Global glaciers are rapidly melting, but glacier melt water is in short supply?
◎Reporter Yang Xue
Recently, Professor Xiao Cunde’s team from the State Key Laboratory of Surface Processes and Resource Ecology at Beijing Normal University and the scientific researchers from the University of Gothenburg in Sweden published an article in the "Science Bulletin". The development opportunities and risks have been systematically studied.
"We all know that climate change has accelerated the melting of glaciers around the world. In the short term, glacier melt will increase, but when it reaches a certain value, it will start to decrease." Xiao Cunde told a reporter from Science and Technology Daily.
Socio-economic scale affects glacier water demand
Xiao Cunde said that due to the different comprehensive factors such as regional climate, glacier area and drainage basin coverage, the time when the inflection point of glacier melt water appears in different regions is different, and the impact of melt water on the region is also different.
For example, in an area with a small population, more water and less water have no obvious impact on the environment, production, and life, but in an area with a large population, this impact may be critical.
The new research has divided the importance of glacier water resources in 193 glacier basins (except Antarctica) from the two aspects of the supply potential of glacier water resources and population dependence.
The results show that glacial water resources play an important role in 36 of these river basins, especially the Indus, Ganges, Tarim, Junggar, Syr Darya and Amu Darya river basins in Asia, and the Lampe, Mapocho and St. Petersburg rivers in South America. The Ta River Basin and the Yukon River Basin in North America.
"This mismatch between the supply and demand of glacier water resources is first of all spatial." The first author of the paper and PhD student in the Department of Geography of Beijing Normal University, Su Bo, introduced that many glacier water-rich areas, such as the Circum-Arctic, New Zealand and Scandinavia In the Navia Peninsula, the local socio-economic scale is small and the demand for glacier water resources is extremely low.
However, some areas with high demand for water resources for local socio-economic development, especially in Africa, have very few water resources in glaciers.
In addition, there is also a mismatch in spatial supply and demand of glacial melt water in different areas of the same basin.
Generally speaking, the contribution of glacial meltwater to local water resources from the upper reaches of the basin continues to decrease, but the population and economic scale generally increase from the upper reaches to the middle and lower reaches.
Sufficient attention should be paid to the mismatch between supply and demand at the time level
At the same time, the mismatch is also embodied in time.
Subo said, for example, under the middle path of greenhouse gas emissions and socio-economic development, some important glacier water replenishment basins in Europe-the Po, Danube and Rhine basins, the inflection point of glacier meltwater has passed, but the local population growth rate Low, the risk of glacier meltwater reduction and population growth will be relatively low.
The situation in South America is different. The local population has grown rapidly and is expected to reach its peak in the 1950s and 1970s, but the melting point of glaciers will arrive earlier than before.
The situation in North America and South America is similar. Many important glacier water recharge basins are estimated to have a population peak after 2090, which will also be significantly later than the inflection point of glacier meltwater. These risks should be paid enough attention.
The study found that glacial meltwater brings the greatest risks and opportunities to the Indus River Basin.
From the 1990s to the 1940s, the cumulative increase in glacier meltwater was equivalent to meeting the basic water needs of an additional 4.65 million people for 60 years. However, as the glacier meltwater continues to decrease and the population will increase by the end of this century, it is estimated A total of 88.57 million people in the basin are facing serious risks of water shortages.
"Relevant international organizations, government management departments and other stakeholders should adopt flexible and differentiated measures in different river basins and periods to seize opportunities and avoid risks with flexible thinking." Xiao Cunde said.
Take my country's Tarim River Basin as an example.
In the past 20 years, the area of crops planted in the Tarim River Basin has shown an expansion trend. Meltwater from glaciers has provided important water resources for agricultural irrigation and alleviation of agricultural drought.
The increasing trend of glacier melt water is expected to reach the 1940s, during which time these water resources must be fully utilized through effective planning and corresponding engineering measures.
At the same time, from now on, we must take the initiative to make effective adaptations to deal with the water shortage caused by the subsequent reduction of glacier meltwater.
Glacier water resources in Asia are particularly important, especially the Indus and Ganges river basins, which span multiple countries and have a large population. It is urgent to carry out cross-border cooperation through collaborative design.