Greenland glaciers are melting twice as fast as they did in the 2000s

A new study of unique glacial records shows coastal glaciers in Greenland have been shrinking more than twice as fast as they did two decades ago.

Researchers in Denmark and the U.S. spent years combing through archived photos and analyzing satellite imagery that preserved a century of history across hundreds of coastal glaciers.

Hundreds of thousands of photos date as far back as the 1930s, before the era of mapping satellites, when Danish pilots spent years photographing glaciers from the air.

The new analysis, published in the journal Nature Climate Change, shows that glaciers in the south of Greenland have lost 18% of their lengths over the last 20 years. Other coastal glaciers lost 5-10% of their length.

Coastal glaciers in Greenland make up only 4% of the island’s ice mass, but they account for about 14% of its ice loss.

The study showed that Greenland’s glaciers have reacted quickly to climate change-driven temperature changes — and continue to be an important bellwether and contributor to global ice loss.

Worldwide, such coastal glaciers “have contributed roughly 21% of observed sea level rise over the last two decades,” said the study’s head author Laura Larocca. “These smaller ice masses are an important part of the sea level problem.”