“The question is not whether sea ice loss is affecting the large-scale atmospheric circulation…. It’s how can it not?”
That was the take-home message from Dr. Jennifer Francis of Rutgers
University, in her talk “Does Arctic Amplification Fuel Extreme Weather
in Mid-Latitudes?”, presented at last week’s American Geophysical Union
meeting in San Francisco.
Dr. Francis presented new research in review for publication, which shows that Arctic
sea ice loss may significantly affect the upper-level atmospheric
circulation, slowing its winds and increasing its tendency to make
contorted high-amplitude loops. High-amplitude loops in the upper level
wind pattern (and associated jet stream) increases the probability of
persistent weather patterns in the Northern Hemisphere, potentially
leading to extreme weather due to longer-duration cold spells, snow
events, heat waves, flooding events, and drought conditions.
Summertime Arctic sea ice loss: 40% since 1980
The Arctic has seen a stunning amount of sea ice loss in recent
years, due to melting and unfavorable winds that have pushed large
amounts of ice out of the region. Forty percent of the sea ice was
missing in September 2007, compared to September of 1980. This is an
area equivalent to about 44% of the contiguous U.S., or 71% of the
non-Russian portion of Europe. Such a large area of open water
is bound to cause significant impacts on weather patterns, due to the
huge amount of heat and moisture that escapes from the exposed ocean
into the atmosphere over a multi-month period following the summer melt.
Read more:
The extent of Arctic sea ice loss in the summer July – August – September period in 2007 was about 1.4 million square miles (3.6 million square kilometers) greater than in 1980, according to the University of Illinois Cryosphere Today. For comparison, the lost ice coverage (orange colors) was equal to an area about 44% of the size of the contiguous U.S., or 71% of the non-Russian portion of Europe.
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