As another huge storm turns south towards the Midwest, some say that the cold winter can be explained by the Arctic Paradox, which links a natural phenomenon (the Arctic Oscillation) to a man-made phenomenon (diminishing ice in the Arctic), which combines to let polar winds escape southward.
First question: Is ice in the Arctic really diminishing?
This chart, from the National Snow and Ice Data Center, says yes:
How does this link up with existing climatological patterns? Climate Central explains:
The atmospheric circulation in question is the same weather pattern that contributed to the post-Christmas blizzard in the northeastern U.S., and the extreme cold and snow that gripped much of Europe during December. Known as the Arctic Oscillation, this pattern is a large-scale variation in surface air pressure between the Arctic and the mid-latitudes. When the Arctic Oscillation is in a strongly negative mode, which has been the case recently, air pressures are higher than average in the Arctic and lower than average in the mid-latitudes. This sets up opposing temperature patterns, with a greater likelihood that cold air will spill out of the Arctic and into North America and Europe.
Scientists refer to weather patterns featuring an abnormally mild Arctic and an unusually cold U.S. and Europe as the "Warm Arctic/Cold Continents Pattern" or an "Arctic Paradox," and it is the subject of ongoing research.
It's still not fully clear to yours truly. But he appreciates new descriptive metaphors, when they come along. Here's one from a recent NY Times story that likened the declining pressure differential between the polar north and the northern hemisphere to a weakening fence, no longer able to restrain the masses of cold air from the arctic from escaping southward.
I got it! I think…
Update: Susan Orlean, the wonderful New Yorker writer, meditates on-line on the wintriest winter in her time in New York.