The Himalayas are approaching a tipping point as glaciers melt faster than a decade ago, threatening water security as the region approaches “peak water” by mid-century, according to a study released this month.

The findings come after the collapse of a Himalayan glacier in late August along the Nepal-Tibet border, which caused cascading landslides and flash floods in the valleys below. At least 1,300 people have been confirmed dead and more than 5,300 are missing across Nepal and China’s ⁠Tibet region.

As glaciers retreat, they are leaving behind unstable glacial lakes held back by little more than loose rock and ice, above valleys where millions of people live, the study found.

The study was produced by Systemiq, a sustainability advisory firm, together with the Integrated Mountain Initiative, the International Centre for Integrated Mountain Development, and India’s G.B. Pant National Institute of Himalayan Environment.

Himalayan glacier mass loss had accelerated in recent decades, while only 21 glaciers were currently monitored ⁠on the ground out of an estimated 40,000 glaciers across the Hindu Kush-Himalaya region, a vast mountain system spanning eight countries from Afghanistan to Myanmar, the study found.

Close to 200 glacial lakes in India had been identified as high risk, with ⁠56 classified as “very high risk”, leaving millions exposed downstream.

As the region neared “peak water”, the point when river flows stop rising and start declining, it would have profound implications ⁠for water security. As the Himalayas underpinned more than 20% of India’s GDP, the region made up a key piece of the country’s national ⁠economic infrastructure, upon which hundreds of millions of people depended.

Though making up around 18% of India’s land, the Himalayan region accounted for roughly 35% of the country’s natural disasters.