BEIJING -- Mother Nature has got it in for Wang Yongxian. In 1988, the farmer fled his hillside cave when flooding triggered landslides on Dragon Treasure Mountain, 70 km north of Beijing. Forced to abandon their traditional cave homes, Wang and neighbors moved down to the safety of the plain. Or so they hoped. Today, a creeping 10-km sand dune threatens to swallow their rebuilt village and set Wang on the run again.

Chinese patriots display giant, PRC flags on the dunes. A section of the dunes near Lognbaoshan has been turned into a desert amusement park by an enterprising local businessman.

"There was very little sand when we settled here," explains the 40-year-old farmer, who serves as Communist Party secretary to an embattled community of almost 700 people. But now the 30-meter high dune that chokes their lungs and stifles their crops looms large just 100 meters away and is closing in by at least 10 meters every year. "Look at it now, it's right in front of our eyes," says Wang. "If we had known, we would never have moved here."

Like Wang, the Chinese government has recently woken up to an ecological disaster that has been decades in the making. Nearly one-third of China's territory, over 50,000 villages and hundreds of cities are plagued by rampant desertification. The danger is greatest in Northern China, where deserts eat up vast quantities of land every year. Combined with dwindling water supplies, the crisis has prompted concerns that China's capital, Beijing, will have to retreat south to a safer location.

"Environmental destruction is very severe," admits Luo Bin, a desertification expert at the State Forestry Administration, the vanguard body fighting to slow the flow of sand. "So many areas have sacrificed the environment for economic development. Vegetative cover shrinks more and more as people waste water resources, plant inappropriate crops and let animals overgraze the grasslands."

The global problem of desertification has hit China far worse than most countries worldwide. The 1.3 billion Chinese people survive on just one quarter of the worldwide per capita average of arable land and fresh-water resources. This month, the State Council, China's Cabinet, is due to release the latest speed check on desert expansion. A significant hike is expected over the current rate of 2,460 sq. km of land lost to desert every year.

And China's problem is going global. Last month, the Japanese, Korean and Chinese governments met in Tokyo to launch joint projects tackling the Chinese sandstorms that darken the skies of Seoul and other Asian cities every spring. Also in April, a massive sandstorm originating in Northwest China and the Gobi desert rose 11 km into the atmosphere, then charged over the Pacific and halfway across North America.

The haze was news over Denver, but it was depressingly familiar to Wang Yongxian. If the winds blow, his family huddles indoors to escape skin-scarring storms that stunt the growth of their sweet-corn and fruit-tree seedlings and lower future yield. When a dozen destructive sandstorms hit Beijing last year, the most severe onslaught for half a century, the central government finally recognized the urgency of the situation.

Keeping tabs on the creeping dunes: Wang Yongxian and a young villager

Visiting Wang's village last May on an emergency inspection of Hebei Province and Inner Mongolia, China's plain-talking Premier Zhu Rongji voiced concerns that the Chinese capital may eventually be forced away from Beijing. Party spin doctors quickly prohibited the Chinese journalists present from printing Zhu's remarks, lest they damage the city's bid for the 2008 Olympic Games. The premier later made a televised speech calling for efforts to fight the sand, without singling out Beijing's peril.

A carpet of wind-blown Gobi Desert covering Tiananmen Square might spare the Beijing government the expense of importing tons of sand for the Olympic beach-volleyball event planned for China's political heartland although the prospect of a lungful of sandy air might horrify the world's sprinters. Government experts, however, are quick to play down the threat.

"I tell the premier, 'Don't worry, there's no need to move the capital,' " says Professor Shi Peijun, dean of science and technology at Beijing Normal University and the top consultant assisting China's anti-desertification drive. Beijing enjoys the lion's share of funds intended to pay for a massive shelter-belt of trees and shrubs that has already been dubbed "the Green Great Wall." Yet two decades of tree-planting campaigns, and some 35 billion new trees, have failed to halt the desert now smothering at least 27 percent of China's landmass.

If the capital's status guarantees efforts to safeguard its 12 million people, the rest of Northern China still has many reasons to worry. Shi cites three: "Heaven, Earth and man." Global warming is exacerbating the crisis, sending stronger winds each spring. These blasts scatter the poor-quality, sandy earth of Northern China, depleted by the planet's most destructive element, humanity. "We must combine desertification control with poverty alleviation," Shi said. "If you can control the sand but people remain as poor as they are now, then the vegetative cover will still be ruined."

Nowhere is this more evident than in Northwest China, home to most of China's desert and source of many of the worst sandstorms. After decades of state-sponsored environmental destruction, when massive earth-moving campaigns reshaped the face of China, the state is trying to remedy past mistakes and cope with new problems. Economic freedom in recent years has permitted families to increase their herds, despite overgrazing, and plant dry areas with inappropriate but high-profit crops like herbs used in traditional Chinese medicine.

As Western China lags well behind the more prosperous east, the government's current priority is to fast-forward development in the region. Yet efforts to raise local living standards may deepen the root causes of poverty in some areas. Large infrastructure projects and thirsty, resource-extracting industries are likely to damage the delicate ecosystems along the upper stretches of China's major river systems.

"No country on Earth has put such funding into building ecosystems as China," claims Luo Bin of the State Forestry Bureau. "Protecting the environment is a fundamental part of the 'Develop the West' policy. But we have many people and little land. In poor areas, peasants want to get richer, and it's hard to control them." It will prove just as hard to control the prospectors seeking underground answers to China's energy needs.

The vast dune shadowing Wang Yongxian's home in Hebei highlights for China's leaders just how close the problem is creeping. Full-fledged deserts lie just 160 km from Beijing and are advancing at a rate of about 3 km a year. But experts like Shi and Luo agree that the key battles of China's war with nature lie in blighted areas of Northwest China, such as Alxa in the western reaches of Inner Mongolia.

This once fertile grassland of Genghis Khan's descendants has degenerated into desert, expanding by 1,000 sq. km annually, through population pressure, overgrazing and shrinking rivers. The efforts of communist central planners to settle the wandering nomads in the 1950s and 1960s resulted in ever greater concentrations of people exhausting limited resources. Nowadays, tradition, more than material need, still encourages herdsmen to keep large herds of goats that strip the local habitat bare.

John Liu, of the Television Trust for the Environment, has documented the crisis at Alxa in the film "A line in the sand," to be aired on BBC World's "Earth Report" and throughout China later this year. "The local people say, 'It used to rain on cloudy days, but now even if it gets cloudy it doesn't rain,' " Liu reports. The runoff from Alxa's Black River has dropped dramatically in recent years, forcing farmers and herdsmen to drain the two ancient reservoirs of underground water under the local-government seat in Bayanhot. One of these "aquifers," which have very slow recharge rates, has now lost all its 700 million cubic meters of water.

"The grassland is a very fragile ecosystem that can easily collapse into desert," explains Liu. "This is the front line. If you keep pulling back, then the front line will come to you. We must be able to find models to slow the devastation. Perhaps it is good that the Chinese are on the front line. They are survivors and will try anything."

Innovations currently on trial include sending grass seeds into space aboard rockets so they can mutate into desert-resistant varieties. Space-mutated tomatoes are already a hit on the streets of Shanghai. Simpler methods involve stabilizing the "walking" dunes with grids of compacted straw. Liu is also encouraged by the substitution of energy-wasting brick with renewable, heat-retaining straw bales to build houses in new settlements occupied by farmers and herdsmen.

Begun in the 1970s, resettlement projects attempt to move people away from areas where human incursion accelerates the desert's advance. The policy represents a new, if far less rigid, form of the collectivization that once gathered every Chinese into people's communes nationwide, even on the grasslands. "The resettlement areas are controversial," says Liu, "but better than having the whole ecosystem destroyed by illiterate herdsmen who raise thousands of animals for status, not subsistence. Their lives will not improve if you leave them out goat-herding."

While experts warn that tree planting is also no panacea for desertification and express concerns about forest maintenance and the dangers of insufficient biodiversity, afforestation remains the concept and cause best calculated to win public support. In 2001, China's "Forest Year," the central government has pledged that tree planting will intensify.

Yet earlier this month, the deputy party secretary of Inner Mongolia, Yang Shijie, complained of insufficient funding for reforesting his impoverished region. China may be the world's most populous nation, but Yang also complained of insufficient manpower to plant the saplings promised by Beijing. He appealed to local entrepreneurs to invest in saving their homeland, of which 60 percent has already been swallowed up by sand.

Facing up to crisis

Liu believes the responsibility is global. "Where is the investment going to come from to resettle the people and stabilize the dunes?" he asks. "If we do not reject the Kyoto Treaty, perhaps we can use carbon-mitigation funds, and then companies like New Jersey Power and Light could be financing this. The rest of the world can ignore this problem for now, but not forever. If we have any moral fiber, we'll face it now, reduce the suffering and come up with working models."

China's parliament, the National People's Congress, is facing the crisis by debating and drafting the nation's first law on desert control. Existing laws touch on desertification, but none have dealt head-on with root causes such as logging and land reclamation. If it is implemented locally, the law should lend legislative muscle to China's vague but ambitious targets: to bring desertification "basically under control" within 10 years; to contain the "overall sand invasion" by 2030; and to bring all desert areas "under control" by 2050. The law may also speed up the resettlement program, but even these new "development areas" may prove only temporary unless China can resolve its water crisis.

Severe droughts over the past decade have quickened the rate of desertification. Of China's 668 cities, at least 400, including Beijing, now suffer water shortages. In Alxa, the ancient underground reserves are being sucked dry, while in Hebei, Wang Xiaoying and his fellow villagers are having to dig their wells ever deeper. Liu urges China to adopt the "ecologically sensible solution" of conserving existing supplies, not searching for new sources to deplete. Compared to the waste that characterizes much Chinese practice, the Israeli "drip-drip" style of irrigation holds many lessons.

Wang Yongxian is Communist Party secretary of Longbaoshan village, now under threat from the Heavenly Desert sand dunes 70 km from Beijing.

But, true to form, the Chinese Communist Party is planning something more grandiose to quench North China's thirst. Next year, construction may finally begin on Chairman Mao Zedong's long-delayed plans to channel water 2,400 km northward from the Yangtze River. The water-diversion project will dwarf even the controversial Three Gorges Dam on the upper Yangtze. Conservation experts fear both the drain on the Yangtze's resources and the possibility that prohibitive costs will make the project irrelevant to most Chinese farmers. "It will be like Evian!" worries one Western environmentalist.

Perhaps this is only fitting for water that may one day wash the grapevines of Dragon Treasure Mountain. Chinese officials suggest Wang Yongxian should pursue viniculture, as his village lies on the same grape-friendly latitude as southern France. To irrigate the new crop, Wang need only wait 15 years for the Yangtze to come lapping at his door -- unless his neighborhood sand dune gets there first.

For now, though, flooding is his most pressing danger, Wang says without a drop of irony. While Chinese scientists warned recently that sandstorms will grow heavier and more frequent in coming years, Wang must organize villagers to clear sand blocking the dry watercourse that diverts flash floods through the village. Summer rains collapsed Wang's cave 13 years ago. This summer, he fears the rains may wash away part of his village once again.