Glaciers across the Himalayas are melting at an extraordinary rate, with new research showing that the vast ice sheets there shrank 10 times faster in the past 40 years than during the previous seven centuries.

Avalanches, flooding and other effects of the accelerating loss of ice imperil residents in India, Nepal and Bhutan and threaten to disrupt agriculture for hundreds of millions of people across South Asia, according to the researchers. And since water from melting glaciers contributes to sea-level rise, glacial ice...

Glaciers across the Himalayas are melting at an extraordinary rate, with new research showing that the vast ice sheets there shrank 10 times faster in the past 40 years than during the previous seven centuries.

Avalanches, flooding and other effects of the accelerating loss of ice imperil residents in India, Nepal and Bhutan and threaten to disrupt agriculture for hundreds of millions of people across South Asia, according to the researchers. And since water from melting glaciers contributes to sea-level rise, glacial ice loss in the Himalayas also adds to the threat of inundation and related problems faced by coastal communities around the world.

“This part of the world is changing faster than perhaps anybody realized,” said Jonathan Carrivick, a University of Leeds glaciologist and the co-author of a paper detailing the research published Monday in the journal Scientific Reports. “It’s not just that the Himalayas are changing really fast, it’s that they’re changing ever 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 especially rapid, the new study found. The researchers didn’t pinpoint a reason but noted that regional climate factors, such as shifts in the South Asian monsoon, may play a role.

The new finding comes as there is scientific consensus that ice loss from glaciers and polar ice sheets results from rising global temperatures caused by greenhouse-gas emissions from the burning of fossil fuels.

Seen in the distance, the Khumbu Glacier in the Himalayas, where ice loss is especially rapid, a new study found.

Photo: Duncan Quincey/University of Leeds

Many peer-reviewed scientific studies have identified human activity as a cause of rising global temperatures. So did a report issued in August by the United Nations Intergovernmental Panel on Climate Change, which said “human influence is very likely the main driver of the global retreat of glaciers since the 1990s.”

For the new study, Dr. Carrivick and his colleagues scanned satellite photos of almost 15,000 glaciers in the region for signs of the large ridges of rock and debris that glaciers leave behind as they slowly grind their way through the valleys. Using the locations of these ancient glacial tracks, the scientists estimated the span of ice sheet coverage in previous centuries.

Then they compared that to the present ice cover to arrive at an estimate of how much ice had been lost since a period of global cooling between 400 and 700 years ago, known as the Little Ice Age. The estimate: between 390 and 586 cubic kilometers of ice—enough to raise global sea levels 0.92 to 1.38 millimeters, or about one-twentieth of an inch.

Summer Rupper, a professor of geography at the University of Utah, called the centurieslong record of Himalayan ice loss resulting from the new research “absolutely critical.” The record will help scientists develop more accurate forecasts of glacial change and sea level rise in coming decades, she said. The new study stands out from previous efforts because of “the sheer number of glaciers that they did this with,” she added.

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

“There’s lots of different parts to sea level rise, but mountain glaciers historically and probably in the coming decades have been the most significant contributors,” Dr. Rupper said.

The impacts of ice loss in the Himalayan region could be especially stark.

Meltwater from the glaciers in the region feeds major rivers that support India’s vast northern agricultural belt. As the glaciers continue to shrink, the availability of water for irrigation and drinking water could drop steeply, according to the researchers. And avalanches could become common, as ice loss renders slopes more unstable.

“The implication of our findings is that if the mass loss is accelerating, then it only heightens the importance of being able to mitigate this on the ground,” Dr. Carrivick said.

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

Mountain glaciers are expected to vanish completely in some regions by 2100, according to some recent studies.

Are certain storms, fires or droughts connected to climate change? Thanks to a relatively new field called attribution science, climate experts are now more able to provide answers. WSJ’s Daniela Hernandez explains. Illustration: Adele Morgan The Wall Street Journal Interactive Edition

SHARE YOUR THOUGHTS

What steps should be taken to slow the melting of the Himalayan glaciers? Join the conversation below.

Write to Nidhi Subbaraman at Nidhi.Subbaraman@wsj.com