CLIMATE -- September 20, 2012 at 5:49 PM EDT
Arctic Sea Ice Melts to Record-Breaking Low
Arctic sea ice melted to 1.32 million square miles this September -- an unprecedented low and a sharp drop from the 2.59 million square mile average for this time of year. It also marks the greatest Arctic ice melt since satellite observations began in 1979.
The animation above from the NOAA Environmental Visualization Laboratory shows the extent and rate of the area's ice melt from January to September 2012.
Arctic sea ice constantly melts and refreezes throughout the year, said Walt Meier, a scientist with the National Snow and Ice Data Center. But September is when the ice typically reaches its minimum extent for the year. This year's dramatic decline could be indicative of greater losses in the future, Meier said.
"One of the things that's defined sea ice is its variability...so we wouldn't expect it to keep going down straight off the map, so to speak," Meier said in a press conference today. "We expect there to be further ups and downs. I think we'll see a general, long-term trend continue toward becoming largely ice-free. How fast we'll get there it's harder to say."
Scientists have seen dramatic declines in ice extent over the past 33 years. This year's minimum is nearly 50 percent lower than the 1979 to 2000 average.
The ice is younger and thinner than it was in the 1980s. Of the ice surveyed this summer, the majority was one to two years old and three to five feet thick on average. That's down from 10 to 13 feet thick in 1985.
Losing sea ice also has immediate impacts on Arctic wildlife. Walruses that normally rest on the ice while hunting ocean fish moved ashore by the thousands last year. Arctic seal populations have already declined as a result of disappearing ice. And a 2009 United States Geological Survey estimated that by 2050, the world could lose two-thirds of its polar bears as their ice-dwelling food sources disappear. The ice is also home to delicate microorganisms, which, if lost, could upset the entire Arctic food chain, Meier said.
Ted Scambos, senior research scientist at NSIDC, said that changes in the Arctic's ice and snow are making the Arctic warmer, which may mean major weather and climate changes for the rest of the planet. Sea ice reflects the sun's rays, which helps regulate the planet's temperatures, especially during the summer. Losing the reflective ice surface causes temperatures to rise. If the North Pole is not as cold as it used to be, that has the potential to change wind and weather patterns throughout the Northern Hemisphere.
"But a wider impact may come from the increased heat and moisture that the Arctic is adding to the climate system," Scambos said in a press release yesterday. "This will gradually affect climate in the areas where we live...We have a less polar pole--and so there will be more variations and extremes."
Ice melt does have some economic benefits, Meier pointed out, at least in the short term. It opens up routes for ships and makes fishing, shipping and exploration for oil and petroleum in the Arctic easier.
Meier said that while the impacts are not yet fully understood, sea ice is a harbinger for future changes.
"We expected that the sea ice would change first, because even a small change in temperature there, from 32 [degrees] to 20 [degrees] is the difference between ice skating and swimming," he said. "We can see very viscerally in the ice how warming temperatures are changing the earth's environment."
Correction: An earlier version of this story listed the annual minimum average as 7 million square miles. That number refers to square kilometers, not miles.