But in the context of Earth’s 4.5 billion-strong history, melting every year or even decades is a blink of an eye.
Whether the rapid disintegration we see today in Greenland is comparable to everything that has happened in the past is a question on which science is not entirely clear.
Over the last two decades, Greenland’s ice sheet has melted at a rate of approximately 6,100 billion tons per century, approaching only during the warm period of between 7,000 and 10,000 years.
“We know there are a lot of variations from year to year, so what we were interested in was catching more significant trends for decades and maybe a century,” said Jason Briner, a professor of geology at the University of Buffalo. and the lead author of the study. “And when you do that and think about the direction Greenland is heading in this century, it̵
The big difference between now and then? The influence of human activity.
The melting observed today is mainly due to greenhouse gas emissions, while the warming that occurred thousands of years ago is the result of natural climate variability, Briner said.
How far Greenland will melt depends on us.
In a scenario in which humans continue to increase concentrations of heat-retaining gases in the atmosphere, ice loss in Greenland could reach unprecedented levels, with more than 35.9 trillion tons of ice potentially lost by the end of this century.
At the moment, Brainer says the current melting rate is being closely monitored with this worst-case scenario.
However, if the world decides to reduce emissions enough so that global warming peaks around 2050, ice losses in this century could last up to 8.8 trillion tonnes – still a huge amount, but only enough to raise sea levels by about an inch compared to the approximately 4 extra inches we can expect in a high-emission scenario.
“Humanity has the buttons and we can turn them to decide what the ice sheet will do,” he said.
What will happen to the ice sheet of Greenland and others around the world will determine the future for the millions of people living off the coast of the world.
In terms of its potential for sea level rise, Greenland is the second most important ice sheet in the world, behind only Antarctica.
“It is clear that sea levels have risen since the melting of ice 12,000 years ago and have affected people, but these people were much more widespread and they did not have garages and integrated modern water systems serving millions of people. “Said Richard Alley, a professor of geoscience at Penn State University who did not participate in the study, published by Nature.
“These results show that human decisions about our energy systems are really important in deciding what sea level rise we are facing from melting ice in Greenland.”