Climate change, dams and a lack of glacial monitoring are making floods of this nature increasingly likely. Urgent action is needed to prevent another disaster.
Rescue operations are still ongoing, more than a week after the devastating glacial flood in Uttarakhand, in northern India. More than 50 people were killed after a piece of a “hanging” Himalayan glacier is thought to have broken off into a stream, blocking it and, in turn, triggering a massive flood that breached two dams, which then caused further flooding downstream. A number of houses, bridges, roads and hundreds of farm animals were also lost in the flood, while two other hydropower projects were damaged. Over a hundred people are still missing, as excavators continue to dredge the area.
The Himalayas have become an increasingly perilous flood zone. Climate change poses an immediate threat to the region, where warming has significantly increased in recent decades. Projections suggest that this warming trend will continue as climate change worsens. By 2100, roughly one-third of the region’s glacial ice is expected to have melted, even if the increase in global temperatures is kept to 1.5 degrees Celsius (a goal that seems increasingly remote, even if countries meet their Paris Agreement commitments).
As Himalayan glaciers melt, there has been a marked increase in the number of glacial lakes in the region – from around 4,600 in 1990, to around 5,700 in 2010. Existing lakes have also grown in size. Glacial lakes pose a considerable risk for the communities living near them. A glacial outburst flood can project water, sediment and debris up to 100 kilometres downstream and offer little to no warning. This phenomenon does not just threaten communities in India, but communities in every country in the Hindu-Kush-Himalaya (HKH) region (China and Nepal are particularly vulnerable).
India’s most recent flooding does not appear to have been strictly related to glacial lakes and the exact cause may not be known for some time, but increased warming was likely responsible for what happened. If the early “hanging glacier” theory is correct, rapid temperature changes associated with climate change are likely to have weakened the glacier enough to cause it to fall. Furthermore, glacier-related landslides in the Himalayas have become more frequent and more severe over the last decade, as glaciers have retreated, meaning climate change is likely to have been a factor in the flood if the “hanging glacier” was not responsible.
While climate change is often at the root of glacial floods, the devastation they cause is exacerbated by government policy. Development in the area has also worsened the impact of flooding, particularly the development of dams and roads. Haphazard development of dams and roads has ignored the fragile ecosystem of the area, destabilising mountain slopes. As a result, floods are able to carry more debris and cause more damage downstream. Glaciers in the region are alarmingly under-monitored. In the HKH region, only 24 glaciers are monitored by government agencies, out of a total of 50,000. In Uttarakhand, where the disaster happened, only 15 glaciers are monitored out of a total of 1,500. Without monitoring, it is difficult to say where it is safe to build new hydropower projects, which puts communities at risk of worse flooding.
India (and other countries in the HKH region) may not be able to completely avoid the increased glacial floods that have come with a warming climate, but by implementing better monitoring of glaciers and by taking the fragility of the region into account when building hydroelectric projects, it may be able to mitigate the effects of such floods.