But little is known about how these important glaciers have changed in the past, especially in the centuries before satellite records existed. Understanding how glaciers have reacted to past changes in the weather can influence scientific predictions and how they can predict future warming.
Researchers have found that Greenland’s glaciers are very sensitive to weather conditions and have lost ice in the late 19th and early 20th centuries at rates that hit or overwhelm viewers today. . With more heat expected in this century, especially in the Arctic, scientists have warned their findings that the loss of ice on Greenland could exceed the worst estimates. .
David Holland, a professor of mathematics and environmental sciences at New York University and co-author of the study, said the team’s findings show that the Arctic is facing “one or two punches for damage to its land and sea ice.” Covers the world. “
Using historical photographs of the Jacobshaven, Halheim and Congerlusuk glaciers, the team calculated the ice loss from 1880 to 2012. He estimated that the amount of ice collected from these three glaciers had risen to 8.1 mm above sea level. Holland said that while the three glaciers are significant in themselves, they also serve as proxies for many other glacial glaciers in Greenland, giving scientists a glimpse into how the entire ice sheet behaves.
Greenland’s ice sheet is a dynamic place that is constantly changing and moving. If we think of the inside of a sheet of ice as a mountain lake, Moon says, these outer glaciers are rivers flowing out of the lake and carrying ice away from it and, in many cases, into the ocean. When ice breaks from a glacier and falls into the ocean, it raises sea levels.
“These three glaciers are one of the fastest moving in Greenland. When we think of these glaciers around the shores of Greenland acting like conveyor belts, they are the fastest, largest conveyor belts on a sheet of ice. “We were not involved in the study,” said Twilla Moon, deputy lead scientist at the National Ice and Ice Data Center in Boulder, Colorado.
Glaciers also hold enough ice to raise sea levels by about 1.3 meters.
Over time, the loss of ice is caused by natural changes in winds and ocean currents, and when hot water approaches glaciers, they melt, Holland says. But human-caused warming has changed the weather and is changing how winds and oceans affect the ice sheet, and therefore the amount of ice damage.
The team found that the ice loss rates for the Jacobshavan Glacier in the early 1900s were comparable to the massive loss rates seen today, and for the Kanjerluaswak Glacier, the ice loss between 1880 and 1930 was actually greater than it is today. .
This is important because it shows that glaciers were losing large amounts of ice when global temperatures were lower than they are now.
In the worst case scenario, as humans continue to condense these heat-releasing gases into the atmosphere, by the end of this century, the planet could have heated up to 3.7 degrees Celsius (.6..66 degrees Fahrenheit).
If glaciers have already suffered massive ice damage when atmospheric and ocean temperatures are low – and the planet is poised to warm even more under a high-emission future, scientists say their findings could mean the future. Snow loss prediction models can be used Greenland cannot predict how much will be lost by the end of the century.
It could also affect current estimates of sea level rise.
“I think when it comes to the pace of change in Greenland and with snow everywhere in the world, we’re already in a five-alarm situation,” Moon said. “And this paper is another piece of paper that says these are really serious changes, they are happening very fast and we need to act as soon as possible so that we can try to reduce the rate of change.” Let’s have a future. “
In the study, scientists said that the probability of ice loss is probably not limited to “these three glaciers,” and that it was important that the models quickly capture the grease retreat as a result of human-induced warming of our oceans and the environment. “Because they are the drivers of the massive damage.”
The team hopes that their findings on how glaciers are sensitive to climate change will help increase the reliability of future ice loss estimates.
“The Arctic is losing ice, and as you look at it in more detail in the last century, you see times of more losses and less losses, but always losses,” Holland said. “With rising warming likely to continue in the future, the potential for serious negative effects of snowfall could be expected for the world’s coastal cities.”
CNN’s Ivana Kotasova contributed to this report.
