Summertime sea ice in the Arctic reached a minimum on September
10 (unless it goes lower still). It’s now tied for the second-lowest
minimum in the satellite era.
NASA and the National Snow and Ice Data
Center (NSIDC) said
on September 15, 2016 that summertime Arctic sea ice appears to have
reached its annual minimum on September 10.
With fall approaching and temperatures in the Arctic
dropping, it’s unlikely more ice will melt, and so the 2016
Arctic sea ice minimum extent will likely be tied with 2007 for the
second-lowest yearly minimum in the satellite record. Satellite data
showed this year’s minimum at 1.60 million square miles (4.14
million square km). The animation above tracks the evolution of
Arctic sea ice cover during 2016.
Since satellites began monitoring sea ice in 1978,
researchers have observed a steep decline in the average extent
of Arctic sea ice for every month of the year …
The sea ice cover of the Arctic Ocean and surrounding seas
helps regulate the planet’s temperature, influences the
circulation of the atmosphere and ocean, and impacts Arctic
communities and ecosystems. Arctic sea ice shrinks every year
during the spring and summer until it reaches its minimum yearly
extent. Sea ice regrows during the frigid fall and winter
months, when the sun is below the horizon in the Arctic.
This has been an usual year for Arctic
sea ice in several ways. A few weeks ago, when scientists were
contemplating this year’s pattern of melting, they were discussing
the need for a possible
new normal for Arctic sea ice.
2016’s summertime Arctic sea ice minimum, in contrast to the
1981-2010 average minimum sea ice extent, shown here as a gold
line. Image via
NASA/NSIDC.
The NASA/NSIDC
statement explained why the melt of Arctic sea ice surprised
scientists in 2016. For one thing, it changed pace several
times:
The melt season began with a record low yearly maximum extent
in March and a rapid ice loss through May. But in June and July,
low atmospheric pressures and cloudy skies slowed down the melt.
Then, after two large storms went across the Arctic basin in
August, sea ice melt picked up speed through early September.
Walt Meier, a sea ice scientist with
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said:
It’s pretty remarkable that this year’s sea ice minimum
extent ended up the second lowest, after how the melt progressed
in June and July. June and July are usually key months for melt
because that’s when you have 24 hours a day of sunlight – and
this year we lost melt momentum during those two months.
But in August, two very strong cyclones crossed the Arctic
Ocean along the Siberian coast. These storms didn’t have as much
of an immediate impact on the sea ice as the great cyclone of
2012, but in late August and early September there was “a pretty
fast ice loss in the Chukchi and Beaufort seas that might be a
delayed effect from the storms.
Meier also said that decades ago, the
melt season would slow down by the middle of August, when the sun
starts setting in the Arctic. He said:
In the past, we had this remaining sea ice pack that was
mostly thick, old ice. But now everything is more jumbled up,
which makes it less resistant to melt, so even late in the
season you can get weather conditions that give it a final kick.
A recently published study led by Claire
Parkinson, a senior climate scientist at NASA Goddard, ranked 37
years of monthly sea ice extents in the Arctic and Antarctic. That
study found that there has not been a record high in Arctic sea ice
extents in any month since 1986. During that same time period, there
have been 75 new record lows. Parkinson commented:
When you think of the temperature records, it’s common to
hear the statement that even when temperatures are increasing,
you do expect a record cold here or there every once in a while.
To think that in this record of Arctic sea ice that goes back
to the late 1970s, since 1986 there hasn’t been a single record
high in any month of the year, and yet, over that same period,
there have been 75 record lows. It’s just an incredible
contrast.
It is definitely not just September that’s losing sea ice.
The record makes it clear that the ice is not rebounding to
where it used to be, even in the midst of the winter.
Bottom line: Summertime sea ice in the
Arctic appears to have reached a minimum on September 10, 2016. It’s
tied for the second-lowest minimum in the satellite era.