Who in her right mind would want to detour from doing world-class atmospheric research at a laboratory tucked under the Rockies to be a co-leader of a years-long, largely administrative review by hundreds of experts from dozens of countries of existing studies on the atmosphere? Dr. Solomon, who won a National Medal of Science in 1999 for linking synthetic chemicals to the seasonal ozone hole over Antarctica, nonetheless chose that course in 2002.

“Thomas Jefferson once said something like, ‘Science is my passion, politics my duty,’ ” Dr. Solomon, 51, said Sunday in a telephone interview. “That’s probably how I think about it, too. Science does have a duty, when called upon, to provide information that’s important to society the best way it can.” In place of making expeditions to the South Pole and Greenland, her old stomping grounds, she spent chunks of the last five years hunkered in gray buildings in Beijing, New Delhi, Marrakech and Paris running meeting after meeting of experts from the Intergovernmental Panel on Climate Change.

The panel was convened by the United Nations in 1988 — a year of record heat, burning forests and the first big headlines about greenhouse gases and global warming — to provide regular reviews of climate science to governments to inform policy choices. Dr. Solomon, a senior scientist for the National Oceanic and Atmospheric Administration, and Qin Dahe, head of the Chinese meteorological agency, were charged with generating the fourth report and summary since 1990 of advances in climate science. The final editing of the 20-page summary through four days and nights last week involved approval by 113 governments. Several participants credited Dr. Solomon with ensuring that last-minute demands, particularly from China and the United States, did not derail the process or distort the science.

Dr. Solomon and many colleagues defend this procedure, melding science and diplomacy, as a way to give nations some ownership of the results and, thus, responsibility for reflecting the findings in policies. But others see it as an opportunity for political meddling.

The summary, released on Friday in Paris, was the first from the group to pinpoint with greater than 90 percent certainty that humans had become the main force driving warming and that centuries of increasing temperatures and seas could be blunted only if emissions of heat-trapping gases were promptly reduced. At a news conference in Paris on Friday, United Nations officials quickly called for action to cut emissions and limit catastrophic effects, particularly on the poorest countries.

When a reporter asked Dr. Solomon “to sum up what kind of urgency this sort of report should convey to policy makers,” she gave the furthest thing from a convenient sound bite. “I can only give you something that’s going to disappoint you, sir, and that is that it’s my personal scientific approach to say it’s not my role to try to communicate what should be done,” Dr. Solomon said. “I believe that is a societal choice. I believe science is one input to that choice, and I also believe that science can best serve society by refraining from going beyond its expertise.

“In my view, that’s what the I.P.C.C. also is all about, namely not trying to make policy-prescriptive statements, but policy-relevant statements.” Almost immediately, and predictably, the findings were criticized by both sides in the debate over what to do, or not do, about human effects on the climate. Politicians and groups with links to industries that oppose restrictions on greenhouse gases said the report played down uncertainties and relied too much on murky computer models. Some scientists and groups pushing for aggressive cuts in the gases said the panel was much too conservative in some projections, particularly in assessing how much melting of ice sheets might raise sea levels in the next 100 years. Some scientists expressed frustration with Dr. Solomon for not making a stronger statement on the conclusions.

“As we all know, Susan is an outstanding scientist, and everybody has to make their own decision how to react to more political questions,” Robert T. Watson, the chief scientist of the World Bank and a former chairman of the panel, wrote in an e-mail message. “Ducking the question of what is needed did weaken the impact of the report to many observers. However, Susan could argue that her neutrality on the policy question provides her greater credibility as an unbiased scientist and chair.” In the interview, Dr. Solomon was steadfast. She said: “I take the view that I’ll talk about science, but that policy is a collective decision. There are a lot of different ways different people view this. This is reflective of the fact that scientists are human beings like everyone else.”

Dr. Solomon, who fell in love with science at age 9 after watching Jacques Cousteau’s films about the sea, said she was unfazed by the pressures of working on the panel. She faces months of additional work on reports related to the summary. After that, she said, she plans to take a little time off and, for the first time, really, enjoy the Rocky Mountains around her base in Boulder, Colo. “I’m going to learn how to fish,” she said.
(Por Andrew C. Revkin, The N.Y. Times, 06/02/2007)