Miriam Jackson, senior cryosphere specialist and cryosphere intervention manager at the International Centre for Integrated Mountain Development that works in the eight countries of the Hindu Kush Himalaya tells AwaazSouthAsia.com in an email interview that South Asia needs to forge a common approach to tackle the unprecedented melting of glaciers in the Himalayas

The glacial lake outburst flood in Sikkim was caused by the collapse of a moraine that dammed a glacial lake. As glaciers retreat due to climate change and get smaller, there is often a lake formed, generally in front of the lake and behind the moraine (a ridge of rocks and sediment formed previously when the glacier was bigger) or at the side of the lake. There was some rain that day, which could have triggered the moraine collapse. Or the moraine could be ice-cored which is common, and sometimes as the ice slowly melts it can suddenly settle and cause this kind of event.

However, the event had disastrous consequences because the lake level hadn’t been artificially lowered (although this usually isn’t possible) and because there was not a functioning Early Warning System in place. There were initial efforts to lower the lake level in 2016 but there was no support to continue/maintain these.  The Sikkim government was apparently in the process of installing an early warning system but it was not yet functional. There has also been substantial development downstream from this lake, especially since the hydropower dam was built, without taking into account the upstream hazards.

Our recent report published this result, that glaciers in the Hindu Kush Himalaya melted faster by a significant amount in the last decade (2010-2019) than in the previous one (2000 – 2009) …the glaciers are shrinking because of increasing temperatures, with the temperature increase in the Hindu Kush Himalaya (HKH) greater than the global average, especially as you go higher. Areas above 4,000 m elevation showed an even greater decadal warming trend (~0.34°C per decade) than areas of lower elevation, lower than 2000 m elevation (~0.20°C per decade).

 

There is not really a clear trend in the change in precipitation as snow. There are generally less days with snow cover, but also a lot of variability in snow. However, the amount of snow would have to increase a lot to make up for the higher temperatures. As the temperature continues to increase, glaciers will continue to melt, and this probably will be even faster.

Glaciers melting cause many problems. A global problem is that as glaciers melt, and especially as the Greenland Ice Sheet and parts of Antarctica melt, then sea level rises (note that sea level rise is also caused by the ocean becoming warmer, due to thermal expansion of water – water takes up more volume at higher temperatures). Sea level rise affects people living on and near the coast and infrastructure built near the coast such as seaports and airports. This disruption means it potentially can affect a large number of people.

 Many people are reliant on meltwater from glaciers. As glaciers melt more, the amount of water first increases, but the glacier continues to shrink and then the meltwater decreases. This causes problems downstream where people rely on the meltwater for irrigation, drinking water, hydropower etc.

Floods from glaciers (like the ones in Sikkim) are one of the biggest potential problems for people living close to glaciers. As glaciers continue to melt, new lakes are formed, existing lakes get bigger and lakes dammed by moraines that have an ice core and other hazardous lake situations can cause more floods and bigger floods.

 There have also been some cases where large parts of a glacier have broken off and the resultant icefall has killed people (e.g. Baklibreen in Norway in 1986). However, even bigger glacier collapses have happened although these situations were complex and not simply due to glacier melt.  As glaciers melt, it exposes the ground underneath and, in some cases, there could be (natural) contaminants. If people get drinking water from such a glacier, then this could also cause ill health. Glacier melt is also a problem for many other reasons, such as in areas where people may use it to traverse, as glaciers melt the resultant landscape can be unstable (causing landslides etc) and for many people they are also a tourist attraction, so can affect tourism in an area.

 Communities and policy makers in the Hindu Kush Himalaya need information on the changes that are happening, including how quickly they will happen. They also need support to understand this information and find solutions, such as adaptation. If there will be less meltwater, should they grow different crops. Communities downstream of glacial lakes need to have Early Warning Systems installed and supported so they know what to do when an alarm goes off (evacuation routes etc). They also need financial support for adaptation to these changes.

Yes, we need a joint effort in South Asia and also globally. We must decrease greenhouse gas emissions quickly to slow down glacier melt. Sometimes disasters can cross national borders, and then communities and countries must work together across the border. We need to work jointly to find adaptation solutions, and share information on what is successful, so that an adaptation that works in one area can then be tried in another area. Furthermore, we have a responsibility to get as much knowledge as we can on what is happening to glaciers, share this knowledge and support adaptation efforts.