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In the early 1980s, Chinese farmers began draining their fields midway through the growing season to increase yields and save water. Methane reduction was an unintended benefit. "But the reduction is highly variable from place to place," says Li. "It's very hard to draw a simple relationship between the management change and methane emissions because there are so many other factors."

That's where the DNDC model comes in. If all the specific variables are provided, Li's model can predict, using different management scenarios, total methane emissions for all of China. For three years, Li and his colleagues collected data at the local level: weather, soil properties, crop types and rotations, tillage, fertilizer and manure use, water management and more. On research trips to China, they visited farms and laboratories. Li walked the fields, talking with farmers in his native Chinese and gathering soil samples from the land he could no longer call home.

Back at UNH, Li's model was used in conjunction with satellite data, which generated new maps of China's rice fields and quantified the total acreage of the country's fields. Researchers then ran the model, which takes into account 2,500 counties in China (two-thirds of which grow rice in a variety of crop rotations), two types of soil and two types of water management scenarios. The findings, based on more than 10,000 simulations, show a 40 percent decline in methane emissions from 1980 to 2000. "If rice farmers around the world change management practices, we can increase yields, save water and reduce methane as a greenhouse gas," Li says. "That's a win-win situation." Based on the success of the research in China, Li is beginning another study, extending his work to include the rest of Asia--millions and millions of rice-producing acres in 15 countries.

Chinese farmers harvest rice plants in a paddy in Anhui Province on a summer day.

In the years ahead, Li will continue research in his homeland, though his visits remain tense. "They are always keeping an eye on my activities over there," says Li. He and his family are American citizens now, so he feels relatively safe. But the impact politics has had on his career and on his life remain indelible, a fact Li seems to regard with quiet acceptance and notable lack of bitterness. "I am not surprised by the political tension," Li says.

Steve Frolking '80, '83G, a research associate professor of Earth science in the Complex Systems Research Center who works closely with Li, wonders whether most people would have the stamina to forge ahead with their research in the face of such setbacks. "He has this incredible capacity to focus," says Frolking, who like others, admires Li for more than his academic accomplishments. "He is extremely humble and always has time for everybody. I think he's one of the most noble people I know."

Changsheng Li, the little boy who once trudged to school in a remote corner of China, now travels the world tracking chemical elements and seeking answers. Forced from his homeland, Li has forged a new and wider sense of community, cultivating cross-cultural relationships with researchers around the globe. He has built his career on the belief that lasting solutions can be found only as we acknowledge our common citizenship and our shared homeland--the beautiful and fragile planet Earth.

Suki Casanave's work has appeared in magazines such as Yankee, Smithsonian, Boston Magazine, Old Farmer's Almanac and Ladies' Home Journal. She earned a master's in English from UNH in 1986.~

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