: Pachauri claimed that all references are from peer reviewed literature. This is clearly not true, but scientists did not step up and say this was incorrect. There aren’t a lot of checks and balances in the system, especially since the SPM engagement with policy makers happens happens behind closed door.

Lindzen. It says nothing overtly false. Its an approach that involved intrinsic compromise. Volunteer efforts, most individuals work on a small piece of the document. In practical terms there is a limit to how much time an individual scientist can devote to the IPCC.

Question: (can’t hear) They haven’t rerun the models with the new aerosol forcing, which would change the whole picture. Is there a sense that we mustn’t rock the boat or place too much weight on evidence that would decrease the concern?

Lewis: Too late to do anything about the models at that point. No intentional distortion by the models. There is conflicting evidence regarding sensitivity.

Question: Even though we are not certain we have to act on the side of caution.

Lindzen: Discusses short feedbacks. Defends his iris hypothesis.

Question: Are we going down the right road?

Lindzen: You are asking a policy question and most scientists would like to avoid it. The range of uncertainties include the possibility that warming of 2C is a net benefit.

Question: we want “science says . . .”

Lindzen: Scientists have their own interests. Whatever the UK decides to do will have no impact on your climate, but will have a profound impact on your economy. Trying to solve a problem that may not be a problem by taking actions that you know will hurt your economy

Lewis: AR4 – models and obs agreed, made the scientific basis for action relatively strong. In AR5 – the basis is decreased. Describes the climate sensitivity issue (Bayesian stuff,very technical). Most of the studies are not statistically sound.

Question: Is the IPCC assessment of natural variability adequate?

Lindzen: I think it is not adequate and there is not much argument about that. No models at present do an acceptable job on ENSO and the multidecadal oscillations. And also not the longer timescale circulations of the oceans on timescales of thousands of years. The fact that the system can change on its own is an important development in public understanding of climate change.

Question: Science is the best guess, we need to go with the best guess.

LaFramboise: If there is bias among the jurors, we need to throw out the jury and start again.

Question: You can add complexity to a model, but you can’t make the model ‘do things’. We like to think of progress as linear. But there has been no discernible increase in model skill. There are notable errors in describing today’s regional climate with models.

Question: Do you think climate models are reliable?

Lindzen: Of course not! If they can’t get today’s regional climate right, why should they be believed for the future.

Question: How significant is the 15 yr hiatus?

Lindzen: The IPCC speaks of attribution for the last 50 years. Before then, we are dealing with natural climate variability. Warming from 1919-1940 almost indistinguishable from the warming 1970-1998.

Lewis: Natural variability may account for a lot of this. In a long period, natural variability will hopefully cancel out

Lindzen: The longer this goes on, it will be harder to reconcile with anthropogenic forcing. There’s not much to say other than it wasn’t predicted

Lewis: Discusses model-obs discrepancy in the tropics for the past 25 years. This indicates the models are not to be relied upon

Question: Are you saying there is not human effect on climate?

Lindzen: Theoretically it should have some effect. That is not the same as saying it’s the major factor, not the same as saying high sensitivity, and not the same as saying there is catastrophe around the corner

Question: regarding explanations for the hiatus

Lindzen: Ocean heat sequestration is an opaque way of saying natural variability, that leaves the atmosphere and ocean out of equlibrium.

Lewis: Good ocean obs down to 2000m have only been in place since 2005. Cites Lyman and Johnson paper, says heat uptake is only half of what the IPCC says.

Question: Doesn’t hiatus imply late 20^th century warming could have been enhanced by natural variability, does the IPCC make this point

Lewis: I don’t think the IPCC brings this out, rather it leans toward making the opposite point

Lindzen: mentions Swanson and Tsonis mentions half of the warming is natural internal variability, but this was not stressed in the IPCC.

Question: previous panel played down the importance of sensitivity

Lewis: (missed it)

Lindzen: Sensitive climates take longer to reach equilibrium than insensitive climates. For 70 years, high sensitivity climates won’t have much of the warming realized. Argues that you can pin it down to lower sensitivity values

Question: Miles Allen says there is wide agreement on the range of sensitivity, is that true?

Lewis: My estimate goes below the 1.5C bound of IPCC, and has very different central estimates (which is policy relevant in context of the economic models). The high tail is particularly important in economic models.

Question? Is the decade 2000-2010 the warmest decade in the historical record?

Lindzen: Of course it is.

Question: You say global warming has stopped.

Lindzen: If temperature was increasing until then, then it is the hottest decade so far. If you are saying you are taking the 16 yr smoothing average, then warming has continued. If you look just at the last 16 years, then there is no change. Nobody is saying global warming has come to an end. For the last 16 years, temperature hasn’t increased.

Question: Are you happy with the way the IPCC expresses uncertainty?

Lindzen: With regards to attribution, no I’m not happy, I don’t know how it was arrived at. I assume they wanted to express to the policy makes that they were very confident, increasingly confident. There is consensus on trivial things, but not things that are policy relevant. Majority view of climate scientists is that climate change is a serious problem.

Question: Striving for consensus: is it a risk of underestimating the problem?

Lindzen: Logically that’s possible but I don’t see any evidence of that.

Question: Would you agree that there is no scientific way to separate natural variation from anthropogenic?

Lindzen: A lot of effort has been put into it (e.g. fingerprint detection), but at the moment there is no successful way of doing this.

Lewis: The analyses of sensitivity that Lewis looks at assumes that all change is externally forced.

Question: Are solar cycles important?

Lindzen: It is pretty clear that actual solar variability is small. Cosmic rays etc may have an influence on the brightness of clouds that can amplify the impact of solar variability. It is an unknown.

Question Should the IPCC be disbanded?

Laframboise: The IAC review that finds significant shortcomings in every major step of the IPCC process. So there are serious reasons to question the IPCC conclusions. The review process needs to be external, independent of the IPCC. After 25 years, it would be very difficult to change the culture of the IPCC.

Lindzen: You are not dealing with a huge field of climate scientists. The IPCC is manpower intensive. 58% of the participants this time were new participants. In a small field you have to keep finding new people, and the meager credentials of some of the IPCC experts reflects the small size of the pool. The climate field isn’t as strong as some other fields

Laframboise: Scientists selected by governments to participate in the IPCC will be different if selected by VP Al Gore vs VP Richard Cheney. Myles Allen remarked that skeptics are involved at the review level, not in the writing. This makes a big difference.

Question: Some argue that this is the most scrutinized document in science

Donna: The reviewers can review whatever section they choose. There may be parts of the report that receive reviews from no one. The review process is haphazard.

Lindzen: Not a normal review when the authors get to decide whether to pay attention or not to the comments

Question: Would smaller more frequent reports help?

Lewis: Argues for the whole, integrative approach, so we can assess how the individual pieces fit and influence each other

LaFramboise: Focus on a few topics that are subject of controversy.

Lindzen: Reports are not currently useful since it is difficult to find things (lack of indexing)

LaFramboise: Concerns about activists (associated with green organizations) on WGII lead author list.

Question: can’t activists be objective?

LaFramboise: If the future of our children and grand children are at stake, we should make every effort to be objective

Lindzen: Author involvement in activism is not very healthy for the IPCC.

Question: we need a good mix of different people.

Laframboise: If you want the public to have confidence in a public body, the body should do its best to be objective

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