Due to most glaciers being “out of balance” with the current climate, new research says 15 million people could lose their lives in glacial lake outburst floods.
The study published in Nature Communications quantifies for the first time on a global scale the number of people at risk.
Glacial lakes have proliferated rapidly since the 1990s — along with downstream populations — particularly in what is called High Mountain Asia.
“More than half of the globally exposed population are found in just four countries: India, Pakistan, Peru and China,” according to the study.
The study points out that over the last three decades there has been a substantial loss in global glacial mass, leading the melting water to form glacial lakes.
The glacial outburst flooding is complex and difficult to predict, marked by mass-movement induced waves. They are highly destructive and can arrive with little prior warning, according to researchers, causing significant damage to property, infrastructure and agricultural land, and extensive loss of life.
“The continued ice loss and expansion of glacial lakes due to climate change therefore represents a globally important natural hazard that requires urgent attention if future loss of life from (glacial outburst flooding) is to be minimized,” the research said.
The risk is growing, the study also warns.
“Since 1990, the number, area, and volume of glacial lakes globally has grown rapidly, increasing by 53%, 51% and 48%, respectively. Concurrent with the rapid growth of glacial lakes, many catchments downstream have experienced rapid and large increases in population, infrastructure and hydroelectric power schemes, while agriculture has intensified,” it said.
In total, 90 million people across 30 countries live in 1,089 basins containing glacial lakes, including the Pacific Northwest in the United States and Canada where the total number and area was highest at 1,000. The lowest is the European Alps.
While a PBS news report notes glacial outburst flooding is a threat Americans and Europeans rarely think about, 1 million people live within just six miles of potentially unstable glacial-fed lakes, according to the study.
It said that heavy rains and a glacial lake outburst flood combined in 2013 in India to kill thousands of people.
A story in the Guardian said the deaths from those events need attention, with more than 12,000 fatalities globally attributed to those kinds of floods.