Global warming caused recent heat waves, say researchers

Bloomberg : The likelihood of unusually warm or cool weather events has increased over the past 30 years, according to NASA’s James Hansen and colleagues, whose paper was published online yesterday in the Proceedings of the National Academy of Sciences. Compared with 1951–80, the period 1980–2010 has seen more heat waves over a wider area. The authors blame global warming for such extreme weather events as last year’s Texas drought and the 2010 Russian heat wave. And, they say, if carbon emissions continue to increase, such events will become even more frequent. The record heat wave and drought that have been plaguing much of the US this year, and which occurred after the group’s research paper was written, lend credence to their theory.