Recently the media has been abuzz with talk of the “polar vortex” which they describe as being an outbreak of cold air over the United States and Canada. In this video I break down what the polar vortex is and isn’t, talk about why it’s suddenly so extremely cold, and ask whether this weather was caused by climate change.
I’d like to stress that this video is specifically looking at a) what the polar vortex exactly is, and b) whether the vortex is experiencing sudden warmings more frequently under climate change. There are however, as I hint in the video, multiple factors forcing all events in the atmosphere, including the current cold snap. The jet stream is ultimately the main mechanism (as forced by the sudden warming) and the effect of climate change on the jet stream itself is still debated.
The conclusion that I draw on this video is perhaps phrased too generally – in my opinion the sudden stratospheric warming, which was a significant factor in the current cold snap, was not made more likely by climate change. There of course remains the possibility that other forcing factors, such as the long-term average strength of the jet stream, were altered by climate change to make the cold snap more likely.
Again this is just my personal opinion, and I encourage informed debate in the comments!