Arctic sea ice melts to its lowest extent. The dotted yellow line indicates the average area from 1979 to 2000
The crew of the Greenpeace ship My Arctic Sunrise construct a heart with the flags of the 193 country members of the United Nations on an ice floe north of the Arctic Circle on September 14, 2012.
SUBHANKAR BANERJEE / AP
Some 23,000 of these magnificent predators roam the Arctic today. By 2100 dwindling ice could wipe them out.
An Arctic tern.
National Snow and Ice Data Cener
Arctic sea ice extent for August 26, 2012 (right) was 4.10 million square kilometers (1.58 million square miles), which was 70,000 square kilometers (27,000 square miles) below the September 18, 2007 daily extent of 4.17 million square kilometers (1.61 million square miles)
Natalia Kolesnikova / AFP / Getty
A sign reading "Gas!" in Novy Urengoi, just below the Arctic Circle in far northern Russia
The Canadian Press, Jonathan Hayward / AP
Arctic sea ice is melting so fast that most of it could be gone in 30 years, according to a report in April 2009
Eric Bouvet / Getty
The Russian Arctic base.
VINCENT J. MUSI
Beyond these mountains lies the Arctic National Wildlife Refuge's coastal plain, a magnificent battleground
Photo by Ronald Martinez/Getty Images
Fans in Green Bay suffered through frigid temperatures, thanks to Arctic air that has come south
Michael Leggero / Getty Images
Antarctica hasn't experienced the rapid melting that the Arctic has, but that is changing
Air Force photo / A1C Peter Reft
Shoveling snow during arctic survival training at Eielson Air Force Base, Alaska.
This visualization shows the extent of Arctic sea ice on Aug. 26, 2012, the day the sea ice dipped to its smallest extent ever recorded in more than three decades of satellite measurements, according to scientists from NASA and the National Snow and Ice Data Center.
Keren Su / Corbis
Polar bears near the Norwegian island of Spitsbergen, which borders the Arctic Ocean
courtesy North Slope Borough
An unknown blob floats in the Arctic Ocean off Alaska's North Slope
Dan Crosbie / Canadian Ice Service / AP
Two polar bears on a chunk of ice in the Arctic off Northern Alaska.
The Phoenix lander on the arctic plains of Mars
Paramount Classics / AP
In this image released by Paramount Classics, young polar bear Nanu is shown with her family in Arctic Tale.