Expanding and melting glacial lakes pose huge dangers

Glacial lakes and water bodies across the Himalayan region have expanded by 11% since 2011, according to a report by India’s Central Water Commission (CWC). The report, highlighted in an India Today (IT) analysis, underscores the growing risk of Glacial Lake Outburst Floods (GLOFs) as climate change accelerates glacial melting and lake expansion largely driven by global warming.

Another IT report presents startling facts that melting glaciers are creating huge lakes in Himalayas and could burst anytime. This is according to satellite analyses by Suhora Technologies, which monitors 33,000 lakes across the Indus, Ganga, and Brahmaputra basins, confirm accelerated growth in high-altitude lakes due to rapid glacier melt. Studies reveal that glacial lakes in the Hindu Kush-Karakoram-Himalaya region – home to the world’s largest ice reserves outside the poles – have grown by over 10% in area since 1990, with the Ganga basin witnessing a 22% surge in lake numbers. Rising global temperatures have pushed lake formation to elevations above 5500 meters, reflecting glacier retreat to higher altitudes. Over 76% of Himalayan glacial lakes are end-moraine-dammed, a fragile structure prone to breaches.

A new study with ETH Zurich, published in the journal Science, finds that if global warming exceeds the Paris Climate Agreement targets, the non-polar glacier mass will diminish significantly, as per an ETHZ press release. Even if global temperatures were stabilised at today’s level of 1.2°C, an estimated 39 per cent of global glacier mass would still be lost compared to 2020 levels – contributing over 10 centimetres to global sea-level rise.

The study states that, however, if warming is limited to 1.5°C, at least 54% could be preserved — more than twice as much ice as in a 2.7°C scenario. Even if the rise in global temperatures were to stabilise at its current level, it is projected that the world would lose around 40% of its glaciers. If global warming can be limited to +1.5 °C, it may be possible to preserve twice as much glacier ice (54%) as in a scenario where temperatures rise by +2.7 °C (only 24%).

For the study, an international team of 21 scientists from 10 countries used eight glacier models to calculate the potential ice loss from more than 200,000 glaciers outside Greenland and Antarctica. The team evaluated a wide range of global temperature scenarios, assuming that temperatures would remain constant for thousands of years in each scenario. In all scenarios, the glaciers lose mass rapidly over decades and then continue to melt at a slower pace for centuries – even without additional warming. This long-term response means glaciers will continue to feel the effects of today’s heat far into the future, gradually retreating to higher altitudes before reaching a new equilibrium.

Melting glaciers reveal the reality of global warming, the study says. And, beyond contributing to sea-level rise, glacier loss has far-reaching consequences. It threatens freshwater availability, increases the risk of glacier-related hazards such as floods and landslides, and jeopardizes glacier-fed tourism economies. These cascading impacts will be felt across regions and generations. While other studies have limited to the year 2100 estimate that around 20% of today’s glacier mass will be lost regardless of future warming, the new study reveals that nearly twice as much would vanish under present-day conditions when multi-centennial timescales are considered.

The IT analysis points out that in India the CWC began monitoring glacial lakes in 2009 to enhance assessment and preparedness strategies. In its 2011 inventory, the CWC recorded 2028 glacial lakes and water bodies larger than 10 hectares. Since then, using advanced tools like remote sensing, satellite imagery, and cloud platforms, the CWC has prioritised monitoring 902 critical water bodies. This latest report from September 2024 reveals a 10.81% area increase in 544 glacial lakes and 358 water bodies over the past decade. While China shows the highest rate, similar trends in India show that 67 lakes have grown significantly. The analysis also underscores recent data from the International Centre for Integrated Mountain Development (ICIMOD) highlights the growing threat of GLOFs. ICIMOD’s analysis shows that over 70% of the 700 recorded GLOFs events since 1833 have occurred in the last 50 years, illustrating the accelerating impact of climate change on glacial stability.