Alarming Melting of Himalayan Glaciers Unveiled by Spy Satellite Imagery

The Himalayan glaciers are melting at an alarming rate, posing an impending threat to over 800 million people who rely on seasonal runoff for irrigation, hydropower, and drinking water.

A study published last February revealed that the melting of Himalayan glaciers has doubled since the turn of the 21st century, compared to the previous 25 years. The study, led by Joshua Maurer from Columbia University's Lamont-Doherty Earth Observatory, analysed Cold War-era spy imagery to reach this conclusion.

The images, taken on rolls of film that were dropped into the atmosphere to be collected by military planes, were part of the Hexagon program. The researchers combined the analysed imagery with modern satellite data to provide a comprehensive look at the melting rates of the Himalayan glaciers over a 40-year time span.

The average rate of glacial ice loss between 1975 and 2000 was approximately 25 cm per year, but it doubled to 50 cm per year in the 21st century. Over 650 of the largest glaciers across India, China, Nepal, and Bhutan have lost the equivalent of a vertical foot and a half of ice each year this century due to global heating caused by human activities.

Warming air temperatures have contributed to the accelerated ice loss. The Himalayan temperatures have risen one degree Celsius higher than those from 1975 to 2000. This increase in temperature has been consistent across all the glaciers studied, indicating global temperature rise as the primary cause.

The melting glaciers can lead to disastrous floods, as glacial water gets blocked by piles of rubble and forms glacial lakes that can burst and flood villages and cities downstream. In May 2012, one such flood killed over 60 people in villages near Pokhara, Nepal, and destroyed houses and infrastructure.

In the worst-hit areas, the ice loss can be as much as 5 metres a year. The study also projected that even in the best-case scenario, the Himalayan glaciers could still lose a third of their total ice, even with rapid decarbonization and carbon neutrality by 2050.

The study provides a grim picture of the future, with projections suggesting significant ice loss by 2050. This includes the possibility that some glaciers like those on Everest could become nearly ice-free by then. The increasing meltwater lakes and exposed glacier ice are evidence of this rapid melting due to climate change.

The researchers found that 8 billion tonnes of ice are being lost every year from these glaciers. The images had lain unused in archives for several years before being digitized by the US Geological Survey for scientific use.

The melting of the Himalayan glaciers is a pressing issue that requires immediate attention. The potential water crisis it could cause could have devastating consequences for the region and its people.