And nothing the deniers say about the polar vortex and frigid temps does anything to change the overwhelming evidence that the world is, on average, warming up, and we’re the cause.

In fact, it’s even possible that this event is due to global warming. Climate scientists are still working on this idea, but warming in the Arctic is melting ice and creating more surface area of water. This is darker than ice, so this open water absorbs more heat from the Sun, which can affect the way air moves in the troposphere and stratosphere. It’s possible this in turn affects the vortex, causing the boundaries to weaken, dropping cold air south. As usual, it’s difficult to pin any given weather event on the changing climate (we do sometimes see dips in the vortex, though usually not this severe). Still, as the climate does change, we’ll see more extreme weather events.