One theory that seems like a plausible explanation for the cold weather experienced in the U.S. east of the Rockies is that Arctic warming has reduced the differential between the cold winds emanating from the Arctic and the warm winds from the tropics. The theory is that the diminishing differential is leading to a slower and wavier jet stream that is dipping south and also allowing the polar vortex to escape the Arctic.
Is there some truth to the above theory? Trying to determine the validity of this theory makes it particularly useful to know what happening to the temperature in the Arctic. For those that like websites that track changes, The Arctic Sea Ice News and Analysis website is a terrific resource. They publish a daily report on the extent of Arctic sea ice.
Viewing the two images produced daily by this site seems to provide tremendously contradictory information. The trend line image shows that yesterday seemingly was a momentous day. The 2013-2014 sea ice extent trend line crossed the 2011-2012 trend line for the first time this winter. This year's trend line for Arctic sea ice also seems to be poised to drop below the 2 standard deviation channel for the first time this winter. The reduced level of Arctic sea ice would seemingly be strong evidence that climate change is having a big and measurable impact.
However, in looking at the map of Arctic sea ice, it is does not product a sense of panic about the loss of sea ice. Viewing the map, the areas that have lost sea ice seem rather unsubstantial.
My guess is that the weather weirdness and the Arctic sea ice level both serve as a litmus test for ones views on climate change. For those that believe climate change is occurring to due to greenhouse gas emissions, both are confirming data points. For global warming skeptics, the weird weather and current Arctic sea ice levels prove absolutely nothing.
|Visit the Arctic Sea Ice News website for larger version of these images|