Melting of the Greenland ice sheet will eventually cause global sea levels to rise even if humans immediately stop burning fossil fuels that are warming the planet to dangerous levels, according to a new study released Monday. It has the potential to raise at least 10 inches.
the study, Published in Nature Climate Change, which focuses on what researchers call “committed” sea-level rise. This is a measure that takes into account the warming that has already occurred.
This approach differs from most previous studies, which are based on computer modeling and predict much less ice loss from the Greenland ice sheet in general. For example, the latest assessment of the United Nations Intergovernmental Panel on Climate Change predicts that by 2100 sea levels will rise 2 to 5 inches.
Jason Box, a glaciologist at the Geological Survey of Denmark and Greenland, said the 10-inch increase forecast may not indicate a timeline if temperatures continue to rise. The lead author of the paper said it could almost certainly go up.
Dr. Box said the computer modeling commonly used by glaciologists to date “doesn’t work” to represent how quickly the ice sheets are melting. In his team’s research, instead, he examined satellite measurements made between 2000 and 2019.
In the new study, researchers looked at what is known as the climatic snow line, the boundary between snow-covered and snow-free surfaces on the ice sheet.
This line fluctuates each year as temperatures cool or warm, and when one area is larger than the other, the ice sheet moves away from ‘equilibrium’. In years of heavy snowmelt, the snowline is pushed further up the ice sheet. This means that the area covered by snow will be smaller, resulting in a smaller ice sheet.
Sophie Nowicki, an ice sheet expert at the University of Buffalo’s Department of Geology who was not involved in the study, said the main problem with the new study is that the projections are not timed. Will we have that number by her year 2100?”Or thousands of years from now?” she wrote in an email.
A good analogy for this study is the typical growth and weight chart you see when you take your child to the doctor for a checkup. However, they are not good at predicting growth spurts or the exact timing of growth.
The approach is more “based on what has already happened” than past ice sheet modeling and goes beyond what has been done before, said John Walsh, chief scientist at the University of Alaska Fairbanks. says. He was not involved in this research. .
This conclusion shows that even the most conservative estimates of melting ice can have dangerous effects on humans, Dr. Walsh said. On average he’s 10 inches might not seem like much, but sea levels don’t rise the same everywhere. Some areas, especially low-lying coastal areas, could experience disproportionately devastating flooding.