Extreme heat has become a global buzzword this summer. The secondary disasters such as diseases, droughts and mountain fires brought by high temperatures have become major threats to social production and people's lives. Chinese scientists recently released a new research report, pointing out that between 2020 and 2050, the frequency of extreme wet and dry events in the Mekong Basin will continue to increase, and the basin countries need to strengthen water cooperation to jointly deal with water and drought disasters.
Frequent floods and droughts in the Mekong Basin in the next 30 years
Long Di, Associate Professor of the Department of Water Resources at Tsinghua University, and his research team have long focused on hydrological research in the Mekong Basin. Their latest paper, "Study of Drought Trends in the Lancang-Mekong River Basin under Changing Environments," published in the academic journal Advances in Water Science, provides a prediction of the evolution of runoff and meteorological and hydrological drought trends in the Mekong from 2020 to 2050.
The results show that the overall wet trend in the Mekong Basin during the 30-year period, but the frequency of extreme dry and wet events increases, with frequent droughts from 2020 to 2029 and more wetting from 2030 to 2050. The study also shows that the frequency and intensity of droughts in Laos and Thailand during this period are higher than those in other countries in the basin.
The Lancang-Mekong River is the most important cross-border river in Asia, with a total length of about 4,350 kilometers, flowing through China, Myanmar, Laos, Thailand, Cambodia and Vietnam in turn, providing important fresh water resources for production and domestic use as well as hydroelectric power generation for the riparian countries.
According to Long Di, droughts have been frequent in the Mekong basin in recent years due to the effects of global warming, affecting more than 66 million people in Southeast Asia during the past 30 years, and 70 percent of the land and 60 percent of the population in Southeast Asia were affected by severe droughts during the past five years.
Lancang River terrace reservoirs effectively "stabilize" the Mekong River
In the current study, the Tsinghua University research team also provided scientific proof of international claims in recent years that the construction and operation of the Lancang River terrace reservoirs have exacerbated drought conditions in the lower Mekong countries.
By quantifying the impact of the Lancang River terrace reservoirs on runoff, the team found that the Lancang River mainstem terrace reservoirs not only did not aggravate the downstream drought, but also effectively increased the dry season runoff of the Mekong River from upstream (99%) to downstream (68%), which can effectively alleviate the dry season drought of the Mekong River and ensure the agricultural production and water security of the downstream countries. The tertiary reservoir scheduling also contributes to downstream flood control, but the effect is more obvious for flood control in China and northern Laos, and limited for northeastern Thailand, Cambodia and Vietnam.
According to Long Di, during the severe drought that hit the Mekong River in 2019, the Xiaowan and Nuodu power stations in China's Lancang River Basin made outstanding contributions to alleviating the drought in the lower Mekong at the cost of reduced reservoir storage, reduced power generation and significantly reduced economic returns. The study released by the Mekong Committee also concluded that the Chinese Lancang River reservoirs have the function of "storing flood water in the rainy season and releasing water in the dry season", which helps maintain the Mekong River's flow stability.
But Long Di also said, "At present, the Lancang River main stream terrace reservoirs only play a seasonal regulating role, it is difficult to effectively alleviate the basin may occur for many years of continuous drought, the future to further strengthen the Lancang Mekong water resources cooperation, to promote water security and water and drought disaster prevention and control in the basin countries."
"China actively promotes Mekong water cooperation
In 2016, China and Cambodia, Laos, Myanmar, Thailand and Vietnam jointly launched the "Lan-Me Cooperation", in which water resources cooperation became one of the five priority areas of cooperation.
In November 2020, China officially started to provide the Mekong countries and the Mekong River Commission with year-round hydrological information on the Lancang River, and took the lead in opening the website of the Lancang Water Resources Cooperation Information Sharing Platform to proactively share relevant information from the Chinese side and work with the Mekong countries to address climate change and flood and drought disasters.
At the 7th Foreign Ministers' Meeting of the Mekong Cooperation in July, Chinese State Councilor and Foreign Minister Wang Yi also announced that China will implement six major initiatives for the benefit of the Mekong, including the Mekong Water Project, to make the Mekong Cooperation truly beneficial to the people of all countries.
Zhang Li, an assistant researcher at the Institute of Belt and Road and Global Governance at Fudan University, also said in a previous interview with the Voice of the South China Sea that water is the cornerstone of development in the Mekong region, and that before participating in Mekong water cooperation, any country needs to consider whether its policies are beneficial to the long-term development of the entire basin.
According to Zhang Li, the Mekong cooperation mechanism is undoubtedly the most superior performance among many mechanisms in this region and has achieved the most results so far. "China, as a basin country, is bound to be in solidarity with the Mekong countries, which is completely different from the fundamental drive and starting point of non-basin countries."