Because everything is caused by global warming.

Via CBC:

This year’s uncommonly cold winter has put to bed the notion global warming is anything but a myth, right?

Wrong, says a group of researchers out of New Jersey’s Rutgers University, who have put out a new study that suggests the prolonged cold snaps we’ve experienced could be a direct result of climate change.

The 2012 paper says melting Arctic ice is weakening the jet stream. This weakening causes the jet stream to dip further south, which in Canada brings severe cold temperatures for prolonged periods of time.

Jet streams are ribbons of wind that blow from west to east in the northern hemisphere, and are formed when cold air from the Arctic comes in contact with warm air from the south.

When there is a big difference between the temperatures of the air masses, the jet stream moves faster and dip far less, said Altaf Arain, director of McMaster University’s Centre for Climate Change.

But as the Arctic air warms, the difference in the temperatures is less severe. The jet stream is now moving slower and pulling more Arctic air into southern latitudes.

HT: JT