When scientists talk about the cryosphere, they mean the places on Earth where water is in its solid form, frozen into ice or snow. Read more ...
On Friday, 17 October 2014 from 8:00 a.m. to 5:00 p.m. (USA Mountain Time), our Web site and FTP services will be unavailable because of system maintenance. We apologize for any inconvenience this may cause you.
Although Arctic sea ice extent as of June 2013 falls within the normal range, sea ice overall is still declining compared to the average. This photograph was taken in August 2009, when sea ice extent nears its lowest annual extent before refreezing for the winter. (Courtesy Patrick Kelley, United States Coast Guard)
NSIDC recently switched the baseline against which we analyze Arctic sea ice extent. Previously, we relied on a baseline that coincided with the beginning of the satellite period and stretched 20 years, from 1979 to 2000. The new baseline runs from 1981 to 2010, covering 30 years. Why did we make such a change?
Switching to a 30-year baseline allows us to be consistent with other climate monitoring agencies, which commonly use a 30-year time period for conducting analyses. This new baseline also helps account for the wider variations observed in Arctic sea ice extent. Continue reading →
Permafrost thaw causes the ground to become unstable as the soil collapses. This can damage building and roads built on permafrost. Cracks also expose the carbon stored within to sunlight, which may speed the release of carbon dioxide, a greenhouse gas. Photo credit: Dentren (http://upload.wikimedia.org/wikipedia/commons/a/ac/Storflaket.JPG)
As greenhouse gas emissions continue to rise, researchers are looking at a source of even more carbon emissions: thawing permafrost. A warming Arctic may cause significant amounts of dead, organic material currently frozen in permafrost to thaw out and decay, releasing more carbon into the atmosphere. How exactly does permafrost store carbon? And what are the consequences if the permafrost thaws?
As higher temperatures create more temperate environments across parts of the Arctic, vegetation is creeping northward. Places like Denali National Park in Alaska may soon see forests encroaching on what are currently tundra biomes. Photo credit: Timothy Wildey (http://www.flickr.com/photos/timothywildey/4964905772/)
If gardening in icy Greenland sounds unbelievable, think again. A chef in Kangerlussuaq has started growing tomatoes, peppers, herbs, and even strawberries for his restaurant, and Greenland’s potato production doubled between 2008 and 2012. These agricultural feats would have been impossible only a hundred years ago. The Arctic has been warming over the past several decades at a rate twice as fast as the rest of the globe. As the region warms, several teams of scientists have been tracking changes in Arctic vegetation, trying to see if higher temperatures mean more green. Continue reading →
A large melt pond on the Greenland Ice Sheet, photographed in 2004. Although melt ponds are normal phenomena during the summer melt season, scientists are paying closer attention to their frequency, extent, and duration. Courtesy John Maurer.
As warming alters the Arctic landscape, people are paying more attention to the changes happening to the Greenland Ice Sheet. The ice is melting more rapidly than before, leaving us to wonder, what’s going on?
To help answer your questions about Greenland, NSIDC’s newest Web site, Greenland Ice Sheet Today, will feature the latest research and imagery that researchers are using to monitor the ice. Scientists are discovering that while the ice sheet is in no danger of instantly melting, it is not immune to the Arctic’s rising temperatures. Continue reading →
These satellite-derived maps show the extent of surface melt over Greenland’s ice sheet during the summer of 2012. On July 8, about 40 percent of the ice sheet had melted at or near the surface. By July 12, nearly 97 percent of the ice sheet surface had melted. High pressure ridges that persisted over Greenland created a lingering heat dome that caused the extensive melt. Credit: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory
During the summer of 2012, scientists noticed something unusual in Greenland. On July 8, about 40 percent of the Greenland Ice Sheet surface showed signs of melting. But a mere four days later, 97 percent of the surface was melting, an extent that was unprecedented in the satellite record.
Just how unprecedented was this event? Does it mean that the Greenland Ice Sheet is possibly on the way out, like summer sea ice in the Arctic? Continue reading →