The accelerated melting of Himalayan glaciers and the expansion of lakes on the Qinghai-Tibet Plateau, a good thing or a bad thing?

The region including the Himalayas and adjacent mountains is the highest mountain range on earth, with an average altitude of more than 4,000 meters and an area of ​​more than 595,000 square kilometers. It is also called the third pole of the world because of the same climatic environment as the North and South Pole. And the abundant glaciers here make it an Asian water tower. However, rising temperatures and human intervention in recent years have increased the hydrological sensitivity of the region and the risk of major flooding events.

Over the next 100 years, global temperatures are estimated to rise by 1.5 degrees Celsius, and this climate change will increase the rate of melting of glaciers, making them vulnerable. It will also lead to accelerated disappearance of glaciers, degradation of permafrost, increased extreme temperature and precipitation events, landslides, rapid snowmelt, and major changes in seasonal river water supplies. In addition, the abundant moisture brought by the summer monsoon from India will bring about 300 cm of annual rainfall on the southern slopes of the Himalayas. In addition, direct human intervention in rivers, such as the construction of hydroelectric power plants. All would leave the region vulnerable to multiple natural disasters, including an increased risk of major flooding events.

Lake changes in the Qinghai-Tibet Plateau

An explosive glacial lake flood event in the Chorabari Glacier Valley in 2013 killed more than 5,000 people and caused staggering damage in India's Mandakini Valley. And this is the natural disaster caused by the combined effect of the melting of glaciers caused by climate anomalies and the increase of water storage lakes and the combination of super strong convective rainfall. Unfortunately, more of these events may be brewing, as new glacial-thawed impoundment lakes continue to form each year, while existing lakes continue to expand until the point of collapse. In the past 50 years alone, 41 high-altitude lakes have appeared in the Eastern Himalayas alone, while existing lakes have expanded by 50%. As early as 1976 to 2018, the lake surface expanded rapidly at a rate of 14.44 square kilometers per year. Therefore, the number, extent and impact of lake flushing events in the Himalayas are likely to continue to increase in the near future.

valley

The most common cause of meltwater surges in mountain streams in the past was short periods of rainfall during the monsoon season (June to July to August). However, more recently (2021), during the dry season, there has been a surge in meltwater in tributaries of the Ganges, indicating that glacial meltwater is expanding. Therefore, in the future, under the combined effect of rainfall brought by monsoons and glacial meltwater, the probability of occurrence of glacial lake flood events will be higher.

Qinghai-Tibet Plateau

At present, we can only rely on satellite remote sensing monitoring to observe and warn the water volume in the valley, but the increase in temperature may be the fundamental way to solve this problem. Whether the increase in temperature is caused by ourselves or whether we can rely on our own efforts to keep the temperature from continuing to rise is unknown.