In recent news, a global study on Glacial Lake Outburst Flood (GLOF) has raised alarms about a potential threat to millions of people worldwide. This study is the first of its kind that maps potential hotspots for such floods and assesses the condition of glacial lakes along with the burgeoning population living downstream from these bodies of water.
Major Findings of the Report
The study indicates that up to 15 million people are at risk of catastrophic flooding from glacial lakes that can potentially rupture their natural dams at any time. Most of those at high-risk reside in mountainous countries in Asia and South America, with the majority, about 9.3 million people (62%), being in the High Mountain Asia (HMA) region. In Asia alone, almost one million people live within just 10 km of a glacial lake.
These threats are highest in India, Pakistan, Peru, and China, accounting for over half of those at risk globally. The study identifies the most dangerous glacial basins being in Pakistan (Khyber Pakhtunkhwa basin), Peru (Santa basin), and Bolivia (Beni basin), where 1.2 million, 0.9 million, and 0.1 million people respectively could face the devastating effects of GLOFs.
The Impact of Glacial Lakes on India
The threat is significant in India as well, where since 2009, 25 glacial lakes and water bodies in the Himalayas have witnessed an increase in their water spread area. This expansion has resulted in a 40% increase in water spread in India, China, and Nepal, posing a threat to seven Indian states and Union Territories, six of which are located in the Himalayas. Given the rapid onset and high discharge of GLOFs, there is often not enough time for effective warning or action for populations located within 10-15 km of the source lake.
Impact of GLOF
The resultant floods can cause widespread devastation, in some cases potent enough to destroy critical infrastructure. The sudden rush of water from a GLOF can pose a catastrophic threat to people’s lives, livelihoods, and regional infrastructure.
Suggested Improvements
The study calls for urgent improvements in designing Early Warning Systems, evacuation drills, and community outreach programs to enable quicker warnings and emergency action in these highly exposed areas.
Understanding GLOF
A GLOF is a type of flood that occurs when the dam containing a glacial lake fails, releasing a significant volume of water. These floods can be triggered by several factors such as rapid melting of glaciers, water buildup due to heavy precipitation or inflow of meltwater, or even seismic activities. For instance, the flash floods in Chamoli district, Uttarakhand in February 2021, are suspected to have been caused by GLOFs.
Causes of GLOFs
As per the National Disaster Management Authority (NDMA), glacial retreat due to climate change in most parts of the Hindu Kush Himalayas has led to the formation of numerous new glacial lakes, which exacerbate the threat of GLOFs.
NDMA Guidelines to Tackle Glacial Burst
To tackle this issue, the NDMA has proposed guidelines that include identifying potentially dangerous lakes, promoting the use of technology such as Synthetic-Aperture Radar imagery to track changes in water bodies, devising ways to channel potential floods, developing uniform codes for construction activity, enhancing early warning systems, training local manpower, and setting up comprehensive alarm systems.
