It seems the U.N. IPCC only tabulates the benefits of climate change when they are outweighed by the costs.

Could global warming actually be good for humanity? Certainly not, at least if we're to believe the endless warnings of floods, droughts, and pestilences to which we are told climate change will inevitably give rise. But a closer look at the science tells a more complex story than unmitigated disaster. It also tell us something about the extent to which science has been manipulated to fit the preconceptions of warming alarmists.

According to a 2004 paper by British geographer and climatologist Nigel Arnell, global warming would likely reduce the world's total number of people living in "water-stressed watersheds"—that is, areas with less than 1,000 cubic meters of water resources per capita, per year—even though many regions would see increased water shortages. Using multiple models, Mr. Arnell predicted that if temperatures rise, between 867 million and 4.5 billion people around the world could see increased "water stress" by 2085. But Mr. Arnell also found that "water stress" could decrease for between 1.7 billion and 6 billion people. Taking the average of the two ranges, that means that with global warming, nearly 2.7 billion people could see greater water shortages—but 3.85 billion could see fewer of them.

Mr. Arnell's paper, funded by the U.K. government, was duly cited in the U.N. Intergovernmental Panel on Climate Change's supposedly authoritative 2007 assessment report. But the IPCC uses Mr. Arnell's research to give the opposite impression, by a form of single-entry book-keeping. While it dutifully tallies the numbers of people he predicts will be left with less water access, it largely ignores the greater number likely to see more water courtesy of climate change.