But the Earth’s billion. In terms of a billion billion plus years of history, melting in any one year or several decades is like the blink of an eye.
It is not entirely clear whether the rapid breakdown we are seeing on Greenland today compares to what has happened in the past.
In the last two decades, Greenland’s ice sheets have melted at a rate of about 6,100 billion tons per century, a rate that was reached during the warmer periods, just between 1,000 and 10,000 years ago.
“We know there’s a lot of diversity from year to year, so what we’re interested in doing gets more meaningful trends over the decades and maybe for a century,” said Jason Briner, a professor of geology at the University at Buffalo. And lead author of the study. “And when you do that, and think about the direction Greenland is heading this century, it’s clear that we’re in a very inconsistent time.”
The big difference between now and then? Influence of human activity.
Briner said the melting seen today is driven primarily by greenhouse gas emissions, whereas thousands of years ago temperatures were the result of changes in the natural environment.
How much Greenland melts going forward is ours.
Under the scenario of increasing the concentration of heat dissipated gases in the human atmosphere, Greenland’s ice loss could reach unprecedented levels, with more than 35,900 billion tons of ice potentially lost by the end of this century.
For now, Briner says current melting rates are closely tracking this worst case scenario.
However, if world emissions are reduced enough to cause global warming peaks around 2050, ice loss could be 8,800 billion tons this century – still a huge amount, but about an inch above sea level. Enough to increase. We can expect about 4 extra inches under the high emission scenario.
“Humanity has a knot and we can turn those gaps to determine what the ice sheet will do,” he said.
What happens to Greenland’s ice sheet and what happens to others around the world will determine the future of millions of people living along the world’s coast.
Greenland is the second most important ice sheet in the world, behind Antarctica, in terms of its potential to raise sea levels.
“Clearly, sea level rise from melting ice 12,000 years ago also affected people, but those people were more widespread, and they did not have parking garages and integrated modern water systems serving millions of people,” Richard Alley said. Professor of Geology at Penn State University who was not involved in the study published by Nature.
“These results say that human decisions about our energy system are really important in determining how much sea level rise we will face as Greenland’s ice melts.”