The Greenland ice sheet lost 22 gigatonnes of ice in one day on July 28 as temperatures in the Northern Hemisphere caused temperatures to more than double their seasonal averages, Reuter reports. The amount of dissolved water was enough to submerge the entire state of Florida by 5 centimeters (2 inches). As the heatwave continued, the Danish Meteorological Institute reported a record high temperature of 23.4 C (74.12 ° F) at Nerlerit Inaat airport the next day.
Considering the average summer temperature in Greenland is only 10 degrees Celsius (50 degrees Fahrenheit), such extreme heat has intensified fears about the stability of Greenland ice. With only a second volume of Antarctic ice sheets, the mass of frozen water covering Greenland is now melting faster than at any time in the last 12,000 years, and researchers believe it has already exceeded its tipping point, meaning now we have nothing to save it.
A recent study found that the sea level has risen by 10.6 millimeters since 1990 as a result of the melting of Greenland’s ice. If it melts completely, the sea level could rise by about 7 meters (23 feet) in the worst-case scenario. In contrast, the Antarctic ice sheet has so far contributed only 7.2 millimeters to global sea-level rise, but it is likely to increase by 58 meters (190 feet) if it melts completely. Two years ago, Greenland’s ice sheet began to shrink to its lowest level since extreme summer temperatures began to be observed in 1981, with the largest single-day melting occur in late July 2019.
Although last week’s large melting did not release as much water as the two summer heatwaves, it affected a larger area and melted an average of 8 metric tons per day as a result of rising temperatures. In addition to the significant increase in sea level, the melting of ice sheets can cause huge amounts of mercury to be pumped into the ocean. Recent studies have shown that the water that is being released in Greenland by melting ice is surprisingly rich in toxic metals.
Scientists are unsure why Greenland has no clear source of mercury, although they suspect it may have originated from a natural geochemical process.
