A study published this week in the journal Nature concludes that the rate of ice loss for the 21st century of Greenland’s ice sheet is likely to outpace that of any previous century since the end of the last ice-age.
The research team reconstructed in great detail the movements of the ice sheet for the last 12,000 years using data from glacier deposits and, in modern times, aerial and satellite surveys. Ice-cores provided climate data needed to correlate values like temperature and precipitation with extent of the ice sheet.
A state-of-the-art model was then used to simulate the ice-sheet movements in the last 12,000 years, and the model reproduced the limits as mapped in the field really well.
After validating the model, the researchers used it to simulate changes to the southwestern sector of the ice sheet extending forward 80 years to 2100. Though the project focused on southwestern Greenland, observations show that changes in the rates of ice loss there tend to correspond tightly with changes across the entire ice sheet.
After the end of the ice-age, some 10,000 to 7,000 years ago, the Greenland ice sheet lost an estimated 6 billion metric tons ice every 100 years. Based on melt rates observed from 2000 to 2018, the modern ice sheet could lose 8.8 billion metric tons of ice until the turn of the century. In the worst-case scenario, with global temperatures and melt rates accelerating exponentially in the near future, the loss of ice could rise to a staggering 36 billion metric tons.
“Basically, we’ve altered our planet so much that the rates of ice sheet melt this century are on pace to be greater than anything we’ve seen under natural variability over the past 12,000 years,” said study leader Jason Briner, a geologist at the University at Buffalo, New York.
A similar study published in Nature and focusing on the Antarctic ice sheet arrived at the same conclusion. If global warming accelerates, the continent could become ice-free in a geologically speaking not-so-distant future for the first time in more than 30 million years.