But in the context of Earth’s more than 4.5 billion-year history, melting in any one year or even a blink of an eye in a few decades.
Does the rapid disintegration we see on Greenland today compare to anything that has happened in the past, a question on which science is not entirely clear.
Over the past two decades, Greenland’s ice sheet has melted at a rate of about 6,100 billion tons per century, during a warm period that occurred only 7,000 and 10,000 years ago.
“We know there is a lot of variability from year to year, so what we were interested in doing is capturing meaningful trends over decades and perhaps for a century,” said Jason Bryner, professor of geology at the University of Buffalo . And lead author of the study. “And when you do that, and think about the direction that Greenland is heading towards this century, it is clear that we are in quite an odd time.”
Big difference between now and then? Effect of human activity.
The melting observed today is mainly driven by greenhouse gas emissions, while the warming that occurred thousands of years ago was a result of natural climate variability.
How far Greenland is going is up to us.
Under a scenario where heat-trap gases in the human atmosphere increase concentrations, Greenland’s ice loss could reach unprecedented levels, potentially destroying more than 35,900 billion tons of ice by the end of this century.
At the moment, Briner states that current melt rates closely track this worst-case scenario.
However, if the world resolves to reduce emissions significantly, so that global warming hovers around 2050, ice loss could be up to 8,800 billion tons in this century – still a huge amount, but the sea level is almost reduced Approximately 4 extra inches sufficient compared to raising an inch we might expect under a high emission scenario.
He said, “Humanity has knobs, and we can change those knobs to decide what the ice sheet is going to do.”
What happens to Greenland’s ice sheet and others around the world will determine what the future holds for millions of people in the world.
In terms of its ability to raise sea level, Greenland is the world’s second most important ice sheet behind only Antarctica.
“Clearly, sea levels were also affected by melting ice 12,000 years ago, but those people were much more widely dispersed, and did not have parking garages and integrated modern water systems serving millions of people , “Said Richard Elle,. A professor of geoscience at Penn State University who was not involved with the study published by Nature.
“These results say that human decisions about our energy systems are really important in determining how much sea level rises as we melt Greenland’s ice.”