Cryospheric Mountain Hazards and Relation to Global Climate Change

The past decades have seen a worldwide trend of increasing economic losses due to weather and climate related disasters. Increasing exposure and wealth of assets have been identified as the main drivers of this trend at a global scale. Yet, the attribution of this trend to anthropogenic climate change can only be made with low confidence.

However, for disasters in high mountains as related to the cryosphere, the picture may be different due to the close linkage of climate change to the cryosphere components snow, glacier and permafrost. Research progress allows us to reasonably understand the effects of climate change on cryosphere mountain hazards. For instance, glacier shrinkage can result in the formation and growth of lakes and ensuing lake outburst floods. Thawing permafrost and vanishing glaciers alter the stability of steep mountain slopes and can imply avalanches and landslides at locations without any historical precedence of such hazards. Retreat of glaciers and permafrost thaw can furthermore expose new sediment material to erosion, resulting in sediment flux rates, debris flows and landslides of previously unknown frequency and magnitude.

A multitude of case studies, anecdotal evidence and basic physical process understanding has shaped our knowledge about the effects of climate change on hazards in the mountain cryosphere. Recent studies and assessments such as by the Intergovernmental Panel on Climate Change (IPCC) show that impacts of anthropogenic climate change can be better traced in the mountain cryosphere than in most other environmental systems.

The mountain cryosphere therefore offers an important opportunity to inform international policies such as the ‘loss and damage’ mechanism, recently anchored in the 2015 Paris Climate Agreement. Loss of glaciers with all related effects can be considered as irreversible loss due to anthropogenic climate change, a field that is particularly contested in international policy. On the other hand, we still miss a more comprehensive and global-scale perspective on cryosphere hazard and disaster trends and the driving forces behind, which would be important to design more effective risk reduction policies and strategies. This contribution will present the most recent progress in this field and develop linkages to current international policies.