Source: The New York Times - Link
Winter storms are influenced by many factors, but the planet’s warming appears to be part of that icy blend — even while climate change is making winters milder over all. The air that sits over the Arctic is now sweeping down into the southern United States, as a result of a weakened jet stream, which circulates around the pole and usually holds in the frigid air of the polar vortex.
But there is evidence that planetary warming is weakening the jet stream and allowing the cold air to escape to the south — especially when a blast of additional warming strikes the stratosphere and deforms the vortex. The result can be plunging temperatures, even in places that rarely get nipped by frost.
You can’t pin any single event on climate change, but the trends are unmistakable. Insurance companies are taking notice as they tot up the losses.