Glacial lake outburst floods threaten millions globally

This study quantifies contemporary global exposure and vulnerability to glacial lake outburst floods (GLOFs), a major hazard that can cause significant damage and loss of life. The authors combine the most up-to-date data on glacial lake conditions, population exposure and socio-economic vulnerability to assess and rank global GLOF danger in 2020. The analysis uses a global inventory of glacial lakes, population data, and indicators of vulnerability, including the Human Development Index, Corruption Perception Index and a Social Vulnerability Index. Exposure was estimated by identifying populations living within 50 km of glacial lakes and within 1 km of potential GLOF runout tracks.

This study shows that 15 million people globally are exposed to impacts from potential GLOFs. High Mountain Asia (HMA) has the highest GLOF danger, with approximately 9.3 million people exposed, while more than half of the globally exposed population is concentrated in India, Pakistan, Peru and China. The authors also identify the Andes as a region of concern, with similar potential for GLOF impacts to HMA but comparatively few published research studies. The findings show that exposed populations and vulnerability play a crucial role in determining GLOF danger and that countries with the largest or most numerous glacial lakes do not necessarily face the highest danger. The authors call for a more holistic approach to GLOF risk assessment that accounts for hazard, exposure and vulnerability, and recommend improvements to early warning systems, evacuation drills, community outreach, targeted risk management and further research, particularly in the Andes and Pakistan.