Two-thirds of Himalayan glaciers, the world’s ‘Third Pole’, could melt by 2100 if global emissions are not reduced, scientists warned in a major new study released on February 4. And even if the “most ambitious” Paris Agreement goal of limiting global warming to 1.5 degrees Celsius is achieved, one-third of the glaciers would go, according to the Hindu Kush Himalaya Assessment.

Glaciers in the Hindu Kush Himalaya (HKH) region are a critical water source for some 250 million people in the mountains as well as to 1.65 billion others in the river valleys below, the report said. The region stretches 3,500 km across Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal 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.

Impacts on people from their melting will range from worsened air pollution to more extreme weather, while lower pre-monsoon river flows will throw urban water systems and food and energy production off-kilter, the study warned. As the glaciers shrink, hundreds of risky glacial lakes that could burst and unleash floods have formed in the foothills of the mountains, which include giants such as Everest and K2.

The report was published by Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD) in Nepal, one of eight countries on the frontline. Five years in the making, it involved more than 350 researchers and policy experts, 185 organisations, 210 authors, 20 review editors and 125 external reviewers.

A critically important geo-ecological asset, the HKH is the origin of 10 major river basins and encompasses over 4.2 million sq km area. This HKH area and Tien Shan mountains together form the largest area of permanent ice cover outside of the North and South Poles, hence the occasional reference to the HKH as the ‘Third Pole’. It is home to four global biodiversity hotspots, 330 important bird areas and hundreds of mountain peaks over 6,000 m.

“This is the climate crisis you haven’t heard of. Global warming is on track to transform the frigid, glacier-covered mountain peaks... cutting across eight countries to bare rocks in a little less than a century,” Philippus Wester of ICIMOD, who led the report, said in a statement.

The region would require up to $4.6 billion per year by 2030 to adapt to climate change, rising to as much as $7.8 billion per year by 2050, according to an estimate in the report.

Glaciers have thinned and retreated across most parts of the region since the 1970s. Ice in the HKH region would push up sea levels by 1.5 m if it all melted, said ICIMOD deputy director general Eklabya Sharma.