America's Coldest Day in 20 Years May Have Been Manmade
Chiberia via Edward Stojakovic/FlickrThanks to the fantastically and ominously titled polar vortex, today was the coldest day in the US in 20 years. In Chicago, temperatures plunged to 16˚F below zero. In New York, temperatures plummeted nearly 50 degrees Fahrenheit in a matter of hours, making it the coldest January 7 since 1896. When I stepped outside to hail a cab, it felt like I was being stabbed by a thousand tiny, angry icicles.
Our media personalities who are least capable of abstract thought have been using the cold weather to denounce global warming—it's cold, after all, a word that is the opposite of warm, ipso facto screw science. But here's a curveball for them: The intense cold may even have been caused by global warming. Somewhere, Donald Trump's head just did the Scanners thing.
Much like the notion that climate change may be causing more blizzards—warmer air holds more moisture, which fuels blizzards—the slightly contradictory-seeming idea is simply too much for many (opportunistic conservative media personalities) to manage. But it might actually be the case that our warming globe is producing more violently cold weather in novel places.
First of all, weather isn't climate—the former's the event, the latter's the system that produces it. Second, a number of climate scientists are postulating that the unusual polar vortex may have been forced out of its Arctic home by warmer Arctic ice. The vortex itself is a west-to-east swirl of 100 mph plus winds that typically stay locked in place over Canada. But when the winds weaken, as TIME's Bryan Walsh points out, the system can get thrown off its base.
Why? Andrei Kucharavy, a PhD life-science student, posted a helpful explanation on Quora, noting that "the cold air from the North Pole is pouring down onto the Canada and US territory, leading to a lower temperature in the USA, but a higher temperature in Europe/England/Norway/Sib
The Coriolis effect usually traps the cold air in place. So something has to push it out—"a huge convective force" rising from warm water. It's like how it happens with hurricanes.
Usually, this convective force doesn't exist on the North Pole, because of a huge sheet of ice, that protects the cold air from warm water and avoids convection. However, with global warming, this is less and less true. This is particularly untrue this year: according to NASA, in 2013 the Arctic Sea Ice Minimum is Sixth Lowest on Record) ... Coupled with the Gulfstream bringing up lots of warm water from equator, this leads to a massive convective cell over Arctic, leading to a cold air warming up over (relatively) warm thin ice and pushing out the masses of cold air over it to the regions where such warming does not occur, i.e. Canada, USA and Siberia.Kucharavy concludes that the "January 2014 cold wave is a direct consequence of global warming, due in the major part to the ice sheet thinning over the North Pole." He says we should be seeing more such events as global warming. Now, he's not a climate scientist, but climatologists concur with the general premise. Here's Rick Grow at the Washington Post:
Large atmospheric waves move upward from the troposphere — where most weather occurs — into the stratosphere, which is the layer of air above the troposphere. These waves, which are called Rossby waves, transport energy and momentum from the troposphere to the stratosphere. This energy and momentum transfer generates a circulation in the stratosphere, which features sinking air in the polar latitudes and rising air in the lowest latitudes. As air sinks, it warms. If the stratospheric air warms rapidly in the Arctic, it will throw the circulation off balance. This can cause a major disruption to the polar vortex, stretching it and — sometimes — splitting it apart.Also worth underlining: while it's cold as frozen hell in the US, it's warmer elsewhere, as is almost always the case. It's still, even at this very moment, warmer than average worldwide. This science is still new—the Arctic hasn't been melting all that long since we've been around to study it, after all—but it foretells a grim future. Welcome to the brave and weird and new world of our climate-changed planet; the coldest weather I've ever felt may in fact have been manmade.