97% of Greenland ice sheet melts in only four days

Courtesy: Nicolo E. DiGirolamo and Jesse Allen for NASA, 2012

After just a few days of intense melting this month, nearly the entire of the surface of Greenland’s massive ice sheet had turned to slush, NASA images show—the fastest thaw rate since satellites began keeping score 30 years ago. It may be tempting to link the event to global warming, but scientists say such melts might occur every 150 years. If such rapid thaws become common, though, they could add to already rising seas, experts say.

Most of the thawing occurred in a span of four days. Melt maps from satellites show that on July 8, about 40 percent of the ice sheet’s surface had melted. By July 12 that figure had jumped to 97 percent.

For comparison, satellite records from the past three decades show that, on average, about half of Greenland’s ice sheet surface melts at some point each July.

The swiftness and extent of the July thaw surprised some scientists. “This was so extraordinary that at first I questioned the result: Was this real or was it due to a data error?” study team member Son Nghiem of NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. The melt even reached Greenland’s coldest and highest place, Summit Station, 2 miles (3.2 kilometers) above sea level.

Read more: National Geographic >>