New technologies can improve agricultural sustainability in developing countries, but only with the engagement of local farmers and the social and economic networks they depend on, say Stanford University researchers. Their findings are published in the May 23 online edition of the Proceedings of the National Academy of Sciences (PNAS).

"Most people tend to think that technology information flows to farmers through a direct pipeline from scientists, but that isn't true," said lead author Ellen McCullough, a former research fellow at Stanford's Program on Food Security and the Environment, now at the Bill and Melinda Gates Foundation.

The study was co-authored by Pamela Matson, dean of the School of Earth Sciences and senior fellow at the Woods Institute for the Environment at Stanford.

To better understand how farmers decide to adopt new technologies, the researchers interviewed growers, farm credit unions and agricultural experts in the Yaqui Valley in Sonora, Mexico – the birthplace of the "green revolution" in wheat and one of Mexico's most productive breadbaskets.

Matson and other Stanford researchers have been working in the Yaqui Valley for nearly 20 years. Among their objectives is demonstrating how science can inform agricultural policy in an area grappling with the kinds of environmental challenges that plague other intensive farming regions.

While Yaqui Valley supplies most of Mexico's wheat, the environmental costs are high, according to the Stanford researchers. Valley farms pollute local drinking water, wreck coastal ecosystems and foul the air with particulates that cause a variety of diseases.

"If scientists want to offer solutions to manage these environmental impacts, they need to understand what influences farmers' decisions about technology and production strategies," McCullough said.

Growers in Mexico's Yaqui Valley are more likely to adopt sustainable farming technologies that have been endorsed by local credit unions.

Credit union clout

In Yaqui Valley, credit unions hold sway among the majority of farmers, McCullough said. In addition to providing loans, crop insurance, fertilizer and seed, credit unions have taken over the government's role in providing technical expertise and management advice.

Valley growers also have a long history of working with the Mexico-based International Maize and Wheat Improvement Center, a world-renowned agricultural research center known by its Spanish acronym, CIMMYT.

But interviews conducted for the PNAS study revealed that most farmers take their cues from local credit unions and not from experts at CIMMYT. As an example, McCullough pointed to a collaborative effort between CIMMYT scientists and farmers to develop a nitrogen diagnostic tool that reduces fertilizer use without sacrificing crop yields.

The device, which gives real-time readings of nitrogen levels in the soil, proved early on that it could save farmers 12 to 17 percent of their profits. Yet most farmers rejected the new technology until CIMMYT researchers finally convinced credit union officials that it was a worthwhile investment.

"The most successful innovations that have been adopted by farmers in the Yaqui Valley have come from collaborations among researchers, farmers and local establishments, like the credit unions," McCullough said. Because of their considerable influence among farmers, credit unions should be included in any effort to effect environmental change in the region, she added.

"The Yaqui case negates the simplistic view of the one-way flow of scientific information from the agricultural research community to the user community," Matson said. "If researchers seek to produce relevant knowledge that ultimately influences decision making, they must recognize the dynamics of the local knowledge system and participate purposefully and strategically in it."

The research was supported with grants from the National Oceanic and Atmospheric Administration and the David and Lucile Packard Foundation.

Ten undergraduates recently received the 2011 Deans' Award for Academic Accomplishment, which honors extraordinary undergraduate students for "exceptional, tangible" intellectual achievements. Among them: CISAC honors student Anand Habib, a senior majoring in biology with honors in international security studies. He is completing an honors thesis focusing on health governance.

Habib sees his work as an intentional synthesis of scholarship and larger social commitments. He has lived this out in many ways at Stanford, including working on behalf of politically and medically disenfranchised people in India, Mexico and Guatemala. On campus, he has turned the Stanford tradition of the annual Dance Marathon into a vehicle dedicated to addressing the HIV/AIDS pandemic by engaging not only Stanford students but also local communities and corporations, raising more than $100,000. His exceptional work was recognized by his participation in the Clinton Global Initiative University Conference in April.

English Associate Professor Michele Elam described Habib as a "superb critical thinker" whose work is characterized by "creative genius" and "mature insights." She holds him up as a model for others, saying that "he exemplifies exactly the kind of deeply informed, pragmatic and caring leadership that the world needs and Stanford enables."

Policy brief: Climate trend and global crop production since 1980

Global warming is likely already taking a toll on world wheat and corn production, according to a new study led by Stanford University researchers. But the United States, Canada and northern Mexico have largely escaped the trend.

"It appears as if farmers in North America got a pass on the first round of global warming," said David Lobell, an assistant professor of environmental Earth system science and center fellow at the Program on Food Security and the Environment at Stanford University. "That was surprising, given how fast we see weather has been changing in agricultural areas around the world as a whole."

Lobell and his colleagues examined temperature and precipitation records since 1980 for major crop-growing countries in the places and times of year when crops are grown. They then used crop models to estimate what worldwide crop yields would have been had temperature and precipitation had typical fluctuations around 1980 levels.

The researchers found that global wheat production was 5.5 percent lower than it would have been had the climate remained stable, and global corn production was lower by almost 4 percent. Global rice and soybean production were not significantly affected.

The United States, which is the world's largest producer of soybeans and corn, accounting for roughly 40 percent of global production, experienced a very slight cooling trend and no significant production impacts.

Outside of North America, most major producing countries were found to have experienced some decline in wheat and corn (or maize) yields related to the rise in global temperature. "Yields in most countries are still going up, but not as fast as we estimate they would be without climate trends," Lobell said.

Lobell is the lead author of the paper, Climate Trends and Global Crop Production Since 1980, published May 5 online in Science Express.

Russia, India and France suffered the greatest drops in wheat production relative to what might have been with no global warming. The largest comparative losses in corn production were seen in China and Brazil.

Total worldwide relative losses of the two crops equal the annual production of corn in Mexico and wheat in France. Together, the four crops in the study constitute approximately 75 percent of the calories that humans worldwide consume, directly or indirectly through livestock, according to research cited in the study.

"Given the relatively small temperature trends in the U.S. Corn Belt, it shouldn't be surprising if complacency or even skepticism about global warming has set in, but this study suggests that would be misguided," Lobell said.

Since 1950, the average global temperature has increased at a rate of roughly 0.13 degrees Celsius per decade. But over the next two to three decades average global temperature is expected to rise approximately 50 percent faster than that, according to the report of the Intergovernmental Panel on Climate Change. With that rate of temperature change, it is unlikely that the crop-growing regions of the United States will continue to escape the rising temperatures, Lobell said.

"The climate science is still unclear about why summers in the Corn Belt haven't been warming. But most explanations suggest that warming in the future is just as likely there as elsewhere in the world," Lobell said.

"In other words, farmers in the Corn Belt seem to have been lucky so far."

This is the first study to come up with a global estimate for the past 30 years of what has been happening, Lobell said.

To develop their estimates, the researchers used publicly available global data sets from the United Nations Food and Agriculture Organization and from the University of Delaware, University of Wisconsin, and McGill University.

The researchers also estimated the economic effects of the changes in crop yield using models of commodity markets.

"We found that since 1980, the effects of climate change on crop yields have caused an increase of approximately 20 percent in global market prices," said Wolfram Schlenker, an economist at Columbia University and a coauthor of the paper in Science.

He said if the beneficial effects of higher carbon dioxide levels on crop growth are factored into the calculation, the increase drops down to 5 percent.

"Five percent sounds small until you realize that at current prices world production of these four crops are together worth nearly $1 trillion per year," Schlenker said. "So a price increase of 5 percent implies roughly $50 billion per year more spent on food."

Rising commodity prices have so far benefited American farmers, Lobell and Schlenker said, because they haven't suffered the relative declines in crop yield that the rest of the world has been experiencing.

"It will be interesting to see what happens over the next decade in North America," Lobell said. "But to me the key message is not necessarily the specifics of each country. I think the real take-home message is that climate change is not just about the future, but that it is affecting agriculture now. Accordingly, efforts to adapt agriculture such as by developing more heat- and drought-tolerant crops will have big payoffs, even today. "

Justin Costa-Roberts, an undergraduate student at Stanford, is also a coauthor of the Science paper. David Lobell is a researcher in Stanford's Program on Food Security and the Environment, a joint program of Stanford's Woods Institute for the Environment and Freeman Spogli Institute for International Studies. Schlenker is an assistant professor at the School of International and Public Affairs and at the Department of Economics at Columbia.

The work was supported by a grant from the Rockefeller Foundation.