Monday, April 23, 2007

The EGU review

I've just spent a week in Vienna at the EGU. I enjoyed Vienna more than on my previous visit two years ago, partly due to jules finding a slightly better hotel and also some good restaurants.

Austria was its usual efficient and clean self. Since many of my foreign trips are to the UK, it's good to see that some parts of Europe can put on a show to rival Japan. On arrival, the first thing we did was find jules' Dad (who was also attending the meeting and who arrived at about the same time) and wander in to town for a look around and a massive Wiener schnitzel at the famous Figlmuller restaurant. In Japan, I'm usually one of the broader customers but here I felt positively skinny. However, after a few days of Viennese meals, I was well on my way to fitting in... I doubt many of the Japanese tourists coming here develop "Vienna syndrome", but rapid-onset diabetic syndrome must be a distinct possibility.

Unlike that slacker Connolley, I didn't have time to blog during the week, so here follows some highlights from my notes. For those who are interested in more details, abstracts can easily be found by searching the authors on the EGU site.

I started off on Monday morning in the CL40 session on model intercomparison (mostly technical stuff with no major insights), before moving on to CL12: monthly to decadal prediction. The most notable presentation here was Mojib Latif explaining that the recent unexpectedly strong warming in western Europe was due to a strengthening of the MOC, which he expected to decline and therefore somewhat ameliorate coming climate change in that region on the decadal time scale. After lunch, there was the session of most direct interest to me, CL20 (probabilistic climate prediction). There were a couple of interesting talks on principles and generalities. However, I was disappointed by some of the the specific applications. Were I in a more optimistic mood I'd probably portray it as a vigrous "zoo" of ideas but from where I was sitting it looked in one or two cases more like people floundering around not really knowing what to do, and as a result just doing "something". Of course my conclusion from this is that I should pursue _my_ ideas because they are clearly the most interesting and valuable ones around :-) Hey, I can dream.

I then went off to drown my sorrows in the free wine at the poster session. This year the CL (climate) division had decided to have all poster sessions in the early evening, with no talks scheduled to compete with them. This scheduling, combined with the wine, made the posters very well attended and the policy must be considered a success. However it also made it difficult for those presenting the posters to go and see other ones, especially as jules also had her poster some distance away at the same time so could not cover for me. Anyway, plenty of people had a look, a large poportion seemed to understand it and no-one tried to argue seriously for uniform priors. Unfortunately the main protagonists were not there so it's possible they will continue with their fingers-in-ears "la-la-la I can't hear you and anyway everyone else agrees with us" approach. Time will tell.

Tuesday morning started off with CL23 (solar and aerosols). There wasn't any "it's the sun wot dun it" stuff, fortunately. Palle said that planetary albedo had changed a lot (in both directions), but all the data seem pretty inconsistent and inconclusive. Someone (Philipona I think) gave another competing (or perhaps complementary) explanation for European warming, that the decline in aerosols had had a significant effect in this area. This "brightening" effect is now running out so the end result (less future warming) might be hard to discriminate fom Latif's theory.

CL28 was hockey stick stuff, in fact one made an appearance in Ray Bradley's excellent Hans Oeschger Medal Lecture. He talked about the various problems of proxy data and reconstructions pretty bluntly, I thought - including the divergence problem and dependence on a very few proxies with limited spatial coverage - and also pointed to some new data sources that might help in the future.

The SSP paleo session on Wed am was very interesting, with some people looking more at model simulations, and others analysing data. Didier Roche thinks that the oceanic dO18 distribution in warm paleoclimates might explain a significant part of the "gradient problem" - that (according to conventional analyses) the data suggest a strong polar warming but little or nothing in the tropics, whereas models give a much more uniform warming. Correcting for his model's estimated dO18 distibution made for a more even warming, more in line with what the models (and perhaps common sense) would suggest. There's plenty more work to be done in bringing models and data closer together in this field.

There was a CL division business meeting at lunchtime, so I rolled up for the promised free rolls (which were better than the stuff on sale, not that I have any complaints about the on-site catering). In amongst the minutiae that my reader won't be interested in, the subject of corporate sponsorship was raised. I didn't comment (others got there first) but think it would be hard to convince everyone that the benefits would outweigh the potential loss of independence.

In NL4.01 (nonlinear time series analysis) Anastasios Tsonis gave a fascinating talk about synchronicity and coupling in networks. He suggested that the sharp changes in global temperature trend were coincident with changes in behaviour of the climate system. He found this behaviour both in 20th century data, and also in a 21st century (A1B?) run of the NCAR model. However, before any sceptics get too excited, this latter result only explains changes in the small drift (perhaps 0.05C/decade) above and below the linear forced trend, not the entire warming itself, so it would be hard to claim that it explains the entire historical record. Nevertheless, it might help to explain the oddly sharp piecewise-linear behaviour observed over the 20th century. It's certainly always looked to me like natural variability probably played a bit of a role here (not that the IPCC have ever denied this, of course).

Overall, the NP (nonlinear processes) stuff seemed a little disappointing this year, with a higher proportion of fluff than usual. It's a bit sad when someone presents "novel method Y", a member of the audience asks "how does novel method Y compare to (well-known and widely used) method X", and the answer is "I don't know about X, so I can't answer that". There were also some boilerplate applications of routine ideas that had probably already been done to death a decade ago. Fortunately there were also some interesting ideas, but perhaps fewer than I've come to expect from these sessions. On the other hand it's important to balance the established and excellent speakers with opportunities for newcomers and the less eminent, and IMO the EGU generally does a pretty good job at that.

The relatively new ERE (Energy, Resources and the Environment) division had some interesting work. Faust from Munich Re was trying to tease out any relationship between SST and hurricanes, and seemed to think he had managed. I was just leaving to dive into to a parallel NP session as someone in the audience started ranting about insurance companies making too much money. Later I returned to hear about some attempts to calculate optimal or tolerable emissions pathways using simple coupled climate/economic models (Bruckner, Held). It turns out that "tolerable" is very much dependent on a large number of rather subjective decisions.

Thursday: CL18 Detection, modelling, impact. There wasn't much here that engaged me other than Douville saying that we still didn't know much about how the hydrological cycle would change, other than on the global scale. He seemed to say that the models don't really agree better than for the TAR, despite the AR4 wording. Right at the end of his talk he slipped in the comment that because demand is forecast to rise sharply, "reliable projections are urgently needed". I would have thought that a strong increase in demand implies that the need to to manage supply and demand more effectively can be confidently predicted (the real question is to what extent it should be centrally planned response versus left up to the magic of the market) irrespective of whether accurate projections of rainfall can ever be made. Indeed some people have been known to argue that the science is adequately settled inasmuch as its relevance to policy decisions is concerned, but I don't expect many climate scientists say that on their grant applications :-)

I didn't stay to hear Fred Singer waste 15 minutes of everyone else's time, but by all accounts he only made himself look like a fraud, so perhaps it was worth letting him have some rope. I also missed the Gregory-Rahmstorf cage fight, so rather than make it up I'll just refer to you Stoat.

At some point Geert Jan van Oldenborg gave his view on the European warmth, which I missed, but I found him in a poster session and asked him about it. His view is that the models are all wrong in having too thick a mixed layer in this region, and therefore in contrast to Latif and Philipona the strong warming will continue. The disagreement between them may not be quite as strong as I've made it sound, as the areas and time scales they considered are not all identical, but it still sounds like there could be the opportunity for a bet here!

Friday's program was pretty thin and so I'd arranged to spend much of it chatting to various people about some admin and science-related ideas. The poor Friday afternoon speakers drew the short straw (although perhaps not quite as short at those who didn't get to talk at all). In any case, the convenor's party was amazing and well worth staying for...

The EGU is back in Vienna again next year, at the same time. I wouldn't mind a change of venue but OTOH I can see why they keep going back.

At the airport, jules was a little ahead of me getting to the gate and asked if the exit seats were available. No, they were already full, she was told. As I approached, looming over the crowd of Japanese midgets and average-height Austrians she cheekily added "are they already full for him too?" 5 minutes later we had our new seat numbers :-) I'll fly Austrian Airlines again.

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