US heatwaves 'proof of global warming'

The relentless, weather-gone-crazy heat that has blistered the United States and other parts of the world in recent years is so rare it cannot be anything but man-made global warming, a top Nasa scientist says.

The research, by a man often called the “godfather of global warming” says the likelihood of such temperatures occurring from the 1950s through the 1980s was rarer than one in 300. Now the odds are closer to 1 in 10, according to the study by Professor James Hansen.