China's Environmental Problem Is a Political One

In January 2007, a geologist named Yong Yang set out from his home in China's western Sichuan Province with five researchers, two sport utility vehicles, one set of clothes, and several trunks of equipment for measuring rainfall and water volume; a camping stove, a rice cooker, canned meat, and more than sixty bottles of Sichuan hot sauce; a digital camera, a deck of cards, and several CDs of Tibetan music; and as many canisters of fuel as his team could strap to the roofs of their SUVs.

No roads cross the part of China to which Yong was traveling, so he also brought topographical charts and satellite photos of the region. His final destination, deep in China's wild western frontier, was the unmarked place on the Tibetan plateau from which the Yangtze River springs.

For several weeks the two vehicles followed the Yangtze west, as the river turned from running water to ice. The thermometer became useless when the temperature dipped below the lowest reading on its scale. Occasionally they spotted an antelope, and once wolves devoured their fresh yak meat. As they climbed in elevation, tracing the course the Yangtze had cut through the Dangla Mountains many millennia ago, the air grew thinner and the wind fiercer.

When the ground rose too steeply into the surrounding peaks for the SUVs to maneuver along the riverbanks, they drove on the frozen river itself, though this approach was not without its perils. About a month into their trip, on the auspicious first day of the Lunar New Year, Yong heard a great crunching sound as his front and then back tires slid through the ice, trapping his vehicle midstream. Fortunately, the vehicle wasn't too far submerged, and the backseat passengers managed to clamber out and signal to the second SUV. With a rope tied to the rear bumper, they dragged the vehicle from the frozen river, with Yong still in the driver's seat, transmission in reverse.

Yong and his companions made it safely out of the river. But since then he's continued to travel, in many senses, on thin ice. A vital question had propelled his journey up the Yangtze: the Chinese government is embarking on the most colossal water diversion project ever attempted, and Yong had taken it upon himself to discover whether it would work.

Water is an unevenly distributed resource in China. Traditionally, the south has been lush while the north has been a land of dry tundra and frozen desert. In 1952, Mao Zedong conjured a solution to this inequity: "Southern water is plentiful, northern water scarce," he said. "Borrowing some water would be good."

Ever since, China's leaders have dreamed of diverting water from one of the country's great rivers to the other -- from the southern Yangtze River into the northern Yellow River. (To fathom the scale of this undertaking, imagine watering the American Southwest by diverting the Mississippi River into the Colorado.)

In recent years, this eccentric scheme has become increasingly appealing to Chinese authorities, as water shortages in northern cities have become more and more dire. In 2002, China's highest executive body, the State Council, converted Mao's grandiose notion into a plan known as the South-to-North Water Transfer Project. Construction on two sections of the project have already begun, but the most ambitious stage is scheduled to begin by 2010.

This phase will divert water from the Yangtze in southwestern China to the north, across mountains that rise to 15,000 feet above sea level. The entire project will cost at least an estimated $60.4 billion, and has aroused intense opposition because it is expected to displace hundreds of thousands of people and devastate fragile ecosystems.

Between January and March, Yong's team traveled more than 16,000 miles in the Yangtze River basin, threading every bend in the western reaches of the river. The previous summer they had driven roughly the same route, so they could compare water levels in different seasons. On both trips they collected data on rainfall, geology, receding glaciers, and other trends that affect the volume of water in the river. Yong had learned from firsthand experience that for about four months each year the upper Yangtze is a ribbon of ice; only an engineering miracle could transport the frozen water north.