Glaciers in the Hindu Kush Himalayan (HKH) region are projected to shrink by one-third by the end of the century even if average global temperature rise is held to within 1.5 degrees Celsius above pre-Industrial Age levels, according to the authors of a new comprehensive report, The Hindu Kush Himalaya Assessment.
Glacier melt of that magnitude has widespread implications. Nearly two billion people live within the 10 river basins that make up the HKH region, and food produced there is consumed by 3 billion people.
The report is likely the most comprehensive climate assessment of the area: It includes input from over 300 experts, researchers, and policymakers.
“This is a climate crisis you have not heard of,” Philippus Wester, a lead author of the report, told The New York Times. “Impacts on people in the region, already one of the world’s most fragile and hazard-prone mountain regions, will range from worsened air pollution to an increase in extreme weather events.”
Key Climate Findings
Factors such as climate change, globalization, human conflict, urbanization, and tourism are quickly altering the HKH region, the assessment authors say.
Warming in the HKH region is strongly attributed to anthropogenic greenhouse gases. The authors say that if average, global temperature rise is 1.5°C, the HKH region will see an additional 0.3°C temperature rise.
In other words: The region could warm as much as 1.8°C even under ambitious efforts to limit human-generated greenhouse gas emissions. And the northwestern Himalayas and Karakoram, an expansive mountain range of 207,000 square kilometers that extends from eastern Afghanistan to southern China, could experience at least a 2.2°C temperature rise.
This warming could lead to increased glacial melt, biodiversity loss, and decreased water availability, the authors say. The Tibetan Plateau, which lies south of the Himalayas, will likely face decreased snow cover as temperatures rise. Elevation-dependent warming is a major contributor to the geographic changes in this region.
Other future climate changes include increased frequency of extremely warm days and decreased frequency of extreme cold ones.
The State of the HKH Cryosphere
The Hindu Kush Himalaya cryosphere is comprised of glaciers, snow, ice caps, ice sheets, and permafrost. Future temperature changes will influence the timing and magnitude of meltwater runoff. The report’s authors find that snow-covered areas will decrease and snowline elevations will rise.
Loss of glacial volume in the region will increase runoff and the size of glacial lakes, resulting in a higher potential for Glacier Lake Outburst Floods, or GLOFs, and other hazards. Thawing permafrost is also expected to continue, resulting in the weakening of mountain slopes and peaks.
Messages to Policymakers
“Climate change impacts in the mountains of the HKH are already substantive. Increased climate variability is already affecting water availability, ecosystem services, and agricultural production, and extreme weather is causing flash floods, landslides, and debris flow,” according to the assessment’s authors.
Without immediate mitigation and adaptation policies, they conclude that the region’s glaciers—and therefore Hindu Kush Himalaya residents—face extraordinary threats.
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