WASHINGTON — The relentless, weather-gone-crazy type of heat that has blistered the United States and other parts of the world in recent years is so rare that it can't be anything but man-made global warming, says a new statistical analysis from a top government scientist.
The research by a man often called the "godfather of global warming" says that the likelihood of such temperatures occurring from the 1950s through the 1980s was rarer than 1 in 300. Now, the odds are closer to 1 in 10, according to the study by NASA scientist James Hansen. He says that statistically what's happening is not random or normal, but pure and simple climate change.
"This is not some scientific theory. We are now experiencing scientific fact," Hansen told the Associated Press in an interview.
Hansen is a scientist at NASA's Goddard Institute for Space Studies in New York and a professor at Columbia University. But he also is a strident activist who has called for government action to curb greenhouse gases for years. His study was published online Saturday in the Proceedings of the National Academy of Science.
In a blunt departure from most climate research, Hansen's study — based on statistics, not the more typical climate modeling — blames these three heat waves purely on global warming:
• Last year's devastating Texas-Oklahoma drought.
• The 2010 heat waves in Russia and the Middle East, which led to thousands of deaths.
• The 2003 European heat wave blamed for tens of thousands of deaths, especially among the elderly in France.
The new research makes the case for the severity of global warming by using simple math instead of relying on complex climate models or an understanding of atmospheric physics. It also doesn't bother with the usual caveats about individual weather events having numerous causes.
The increase in the chance of extreme heat, drought and heavy downpours in certain regions is so huge that scientists should stop hemming and hawing, Hansen said. "This is happening often enough, over a big enough area that people can see it happening," he said.