This summer’s Arctic sea-ice melt surprised many scientists by breaking the previous record, set in 2007. At its seasonal peak, the full extent of Arctic sea ice covered 1.3 million square miles, about 300,000 square miles less than the previous record low (as measured since the advent of satellite imagery). Particularly alarming was the case of Greenland, three-fourths of which lies within the Arctic Circle. Nearly all of Greenland’s surface ice underwent thawing (as dramatically shown in the maps above). In mid-July, an estimated 97 percent of its glacial ice was melting—another record extreme.
The extent of the annual Arctic sea-ice melt has been increasing, particularly over the last six years. Although it is a seasonal event—the ice refreezes as winter approaches—it is seen as evidence of a long-term decline in the amount of Arctic ice. The impact of a less extensive ice cap is being felt, such as in changes to animal habitat, among other impacts. Reduced Arctic ice cover means that less of the sun’s light energy is reflected and thus more heat is absorbed by Arctic waters. The thawing of glacial ice such as on Greenland can contribute to sea level rise.
A major Arctic storm in early August is believed to have contributed to the breaking up of sea ice, thus aggravating this season’s melt. Some scientists who are analyzing the recent satellite data and comparing it with what is known from ice-core samples have indicated that a once-every-150-years “melting event” may be occurring. One research scientist who calls the Arctic ice cap the planet’s “air-conditioner” warns that extensive climate effects are looming, far beyond the loss of polar bear habitat or disruption of native communities’ lifeways.
Image Credit: © Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory
- Dramatic Arctic Ice Melt Blows Away Previous Record
Learn about the record-breaking Arctic sea-ice melt, especially the effects of weather and black carbon soot.
(Source: LiveScience, September 19, 2012)
- Ending Its Summer Melt, Arctic Sea Ice Sets a New Low That Leads to Warnings
This article highlights the alarms of scientists regarding the increased extent of Arctic sea-ice melt; includes a map comparing this year’s extent of Arctic sea ice to the 30-year average low.
(Source: New York Times, September 19, 2012)
- Race Is On as Ice Melt Reveals Arctic Treasures
This article explores consequences of Arctic sea-ice melt, in terms of access to and competition for mineral deposits; includes map with polar view showing countries that border the Arctic and the line of international waters.
(Source: New York Times, September 18, 2012)
- Satellites See Unprecedented Greenland Ice Sheet Surface Melt
View satellite imagery and read about NASA’s ice-cap monitoring projects.
(Source: National Aeronautics and Space Administration, July 24, 2012)
- NASA Earth Observatory: ICESat
Learn about NASA’s ICESat project, which is dedicated to the study of changes in Earth’s polar ice caps and glaciers and their relation to climate change.
(Source: National Aeronautics and Space Administration; accessed September 30, 2012)
- Cryosat Eyes Ice Thickness Change
View this animation of data (for winter 2010–11) from the European Space Agency’s Cryosat spacecraft, which monitors changes in the Arctic sea ice thickness.
(Source: BBC News: accessed September 30, 2012)