American scientists have found that in recent years the Greenland ice sheet was on average lose weight faster than build it, reported in the journal Nature Communications, Earth and Environment. This is due to global climate change, and scientists say that even if it stopped, the mass of ice in Greenland would have continued for some time to shrink.
The Greenland ice sheet almost completely covers the island and extends over 1.7 million square kilometers. It contains nearly three million cubic kilometers of ice: if all this ice melted, sea level would rise more than seven meters. Global climate change leads to increased melting of the Greenland ice sheet: in 2019 it lost a record in the history of measurements 600 billion tons. Since this leads to an increase in Global sea level, scientists are trying to estimate the rate of melting and increase of ice mass to better predict what will happen to humanity in the near future.
Each year, the Greenland ice sheet loses mass from the surface flow of meltwater, and then restores it at the expense of snowfall (the difference between these processes is expressed in the form of the surface mass balance of the Greenland ice sheet). Climatologist Michael D. king (Michaela D. King) from the Ohio state University, together with colleagues examined how changing the amount of ice on the edges of the ice sheet: melting it runs into the ocean and is filled with falling snow. Using satellite images and data obtained by other experiments, the authors estimated the amount of ice melted or broke off in icebergs over the past 30 years, as well as intense snowfall in those years.
It turned out that from 1985 to 1999, the accumulated snow and melted ice as a whole are in balance. During this period the ice sheet is on average lost about 450 billion tons of ice annually: this is replenished by snowfall. However, since the 2000s, the amount of ice, we lose the Greenland ice shield beginning to increase steadily, and in 2017-2018, the average annual figure reached 500 billion tons, which is 17 percent more than the average value in 1980-ies. The amount of snow in the last decade did not grow at the same rate, which means that the ice sheet is losing ice faster than it is restored.