Himalayan Glaciers Are Retreating, Study Shows

The Himalayas are big in every way. They’re home to nine of the world’s 10 highest peaks, for instance, including Mt. Everest. They’re the source of Asia’s longest river, the Yangtze River. And they represent the third-largest deposit of ice and snow in the world, after only Antarctica and the Arctic.

After spending millions of years getting larger, however, the Himalayas are now becoming smaller, according to researchers at England’s University of Leeds. In a new study published this month in the journal Scientific Reports, they conclude that Himalayan glaciers are melting at an “exceptional” rate compared to glaciers elsewhere in the world.

The scientists used satellite imagery and digital elevation models to reconstruct the size and ice surfaces of nearly 15,000 glaciers as they would have existed during the last major glacier expansion 400 to 700 years ago, a period known as the Little Ice Age. Since then, they discovered, the glaciers have lost approximately 40% of their area, shrinking from a peak of 28,000 square kilometers to approximately 19,600 square kilometers today.

At the same time, the glaciers have lost between 390 and 586 cubic kilometers of ice, which is equivalent to all of the ice that currently exists in the central European Alps, the Caucasus, and Scandinavia. Now melted, that ice is responsible for up to 1.38 millimeters of global sea-level rise, the study concludes.

While those findings are alarming in their own right, what’s even more concerning, the study asserts, is the rate at which ice is melting, which has accelerated dramatically in modern times. Himalayan ice sheets have shrunk 10 times faster in the past four decades than during the previous seven centuries, it observes.

“Our findings clearly show that ice is now being lost from Himalayan glaciers at a rate that is at least 10 times higher than the average rate over past centuries,” study co-author Jonathan Carrivick, deputy head of the University of Leeds School of Geography, said in a news release. “This acceleration in the rate of loss has only emerged within the last few decades, and coincides with human-induced climate change.”

Owing to differences in geographical features that impact weather patterns and warming effects, Carrivick and his colleagues observed different rates of melting at different points across the Himalayan region. For example, glaciers appear to be melting fastest in the east, in areas where glaciers end in lakes, and in places where glaciers have significant amounts of natural debris on their surfaces.

While the Himalayas might sound remote to people in the West, their glaciers are hugely consequential to millions of people who live in South Asia. Because they release meltwater that forms the headwaters of several major rivers that traverse Asia—including the Brahmaputra, Ganges, and Indus rivers—their disappearance could threaten agriculture, drinking water, and energy production in countries such as Afghanistan, Pakistan, India, Nepal, China, Bhutan, Bangladesh, and Myanmar.

But the impact isn’t just regional. When one considers the aforementioned effect of melted glaciers on sea level rise and the damage that rising oceans can wreak on coastal communities everywhere, it’s global.

“We must act urgently to reduce and mitigate the impact of human-made climate change on the glaciers and meltwater-fed rivers,” Carrivick said.

Added co-author Simon Cook, senior lecturer in geography and environmental science at Scotland’s University of Dundee, “People in the region are already seeing changes that are beyond anything witnessed for centuries. This research is just the latest confirmation that those changes are accelerating and that they will have a significant impact on entire nations and regions.”