As many of you may have heard by now, 2015 was the hottest year in recorded history (1), dispelling the notion that the climate has not been warming since 1998. When one views the global pattern of warming on a map, a striking feature is that the most warming has occurred in the Arctic region. This troubling fact is the result of a positive feedback mechanism known as Arctic Amplification, which goes a little something like this: as the climate warms, we lose more of the snow and ice cover in the Arctic. This subsequently exposes more dark ocean, decreasing global albedo and allowing the Arctic to absorb ever more heat. This effect serves to decrease the temperature gradient between the Tropics and the Arctic that is responsible for the Polar Jet Stream, a ribbon of high-altitude, fast flowing air that marks the boundary between the Polar and Tropical air masses. This boundary, also known as the Polar front, is the place where weather is primarily controlled. Decreasing the temperature gradient allows the jet stream to flow more slowly, and the air masses to protrude farther North or South than would otherwise be possible. As Jennifer Francis and Stephen Vavrus have shown in their study, a less restrictive jet stream tends to “set-up” in particular patterns that favor droughts in some areas and excessive precipitation in others. (2) Among the many obvious challenges that are coming along with global warming, a less obvious but still alarming one is the persistence of these strange weather patterns which will continue to create extreme conditions such as the recurring drought in California. For this and all the other reasons, climate change must be abated as quickly as possible to mitigate the consequences that are coming our way.

References:

(1) http://www.nytimes.com/2016/01/21/science/earth/2015-hottest-year-global-warming.html?ref=earth&_r=0

(2) http://marine.rutgers.edu/~francis/pres/Francis_Vavrus_2012GL051000_pub.pdf