There's
some really intense melting in the Arctic right now
14
June, 2019
Records
are falling at the top of the world.
The
Arctic summer has a long way to go, but already sea ice levels over
great swathes of the sprawling Arctic ocean are at historic lows (in
the 40-year-long satellite record) for this time of year. The most
striking declines are in the Chukchi and Beaufort seas, located above
Alaska.
The
melt is exceptional, but right in line with accelerating melting
trends occurring as the
Arctic warms.
"Every
year we smash a record that we’re shocked at," said Jeremy
Mathis, a longtime Arctic researcher and a current board director at
the National Academies of Sciences.
By
the end of May, Arctic sea ice overall was vastly diminished, running
some 436,000
square miles below average. Now, the downward trend continues,
with the lowest
sea ice on record for mid-June.
We
should get used to these Arctic records, emphasized Mathis. "The
extraordinary change is a given," he said. "The Arctic is
superseding any projection we had for how quickly sea ice was going
to go away."
The
climate regime in the Arctic has changed sharply over the last few
decades. The Arctic was once blanketed with older, thicker ice. But
now the ice
is younger, thinner, and easily melted.
"This
is due to the long-term warming of the Arctic," said Zack Labe,
a climate scientist and PhD candidate at the University of
California, Irvine. "Air temperatures are now rising at more
than twice the rate of the global mean temperature — a phenomenon
known as 'Arctic Amplification'."
This
warm air means thinner and less hardy ice that's more susceptible to
melt during the summer, noted Labe.
And
with warmer air temperatures comes warmer oceans. The Arctic suffers
from a vicious feedback loop, wherein the bright, reflective ice
melts, and then more of the dark ocean absorbs sunlight. This drives
even more melting.
And
the oceans in large parts of the Arctic are indeed warmer than usual,
said Lars Kaleschke, a sea ice researcher at the Alfred Wegener
Institute for Polar and Marine Research. Kaleschke, who has been
watching the recent melting with "great interest," noted
that the waters in the Pacific Arctic and parts of the inner Arctic
are warmer than average. The ice is thinner there, too.
"In
consequence, the thinner ice now retreats much faster than usual,"
said Kaleschke.
For
the many of us viewing the melting Arctic on
satellite images from thousands of miles away, the rate of
change in the high north can be difficult to grasp. But not for
scientists like Mathis, who have traveled through these icy oceans.
"I’m
losing the ability to communicate the magnitude [of change],"
said Mathis. "I’m running out of adjectives to describe the
scope of change we’re seeing."
Though
the longer term melting trends are unmistakable, in the shorter term,
like this summer, Labe noted that cooler weather patterns can still
swoop in and potentially chill the region. Although ice is now at
record lows in many places — and overall is currently at the lowest
point in the satellite record — this year might not necessarily end
up breaking the all-time record low, set in 2012 at summer's end.
Regardless,
the big picture is clear. "The 12 lowest extents in the
satellite record have occurred in the last 12 years," the
National Oceanic and Atmospheric Administration (NOAA) noted
in 2018.
This
means a melting Arctic that's opening
up for more shipping and a militarization of the region from
the likes of Russia and China, explained Mathis. There's strong
evidence that a warmer Arctic also perturbs
global weather patterns and stokes weather extremes
thousands of miles away, in heavily populated areas.
The
difference today, compared to the last hundreds of thousands of
years, comes down to the heat-trapping gas carbon dioxide saturating
the atmosphere, noted Mathis. Atmospheric carbon dioxide
concentrations are now accelerating at geologically
and historically unprecedented rates.
Even
if global civilization is able to slash
carbon emissions and curb temperatures at levels that would
avoid the worst
consequences of climate change, the exceptionally warmed Arctic
will still feel the heat.
"Regardless
of any mitigating efforts, the Arctic is going to be a fundamentally
different place," said Mathis.
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