A Third of Himalayan Glaciers Doomed to Melt Away

The International Centre for Integrated Mountain Development (ICIMOD), Nepal, released a report entitled ‘The Hindu Kush Himalaya Assessment:

Mountains, Climate Change, Sustainability and People’ in February 2019. Five years in the making, the study involved more than 350 researchers and policy experts, 185 organisations, 210 authors, 20 review editors and 125 external reviewers.

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 in eight countries: India, Pakistan, China, Afghanistan, Nepal, Bhutan, Bangladesh, and Myanmar.

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

The HKH region is the planet’s ‘third pole’, harbouring more ice than anywhere outside the Arctic and Antarctica. The Himalayan glaciers, which formed some 70 million years ago, are highly sensitive to changing temperatures. Since the 1970s, they have thinned and retreated, and the area covered by snow and snowfall has sharply decreased.

The HKH range is 3500 km long and the impact of warming is variable. Some glaciers in Afghanistan and Pakistan are stable and a few are even gaining ice, most probably due to increased cloud cover that shields the sun and changed winds that bring more snow. But even these will start melting with future warming.

Key messages of the report:

·      Two-thirds of Himalayan glaciers could melt by 2100 if global emissions are not sharply reduced.

·      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. If the global rise is 2 degrees, half of the glaciers are projected to melt away by 2100.

·      Air pollution from the Indo-Gangetic Plains—one of the world's most polluted regions—also deposits black carbon and dust on the glaciers, hastening melting and changing monsoon circulation.

·      1.5 degrees C increase in global temperatures would mean a rise of at least 2.1 degrees C in the Himalayas region. If emissions continue unabated, the roof of the world would warm by an unlivable 5 degrees C.

·      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 melting glaciers will increase river flows through to 2050 to 2060 pushing up the risk of high-altitude lakes bursting their banks and engulfing communities. Satellite data shows that numbers of such lakes in the region grew to 4,260 in a decade from 3,350 in 1990.

·      From the 2060s, river flows will go into decline. The Indus and central Asian rivers will be most affected. Without the ice reserve in the mountains to top up the rivers through the melt season, droughts will be harsher on those living downstream.

·      Lower flows will cut the power from the hydrodams that generate much of the region’s electricity.

·      The most serious impact will be on farmers in the foothills and downstream. They rely on predictable water supplies to grow the crops that feed the nations in the mountains’ shadows. But the changes to spring melting already appear to be causing the pre-monsoon river flow to fall just when farmers are planting their crops. Worse, the monsoon is also becoming more erratic and prone to extreme downpours. One-in-100 year floods are starting to happen every 50 years.

·      Political tensions between neighbouring nations such as India and Pakistan could add to the difficulties. Because many of the disasters and sudden changes will play out across country borders, conflict among the region’s countries could easily flare up,

·      The region would require up to US$4.6 billion per year by 2030 to adapt to climate change, rising to as much as US$7.8 billion per year by 2050.