date: Tue, 9 Mar 2004 13:01:04 -0800 from: Richard Somerville subject: Re: REQUEST FOR INFORMATION ON CLIMATE CHANGE AND HUMAN to: Chick Keller , Kevin Trenberth , Tom Wigley , "Howard Hanson, LDRD" , "James E. Hansen" , Michael Schlesinger , Phil Jones , Thomas R Karl , Mike MacCracken , Ben Santer , Tom Crowley , , rbradley@geo.umass.edu, mhughes@ltrr.arizona.edu, Keith Briffa , Tim Osborn Hi Chick and friends, Good to hear from you, Chick. I'm busy, like all of us, and responding to Singer is not my cup of tea, so I'm glad you and others are willing. I hate to be in the same room with him, frankly. He's a third-rate scientist and is ethically challenged, to say the least. From others on your email list, I am sure you will receive tons of useful information. However, I think your entire basic strategy for confronting Singer might not be optimal. Sometimes the most pressing issues in the research community, or the most interesting questions scientifically, are not necessarily the best ways to carry on the public conversation. I am thinking in particular of your statement: "Perhaps the most important is that satellites don't show much warming since 1979 and disagree substantially with the surface record, which must then be incorrect. Were we able to resolve this conundrum, I think most of the other objections to human generated climate change would lose their credibility." For what it's worth, here's my take on your approach. I respectfully disagree with you that hammering away on reconciling the MSU data with radiosonde and surface data is the right way to go in dealing with the Fred Singers of the world. Even though much of the differences may now be apparently explained, it's still a terribly messy job. The satellite system wasn't designed to measure tropospheric temperatures, the calibration and orbital decay and retrieval algorithm and all the other technical issues are ugly, and nobody knows how much the lower stratospheric cooling ought to have infected the upper troposphere, among other points one might make. No matter what one does on trying to make the MSU data tell us a clean story, there are remaining serious uncertainties. That's basically what the NAS/NRC study chaired by Mike Wallace concluded, and it's still true, in my view. Plus the data record is so short. In addition, as you say, you are retired, and research on these things is not what you have first-person experience with, so when you try to study up on the latest published results, you're at a disadvantage compared with the Singers of the world, whose full-time job is to cherry-pick the literature for evidence to support their preconceived positions. One of the tactics of the skeptics is to create the impression among nonscientists, especially journalists, that the entire science of climate change rests on the flimsy foundation of one or two lines of evidence, so that casting doubt on that foundation ought to bring down the entire structure. For temperature, that approach is clearly behind the attacks on the "hockey stick" curve over the last 1,000 years or the satellite vs. in situ differences over the last 25 years. Refuting the errors of the papers by Soon and Baliunas or by McIntyre and Mckitrick doesn't faze these people. They just shift their ground and produce another erroneous attack. Their goal is not to advance the science, but to perpetuate the appearance of controversy and doubt. I don't think the skeptics should be allowed to choose the battlefield, and I certainly don't think the issue of whether anthropogenic influences are a serious concern should be settled by looking at any single data set. I do think the IPCC TAR was right to stress that you simply can't plausibly make GCMs replicate the instrumental record without including GHGs (and aerosols). I also think the recent AGU and AMS public statements, which you will doubtless find on their web sites, are right on target. Many of us were pleasantly surprised that our leading scientific societies have recently adopted such strong statements as to the reality and seriousness of anthropogenic climate change. There really is a scientific consensus, and it cannot be refuted or disproved by attacking any single data set. I also think people need to come to understand that the scientific uncertainties work both ways. We don't understand cloud feedbacks. We don't understand air-sea interactions. We don't understand aerosol indirect effects. The list is long. Singer will say that uncertainties like these mean models lack veracity and can safely be ignored. What seems highly unlikely to me is that each of these uncertainties is going to make the climate system more robust against change. It is just as likely a priori that a poorly understood bit of physics might be a positive as a negative feedback. Meanwhile, the climate system overall is in fact behaving in a manner consistent with the GCM predictions. I have often wondered how our medical colleagues manage to escape the trap of having their entire science dismissed because there are uncured diseases and other remaining uncertainties. Maybe we can learn from the physicians. People on airplanes, when they find out what I do for a living, usually ask me if I "believe in" global warming. It's not religion, of course. What I actually tend to believe in, if they really wanted to try to understand, is quantum mechanics. CO2 and CH4 and all those other interesting trace gases have more than two atoms, and that fact simply has inescapable consequences. You just can't keep adding those GHG molecules indefinitely without making the atmosphere significantly more opaque in the IR. The "debates" in the reputable research community are all quantitative. If skeptics don't worry about doubling, they ought to be pressed to tell us why they are unconcerned about tripling or quadrupling or worse. That's where the planet is headed. The fact that remote sensing and model building are hard work, and that much remains to be done, shouldn't be allowed to obscure the basic obvious facts. Bonne chance et bon courage, Richard -- Prof. Richard C. J. Somerville Scripps Institution of Oceanography University of California, San Diego 9500 Gilman Drive, Dept. 0224 La Jolla, CA 92093-0224,USA Phone: 858 534-4644 Fax: 858 534-8561 http://myprofile.cos.com/somerv96