Newswise — A paper co-authored by two UC San Diego researchers showing that reductions of air pollution could create agricultural benefits in one of the world's poorest regions was one of six awarded the Cozzarelli Paper of the Year Prize by the journal Proceedings of the National Academy of Sciences (PNAS).

UC San Diego scientists V. "Ram" Ramanathan, a Scripps Institution of Oceanography climate scientist and Jeffrey Vincent, an economist in the Graduate School of International Affairs and Pacifc Studies, collaborated with Maximilian Auffhammer of UC Berkeley's College of Natural Resources on the winning paper, entitled "Integrated model shows that atmospheric brown clouds and greenhouse gases have reduced rice harvests in India," which appeared in the Dec. 4 issue of PNAS. The paper related trends in Indian rice production to the influence of climate trends from the 1960s through the 1990s.

Rice harvests increased dramatically in India during the "Green Revolution" of the 1960s and 1970s, making the country self-sufficient in its staple food. Harvest growth has slowed since the mid-1980s, however, raising concerns that food shortages could recur in this densely populated developing nation. Several explanations for the slowdown have been proposed, but until this paper, none had taken into account the complex interactions of two pollution-related sources of climate change: atmospheric brown clouds (ABCs), which form from soot and other fine particles in the air (collectively termed aerosols), and the better-known problem of global warming caused by greenhouse gases such as carbon dioxide.

In the PNAS paper, Auffhammer, Ramanathan and Vincent analyzed historical data on Indian rice harvests and examined the combined effects of atmospheric brown clouds and greenhouse gases on growing conditions. They found that the combined effects were negative and were greater after the mid-1980s than before, coinciding with the observed slowdown in harvest growth. They estimated that harvests would have been 20 to 25 percent higher during some years in the 1990s if the negative climate impacts had not occurred.

PNAS awarded the Cozzarelli Prize to recipients representing six categories of science that were considered the best among 3,300 research articles published in the journal. The paper authored by Auffhammer, Ramanathan and Vincent took top honor in the Applied Biological, Agricultural, and Environmental Sciences category.

"I discovered a whole new world," said Ramanathan. "It was really amazing what new findings one can come to when one crosses disciplines. That was one of the most rewarding experiences."

"The prize was utterly unexpected," added Vincent. I hope it will motivate others to engage in interdisciplinary research on environmental issues that affect global welfare."

The prize is named for Nick Cozzarelli, the late editor-in-chief of PNAS. This year's awards will be presented at the PNAS Editorial Board Meeting on April 29, 2007, in Washington, D.C.

The paper was the result of a three-year collaboration between Auffhammer, Ramanathan and Vincent. Their work was supported in part by the Giannini Foundation, the National Science Foundation, the National Oceanic and Atmospheric Administration and the University of California's Institute on Global Conflict and Cooperation.

University of California Institute on Global Conflict and Cooperation (IGCC)_Since 1983, the UC Institute on Global Conflict and Cooperation (IGCC) has facilitated innovative research into the causes of international conflict and cooperation. As a research unit serving the entire UC system, IGCC has the capacity to build project teams from all 10 UC campuses and the UC-managed Lawrence Livermore and Los Alamos national laboratories.

IGCC builds bridges between the theory and practice of international policy, injecting fresh ideas into the process by establishing the intellectual foundations for effective policymaking, and providing ways for UC faculty and students to interact with policymakers at home and abroad through its collaborative, multi-campus projects.

IGCC is committed to educating the next generation of international problem-solvers and peacemakers through its research and teaching activities. The institute is one of the largest sources of dissertation and fellowship support for international studies students in the United States.

For more information on IGCC and its programs, visit http://igcc.ucsd.edu