HANJING, China — One of China's lesser-known exports is a dangerous brew of soot, toxic chemicals and climate-changing gases from the smokestacks of coal-burning power plants. . . .
Unless China finds a way to clean up its coal plants and the thousands of factories that burn coal, pollution will soar both at home and abroad. The increase in global-warming gases from China's coal use will probably exceed that for all industrialized countries combined over the next 25 years, surpassing by five times the reduction in such emissions that the Kyoto Protocol seeks. . . .
The sulfur pollution is so pervasive as to have an extraordinary side effect that is helping the rest of the world, but only temporarily: It actually slows global warming. The tiny, airborne particles deflect the sun's hot rays back into space.
But the cooling effect from sulfur is short-lived. By contrast, the carbon dioxide emanating from Chinese coal plants will last for decades, with a cumulative warming effect that will eventually overwhelm the cooling from sulfur and deliver another large kick to global warming, climate scientists say.
A warmer climate could lead to rising sea levels, the spread of tropical diseases in previously temperate climes, crop failures in some regions and the extinction of many plant and animal species, especially those in polar or alpine areas.
Coal is indeed China's double-edged sword — the new economy's black gold and the fragile environment's dark cloud.
Already, China uses more coal than the United States, the European Union and Japan combined. And it has increased coal consumption 14 percent in each of the past two years in the broadest industrialization ever. Every week to 10 days, another coal-fired power plant opens somewhere in China that is big enough to serve all the households in Dallas or San Diego.
To make matters worse, India is right behind China in stepping up its construction of coal-fired power plants — and has a population expected to outstrip China's by 2030. . . .
The difference from most wealthy countries is that China depends overwhelmingly on coal. And using coal to produce electricity and run factories generates more global-warming gases and lung-damaging pollutants than relying on oil or gas.
Indeed, the Wu family dislikes the light gray smog of sulfur particles and other pollutants that darkens the sky and dulls the dark green fields of young wheat and the white blossoms of peach orchards in the distance. But they tolerate the pollution.
"Everything else is better here," Mr. Wu said. "Now we live better, we eat better.". . .
The government has set one of the world's most ambitious targets for energy conservation: to cut the average amount of energy needed to produce each good or service by 20 percent over the next five years. But with an economy growing 10 percent a year, and with energy consumption climbing even faster, a conservation target amounting to 3.7 percent a year does not keep pace. . . .
The Hunt for Efficiency
The second big decision facing China lies in how efficiently the heat from burning coal is converted into electricity. The latest big power plants in Western countries are much more efficient. Their coal-heated steam at very high temperatures and pressures can generate 20 to 50 percent more kilowatts than older Chinese power plants, even as they eject the same carbon-dioxide emissions and potentially lower sulfur emissions. . . .
A New Technology
The third big choice involves whether to pulverize coal and then burn the powder, as is done now, or convert the coal into a gas and then burn the gas, in a process known as integrated gasification combined combustion, or I.G.C.C.
One advantage of this approach is that coal contaminants like mercury and sulfur can be easily filtered from the gas and disposed. Another advantage is that carbon dioxide can be separated from the emissions and pumped underground, although this technology remains unproven.. . .
With Chinese leaders under constant pressure to create jobs for the millions of workers flooding from farms into cities each year, as well as the rapidly growing ranks of college graduates, there has been little enthusiasm for a change of strategy.
Indeed, China is using subsidies to make its energy even cheaper, a strategy that is not unfamiliar to Americans, said Kenneth Lieberthal, a China specialist at the University of Michigan. "They have done in many ways," he said, "what we have done."