Nearly 40 years of satellite data from Greenland show that its glaciers have shrunk so much that even if global warming stopped today, the ice sheet would continue to shrink.
The finding, published in the journal Nature Communications Earth and Environment, means that Greenland’s glaciers have passed some kind of tipping point, where the snow that replenishes the ice sheet each year cannot keep up with the ice that flows into the ocean.
“We have been analyzing these remote sensing observations to study how ice discharge and accumulation have varied,” said in a statement Michalea King, lead author of the study and a researcher at the Ohio State University Byrd Center for Polar and Climate Research. “And what we have found is that the ice discharged into the ocean far exceeds the snow that accumulates on the surface from the ice sheet “.
King and other researchers analyzed monthly satellite data from more than 200 large glaciers that drain into the ocean around Greenland. His observations show how much ice breaks into icebergs or melts from glaciers to ocean. They also show the amount of snow that falls each year, how these glaciers replenish themselves.
The researchers’ analysis found that the baseline of the ice sheet pulse, the amount of ice that is lost each year, began to increase steadily around 2000, so the glaciers were losing around 500 gigatons every year. Snowfall did not increase at the same time, and over the past decade, the rate of ice loss from glaciers has stayed about the same, meaning that the ice sheet has been losing ice faster than it is being replenished. .
Before 2000, the ice sheet would have roughly the same chance of gaining or losing mass each year. In today’s climate the ice sheet will gain mass in just one out of every 100 years. Warm ocean water melts glacier ice and also makes it difficult for glaciers to grow back to their previous positions.
The reduction of glaciers in Greenland is a problem for the entire planet. Ice that melts or breaks off the Greenland ice sheets ends up in the Atlantic Ocean and eventually all of the world’s oceans. Greenland ice is one of the main contributors to sea level riseLast year enough ice melted or broke off the Greenland ice sheet to cause the oceans to rise 2.2 millimeters in just two months.