Melting Himalayan glaciers could leave 2 billion people facing water scarcity

New study finds that glaciers in the region disappeared 65 per cent faster in the decade from 2011 to 2020

Water forms under Nepal's Khumbu glacier as the ice melts. Reuters

Himalayan glaciers providing critical water to nearly two billion people are melting faster than ever before due to climate change, exposing communities to unpredictable and costly disasters, scientists warned on Tuesday.

The glaciers disappeared 65 per cent faster from 2011 to 2020 compared with the previous decade, according to a report by the International Centre for Integrated Mountain Development (Icimod).

“As it gets warmer, ice will melt, that was expected, but what is unexpected and very worrying is the speed,” said lead author Philippus Wester. “This is going much faster than we thought.”

Glaciers in the Hindu Kush Himalaya region are a crucial water source for about 240 million people in the mountainous regions, as well as another 1.65 billion people in the river valleys below, the report said.

Based on current emissions trajectories, the glaciers could lose up to 80 per cent of their current volume by the end of the century, said the Nepal-based centre, an inter-governmental organisation that also includes Afghanistan, Bangladesh, Bhutan, China, India, Myanmar and Pakistan.

The glaciers feed 10 of the world's most important river systems, including the Ganges, Indus, Yellow, Mekong and Irrawaddy, and directly or indirectly supply billions of people with food, energy, clean air and income.

“With two billion people in Asia reliant on the water that glaciers and snow here hold, the consequences of losing this cryosphere [frozen zone] are too vast to contemplate,” said Icimod's deputy chief Izabella Koziell.

Even if global warming is limited to the 1.5°C to 2.0°C above pre-industrial levels agreed to in the Paris climate treaty, the glaciers are expected to lose a third to a half of their volume by 2100, the peer-reviewed report said.

“It underscores the need for urgent climate action,” Mr Wester said. “Every small increment will have huge impacts and we really, really need to work on climate mitigation … that is our plea.”

He said improving technologies and previously classified high-resolution satellite imagery meant predictions could be made with a good degree of accuracy.

The world has warmed an average of nearly 1.2ºC since the mid-1800s, unleashing a cascade of extreme weather, including more intense heatwaves, more severe droughts and storms made more ferocious by rising seas.

Hardest hit are the most vulnerable people and the world's poorest countries, which have done little to contribute to the fossil fuel emissions that drive up temperatures.

Amina Maharjan, a livelihoods and migration specialist at the centre, said communities do not have the support they need.

“Most of the adaptation is communities and households reacting” to climate events, she said. “It is inadequate to meet the challenges posed by climate change.

“What is going to be very critical moving forward is anticipating change.”