Arctic Ocean: Ice melt

polar bear photo from M. Zinkova
Photographed by Mila Zinkova

Amid the concern about diminishing sea ice extent in the Arctic Ocean, and there’s plenty of concern to go around, came a report adding to that unease: An announcement from the US National Snow and Ice Data Center indicates that the sea ice extent averaged only a little over 3.06 million square miles during the July 2011, down more than 80,000 square miles below the low that was recorded in 2007. Apparently, weather patterns have changed in the last couple of weeks, but the overall effect is still dramatic.

Meanwhile, however, a report from a study of driftwood indicates that sometime between 8000 and 5000 years ago sea ice extent in the Arctic was less than half of what it is now. Based on studies of driftwood found in Greenland, Svend Funder and colleagues from the Danish National Research Foundation for Geogenetics at the University of Copenhagen, found that

there have been large fluctuations in the amount of summer sea ice during the last 10,000 years. During the so-called Holocene Climate Optimum, from approximately 8000 to 5000 years ago, when the temperatures were somewhat warmer than today, there was significantly less sea ice in the Arctic Ocean

So, it’s looking pretty grim. The ice is retreating, perhaps more rapidly than previously thought. Sections of the Arctic have had some low-ice times before, but these driftwood data don’t mean that climate change isn’t happening or that we can ignore it. Professor Funder and his colleagues leave little room for the so-called deniers when they begin their article in Science with “Global warming will probably cause the disappearance of summer sea ice in the Arctic Ocean during this century….”


For more information:
Neven (Arcticnev) has made available an extensive library of images of graphs and maps; they are updated frequently and there are also links to many other resources for those who are curious about news, commentary, and even live video (yep, Webcams!) about the state of Arctic sea ice.

Read about shrinking sea ice extent and its effects on the ecology and shipping in “Melting Arctic sea ice: Alaska-sized polar bear habitat disappears” by Doug O’Harra in the Alaska Dispatch. Also, see “Arctic Sea Ice Melting: Rapid Changes Will Bring Good With Bad, Climate Scientist Says” by a staff reporter for the International Business Times. To get some journalists’ takes on the driftwood story, see Bob Berwyn’s “Global warming: Ancient driftwood offers sea ice clues” for the Summit County Citizens Voice and “Study finds large variability in Arctic summer ice extent over last 10,000 years; less than half of current amounts for several thousand years” from Green Car Congress. Also see the National Geographic essay and photos for “On Thin Ice.”

Funder, S., Goosse, H., Jepsen, H., Kaas, E., Kjær, K. H., Korsgaard, N. J., Larsen, N. J., Linderson, H., Lyså, A., Möller, P., Olsen, J., & Willerslev, E. (2011). A 10,000-year record of Arctic Ocean sea-ice variability—view from the beach. Science, 333, 747-750. doi: 10.1126/science.1202760

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