Greenland's melting ice sheet has passed the point of no return, scientists say – USA TODAY


Greenland and Antarctic ice sheets are melting at a rate of 283 and 145 gigatonnes per year, respectively. But what does one gigatonne actually look like? Buzz60

Greenland’s melting ice sheet has passed the point of no return. 

In fact, glaciers on the island have shrunk so much that even if global warming were to stop today, the ice sheet would continue shrinking, a new study suggests.

“Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss,” study co-author Ian Howat, an earth scientist from Ohio State University, said in a statement. “Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass.”

This “tipping point” means the snowfall that replenishes the ice sheet each year cannot keep up with the ice that is flowing into the ocean from melting glaciers.

“The ice that’s discharging into the ocean is far surpassing the snow that’s accumulating on the surface of the ice sheet,” said study lead author Michalea King, a researcher at Ohio State University.

Overall, according to NOAA, ice loss from the Greenland ice sheet increased sevenfold from 34 billion tons a year from 1992 to 2001 to 247 billion tons a year from 2012 to 2016.

For the study, scientists analyzed 40 years of satellite data from more than 200 large glaciers draining into the ocean around Greenland. 

Greenland’s shrinking glaciers are a problem for the entire Earth. Melting ice from the island is a leading contributor to sea-level rise worldwide: The ice that melts or breaks off from Greenland’s ice sheets ends up in the Atlantic Ocean – and, eventually, all of the world’s oceans.

Greenland’s ice sheet now dumps more than 280 billion metric tons of melting ice into the ocean each year, making it the greatest single contributor to global sea level rise, King told CNN

By the end of the century, global sea level is likely to rise at least one foot above 2000 levels, even if greenhouse gas emissions follow a relatively low pathway in coming decades, the National Oceanic and Atmospheric Administration said. How much it will rise depends mostly on the rate of future carbon dioxide emissions and global warming.

The Greenland study was published recently in the peer-reviewed British journal  Communications Earth and Environment. 

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