The latest satellite imagery shows that Arctic sea ice melted during the summer to its third-lowest level on record — continuing a trend that scientists say could lead to the total disappearance of sea ice within two decades.
The low ebb of the northern polar area covered by sea ice shrank by 130,000 square miles compared with 2009, said Mark Serreze, director of the federally funded National Snow and Ice Data Center at the University of Colorado at Boulder.
The images his team received Wednesday from a Department of Defense satellite showed that 1.84 million square miles remain covered.
“By the year 2030, you may go up there, and it will look like a blue ocean. We are losing it that fast,” Serreze said.
Arctic ice melts as late as October, though the September snapshot is considered to represent the low-ice mark of the year. New ice forms in winter.
The four lowest ebbs of sea ice recorded since 1979 occurred in 2007, 2008, 2009 and this year. While the sea ice cover appeared to recover somewhat in 2008 and 2009, the new data indicate a 6.5 percent shrinkage compared with the low ebb in 2009 and a 22 percent decrease from the 1979 to 2000 average.
This year’s sea ice cover exceeded the record low ebb of 1.595 million square miles in 2007 and is 93,000 square miles more than was in the Arctic after summer 2008.
Scientists regard sea ice as a sensitive indicator of climate change. Arctic sea ice functions as a refrigerator for the northern hemisphere, reflecting sunlight and regulating the climate.
“If you lose the sea ice cover, you start to change the nature of that refrigerator. We could see shifts in precipitation that are driven by losing the sea ice cover,” Serreze said.
Winters may become less severe, he said. “You might say that’s great, unless you’re involved in the ski industry or the management of Western water resources.”
CU-based researchers who monitor Arctic ice also are looking at geopolitical impacts. Oil and gas exploration in Arctic regions has intensified. And as northern sea transport routes open, U.S. officials argue that international conventions favor free passage, while northern countries have invoked sovereignty rights.
Some scientists say climate changes may be the result of natural fluctuations, though CU scientists believe the amount of melting is “well outside the range of natural climate variability,” according to a release. A growing body of controversial research points to intensifying human industrial activity that releases gases into the atmosphere as a cause.
CU’s team is just conveying data, Serreze said. “What our elected leaders end up doing with this is not in our control.”
Bruce Finley: 303-954-1700 or bfinley@denverpost.com
