On the edge of Beijing, people can be seen fervently clutching at caps and shawls, bodies bending forward as if leaning against some invisible wall. Then from the north can be seen a cloud, dirty orange in colour.
Initially a dark smear on the horizon, it grows until the blue sky above has vanished and all that is left is an impenetrable mass of sand and dust, spiralling towards the city at 40kph.
Sandstorms, ostensibly the preserve of the desert regions, have returned on their annual campaign to wreak havoc across much of northern China and neighbouring countries.
Beginning in the western China desert regions of the Gobi and Taklamakan, explains Zhang Mingying of the Beijing Meteorological Bureau to Aljazeera.net, strong winds sweep in from Siberia and pick up the loose and recently thawed sand and soil that covers much of the area.
A mixture of hot and cold air that is common in spring accentuates the violence of the winds, creating vortices of twirling sand that grow in size during the day as the ground, heated by the rising sun, furthers the displacement of warm air with cold.
Spring weather patterns help
form whirlwinds of sand
Thundering eastwards across northern China, sandstorms can grow to be as large as several million square kilometres in size.
"It is a combination of three basic factors: strong wind, vertical air movement and loose sand," says Zhang Mingying, "and come spring, China has all three."
Existing as long as there have been deserts, sandstorms have in recent years come to be seen as an issue of national urgency.
It is not just that the capital city receives annual deposits of unwanted silicon, but more crucially, some 400 million people live under the threats posed by sandstorms and their more foreboding associate, desertification.
According to government figures, desert already accounts for 27.3% of China’s land surface.
Rapid population growth over the past fifty years, from 550 million in 1950, to some 1.4 billion today has put pressure on available natural resources, lowering the water table and destabilising the soil through overgrazing.
Dusty winds spiral into Beijing at
speeds of 40kph
"At present, several thousand square kilometres of land succumb annually to the desert sands and a further 4.4 million square kilometres of land are now under threat from desertification. It's a major problem," says Lu Xinshi, an expert on desertification at the Beijing Forestry University.
Living on the open plains of northern China, residents are negatively affected by exposure to the sandstorms and encroaching desert.
According to the China Desertification Network, economic and social development is being constrained and there are reports of poverty and hunger as a by-product of land degradation.
The change in land use does not just affect those who lie in the deserts' immediate path.
Trying to feed a quarter of the world’s population on roughly seven percent of the world’s arable land has required intensive agricultural techniques, particularly in livestock rearing, as the government is keen to achieve a level of nation self-subsistence in agriculture.
Now, though, experts say that overgrazing has been one of lead causes of desertification. By eating the flora that helps bind the soil, animals have left the earth vulnerable to the destructive power of the winds.
Livestock numbers across China rose from 200 million in the early 1990s to 427 million in 2002, says a report by environmental group Greenpeace.
Lu Xinshi has experimented with
plants that can help bind the soil
"It is a difficult balance for the government," Greenpeace spokesman in Hong Kong, Martin Baker, tells Aljazeera.net.
"They are under pressure to feed and provide energy for their people," says Baker - a reference to the notion that large infrastructure projects such as oil-drilling in western China have also contributed to the desert growth through their use of water reserves.
In addressing what Lu Xinshi labelled a "reversible problem given time and energy", the government has been employing the concept of the Great Wall. Not the stone one that was once used to ward off northern barbarians but rather a Great Wall of trees designed to halt a more modern menace.
Built around key areas like Beijing, the idea is to reverse the damage done by overgrazing and ploughing, by rebinding the soil using plant roots.
Currently, some 12.1 million square kilometres have been placed under the big character banner of "retire the grazing, return to nature".
The project has met mixed results, a UN environment officer, Miao Hongjun tells Aljazeera.net. "In some areas, there has been an issue with balancing long-term benefits with short term gain."
Particularly in the poorer areas, more immediate needs of existence among farmers who use the land for grazing and crops are outweighing results that will not be seen for at least a decade.
Hopes are being pinned on
a technological breakthrough
As with many aspects of environmental development in China, hopes are instead being pinned on technological breakthroughs.
In the laboratories of the Beijing Forestry University, Lu Xinshi has been playing with the genes of the alfalfa shrub.
Naturally very resistant to tough meteorological conditions, the plant is being put under the microscope with the aim of creating something even more resilient to the freezing winters and dry climate of northern China.
"It is designed to have stronger, longer roots and be more drought-tolerant," explained Lu Xinshi. "We have planted some test fields around Beijing and in China’s northeast with the ultimate aim of being able to cut and sell them to farmers."
Real results he says will not yet be known for several years to come. In the meantime, Beijing will just to have to turn itself into the wind and ride out the storm.