"We evaluated the vulnerability of 78 water tower units in the world and found that the Asian water tower is the most vulnerable water tower in the world." On the 18th, Yao Tandong, the second Qinghai-Tibet scientific research team leader and academician of the Chinese Academy of Sciences, introduced at the scientific research results conference, Eminem. Rivers, Indus, Ganges-Yarlung Tsangpo, Syr, and Tarim rivers rank among the top 5 in Asian water towers for vulnerability. Among them, the Indus water tower unit ranks first in the global water tower vulnerability.
The Qinghai-Tibet Plateau is the region with the largest ice and snow reserves besides the North and South Pole. It is the birthplace of more than ten major rivers in Asia and is called the "Asian Water Tower". It is also one of the regions with the strongest climate warming, with a heating rate twice the global average. Under the background of climate warming and humidification, the Asian water tower is undergoing a change in the imbalance of solid-liquid ratio, which affects the survival and development of more than 2 billion people in China and countries along the “Belt and Road”.
Asia's most important, most vulnerable and most risky water tower
The Asian Water Tower consists of glaciers, permafrost, seasonal snow, lakes and rivers. Over the past 50 years, the glacial area of the Qinghai-Tibet Plateau and its adjacent areas has been reduced from 53,000 square kilometers to 45,000 square kilometers, a 15% shrinkage; the area of plateau permafrost has been reduced from 1.5 million square kilometers to 1.26 million square kilometers, a 16% decrease. The number of lakes greater than 1 square kilometer on the Tibetan Plateau increased from 1081 to 1236, and the area of lakes increased from 40,000 square kilometers to nearly 50,000 square kilometers; affected by the increase of glacial meltwater runoff, the annual runoff of the Yarlung Zangbo River and the Indus River Showing an increasing trend.
The scientific research team has determined 78 water towers around the world based on the water system of high mountains and glaciers. These water systems were evaluated and ranked based on their importance to adjacent lowlands and their vulnerability to future environmental and socioeconomic changes. The findings are published in the journal Nature.
The study found that of the 78 water tower units in the world, Asian water towers accounted for 16 and were the world's most important water towers. The Indus River, Tarim River, Amu Darya, Syr Darya, and Ganges-the Yarlung Tsangpo River are the top 5 water tower units in Asia, and the 5 most vulnerable water tower units in Asia.
The Indus Water Tower Unit is the most important water tower unit in the world with abundant water resources upstream and huge downstream water consumption. At the same time, it is also the most vulnerable water tower unit in the world due to the government's water resource management efficiency and climate change. It is expected that by 2050, the population of the basin will increase by 50%, GDP will increase by nearly 8 times, temperature will increase by 1.9 ° C, and precipitation will increase by 0.2%. The vulnerability of the Indus water tower unit is increasing.
Monitor water tower changes and establish an early warning system
"The changes in key processes such as glaciers, snow, frozen soil, lakes, and rivers in Asia's water towers are a multi-circle-interaction problem of the frontiers of the Earth's system science." Yao Tandong said that the main feature of the change is that solid glaciers—permafrost— Accelerated liquefaction of snow and the increase in liquid lakes and runoff and the accompanying water cycle process have intensified. Aiming at the water vapor transport of the Asian water tower, the scientific research team carried out three-dimensional stereo observation of the Asian water tower, and proposed an integrated Asian water tower observation-simulation- early warning integrated solution.
The change in water towers is accompanied by increased disaster risk. For example, in 2016, the Aru Glacier in the Ali region of Tibet suffered two consecutive ice avalanches; in 2018, an ice avalanche blocked the Sedongpu ditch near the Gala village on the lower reaches of the Yarlung Zangbo River; in 1981 and 2016, Zhanglam, Nielam County, Tibet The collapse of the Tsangpo Ice Lake has had a significant impact on Nepal.
Yao Tandong said that global warming is a big trend, and we can do some "mitigation" work, but "adaptation" is always the core. "This requires the establishment of a corresponding early warning system to minimize losses." Take the ice fall to block the river as an example: The Tibetan population is sparse. When the moraine carried by the ice fall causes the river to be blocked, no one knows it. The problem was not discovered until the upstream water level rose and the water entered the courtyard of the village. That's too late.
In response to the Yarlung Tsangpo River ice collapse disaster, the scientific research team set up a 10-meter monitoring tower at the blocking point, using all-weather monitoring technology to monitor the blocking point at different angles at the same time, and simultaneously conducting real-time meteorological-water level monitoring. The mobile signal was transmitted to the scientific research office's data platform, and early warning was successfully implemented. (Science and Technology Daily, Beijing, December 18th)
(Source: Science and Technology Daily Reporter: Yang Xue Chief Editor: Luan Fei)