Greenland’s glaciers may lose more ice than before, raising concern for sea level rise


But experts have little knowledge of how these important glaciers have changed in the past, especially in the centuries before satellite records took place. Understanding how glaciers respond to past changes in climate may affect estimates of how scientists might react to future warming.

Researchers found that Greenland’s glaciers are very sensitive to climatic conditions, and lost ice in the late 19th and early 20th centuries that are seen or surpassed today. With the planet – and the Arctic in particular – expected to be much warmer this century, scientists have warned their findings that ice loss over Greenland may be more than the worst.

David Holland, professor of mathematics and environmental science at New York University and co-author of the study, said the team’s findings show that the Arctic is “going through a one-two punch in relation to the loss of its land and sea ice. A warmer Is included in the world. “

Using historical photographs of the Jakobshaven, Helheim and Kangerrelsuk glaciers, the team calculated snow losses from 1880 to 2012. He estimated that the amount of ice lost from these three glaciers alone had increased by 8.1 millimeters at sea. Holland said that while the three glaciers are significant in themselves, they also serve as predictors for the majority of other outlet glaciers in Greenland, allowing scientists to see how the entire ice sheet behaves.

Greenland's ice sheet has been melting faster than at any time in the past 12,000 years, the study shows

Greenland’s ice sheet is a dynamic place that is constantly moving and moving. If we think of the interior as the lake of a mountain of ice sheets, the moons say, these outlets are streams extending from the glacier lake from which the ice is carried away and, in many cases, into the ocean. When ice breaks from the glacier and lands in the sea, it raises the sea level.

“All three of these glaciers are the fastest moving in Greenland. When we think of these glaciers around Greenland, such as the conveyor belt (sea-moving ice), these are the fastest, fastest on the ice sheet. Some of the larger conveyor belts are. “, Twila Moon, deputy chief scientist at the National Snow and Ice Data Center in Boulder, Colorado, was not involved in the study.

The glaciers also have enough ice to raise the global sea level by about 1.3 meters.

The loss of ice over time is driven by natural changes in winds and ocean currents, and when the glaciers get hot water, they melt, Holland says. But human-caused warming has changed the climate and is changing how the wind and ocean align with the ice sheet, and therefore affect the amount of ice loss.

The team found that the rate of snow loss for the Jacobsen glacier in the early 1900s was comparable to the large rates of damage seen today, and for the Kangerlasuac glacier, the ice loss between 1880 and 1930 was actually comparable to the present day I was less.

This is important because it shows that glaciers were losing large amounts of ice at a time when global temperatures were now lower.

In a worst-case scenario, under which humans continue to increase concentrations of these heat-trapping gases in the atmosphere, by the end of this century the planet may have warmed up to 3.7 degrees Celsius (6.66 degrees Fahrenheit).

If glaciers have already suffered major ice losses when atmospheric and oceanic temperatures are low – and the planet is poised to heat up even more under a high-emission future – scientists say their findings mean Maybe Greenland, the model used to estimate future snow losses, may have underestimated how much damage will occur by the end of the century.

Talk about climate apocalypse

It may also affect current estimates of sea level rise.

Rising seas are already causing problems in many low-lying coastal areas. And for places like New York and Shanghai, a rise of 1 meter or more above sea level can cause disaster. Another recent study found that rising seas cost the global economy $ 14.2 trillion in lost or damaged wealth by the end of the century, and today exposed 287 million people to episodic floods as over 171 million. can go.

“I think when it comes to the pace of change in Greenland and really snow everywhere in the world, we’re already in a five-alarm state,” Moon said. “And this paper is another paper in that monstrous heap that says these are really serious changes, they are happening very quickly and we need to take action as soon as possible so that we are trying to reduce the rate of change Future. “

In the study, scientists said that it is possible to underestimate the loss of ice “not limited to just these three glaciers,” and that it was important that the models rapidly retreat glacial as a result of human-induced warming of our oceans and atmospheres . “Because they are the primary drivers of mass loss.”

The team hopes the glaciers are sensitive to climate change and will help increase the reliability of future estimates of ice loss.

“Arctic ice is losing, and as you look at more detail in the last century, you see periods of more damage and less damage, but there is always damage,” Holland said. “With increasing warming to continue into the future, increased ice loss can be expected with potentially serious negative consequences for coastal cities around the world.”

Ivana Kotasova of CNN contributed to this report.

.

Leave a Reply