What have we done to prevent and control desertification? What else can be done

Newsweek丨What have we done to prevent and control desertification? What else can be done →

This week, much of northern China hit sandstorms head-on, affecting 17 provinces, autonomous regions and cities in China from Tuesday to Wednesday, with more than 500 air quality monitoring sites nationwide bursting on Wednesday. The numbers may not be understood, but the picture is very shocking, a dust curtain wall appeared in the sky in a certain place in Inner Mongolia, Liaoning, Jilin and other underground mud rain, affected by sandstorms, from Xinjiang to Gansu direction there are more than ten train delays, Heilongjiang, Xinjiang some airports have to cancel some flights. Many people feel that the sandstorm has not been seen for a long time, why is it coming back? Did the planted tree work? What else do you have to do next?

On Monday, a citizen of Zhangye, Gansu Province, photographed a 100-meter-high "sand wall" rolling in. After a while, the horse farm where the photographer was located was engulfed, and the visibility in the sand wall was less than ten meters.

In the afternoon of the same day, due to the impact of a sandstorm in Jinta County, Gansu Province, a four-vehicle rear-end accident occurred, in which the cab of the agricultural vehicle was seriously deformed, and the driver was trapped and unable to break free. In the wind and sand, after 20 minutes of rescue, rescuers successfully rescued the trapped person and sent them to the hospital. At the same time, sandstorms have reached the border of Alxa in Inner Mongolia, and the same sand wall has reappeared.

Experts said that thanks to China's perfect meteorological monitoring system, there are relatively fast and accurate forecasts in transmission path tracking and early warning. Although the meteorological department provided early warnings, the places where the sand and winds passed still had a considerable impact on the agricultural facilities in the areas they passed.

Some township facilities in Yumen City were damaged in agricultural sheds and quilts, and some of the planted pepper seedlings suffered from low temperature and cold damage and wind damage. Local agricultural technicians rushed to the site for technical guidance, and farmers laid mulch films, which were used to press soil belts to prevent strong winds from uncovering the membranes and intercept precipitation runoff in the ridges.

On Wednesday, the sand and dust weather continued to spread eastward to south, affecting Heilongjiang, Jilin, Liaoning and other places, and muddy rain in some areas. On Thursday, it continued south to Hubei, Anhui, Jiangsu, Shanghai, northern Zhejiang and other places, and then weakened and dissipated. According to the statistics of the Central Meteorological Observatory, China has been weakened year by year by the influence of sandstorm weather.

Bai Yansong: Sand and dust weather has a long history in the north, in a few decades ago, a common picture in northern cities is that the lesbian in front of the dust with a scarf wrapped in her face and riding a bicycle in the wind walking slowly, frankly speaking, the big sand and dust days are still few in recent years, but have not really left, after all, it is just after "312 Arbor Day", these years, tree planting achievements are not small, the three north shelter forest projects have been carried out for 45 years, and the forest coverage rate has increased from 5.05% to 13.57%, Plus other ecological construction projects, but why can't you stop the wind and sand in spring?

The sand and dust weather in many places in northwest China this spring not only made local residents remember it vividly, but also attracted the attention of scientific researchers. Researcher Gao Xin has been engaged in physical research on aeolian sand in Xinjiang for more than ten years, and has been exploring the formation mechanism of sand and dust.

Gao Xin, researcher at the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences: In March this year, sand and dust weather occurred more frequently throughout northern China, mainly because our climatic conditions are conducive to the occurrence and development of sandstorms this year. Generally, there are three conditions for the formation of sandstorms or sand, the first is a source of sand, the second is a strong wind, and the third is an unstable atmospheric junction, which means that cold air and hot air flow converge together, so that the atmosphere produces an unstable cyclone.

Through the investigation of the three main causes of sand and dust, people eager to get rid of the harm of sand and dust are also trying to find ways to reduce sand and dust weather.

Therefore, when the law of atmospheric circulation cannot be changed, people mainly focus on controlling sand sources, such as the Sanbei shelter forest and other ecological construction projects, as early as the 20s of the 70th century, after more than forty years of continuous cultivation, people are eager to know the specific relationship between ecological construction projects and sand and dust reduction.

Gao Xin, researcher at the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences: On the one hand, afforestation can play a good role in protecting and controlling the source of sand and dust. Second, it can intercept some coarse sand. If this sand becomes fine sand, between 125 microns and 250 microns, then its jump height can reach a height of 500 meters, and our shelter forest is only 20 meters to 30 meters high, which cannot stop these sands.

In fact, ecological construction projects such as afforestation mainly focus on fixing sand, not blocking it. According to the data, at the end of 2020, the Sanbei shelterforest project completed a cumulative afforestation area of more than 3000 million hectares, and the monitoring of the State Forestry and Grassland Administration also showed that since 2004, China's desertification land area has continued to decrease net for three consecutive monitoring periods. With continuous cultivation, the frequency and intensity of sand and dust also begin to change.

Born in northern Shaanxi, Gao Xin accompanied his childhood memories with dusty days, and after graduating with his doctorate, he took root in Xinjiang, which has the largest desert in the country, and dealt with deserts. In his eyes, deserts have their own unique and fragile ecosystems, and humans need to find a way to get along with them.

Gao Xin, researcher at the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences: Sometimes human activities (around deserts) are very frequent, and even some herders around rivers are very frequent, of course, we must implement banning and protection in such areas to reduce human intervention in them. We often talk about protecting deserts, and some people may ask whether deserts still need protection? Native desert, little precipitation, such as the Taklamakan Desert, it was formed in the geological history period, human beings are also difficult to change it, let alone eliminate it, then we have to protect the desert, we call Yisha Zesha.

Native deserts are limited by water resources and other factors, and cannot be eliminated through human transformation, and the "National Desertification Prevention and Control Plan (2021-2030)" issued by the State Forestry and Grassland Administration at the end of last year also emphasized that for natural relics such as native deserts and Gobi, Yisha Zesa should be adhered to.

Sand sources cannot be completely wiped out, which means that reforestation cannot be the ultimate solution to all problems. In the face of nature, we cannot achieve the victory of man, we can only focus on protecting the fragile ecology and reducing the harm caused by sand and dust.

Gao Xin, researcher at the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences: It is impossible to completely eliminate sand and dust weather, but only to reduce the time, frequency and intensity of sand and dust weather through some means such as our afforestation. It is an objective natural phenomenon, when our weather forecast says that there is a warning of dust weather, then we do a good job of self-protection.

Bai Yansong: Sandstorm has returned, where did this soil come from? Two years ago, the once-in-a-decade sandstorm in March was very impressive, when it was said that the main source of the sandstorm was "imported sand" that crossed the border, but this year's sandstorm is "imported sand" and "domestic sand" working together. It can be seen that sand and dust management cannot divide national boundaries, and they must do their own things well and help each other. In the past two years, in order to support Mongolia's "One Billion Tree Plan", more and more institutions and enterprises have been busy, what are they doing? How effective is it?

Wang Tao is a researcher at the Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences. As soon as he got to work, Wang Tao made a video call from Mongolian experts as soon as he arrived at work, hoping to share his experience in the sandstorm.

Sand and dust weather knows no borders, and requires joint response and cooperative prevention and control. At Wang Tao's institute, cooperation with Mongolian counterparts began 16 years ago. The expert who spoke to Wang Tao, Colenbeck, came to Lanzhou to study during that period and became Wang Tao's postdoctoral student.

From "sand into people retreating" to realizing "green sand retreat", over the years, China has accumulated relatively mature experience in the field of sand prevention and control, attracting experts and scholars from many countries to come to learn from experience. Most of the previous output of this experience was mainly based on personnel exchanges such as training and learning. In 2017, the Northwest Research Institute of the Chinese Academy of Sciences and the Institute of Geography and Geoecology of the Mongolian Academy of Sciences signed an agreement to deepen cooperation in the field of desertification prevention and control, and Wang Tao and his colleagues came to the Gobi Desert in southern Mongolia to establish two experimental demonstration bases, allowing China's desertification control technology to take root in Mongolia.

Wang Tao, researcher at the Northwest Institute of Eco-Environmental Resources of the Chinese Academy of Sciences: We have made different demonstrations in a typical desert grassland desert area, which probably exceeds 1700,<> acres. One is quicksand fixation, the second is to carry out mechanical sand fixation and biological sand fixation technology in combination, carry out grassland restoration, and then make greenhouses, give them seedlings, breed local seedlings, and then transplant. Our idea is still not to introduce seeds from our country, but to use local species to breed and sow these seeds, which is to adapt to local conditions.

In Wang Tao's view, overgrazing is an important cause of desertification in Mongolia. Researchers replant grass seeds in mildly desertified areas while controlling herders' grazing to restore vegetation; In areas with moderate to severe desertification, replanting grass seeds and fencing to allow natural vegetation recovery; In heavily desertified areas, the technical model of "rapid fixation of quicksand" is adopted.

Wang Tao and Koulenbeck, who had not seen each other for more than three years, met in Beijing in May. During the epidemic, the offline exchanges between scholars and enterprises of the two countries were greatly affected, and institutions such as the Chinese Academy of Sciences and the Chinese Academy of Forestry continued to provide assistance through online training. After Mongolia launched the "One Billion Trees Plan", last year, China and Mongolia reached a preliminary intention to promote a series of project cooperation in desertification control, and the prospects for the two sides to work together to control desertification are promising. However, in the view of experts, it is also difficult to practice and promote China's experience, and desertification prevention and control is both an environmental issue and a development issue.

Bai Yansong: In the face of dusty weather, people's mentality is also helpless. In recent years, everyone is most afraid of smog weather, afraid of PM2.5, therefore, everyone hopes that on the one hand, people work the other side there is more wind, but this wind, if you carry sand, and become sandy weather, everyone feels annoyed. In fact, sandstorms want to be cured, it is very difficult, but through afforestation, less damage to the ecological environment, do not abuse natural resources, let desertification be reduced, but can reduce the harm of sandstorms, therefore, we still have a lot to do. (CCTV News Client)