By Salam Rajesh
The recent Nepal mountain tragedy highlights a growing challenge for the Himalayas with this stark message: mountain hazards are becoming increasingly complex, with little or no warning.
Simon Stiell, Executive Secretary, UN Climate Change, noting on the colossal tragedy observed that the catastrophic glacial collapse in the Himalayan region is a devastating reminder of how fragile the Hindu Kush Himalayas (HKH) environments can be, adding that for years, scientists and local communities have been warning that the Hindu Kush Himalayas are at huge risk from climate change.
Global climate models predict that the HKH region would warm faster than the global average, with temperature increases ranging from 2 degrees Celsius to 5 degrees Celsius by 2100, depending on emission scenarios, according to latest projections.
This warming is predicted to speed up glacier mass loss, drastically affecting glacial systems and their downstream implications. Under high-emission scenarios (RCP 8.5), studies predict that the Himalayan glaciers may lose more than 60 percent of their current ice volume by 2100. This retreat is said to be influenced by regional changes in climatic drivers like as temperature, precipitation, and aerosol deposition.
As glaciers retreat, a period of greater meltwater availability, known as “peak water”, will offer temporary increases in river flow. However, as glacier volume depletes, runoff declines, resulting in water scarcity in glacier-fed rivers, warns Kathmandu-based ICIMOD.
The inter-governmental body ICIMOD (International Centre for Integrated Mountain Development) warns that the Rasuwa event shows that it is not simply about better early warning systems in the Himalayas but also about preparedness. Warning systems can save lives where sufficient lead time exists, but they cannot prevent infrastructure from being damaged by a sudden avalanche or debris flow, the organization noted.
Climatologist Dr Farooq Azam notes that the immediate priorities include stronger land-use planning, resilient infrastructure and greater community awareness of high-altitude hazards.
“We need to reconsider how infrastructure is planned in the Himalayas. There is a need to assess how changing environmental and mountain conditions could affect that infrastructure over its lifetime and, lastly, the community awareness of such hazards”, says Dr Farooq.
According to ICIMOD’s report, ‘HKH Glacier Outlook 2026: Insights from 50 Years of Himalayan Glacier Monitoring’, glaciers in the Hindu Kush Himalaya are rapidly shrinking due to climate change, with mass loss accelerating significantly since 2000. Over 50 years of observations show that about 89% of recorded years had negative glacier mass balance, indicating consistent decline.
This glacier loss is affecting water availability, increasing glacial lake outburst flood (GLOF) risks, and threatening the livelihoods of nearly two billion people dependent on these water systems across India, Nepal, Bhutan, Bangladesh, Pakistan, Afghanistan, China and Myanmar.
The Himalayan region, geologically the youngest and extremely fragile, has experienced significant warming in the 21st century, with rates ranging from 0.15 degrees Celsius to 0.60 degrees Celsius per decade, far exceeding the global average of 0.74 degrees Celsius per century, according to ICIMOD’s readings.
Meantime, a Climate Trends study on the Indian side of the Himalayas says the rising Black Carbon concentration on the Himalayas is a serious concern that requires immediate attention.
Its recent study, ‘Impact of Black Carbon on Himalayan Glaciers: A 23-Year Trends Analysis’, noted that black carbon is critically influencing the Himalayan cryosphere, particularly in increasing snow surface temperatures and reducing snow depth.
Black carbon concentrations have risen notably in the Eastern and Central Himalayas, primarily due to emissions from biomass burning and fossil fuel use in the Indo-Gangetic Plain, the study indicated.
The study further noted that snow surface temperature in the Himalayas has shown a consistent warming trend over the past two decades, which may have serious implications for snow and glacier stability.
Average snow surface temperature has increased from -11.27°C during 2000–2009 to -7.13°C during 2020–2023, with an overall mean of -8.57°C for the 23-year period. This warming is likely driven in part by the deposition of light-absorbing particles like Black Carbon. Thus, temperature increases, in conjunction with black carbon presence, are significantly altering the snow thermal regime in the Himalayas, the Climate Trends study elaborated.
Another study, ‘Decoding the Fate of Himalayan Glaciers under Climate Change: Impacts, Challenges, Research Gaps, and Policy Pathways’, warns that the loss of snow cover and degradation of permafrost are key markers of climate change in the Himalayan region, with far-reaching consequences for hydrology, ecology, and infrastructure.
The study noted that snow cover, which acts as temporary storage of water, is fast decreasing in both extent and duration in the HKH region. The decreasing seasonal snowpack has resulted in dramatic changes to the timing and amount of river flow, affecting usual water supply patterns for agriculture and downstream settlements.
Early snowmelt has pushed peak runoff to earlier months, exacerbating water shortages in the late summer and autumn, when demand is strongest. Permafrost, the permanently frozen ground found at high altitudes, is rapidly deteriorating owing to rising temperatures. This thawing is exposing formerly stable landscapes to increased erosion, landslides, and slope instability, endangering Himalayan infrastructure such as railways, roads, and power plants.
So, what are the climatologists and other scientists suggesting for the future? They are coming up with a few practical suggestions.
Preparing for increasing mountain hazards: The Rasuwa disaster highlights the need to strengthen the preparedness for sudden-onset of hazards in mountainous regions across the Hindu Kush Himalaya, which is likely to become more challenging as the climate warms.
Strengthen and enforce land-use planning: Develop a clear land-use policy for the HKH region and ensure strict implementation, particularly in areas exposed to river, slope and mountain hazards.
Assess how the environment can impact infrastructure:Early warning systems can help save lives, but they cannot necessarily protect infrastructure from sudden events. Alongside conventional Environmental Impact Assessments (EIAs) before infrastructure is built, governments should assess how changing environmental conditions could affect infrastructure over its lifetime.
Bring indigenous knowledge back into risk planning: Revisit traditional settlement and indigenous land-use practices. Historically, communities lived on higher ground and away from river channels, while newer development has increasingly moved closer to riverbanks and, in some cases, onto riverbeds. Indigenous knowledge should inform contemporary disaster-risk and land-use planning.
