Wrong agricultural polices and water overuse have favoured the process of desertification. They have increased manifold the number of sand and dust storms, which can reach the Koreas and Japan as well as across the Pacific. The government is now trying to stop the desert.

Beijing (AsiaNews/Agencies) – In northern China, deserts are spreading and dust storms caused by Siberian winds blasting across the north of Asia are increasingly destructive.

North-western deserts are advancing towards north-central regions, including Beijing, at a rate of 3,650 sq km a year. Deserts or desertified areas are 1.74 million sq km of China's area and respectively represent about 18 and 4 per cent of the mainland's land mass. According to the United Nations, 400 million Chinese live in areas threatened by desertification.

Government policies of the last 50 years are to blame. Farming, grazing, deforestation and irrigation have all helped giant dunes up to 400 metres high shift forward, swallowing all in their path, forcing of people to move.

Wang Tao, director-general of the Chinese Academy of Sciences' Cold and Arid Regions Environmental and Engineering Research Institute, said northern China's ecosystem has been seriously damaged through over-cultivation and over-grazing. For instance, with grazing capacity comparable to that of the US and a similar number of cattle, China has however 339 million sheep and goats compared to 7 million in the US.

Farming is no better. Dust from frequent ploughing is picked up each spring by Siberian winds and coat all in yellow. Irrigation facilities have overused water reservoirs, increasing aridity around them. When deserts advance, they are simply abandoned and fill up. And Deforestation and more dust in the air have increased the frequency and intensity of sand storms.

The one that struck Beijing on April 16 this year dumped an estimated 330,000 tonnes of yellow dust and sand on the city, before moving on to the Korean peninsula. "The sky was yellow—it was terrible," witnesses remember. "The air was choking and much thicker."

When bad storms reach Beijing, Tianjin, Seoul and elsewhere, airports and schools are forced to close and people just stay put at home. Transportation and services such as sanitation and water grind to a halt. Signals from mobile phone networks, radar, television and radio are also affected.

Storms eventually reach the Koreas and Japan and, if the atmospheric conditions are right, can cross the Pacific Ocean—as happened in April 2001—and rain fine particles of yellow dust on to cities and towns in the US and Canada.

According to John Barnes, station chief at the Mauna Loa Observatory in Hawaii, the micron-sized dust particles from China in recent years contained chemicals and other toxins such as mercury, a by-product of the coal burned by power plants.

The spring winds can sometimes lift the dust up several kilometres into the atmosphere, he said, and if strong air currents prevail and there is no rain, the particles can reach the west coast of North America in four or five days. Dust from China has even been tracked to the east coast of the US. Unfortunately, forecasting the storms is difficult because they're governed by atmospheric conditions and therefore move unpredictably.

Beijing residents had little warning of the record 10 dust storms they experienced between February and May this year and people in South Korea were similarly unprepared for the seven their country received.

"We cannot stop the deserts," Dr Wang said. But we "can try as much as possible to protect the land surface and increase the vegetation cover. That will maybe decrease the degree and number of dust storms, but they will not be stopped altogether."

This year the situation was made worse by an exceptional drought. According to official figures, excess dryness has affected a total of 17.6 million hectares (44 million acres) of farmland across the country, up 21 percent compared with the figure for the same period of last year.

Now Beijing is taking emergency steps, encouraging new methods of farming and animal husbandry as well as replanting forests.

In a Balinzuoqi, Inner Mongolia, the "Vallerani" system is among the approaches being tried. The project, which is funded by the Ministry of the Environment and Land Preservation, involves new farming methods, special ploughs and other machinery that enhance the land's capacity to retain rain water, reduce costs and labour inputs and favour a faster and more thorough reforestation. (PB)

• china
• inner
• mongolia
• balinzuoqi
• desertification
• land
• losses
• environmental
• degradation