PARIS: Asia’s mountain glaciers will lose at least a third of their mass through global warming by century’s end, with dire consequences for millions of people who rely on them for fresh water, researchers said on Wednesday.

This is a best-case scenario, based on the assumption that the world manages to limit average global warming to 1.5 degrees Celsius over pre-industrial levels, a team wrote in the journal Nature.

“To meet the 1.5°C target will be a task of unprecedented difficulty,” the researchers said, “and even then, 36 per cent [give or take seven per cent] of the ice mass in the high mountains of Asia is projected to be lost” by 2100.

With warming of 3.5°C, 4°C and 6°C respectively, Asian glacier losses could amount to 49 per cent, 51 per cent or 65 per cent by the end of the century, according to the team’s modelling study.

Nearly 200 nations adopted the Paris Agreement in 2015, which sets the goal of limiting warming to a level “well below” 2°C, while “pursuing efforts” to achieve a lower ceiling of 1.5°C. Earth’s surface has already warmed by about 1°C, according to scientists.

For high warming scenarios, experts predict land-gobbling sea-level rise, worsening storms, more frequent droughts and floods, species loss, and disease spread.

The Asian high mountains, the new study said, were already warming more rapidly than the global average.

A global temperature rise of 1.5°C would mean an average increase in the region of about 2.1°C, with differences between mountain ranges — all of which will warm by more than 1.5°C.

The Hindu Kush mountain range would warm by about 2.3°C and the eastern Himalayas by some 1.9°C, the study forecast. “Even if temperatures stabilise at their current level, [glacier] mass loss will continue for decades to come,” the researchers added. For the high mountain glaciers to survive, “it is essential to minimise the global temperature increase.”

Swathes of South Asia and China depend on meltwater from Himalayan glaciers for drinking water, electricity generation and irrigation. At the same time, the regions are also vulnerable to more intense flooding from accelerated glacier melt, combined with heavier rains and superstorms boosted by global warming.

Published in Dawn, September 14th, 2017