In this video Simon Clark, a science communicator on YouTube holding a PhD in atmospheric physics, breaks down a recent academic paper investigating an interesting (and somewhat paradoxical) phenomenon: climate change producing colder winters in North America.

Simon explains that these extreme cold events are due to the Polar Vortex, a large body of cold air formed over the Arctic, stretching southwards and in turn influencing pressure gradients across the continent and pulling frigid Arctic air south.

The paper shows that these stretching events are happening more frequently due to climate change as a result of Arctic Amplification (the warming of the Arctic at nearly twice the rate of the midlatitudes as 1. its albedo decreases causing more energy to be absorbed and 2. the increased energy being stored in the climate system by the GHG effect ultimately being transported to the polar regions via global wind patterns) and declines in Arctic sea ice coverage.

These were identified as precursor conditions causing the Polar Vortex to stretch, and thus as the Arctic continues to warm and sea ice retreats, the occurrence of these extreme cold events in North America during the winter are projected to increase as well.