According to data collected between April 2002 and August 2021 by the Gravity Recovery and Climate Experiment (GRACE) satellites, the Greenland Ice Sheet has lost 4,700 gigatons of ice over the last two decades – a quantity which would be large enough to submerge the entire United States under 1.5 feet of water. This massive ice loss has contributed to a global sea level rise of 0.47 inches (1.2 centimeters).
“Data shows that most of the loss of ice occurs along the edge of the ice sheet, where independent observations also indicate that the ice is thinning, that the glacier fronts are retreating in fjords and on land, and that there is a greater degree of melting from the surface of the ice,” wrote the authors of the most recent report regarding the status of the Greenland Ice Sheet.
Ice loss appears to be particularly severe along the West Greenland coast, where the increasing warming of subsurface waters is accelerating glacier melt.
“High on the central region of the ice sheet, however, the GRACE satellites show that there is a small increase in the mass of the ice. Other measurements suggest that this is due to a small increase in precipitation/snowfall,” said the researchers.
Overall, the data show that during the period between 2002 and 2011, the Greenland Ice Sheet has lost an average of 234 km3 of water per year. If the entire ice sheet would vanish, it would release enough water to increase global sea levels by 24 feet, or 7.4 meters.
According to an earlier study published in 2019 in the journal Nature, at the current rate of global warming, Greenland’s ice loss will likely cause the sea levels to rise between three to five inches (7-13 centimeters) by the end of the 21st century. This rise will negatively impact hundreds of millions of people all over the globe.
“As a rule of thumb, for every centimeter rise in global sea level, another six million people are exposed to coastal flooding around the planet,” said the 2019 study lead author Andrew Shepherd, a climate scientist at the University of Leeds.
“On current trends, Greenland ice melting will cause 100 million people to be flooded each year by the end of the century, so 400 million in total,” he warned. Urgent measures are needed to mitigate climate change and protect human societies and ecosystems.