In the last week of December 2015, a storm from the northern
United States surged northwards, reaching a near-record low barometer reading
and, for a period of about 22 hours, heating the air on a line running along
the eastern coast of Greenland to the North Pole to above freezing – or more
than 50 degrees F above the average temperature at this time of year. It was the deepest into winter that
above-freezing temperatures had been recorded by almost a month, and it was
accompanied by rain whose warm moisture caused serious melting of sea and land
(Greenland) ice.
The consensus of scientific observers has been that such an
occurrence at this time of year will not by itself significantly reduce the sea
ice at maximum or minimum. However, it
will give a significant acceleration to melting of Greenland’s glaciers into
the sea, thus keeping the “doubling every decade” trend of Greenland land ice
melt going. This is not a one-off event,
but rather related to the “wavy jet stream” pattern of weather in the winter
that will not only export colder air south but also import much warmer air
north into the Arctic. In other words,
this event suggests that the pessimistic forecast of sea rise of 15-30 feet
this century is more in line with what is happening than more optimistic
forecasts of 1-15 feet.
That is all.
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