Saturday, March 7, 2015

Extreme Winter Weather in the Lower Latitudes and Warming of the Arctic Ocean

For the past two winters, the continental United States has experienced harsh weather conditions with unusual amounts of precipitation in the form of snow.  Meteorologists have established that arctic-born weather has been directed to the Northeastern, Midwestern and even Southeastern continental United States as a result of a shift in the direction, depth and pattern of the jet stream described as “wavy.”

Dr. Jennifer Francis, a climatologist, and her colleagues at Rutgers University in collaboration with Dr. Steven Vavrus from the University of Wisconsin at Madison have published data establishing a connection between warming in the Arctic Ocean and the extreme winter weather in the lower latitudes. 
Ordinarily sea ice exerts an influence on global temperature by its ability to reflect back solar radiation into space on account of its whiteness through what is referred to as the albedo effect.  However, as a result of the gradual warming of the planet due to the accumulation of greenhouse gases, the temperature in the Arctic has increased at twice the rate as the rest of the earth.   This increased temperature is accelerating the melting of Artic sea ice.  As this sea ice melts, it reduces the albedo effect and results in increased warming and therefore the further melting of sea ice.  This cycle of increased warming is referred to as negative feedback.
It seems that this warming trend in the Arctic has disrupted normal climate conditions in the following way - cold air that is usually contained within the Arctic region by so-called “polar vortex winds” has moved southward into the mid-latitudes as a result of the high pressure that is a direct consequence of the enhanced melting of the sea ice.   Accordingly, the lower latitudes have experienced unusually extreme winter weather.

If this explanation is proven to be correct for seasonal aberrations in weather in the lower latitudes, then these changes would suggest a permanent alteration in weather patterns for the regions impacted.

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