Himalayan glaciers are melting at a wild pace. This is what new studies show

Analysis of nearly 15,000 layers of ice in the area shows that they are shrinking 10 times faster now than in previous centuries.

Glaciers across the Himalayas are melting at an unusual rate, with new research showing that the vast ice sheets there have shrunk 10 times faster in the last 40 years than in the previous seven centuries.

Avalanches, floods and other effects of accelerated ice loss endanger residents of India, Nepal and Bhutan and threaten to disrupt the agriculture of hundreds of millions of people across South Asia, according to the researchers. And because the water from melting glaciers contributes to sea level rise, the loss of glacial ice in the Himalayas also adds to the threat of flooding and related problems facing coastal communities around the world.

“This part of the world is changing faster than anyone might have realized,” said Jonathan Carrick, a glacier scientist at Leeds University and co-author of an article detailing the study published Monday in the journal Scientific Reports. “It’s not just that the Himalayas are changing really fast, but they’re changing faster.”

Scientists have long observed ice loss from large glaciers in New Zealand, Greenland, Patagonia and other parts of the world. But ice loss in the Himalayas is particularly rapid, the new study found. The researchers found no reason but noted that regional climate factors, such as changes in monsoon storms in South Asia, may play a role.

The new finding comes when there is scientific agreement that ice loss from glaciers and polar ice surfaces is due to rising global temperatures caused by greenhouse gas emissions from burning fossil fuels.

Many peer-reviewed scientific studies have identified human activity as a cause of rising global temperatures. So did a report released in August by the UN Intergovernmental Panel on Climate Change, which said that “human impact has probably been the main motive for the global retreat of glaciers since the 1990s.”

For the new study, Dr. Caribik and colleagues scanned satellite images of nearly 15,000 glaciers in the area for signs of large ridges of rocks and debris that glaciers leave behind as they slowly grind their way through valleys. .

Then they compared it to the current ice cover to get an estimate of how much ice has been lost since a global cooling period between 400 and 700 years ago, known as the Little Ice Age. Estimated: Between 390 and 586 cubic kilometers of ice – enough to raise the global sea level by 0.92 to 1.38 millimeters, or about twenty inches.

Summer Roper, a professor of geography at the University of Utah, called the centuries-old documentation of ice loss in the Himalayas as a result of the new study “absolutely critical.” The record will help scientists develop more accurate forecasts of glacier changes and sea level rise in the coming decades, she said. The new study stands out from previous efforts because of “the sheer number of glaciers with which they have done so,” she added.

In addition to floods, rising sea levels could cause soil erosion and jeopardize the structural integrity of roads and bridges, as well as power plants and other critical critical industrial facilities located in coastal areas. In the U.S. as of 2014, nearly 40 percent of the population lives in coastal areas that may be affected by these changes in the coming years, according to the National Oceanic and Atmospheric Administration.

“There are a lot of ‘contributors’ to sea level rise, but mountain glaciers historically and probably in the coming decades have been the most significant contributors,” Dr. Roper said.

Between 1994 and 2017, the Earth lost enough ice to cover the state of Michigan with a 100-foot-thick sheet, according to a study published in the January issue of the journal Cryosphere.

Mountain glaciers are expected to disappear completely in some areas by 2100, according to some recent studies.

By Editor

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