The loss of 28 trillion tons of ice over the past 23 years is reflected in the situation of the Greenland ice cap, the second largest freshwater reserve on Earth: there is no way to stop its melting. These and other data are contained in two studies that point to the effects of global warming on the planet’s cryosphere.
Using satellite data on glaciers, glaciers and ice mountains, researchers at Leeds and Edinburgh universities and Imperial College London were able to define how much ice the Earth lost between 1994 and 2017.
“If nothing changes, the sea level is expected to rise between 60 centimeters and 1 meter by the end of this century, which corresponds to the worst scenario predicted by the United Nations Intergovernmental Panel on Climate Change (IPCC). Every inch of sea level rise means the displacement of 1 million people, “explained Andy Shepherd, glaciologist and director of the Center for Modeling and Polar Observation at the University of Leeds.
Less ice than counted
According to him, “what we found surprised us. There can be no doubt that the loss of ice on Earth is a direct consequence of the warming of the planet”.
The research, published in the journal Cryosphere, used data from other works, including that of an international team of researchers led by Swiss glaciologist Matthias Huss, in 2019, which determined the thickness of the ice and the progress of the melting of all glaciers in the world (about 215 thousand), except Antarctica and Greenland.
The study found that they hold 158 billion tonnes of ice, but much of it could disappear faster than anticipated. In the so-called Upper Asia, a region that includes the Tibetan plateau and the mountains of Central Asia, there is 27% less ice than previously thought. The conclusions of the survey are consistent with those of the IPCC: it will be in 2060, not a decade later, that the ice cover in the region will reach half of what it is now, which will reduce the water supply of 600 million by up to 24% to 1 billion people by 2090.
Point of no return
The planet’s massive loss of ice cover is not the only bad news: Greenland’s ice sheet may no longer recover. “The ice that is breaking and falling into the ocean has far exceeded the snow that accumulates on the surface of the ice sheet,” said geologist and planetary scientist Michalea King at Ohio State University’s Byrd Polar and Climate Research Center, lead author of the study published in Communications Earth and Environment.
Forty years of data collected by satellites showed that even if temperatures today dropped Greenland’s ice loss would not cease. Between 1980 and 2000, the annual loss of 450 billion tons of ice was compensated by the fall of an equal amount of snow, keeping the Greenland mantle intact. Thereafter, the melt rose to 500 billion tons of ice annually, not accompanied by the accumulation of snow.
If the level of the oceans rose 15 centimeters in the 20th century, in this one the speed has increased: 3.6 millimeters every year, and the pace is accelerating. In 2019, Greenland’s melted ice was responsible for making the oceans rise 2.2 millimeters in just 2 months.