Drafts seen by Reuters of the study by the UN panel of experts, due to be published next month, say it is at least 95 percent likely that human activities – chiefly the burning of fossil fuels – are the main cause of warming since the 1950s. That is up from at least 90 percent in the last report in 2007, 66 percent in 2001, and just over 50 in 1995 [Were those numbers calculated, or just pulled out of some orifice?], steadily squeezing out the arguments by a small minority of scientists that natural variations in the climate might be to blame….
And gauging how warming would affect nature, from crops to fish stocks, was also proving hard since it goes far beyond physics. “You can’t write an equation for a tree,” [Reto Knutti] said.
…it is likely to play down some tentative findings from 2007, such as that human activities have contributed to more droughts.
…Drew Shindell, a NASA climate scientist, said the relative lack of progress in regional predictions was the main disappointment of climate science since 2007. “I talk to people in regional power planning.
…The report slightly tones down past tentative findings that more intense tropical cyclone are linked to human activities. Warmer air can contain more moisture, however, making downpours more likely in future. “There is widespread agreement among hurricane scientists that rainfall associated with hurricanes will increase noticeably with global warming,” said Kerry Emanuel, of the Massachusetts Institute of Technology. “But measuring rainfall is very tricky,” he said.