I am sure a lot of wingnuts are celebrating the recent "snowpocalypse"
as a sign that climate change/global warming is all a hoax, and the fact it is centered in Washington is the perfect irony. "Hope you enjoy digging out the 3 feet of global warming ha ha" etc. To add insult to injury, there is going to be another snow event in the Northeast this week, with snow in most if not all of the megalopolis- then a potential snow event in the South late next week.
Well, join me after the jump for an explanation why the snowy US patten may actually be related to AGW as opposed to refuting it.
Of course the first part of the equation is that the term is global warming, not eastern United States warming. The globe as a whole just experienced the fifth warmest year on record, and a good map illustrating this is here. As you see, the US was one of only a few small areas below average, while rest of the globe was baking, especially the southern hemisphere. Notice also how that north polar regions have the biggest red dots, meaning it was far above average up there. Of course this affects sea ice- and right now we are headed for at least a tie for the lowest sea ice on record.
The reason for the north pole area being so warm is actually in a perverse way helping cause the snow and cold here, and also recently in Europe. A recent article in RealClimate by James Hansen explains this phenomenon:
If It’s That Warm, How Come It’s So Damned Cold?
The article is long and rather technical but is worth reading. The part relevant to this discussion is something called the Arctic Oscillation:
It is obvious that in December 2009 there was an unusual exchange of polar and mid‐latitude air in the Northern Hemisphere. Arctic air rushed into both North America and Eurasia, and, of course, it was replaced in the polar region by air from middle latitudes. The degree to which Arctic air penetrates into middle latitudes is related to the Arctic Oscillation (AO) index, which is defined by surface atmospheric pressure patterns and is plotted in Figure 6. When the AO index is positive surface pressure is high low in the polar region. This helps the middle latitude jet stream to blow strongly and consistently from west to east, thus keeping cold Arctic air locked in the polar region. When the AO index is negative there tends to be low high pressure in the polar region, weaker zonal winds, and greater movement of frigid polar air into middle latitudes.
Gist is: our cold and stormy weather is in part caused by the fact the Arctic has an unusual amount of warm air and anomalous upper level high pressure, which forces the jet stream south and voila! record snows. A thing people always forget: say the most dire AGW models are correct and the globe warms several degrees over the next 50 years. It does not mean winter goes away! It will still be cold and snowy in the north every winter. Plus maybe your little corner of the world will actually get colder or stay steady. But of course logic and science means nothing to the Inhofes of the world, but maybe you can use this to convince someone that cold and snow does not refute global warming.