Nav: Home

Without its insulating ice cap, Arctic surface waters warm to as much as 5 degrees C above average

December 12, 2007

Record-breaking amounts of ice-free water have deprived the Arctic of more of its natural "sunscreen" than ever in recent summers. The effect is so pronounced that sea surface temperatures rose to 5 C above average in one place this year, a high never before observed, says the oceanographer who has compiled the first-ever look at average sea surface temperatures for the region.

Such superwarming of surface waters can affect how thick ice grows back in the winter, as well as its ability to withstand melting the next summer, according to Michael Steele, an oceanographer with the University of Washington's Applied Physics Laboratory. Indeed, since September, the end of summer in the Arctic, winter freeze-up in some areas is two months later than usual.

The extra ocean warming also might be contributing to some changes on land, such as previously unseen plant growth in the coastal Arctic tundra, if heat coming off the ocean during freeze-up is making its way over land, says Steele, who is speaking Wednesday at the American Geophysical Union meeting in San Francisco.

He is lead author of "Arctic Ocean surface warming trends over the past 100 years," accepted for publication in AGU's Geophysical Research Letters. Co-authors are physicist Wendy Ermold and research scientist Jinlun Zhang, both of the UW Applied Physics Laboratory. The work is funded by the National Science Foundation.

"Warming is particularly pronounced since 1995, and especially since 2000," the authors write. The spot where waters were 5 C above average was in the region just north of the Chakchi Sea. The historical average temperature there is -1 C - remember that the salt in ocean water keeps it liquid at temperatures that would cause fresh water to freeze. This year water in that area warmed to 4 C, for a 5-degree change from the average.

That general area, the part of the ocean north of Alaska and Eastern Siberia that includes the Bering Strait and Chukchi Sea, experienced the greatest summer warming. Temperatures for that region were generally 3.5 C warmer than historical averages and 1.5 C warmer than the historical maximum.

Such widespread warming in those areas and elsewhere in the Arctic is probably the result of having increasing amounts of open water in the summer that readily absorb the sun's rays, Steele says. Hard, white ice, on the other hand, can work as a kind of sunscreen for the waters below, reflecting rather than absorbing sunlight. The warming also may be partly caused by increasing amounts of warmer water coming from the Pacific Ocean, something scientists have noted in recent years.

The Arctic was primed for more open water since the early 1990s as the sea-ice cover has thinned, due to a warming atmosphere and more frequent strong winds sweeping ice out of the Arctic Ocean via Fram Strait into the Atlantic Ocean where the ice melts. The wind effect was particularly strong in the summer of 2007.

Now the situation could be self-perpetuating, Steele says. For example, he calculates that having more heat in surface waters in recent years means 23 to 30 inches less ice will grow in the winter than formed in 1965. Since sea ice typically grows about 80 inches in a winter, that is a significant fraction of ice that's going missing, he says.

Then too, higher sea surface temperatures can delay the start of freeze-up because the extra heat must be discharged from the upper ocean before ice can form. "The effect on net winter growth would probably be negligible for a delay of several weeks, but could be substantial for delays of several months," the authors write.
-end-
For more information:

While he's attending AGU meeting Dec. 9 through afternoon of Dec. 14, contact Steele via Sandra Hines, (206) 543-2580, shines@u.washington.edu; after that, Steele's office (206) 543-6586, mas@apl.washington.edu

University of Washington

Related Arctic Ocean Articles:

A rare snail living on wood is discovered in the Arctic ocean
Postgraduate student Ekaterina Krol and Senior Research Associate at the Department of Applied Ecology of St Petersburg University Ivan Nekhaev have found a marine snail from the subclass Neomphaliones in a collection from the Soviet Arctic expeditions of the 1930s.
Arctic research expedition likely faces extreme conditions in fast-changing Arctic
Scientists at the National Center for Atmospheric Research (NCAR) have simulated conditions along potential routes for the MOSAiC polar expedition, using today's conditions in the 'new Arctic.' The results suggest that thinner sea ice may carry the ship farther than would be expected compared to historical conditions and the sea ice around the ship may melt earlier than the 12-month goal.
Stronger Atlantic currents drive temperate species to migrate towards the Arctic Ocean
The Arctic Ocean increasingly resembles the Atlantic, not only regarding its temperature but also the species that live there.
Seafloor of Fram Strait is a sink for microplastic from Arctic and North Atlantic Ocean
Working in the Arctic Fram Strait, scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have found microplastic throughout the water column with particularly high concentrations at the ocean floor.
Researchers make critical advances in quantifying methane released from the Arctic Ocean
A new study, lead by researchers at Stockholm university and published in Science Advances, now demonstrate that the amount of methane presently leaking to the atmosphere from the Arctic Ocean is much lower than previously claimed in recent studies.
Climate gas budgets highly overestimate methane discharge from Arctic Ocean
There is a huge seasonal variability in methane seeps in the Arctic Ocean, according to a new paper in Nature Geoscience.
New threat from ocean acidification emerges in the Southern Ocean
Scientists investigating the effect of ocean acidification on diatoms, a key group of microscopic marine organisms, phytoplankton, say they have identified a new threat from climate change -- ocean acidification is negatively impacting the extent to which diatoms in Southern Ocean waters incorporate silica into their cell walls.
Ocean's 'seasonal memory' affects Arctic climate change
Researchers found out that the Arctic does not lose ice uniformly.
Ocean fertilization by unusual microbes extends to frigid waters of Arctic Ocean
Microbes that provide natural fertilizer to the oceans by 'fixing' nitrogen from the atmosphere into a form useable by other organisms are active in the cold waters of the Bering and Chukchi Seas.
Life on the floor of the Arctic Ocean, with rigor and in detail
In an extensive and rigorous study of animal life on the Central Arctic Ocean floor, researchers have shown that water depth and food availability influence the species composition, density, and biomass of benthic communities, according to a study published Oct.
More Arctic Ocean News and Arctic Ocean Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.