This winter has been a humdinger. The month of January has brought subzero temperatures to much of North America, while to the north, the waters of the usually frosty arctic circle are warmer than normal for this time of year.
Could the problem be, as the amusing image above, created by science blogger Greg Laden, suggests, that the arctic is actually confused about where it belongs? While Laden was clearly being tongue-in-cheek, in a way, the answer to that question is yes.
Both Laden’s blog and a more recent update at Mother Jones Magazine explain that the “polar vortex” that’s placed much of the United States and Canada into a deep freeze is actually a result of a “drunkenly staggering” jet stream.
The jet stream is a strong current of fast flowing air that cuts across the Northern Hemisphere. It has a powerful affect on the climate in North America. As Mother Jones explains:
Its motion–sometimes in a relatively straight path, sometimes in a more loopy one–is driven by a difference in temperatures between the equator and the north pole. Southern temperatures are of course warmer, and because warm air takes up more space than cold air, this leads to taller columns of air in the atmosphere.
As the Arctic rapidly heats up, however, there’s less of a temperature difference between the equator and the poles, and the downhill slope in the atmosphere is accordingly less steep. This creates a weaker jet stream, a jet stream that meanders more or, if you prefer the new analogy, staggers around drunkenly.
This weak, meandering jet stream can’t contain the strong weather systems from farther north that it normally holds back from sweeping down on us. So, in a perverse way, the reason we’re all freezing right now is because the Earth is getting warmer.
One thing is for sure, we predicted these frigid temperatures in the 2014 Farmers’ Almanac, which is something we’re happy to drink to.