Climate Change, Cryosphere and Impacts in the Indian Himalayan Region

Abstract

Climate change and related impacts over the Indian Himalayan Region (IHR) remains poorly quantified. The present study reviews observed and modelled changes in the climate, cryosphere and impacts related to hazards, agriculture and ecosystems. An increasing temperature trend over the IHR is reported, which over a few locations is found to be higher than the global average. For precipitation, a complex and inconsistent response with considerable variation in the sign and magnitude of change is observed. Future projections show significant warming. Climate-driven changes and impacts are clearly observed. Snow cover has declined since the 1960s, with an enhanced decreasing trend during the 1990s and variable trends since 2000. Glaciers are losing mass and retreating at varying rates since the early 20th century, with an exception over the Karakoram region. An observed heterogeneous response of glaciers to atmospheric warming is controlled by regional variations in topography, debris cover, circulation and precipitation. Initial assessments of permafrost extent of 1 million km2 across the IHR roughly translate into 14 times the glacier area. Extreme floods represent the most frequent natural disaster in the IHR. Studies have highlighted the significant threat from glacial lakes. Landslides occur in combination with heavy rainfall and flooding, with poor land-use practices such as road-cutting and deforestation being additional drivers. Climate change has also stressed traditional subsistence agriculture and food systems. Improving systematic and coordinated monitoring of climate and related impacts is crucial to contribute to effective climate change adaptation and response strategies.