Arctic Sea Ice Falls into Record Low Ranges — Again
Extreme
Arctic warmth this fall has again pushed sea ice levels into record
low ranges.
18
October, 2016
Across
the Arctic, temperatures
for the months of September and October have ranged between 3 and 5
degrees Celsius above normal for the entire region above the 66
degree north latitude line.
Such extremely high temperatures have served to slow the rate of sea
ice accumulation. The result is that the line in the sea ice graphs
appears to be moving more sideways than following the traditional
upward trend for this time of year.
(2016
enters near record low extent ranges on October 17 of 2016. Green
dashed line represents 2012 sea ice extent, blue line represents
2007, black line the 1981 to 2010 average, orange line 2003, blue
line 1994, and yellow line 1980. The gray border represents the 2
standard deviation from trend boundary. Image source: NSIDC.)
Trend
lines for 2016 are also now within 90,000 square kilometers of
exceeding previous record lows for sea ice extent set in 2007 and
nearly matched in 2012 for the date of October 17.
Big
Arctic Temperature Spike Driving Losses
Over
the next few days, GFS model runs predict that a strong warming trend
will take hold over the Arctic Ocean environment. As a result,
temperature anomalies for the region above 66 North are expected to
again spike to near 5 C above average for this time of year.
Given
this predicted heat build-up, it’s certainly possible that refreeze
rates will continue to be inhibited and that new record daily lows
will be breached this week. Meanwhile, the overall trend for 2016
from January through middle October shows a year that is likely to
see the lowest averaged levels of sea ice ever recorded for an entire
year.
(Arctic
temperatures have remained high throughout the fall — which has
contributed to a very slow sea ice re-freeze so far. By Sunday, GFS
model runs predict that temperatures over the Arctic Ocean will again
push into much warmer than normal ranges for this time of year —
possibly further delaying this region’s return to an ice-covered
state. Image source: Climate
Reanalyzer.)
Polar
Amplification in Evidence
Loss
of sea ice is a primary feature of polar amplification in the Arctic
due to human-forced climate change. Under polar amplification,
warming of this region occurs faster than in the rest of the world.
During summer, lower sea ice levels allow more sunlight to be
absorbed by dark ocean waters — which preferentially traps heat in
the Arctic environment. Less ice coverage during winter allows ocean
heat to re-radiate into the Arctic which provides a significant boost
to temperatures during the cold season.
(Anomalously
warm temperatures over the Arctic Ocean have represented more a
strange hybrid between fall and summer than a typical drop-off toward
winter patterns during 2016. In the graph above, global warming
appears to have basically levitated temperatures in the region above
80 North right off the chart. Image source: DMI.)
Last
year, a never-before-seen late December warming of the Arctic pushed
temperatures at the North Pole above freezing. If human fossil fuel
burning continues and greenhouse gas accumulations in the Earth’s
atmosphere keep rising, the Arctic is in for more dramatic fall,
winter, and spring warming events than even those it is experiencing
today. And with global temperatures entering a range of 1-2 C above
preindustrial averages, the risk of a complete loss of Arctic sea ice
over the coming years is on the rise.
Links:
Hat
tip to Colorado Bob
Hat
tip to Marcel Guldemond
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