A team led by FSE fellow David Lobell has found a valuable, untapped resource in historical data from crop yield trials conducted across sub-Saharan Africa. Combined with weather records, they show that yield losses would occur across 65 percent of maize-growing areas from a temperature rise of a single degree Celsius, even with sufficient water. Data from yield tests in other regions of the world could help predict changes in crop yields from climate change.

A hidden trove of historical crop yield data from Africa shows that corn - long believed to tolerate hot temperatures - is a likely victim of global warming.

Stanford agricultural scientist David Lobell and researchers at the International Maize and Wheat Improvement Center (CIMMYT) report in the inaugural issue of Nature Climate Change next week that a clear negative effect of warming on maize - or corn - production was evident in experimental crop trial data conducted in Africa by the organization and its partners from 1999 to 2007.

Led by Lobell, the researchers combined data from 20,000 trials in sub-Saharan Africa with weather data recorded at stations scattered across the region. They found that a temperature rise of a single degree Celsius would cause yield losses for 65 percent of the present maize-growing region in Africa - provided the crops received the optimal amount of rainfall. Under drought conditions, the entire maize-growing region would suffer yield losses, with more than 75 percent of areas predicted to decline by at least 20 percent for 1 degree Celsius of warming.

"The pronounced effect of heat on maize was surprising because we assumed maize to be among the more heat-tolerant crops," said Marianne Banziger, co-author of the study and deputy director general for research at CIMMYT."

"Essentially, the longer a maize crop is exposed to temperatures above 30 C, or 86 F, the more the yield declines," she said. "The effect is even larger if drought and heat come together, which is expected to happen more frequently with climate change in Africa, Asia or Central America, and will pose an added challenge to meeting the increasing demand for staple crops on our planet."

Similar sources of information elsewhere in the developing world could improve crop forecasting for other vast regions where data has been lacking, according to Lobell, who is lead author of the paper describing the study.

"Projections of climate change impacts on food production have been hampered by not knowing exactly how crops fair when it gets hot," Lobell said. "This study helps to clear that issue up, at least for one important crop."

While the crop trials have been run for many years throughout Africa, to identify promising varieties for release to farmers, nobody had previously examined the weather at the trial sites and studied the effect of weather on the yields, said Lobell, who is an assistant professor of environmental earth system science and fellow at Stanford's Program on Food Security and the Environment.

"These trials were organized for completely different purposes than studying the effect of climate change on the crops," he said. "They had a much shorter term goal, which was to get the overall best-performing strains into the hands of farmers growing maize under a broad range of conditions."

The data recorded at the yield testing sites did not include weather information. Instead, the researchers used data gathered from weather stations all over sub-Saharan Africa. Although the stations were operated by different organizations, all data collection was organized by the World Meteorological Organization, so the methods used were consistent.

Lobell then took the available weather data and interpolated between recording stations to infer what the weather would have been like at the test sites. By merging the weather and crop data, the researchers could examine climate impacts.

"It was like sending two friends on a blind date - we weren't sure how it would go, but they really hit it off," Lobell said.

Previously, most research on climate change impacts on agriculture has had to rely on crop data from studies in the temperate regions of North America and Europe, which has been a problem.

"When you take a model that has been developed with data from one kind of environment, such as a temperate climate, and apply it to the rest of the world, there are lots of things that can go wrong" Lobell said, noting that much of the developing world lies in tropical or subtropical climates.

But he said many of the larger countries in the developing world, such as India, China and Brazil, which encompass a wide range of climates, are running yield testing programs that could be a source of comparable data. Private agribusiness companies are also increasingly doing crop testing in the tropics.

"We're hoping that with this clear demonstration of the value of this kind of data for assessing climate impacts on crops that others will either share or take a closer look themselves at their data for various crops," Lobell said.

"I think we may just be scratching the surface of what can be achieved by combining existing knowledge and data from the climate and agriculture communities. Hopefully this will help catalyze some more effort in this area."

Lobell is a Center Fellow at the 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.

The work was funded by the Rockefeller Foundation

A team of researchers from Stanford University, the Carnegie Institution for Science, and Arizona State University has found that converting large swaths of land to bioenergy crops could have a wide range of effects on regional climate.

In an effort to help wean itself off fossil fuels, the U.S. has mandated significant increases in renewable fuels, with more than one-third of the domestic corn harvest to be used for conversion to ethanol by 2018. But concerns about effects of corn ethanol on food prices and deforestation had led to research suggesting that ethanol be derived from perennial crops, like the giant grasses Miscanthus and switchgrass. Nearly all of this research, though, has focused on the effects of ethanol on carbon dioxide emissions, which drive global warming.

"Almost all of the work performed to date has focused on the carbon effects," said Matei Georgescu, a climate modeler working in ASU's Center for Environmental Fluid Dynamics. "We've tried to expand our perspective to look at a more complete picture.  What we've shown is that it's not all about greenhouse gases, and that modifying the landscape can be just as important."

Georgescu and his colleagues report their findings in the current issue (Feb. 28, 2011) of the Proceedings of the National Academy of Sciences (see Direct Climate Effects of Perennial Bioenergy Crops in the United States). Co-authors are David Lobell of Stanford University's Program on Food Security and the Environment and Christopher B. Field of the Carnegie Institution for Science, also located in Stanford, California.

In their study, the researchers simulated an entire growing season with a state-of-the-art regional climate model. They ran two sets of experiments - one with an annual crop representation over the central U.S. and one with an extended growing season to represent perennial grasses. In the model, the perennial plants pumped more water from the soil to the atmosphere, leading to large local cooling. 

"We've shown that planting perennial bioenergy crops can lower surface temperatures by about a degree Celsius locally, averaged over the entire growing season. That's a pretty big effect, enough to dominate any effects of carbon savings on the regional climate." said Lobell.

The primary physical process at work is based on greater evapotranspiration (combination of evaporated water from the soil surface and plant canopy and transpired water from within the soil) for perennial crops compared to annual crops. 

"More study is needed to understand the long-term implication for regional water balance." Georgescu said. "This study focused on temperature, but the more general point is that simply assessing the impacts on carbon and greenhouse gases overlooks important features that we cannot ignore if we want a bioenergy path that is sustainable over the long haul."

OMAHA (DTN) -- China is the world's No. 1 producer and consumer of pork and poultry, producing more than five times the pork raised in the U.S. and 80 percent as much poultry. With its economic growth and increasing middle class, it is inevitable that meat consumption will rise.

The question is: Will China be able to continue to boost production sufficiently to meet that demand? The answer has implications for U.S. grain and meat producers.

"Rapidly rising incomes will have wrenching effects on the demand for food," said Scott Rozelle, agricultural economist at Stanford University. "As increasingly well-off consumers get fewer of their calories from rice and wheat, they will demand more from high-value products such as meat, fish, dairy and fruit. Urbanization has similar impacts, dampening the demand for rice and wheat and raising the demand for meat, fish, dairy and fruit. Trying to meet these rising -- and shifting -- demands will pose a large challenge."

Most importantly, given the great constraints China faces in arable land and water, the government has chosen to focus its agriculture in two ways: staple food crops such as rice and oilseeds and value-added products, said Francis Tuan, with USDA's Foreign Agriculture Service. It is aiming for a high percentage of self-sufficiency in staples to ensure its population doesn't go hungry. On the other hand, it wants to garner as much economic growth from agricultural production as possible.

"China is exporting more labor-intensive fruits and vegetables and higher-value commodities, while it is importing more land-intensive agricultural commodities, such as soybeans, cotton, sugar and dairy," Rozelle added. "These shifts are obviously more in line with China's comparative advantage."

One example of that trend is China's purchases of raw soybeans to be crushed in China for oil. Another is some farmers leaving crop production to focus on livestock.

New scientific tool, GAPI, assesses impact of global aquaculture. FSE research associate Alice Chiu on the advisory committee that pulled together this new tool and report.

Industrial-scale aquaculture production magnifies environmental degradation, according to the first global assessment of the effects of marine finfish aquaculture (e.g. salmon, cod, turbot and grouper) released today. This is true even when farming operations implement the best current marine fish farming practices.

University of Victoria marine ecologist Dr. John Volpe and his research team have developed the Global Aquaculture Performance Index (GAPI), an unprecedented system for objectively measuring the environmental performance of fish farming.

"Scale is critical," says Volpe. "Over time, the industry has made strides in reducing the environmental impact per ton of fish, but this does not give a complete picture. Large-scale farming of salmon, for example, even under the best current practices, creates large-scale problems."

The fish farming industry is an increasingly important source of seafood, especially as many wild fisheries are in decline. Yet farming of many marine fish species has been criticized as causing ecological damage. For instance, the researchers found that the relatively new marine finfish aquaculture sector in China and other Asian countries lags in environmental performance.

Adds Volpe: "The fastest growing sector is Asia, where we found a troubling combination of poor environmental performance and rapidly increasing production."

With support from the Lenfest Ocean Program, Volpe and his team developed GAPI, which uses 10 different criteria to assess and score environmental impacts. Incorporating information such as the application of antibiotics and discharge of water pollutants, GAPI allows researchers to gauge which farmed species and countries of production have the best or worst environmental performance.

The researchers examined the environmental impact of marine fish farming per ton of fish produced and the cumulative environmental impact for each country producing a major farmed species.

"GAPI provides a valuable tool for developing environmentally responsible fish farming. Governments can use GAPI to inform policies and regulations to minimize the environmental footprint of fish farming. Farmers can use it to improve production practices. And buyers can use it to compare and select better, more environmentally friendly seafood options," says Chris Mann, senior officer and director of the Pew Environment Group's Aquaculture Standards Project, which collaborated on the work.

For further information on GAPI, including a summary of the methodology and findings, visit www.lenfestocean.org.

The GAPI 2010 report released today is based on 2007 data, the most recent year for which data for all aquaculture indicators are available. GAPI analysis will be updated periodically as additional data becomes available. For additional information, updated research and analysis, please see the GAPI website at www.gapi.ca.

The Lenfest Ocean Program supports scientific research aimed at forging solutions to the challenges facing the global marine environment. The program was established in 2004 by the Lenfest Foundation and is managed by the Pew Environment Group.

The University of Victoria is a national and international leader in the study of the oceans, with expertise as far-ranging as ocean-climate interactions, ocean observation systems, physical and chemical oceanography, marine ecology, coastal resource management and ocean engineering