It is an astronomical number: 28 billion tons. This is the global value of ice that was lost on Earth in less than three decades, according to a study by British scientists at the universities of Leeds, Edinburgh and University College London.
Published in the scientific journal The Cryosphere, on August 14, research shows that the majority of this meltdown (7.6 billion tonnes) occurred on the icy cover of the Arctic Ocean, and on the icy platforms of Antarctica (6.5 billion tonnes), followed by glaciers (6 , 2 billion tonnes), Greenland (3.8 billion), in the coverage of Antarctica (2.5 billion) and in the Southern Ocean, with 0.9 billion tonnes of lost ice.
“It is the equivalent of a layer of ice 100 meters thick that covers the entire territory of the United Kingdom, crazy,” compared one of the study’s authors, Tom Slater, from the University of Leeds, quoted in the The Guardian.
Most of these losses, in the amount of 60%, occurred in the northern hemisphere, while the rest (40%) were lost in the southern hemisphere, write the authors, who have no doubt that the phenomenon is due to the increase in the temperature of the planet , which in turn is due the accumulation of greenhouse gases in the atmosphere, as a result of human activities. That is, climate change.
To arrive at these results, which guarantee to be the first global assessment of melting on the planet, in recent decades, the researchers used satellite observation data collected between 1994 and 2017 and worked with numerical models. The news is not good.
In addition to contributing to rising sea levels, this melt also reinforces the increase in the temperature of the planet, since the loss of icy surfaces decreases the capacity of the terrestrial system to reflect solar radiation.
Instead, what happens is that the ocean absorbs that unreflected heat, which in turn contributes to its expansion, in what is yet another contribution to the rise in sea level.
This is what has been happening. As all studies show, so far, sea levels have been rising since the industrial era began more than 150 years ago. It is now more than 20 centimeters above what it was in 1880.
But that’s not all: the rate at which this is happening it has also become faster since the 90s of the 20th century, increasing from two to three millimeters per year.
NASA data from 2015 shows that, since 1993 alone, there has been a global rise in sea level of 7.62 cm, with some regions of the Atlantic, Indian, Pacific and Southern Sea registering even higher values, in the order of 22.8 cm, while only a few areas, few in the United States, showed an opposite trend.
The calculations of the authors of the study now published point out that the trend of the ongoing thaw could lead to an increase in sea level of about one meter at the end of the century, an estimate that is in line with identical values found by other studies.
The impact of rising sea levels on human societies is immense and it is already visible in some regions, such as some islands and coastal areas of the Pacific.
“For every centimeter of sea level rise, around one million people living in coastal regions at sea level are displaced,” he concludes, quoted in the The Guardian, Andy Shepherd, who runs the Polar Modeling and Observation Center at the University of Leeds and one of the study’s authors,
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