12 million individuals globally reside in the flood paths of lakes created by the melting of mountain glaciers, which can suddenly overflow their banks.
Globally, since 1990, the number and size of glacial lakes has grown rapidly along with downstream population, while socio-economic vulnerability has decreased. A study published by the journal Nature Communications is the latest warning about the threats posed by melting mountain ice. More than half of the people in the flood paths are concentrated in four countries: India, Pakistan, Peru and China.
Glacial lakes, which are vast reservoirs of meltwater at the base of diminishing glaciers, can become hazardous and erratic as they enlarge. Elevated water levels or compromised lake barriers can lead to catastrophic breaches, unleashing floods that cascade down mountainsides with the potential to claim hundreds of lives. The past thirty years have witnessed significant reductions in global glacier mass, a trend expected to continue throughout the 21st century, as most glaciers are currently not in equilibrium with ongoing climatic shifts.
During glacier retreat, deep caverns and sinkholes in former glacier beds are often exposed, leading to the formation of glacial lakes as melt water accumulates. These lakes pose a serious threat in the form of glacial lake outburst floods (GLOFs), which can be extremely destructive and occur suddenly, causing extensive damage to property, infrastructure, and agricultural areas, as well as resulting in significant loss of life. The impact of GLOFs varies worldwide; in the Cordillera Blanca alone, over the past three decades, GLOFs have claimed the lives of two thousand people. Since 1990, there has been a rapid increase of 55% in the number, size, and volume of glacial lakes globally.
Scientists are concerned that such events are likely to become more frequent. Mountain glaciers, ranging from the Andes to the Himalayas and the European Alps, are shrinking as global temperatures rise.
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