Snowmageddon has become something of an annual tradition. Barely a year goes by without someone, somewhere, finding themselves on the receiving end of a severe snowstorm. The latest unlucky people, of course, are the inhabitants of New York.
Given that the world is getting steadily warmer as a result of man-made climate change, this strikes many people as pretty weird. Surely we should not be seeing so many extreme snowstorms if the world is getting warmer?
One response, which arrives almost without fail after a heavy snowfall, is the claim that climate change is a myth. But even if you accept the overwhelming scientific consensus that climate change is real, the snowfall still looks puzzling. Maybe the world just hasn't got warm enough to melt all the snow yet?
The real answer is rather surprising. Extreme snowfall is actually an expected consequence of a warmer world.
This may seem paradoxical, but that is because we often assume that the only requirement for snow is cold weather.
In reality, heavy snow requires something else: a lot of atmospheric moisture. That moisture generally builds up in pockets of warm air, because the atmosphere can carry 7 per cent more water vapour every time its temperature rises 1C.
Such pockets of warm air are made more abundant by climate change, and they help explain what happened on the US east coast last week.
Partly as a consequence of climate change, the Atlantic Ocean is warmer now than it was even a few decades ago. As a consequence of this ocean warming, the air above the Atlantic is also unusually warm and moist.
When that warm air met cold, dry air from the Arctic, it formed a winter storm, so conditions were just right for a monster snowfall.
Read the full article here.