2007: IPCC lead author admits that pre-2007, AGW was just "arm-waving with models"

Question: If the science was so settled, why was the debate within the IPCC so "fierce" and "contentious"?

April '07: Bleakest report ever on global warming - SETH BORENSTEIN - thestar.com

Yet that grim and still preventable future is a toned-down prediction, a compromise brokered in a fierce, around-the-clock debate among scientists and bureaucrats.
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That edict made for a deadline-busting contentious final [IPCC] editing session that was closed to the public. However, The Associated Press witnessed the hectic final 3 1/2 hours of objections and conflict.

At one point, Chinese and Saudi Arabian delegates tried to reduce the scientific confidence level about already noticeable effects of global warming. They lower the confidence level from 90 per cent to 80 per cent. Scientists objected, and one lead author from the United States, NASA's Cynthia Rosenzweig, left the building after filing an official protest.

"There is a discernible human influence on these changes" that are already occurring through flooding, heat waves, hurricanes and threats to species, she said.

Under a U.S.-proposed compromise, the final report deleted any mention of the level of confidence about global warming's current effects. And that may have saved the day, according to some scientists who said the report had appeared doomed over that issue.
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"This is a glimpse into an apocalyptic future," the Greenpeace environmental group said of the final report.
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"Don't be poor in a hot country, don't live in hurricane alley, watch out about being on the coasts or in the Arctic, and it's a bad idea to be on high mountains with glaciers melting," said Schneider, the Stanford scientist who was one of the study authors.
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Martin Parry, who conducted the tough closed-door negotiations, said that with 29,000 sets of data from every continent include Antarctica, the report firmly and finally established "a man-made climate signal coming through on plants, water and ice.

"For the first time, we are not just arm-waving with models," he said.

About Martin Parry

Martin Parry is a professor of climatology at the Imperial College London. He has been a lead author in all the IPCC's reports, and is a co-chair of the IPCC’s Working Group II on Impacts, Adaptation and Vulnerability.