Michael LePage:
Has global warming brought an early summer to the US?: North America has been experiencing unusual weather of late. After a mild winter over much of the continent, last week it experienced record-breaking summer-like conditions. In Canada, for instance, the thermometer in St John's, New Brunswick, hit 25.4 °C on 21 March, smashing the previous record high for March of 17.5 °C.
"We've never seen these kinds of temperatures before. It's quite remarkable," Dave Phillips, a senior climatologist at Environment Canada, a government agency, told local media. "The duration, areal size, and intensity of the 'summer in March' heat wave are simply off-scale," says Jeff Masters of the Weather Underground. "The event ranks as one of North America's most extraordinary weather events in recorded history."…
Meteorologists have been pointing to two main factors. First, as pointed out by Masters, there was a big loop in the jet stream over the continent, funnelling warm air northwards from the Gulf of Mexico…. And the second factor? Phillips points out that air flowing northwards in the spring would normally be cooled as it passes over cold, snowy ground. But this year there is very little snow because of the mild winter and the air was hardly cooled at all.
So is there a link with global warming? There may be. "Global warming boosts the probability of really extreme events, like the recent US heat wave, far more than it boosts more moderate events," point out climate scientists Stefan Rahmstorf and Dim Coumou in a blogpost on RealClimate.org…
