The National Snow and Ice Data Center at the University of Colorado has reported that there is less ice in the Arctic Ocean this summer than at any time since satellite measurements were first taken back in 1979, a finding that underscores the reality of global climate change.
Johns Hopkins oceanographer Thomas Haine, who studies how the physics of ocean currents affects global climate, is available to put these findings into perspective.
“The record-breaking Arctic sea ice loss in summer is very likely due to anthropogenic (man-made) climate change,” said Haine. “That means increasing carbon dioxide in the atmosphere (much of it from manmade greenhouse gas emissions) is the major reason for the large decline since 1979.”
Year-to-year variations, however, also are likely caused by other factors, such as changes in ocean currents and Arctic weather in the months before the measurements were taken. Arctic sea ice annually reaches its minimum extent (coverage) in mid-September before it begins to freeze again as winter approaches. But NSIDC researchers found that late this month, the ice had already shrunk to 1.58 million square miles. The previous record low was 1.61 million square miles in September 2007.
Haine says this new low could have myriad impacts -- on the Arctic ecosystem and on business and the economy -- and as a herald for future Arctic environmental change.
“First, losing sea ice accelerates the warming of the Arctic because the sea absorbs sunshine, whereas sea ice reflects it,” he explains. “Second, changes to the sea ice cause changes in the Arctic ecosystem, although we don’t have a clear picture of what’s happening. Third, loss of sea ice makes the Arctic more open to shipping and extraction of natural resources. And finally, the Arctic sea ice changes are related to other environmental changes in the northern high latitudes, like the melt of the Greenland ice cap, which is important for sea levels.”
To reach Haine, please email Lisa De Nike at Lde@jhu.edu or call her at (443) 287-9960 (office) or (443) 845-3148 (cell.)
Haine is chairman of the Morton K. Blaustein Department of Earth and Planetary Sciences at The Johns Hopkins University’s Krieger School of Arts and Sciences.