Himalayan Snow Decline Puts Water and Ecosystems at Risk

The Hindu Kush Himalaya (HKH) — a region critical to global water cycles and biodiversity — is experiencing a sharp decline in seasonal snow persistence. According to the HKH Snow Update 2025, snow cover across the region was 23.6% below normal this winter, marking the lowest level in 23 years. This alarming trend threatens not only the water security of nearly two billion people but also the health of fragile ecosystems that depend on seasonal meltwater​.

Environmental Warning Signs from the Cryosphere

Snow cover in the HKH regulates regional temperatures and sustains major river systems. With four of the last five winters showing below-normal snow persistence, the latest data point to an accelerating collapse of the region’s cryosphere​.

Less snow cover means lower surface reflectivity, leading to greater heat absorption and contributing to regional and global warming. As snowpack retreats, ecosystems tied to river flows — including wetlands, forests, and alpine grasslands — face increasing stress.

Drivers Behind the Collapse of the Himalayan Cryosphere

The retreat of the HKH's cryosphere is not an isolated phenomenon but the result of intensifying climate pressures and regional environmental stressors.

Several interlinked factors are accelerating snow loss across the region:

• Accelerated Warming: The HKH region is warming at nearly twice the global average, leading to reduced snowfall, earlier melts, and shortened snow seasons​.
• Shifting Precipitation Patterns: Climate change is transforming traditional snowfall periods into rainfall events, particularly at mid-elevations, reducing snowpack formation and stability.
• Black Carbon Pollution: Deposition of black carbon from regional industrial activities and biomass burning darkens snow surfaces, reducing albedo and speeding up melting.
• Glacier Retreat and Surface Exposure: As glaciers retreat, darker land and thin ice are exposed, absorbing more solar radiation and creating localized warming that exacerbates snowpack loss.
• Feedback Loops: Declining snow cover diminishes Earth's natural reflectivity, causing greater heat absorption and establishing a self-reinforcing cycle of warming and snow decline.

The cumulative effect of these forces threatens not only seasonal water supply but also the broader environmental balance that rivers, wetlands, forests, and human communities rely on.

River Basins Show Broad-Based Snow Deficits

Environmental impacts are evident across all twelve major HKH river basins:

• Mekong Basin: Snow persistence declined by 51.9%, raising concerns for aquatic ecosystems and agriculture​.
• Brahmaputra Basin: Snow levels dropped by 27.9%, threatening hydropower generation and fisheries.
• Tibetan Plateau: Snow persistence fell by 29.1%, destabilizing the region known as the "Water Tower of Asia."

Even snow-dependent basins such as the Indus and Amu Darya recorded significant declines, putting downstream ecosystems and food systems at heightened risk.

Urgent Call for Ecosystem-Based Adaptation

The HKH Snow Update 2025 calls for decisive, coordinated action:

• Integrate snow monitoring into national water and biodiversity policies.
• Invest in nature-based solutions, such as wetland restoration and forest conservation, to buffer climate impacts.
• Strengthen regional cooperation among HKH countries to protect shared ecosystems and watersheds.
• Advance early warning systems to prepare for hydrological and ecological disruptions.

Protecting the snow-dependent ecosystems of the HKH is essential not just for immediate water needs, but for maintaining long-term environmental and economic stability across Asia.