Benin solar market garden project one of five most hopeful energy projects of 2012
The Center on Food Security and the Environment is a joint effort of the Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment.
Scientists are making progress in helping millions of wheat farmers adapt to hotter conditions, but the gains have been uneven, reports a new study led by Stanford University. New approaches to breeding are needed to withstand increasingly common heat waves and keep pace with growing global food demand.
Wheat is the most widely grown crop in the world; unfortunately it is also one of the most sensitive to future global warming. Scientists around the world strive to develop new wheat varieties each year that incorporate improved features, much like car companies release new models each year. Different strategies are commonly used; some target fully irrigated conditions that favor very high yields, while others focus on dry and hot conditions where yield maintenance under stress is a priority.
The team, which includes scientists from Stanford and the International Maize and Wheat Improvement Center (known as CIMMYT), evaluated 25 years of data from historical trials around the globe and analyzed the outcome of different past breeding approaches to help prioritize future strategies. The fully irrigated nursery, known as the elite spring wheat yield trials, produces varieties that are released for the majority of wheat farmers in countries like India and Egypt each year. While cultivars selected under stressed conditions showed significant yield progress at higher temperatures, the elite trials did not.
“There has been very impressive progress in improving yields for the elite varieties at the cooler temperatures that wheat prefers,” explains lead author Sharon Gourdji, a post-doctoral scholar in Stanford’s department of Environmental Earth System Science and Center on Food Security and the Environment (FSE).
“However, to date, our analysis shows a lack of yield gains for these varieties in hot environments over the past 25 years. Along with the gains in cool conditions, this means that the yield difference between cool and hot conditions is getting larger.”
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A CIMMYT researcher plants wheat seed in pots in the center's greenhouse facilities. Photo credit: X. Fonseca/CIMMYT
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"I think we have learned that the current main approach to breeding won't quite cut it in terms of adapting wheat to climate change,” said co-author David Lobell, assistant professor in Environmental Earth System Science and FSE center fellow. “That is useful information as breeding centers try to raise their game to contend with long-term warming."
Lobell notes that there are good reasons why improved heat tolerance for the elite varieties has not happened naturally.
“Breeding is tough since scientists are aiming for so many traits at once – for example, disease resistance, high yields, and good quality for bread making. Adding heat tolerance is like telling a scout looking for a superstar athlete, ‘by the way, make sure he’s a straight A student’,” said Lobell.
One important lesson from the study is that sifting through historical data can help identify what works and what does not.
“It can often be a hard sell to have breeders take the time to send their data back once they have selected their varieties and moved on,” explains CIMMYT wheat physiologist and co-author Matthew Reynolds. “This study clearly demonstrates the advantage of having these data to assess progress. It shows the genetic potential of wheat to adapt to warmer-than-usual conditions, and reinforces the value of screening under stress as a strategy for adaptation to climate change.”
The progress in the nursery targeted towards stress conditions shows that it is possible to make sizable gains in improving heat tolerance. But whether this can be combined with continued high performance under cooler conditions remains to be seen.
“It is critically important for farmers that they not only survive the bad or hot years, but that they can take full advantage of the favorable years” says Gourdji. “What is needed is a breeding strategy that can successfully achieve both.”
This work was supported by a grant from the Rockefeller Foundation. Additional co-authors of the study include CIMMYT’s Ky Mathews and Jose Crossa.
Genetic improvements in heat tolerance of wheat provide a potential adaptation response to long-term warming trends, and may also boost yields in wheat-growing areas already subject to heat stress. Yet there have been few assessments of recent progress in breeding wheat for hot environments. Here, data from 25 years of wheat trials in 76 countries from the International Maize and Wheat Improvement Center (CIMMYT) are used to empirically model the response of wheat to environmental variation and assess the genetic gains over time in different environments and for different breeding strategies. Wheat yields exhibited the most sensitivity to warming during the grain-filling stage, typically the hottest part of the season. Sites with high vapour pressure deficit (VPD) exhibited a less negative response to temperatures during this period, probably associated with increased transpirational cooling. Genetic improvements were assessed by using the empirical model to correct observed yield growth for changes in environmental conditions and management over time. These ‘climate-corrected’ yield trends showed that most of the genetic gains in the high-yield-potential Elite Spring Wheat Yield Trial (ESWYT) were made at cooler temperatures, close to the physiological optimum, with no evidence for genetic gains at the hottest temperatures. In contrast, the Semi-Arid Wheat Yield Trial (SAWYT), a lower-yielding nursery targeted at maintaining yields under stressed conditions, showed the strongest genetic gains at the hottest temperatures. These results imply that targeted breeding efforts help us to ensure progress in building heat tolerance, and that intensified (and possibly new) approaches are needed to improve the yield potential of wheat in hot environments in order to maintain global food security in a warmer climate.
Soybean production has become a significant force for economic development in Brazil, but has come at the cost of expansion into non-protected forests in the Amazon and native savanna in the Cerrado. Over the past fifty years, production has increased from 26 million to 260 million tons. Area planted to soybeans has increased from roughly 1 million hectares in 1970 to more than 23 million hectares in 2010, second only to the United States.
A new study out of Stanford University examines the role of institutions and supply chain conditions in Brazil’s booming soybean industry and the relationship between soy yields and planted area. With the demand for soybeans projected to increase far into the future a better understanding of the economic and institutional factors influencing production can help policymakers better manage land use change.
Using county level data the researchers found that soy area and yields are higher in areas with high cooperative membership and credit levels, and where cheap credit sources are more accessible. Cooperatives help producers secure lower prices for inputs or higher prices for outputs through group purchases and sales. They also enable producers to store their grain past the harvesting period and sell it when prices are higher.
“This suggests that soybean production and profitability will increase as supply chain infrastructure improves in the Cerrado and Amazon,” said lead author Rachael Garrett, a PhD student in Stanford’s Emmett Interdisciplinary Program in Environment and Resources.
The authors did not find a significant relationship between land tenure and planted area or land tenure and yields. But found that yields decline and planted area actually increases as transportation costs increase. More importantly, the study showed counties with higher yields have a higher proportion of land planted in soy.
“Policies intending to spare land through technological yield improvements could actually lead to land expansion in the absence of strong land use regulations if demand and per hectare profits are high,” said co-author Rosamond L. Naylor, director of Stanford’s Center on Food Security and the Environment.
The current Forest Code requires rural land users in the Amazon to conserve 80% of their property in a ‘Legal Reserve’, and landowners in the Cerrado to conserve 20%. Historically, illegal clearings have been common and enforcement of the Legal Reserve requirements remains poor.
While this study focuses on Brazil, the results underscore the importance of understanding how supply chains influence land use associated with cash crops in other countries. Future demand for soybeans, as well as for cash crops like Indonesian palm oil, will continue to grow as demand for cooking oil, livestock feed, and biodiesel increase with income growth and changing dietary preferences in emerging economies.
Wheat is a staple crop throughout much of India, but in many areas it is commonly sown past the optimum yield window. A study led by FSE associate director David Lobell uses satellite measurements to estimate a decade’s worth of sow dates in wheat-growing areas of India.
The study finds, among other developments, that wheat was sown one week earlier by 2010 than it was at the beginning of the decade, a change that explains 5% in country-wide yield gains. It also predicts that yield benefits from sow date shifts will likely diminish in the next decade.
"There's an important, one time boost farmers have gotten recently from moving into the optimum sowing window, but the data suggest this effect will run out of steam in the coming years," says Lobell.
Without coordinated global action on climate change, it will be increasingly hard to reduce poverty in the world's poorest countries, said UN Development Program Administrator Helen Clark. Clark's visit to campus comes a few weeks before global climate negotiations are set to begin in Doha, Qatar.
She highlighted ways in which climate change will, and is already, impacting food security in the world's most vulnerable regions:
Summary
Climate change can reasonably be expected to increase the frequency and intensity of a variety of potentially disruptive environmental events-slowly at first, but then more quickly. It is prudent to expect to be surprised by the way in which these events may cascade, or have far-reaching effects. Over the coming decade, some climate-related events will produce consequences that exceed the capacity of affected societies or global systems to manage; these may have global security implications. Although focused on events outside the United States, Climate and Social Stress: Implications for Security Analysis recommends a range of research and policy actions to create a whole-of-government approach to increasing understanding of complex and contingent connections between climate and security, and to inform choices about adapting to and reducing vulnerability to climate change.
Stanford Woods Institute for the Environment
473 Via Ortega
Stanford, CA 94305-4020
Amy Pickering is a research associate and lecturer at Stanford University. She received a BS in biological engineering at Cornell University, a MS in environmental engineering from the University of California, Berkeley and a PhD in interdisciplinary environment and resources at Stanford University. Her current research interests include understanding the relationship between water access, food security, sanitation and infectious disease in rural communities in Kenya, Bangladesh, and Mali.
Outside of China, the world now has more food insecure and nutrient deficient people than it had a decade ago, and the prevalence of obesity-related diabetes, high blood pressure and cardio-vascular diseases is increasing at very rapid rates. Expanded food production has done little to address the fact that between one-third and one-half of all deaths in children under five in developing countries are still related to malnutrition.
“With only three years away from the Millennium Development Goals deadline, this is a terrible track record,” said food and nutrition policy expert Per Pinstrup-Andersen at FSE's Global Food Policy and Food Security Symposium Series last week.
Pinstrup-Andersen, the only economist to win the World Food Prize (the ultimate award in the food security field), has dedicated his career to understanding the linkages between food, nutrition, and agriculture. What is driving persistent food insecurity and malnutrition in a food abundant world?
Poor food supply management is part of the problem. According to the United Nations Food and Agricultural Organization (FAO), 20-30% of food produced globally is lost every year. That’s enough to feed an additional 3-3.5 billion people.
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Jatropha in Africa. Photo credit: Ton Rulkens/flickr.
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Biofuels production, such as jatropha in Africa, now competes with food for land, and climate change is already negatively impacting crop yields in regions straddling the equator—with major implications for food supply.
For low-income consumers in both the U.S. and developing countries increasing and more volatile food prices, such as those seen in 2007, are also driving food insecurity. Poor consumers respond by purchasing cheaper, less nutrient food, and less of it.
Nutritional value chain
Consensus is developing—at least rhetorically—among national policymakers and international organizations that investments in agricultural development must be accelerated. Members of the G8 and G20 have committed $20 billion in international economic support for such investments and some developing countries such as Ethiopia and Ghana are planning large new investments.
While most of these recent initiatives focus on expanded food supplies, there is an increasing understanding that merely making more food available will not assure better food security, nutrition, and health at the household and individual levels.
“It matters for health and nutrition how increasing food supplies are brought about and of what it consists,” said Pinstrup-Andersen. “We need to turn the food supply chain into a nutritional value chain.”
Diet diversity is incredibly important for good nutrition. Agricultural researchers and food production companies need to look at a number of different commodities, not just the major food staples, said Pinstrup-Andersen.
“The Green Revolution successfully increased the production of corn, rice, and wheat, increasing incomes for farmers, and lowering prices for consumers, but now it is time to invest in fruits, vegetables and biofortification to deal with micronutrient deficiency,” said Pintrup-Andersen.
Biofortification, the breeding of crops to increase their nutritional value, offers tremendous opportunity for dealing with malnutrition in the developing world, but is not widely available.
This is particularly important for areas in sub-Saharan Africa where between one and three and one and four people are short in calories, protein, and micronutrients. Obesity is actually going up in these countries with the introduction of cheap, processed, energy-dense foods (those high in sugar and fat) contributing to the diabetes epidemic.
Pathways to better health
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Women hauling water to their gardens in Benin.
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The path to better health and nutrition must look beyond the availability of food at affordable prices, clean water, and good sanitation, and consider behavioral factors such as time constraints for women in low-income households.
“Field studies have shown time and time again that one of the main factors preventing women from providing themselves and their families with good nutrition is time,” explained Pinstrup-Andersen.
He told the story of a woman in Bolivia too burdened with farm and household responsibilities to take the time to breastfeed her six-month old daughter. Enhancing productivity in activities traditionally undertaken by women could be a key intervention to improving good health and nutrition at the household level.
Access is another issue. A household may be considered food secure, in that sufficient food may be available, but food may not be equally allocated in the household.
“If we focus on the most limiting constraint we can be successful,” said Pinstrup-Anderen. “But we must tailor our response to each case.”
For sub-Saharan Africa, this includes investments in rural infrastructure, roads, irrigation systems, micronutrient fertilizer, climate adaptation strategies, and other barriers holding back small farmers.
Fortunately, there has been a renewed attention to the importance of guiding food system activities towards improved health and nutrition. The Global Agriculture and Food Security Program (GAFSP), which facilitates the distribution of some of the G8 and G20 $20 billion commitments, prescribes that country proposals for funding of agricultural development projects must show a clear pathway from the proposed agricultural change to human nutrition.
“But it’s not going to be easy to implement good policies,” warned Pinstrup-Andersen. “There are few incentives in government for multidisciplinary problem solving. The economy is set up around silos and people are loyal to their silos. Agricultural and health sectors are largely disconnected in their priorities, policy, and analysis."
Incentives must change to encourage working across ministries and disciplines to identify the most important health and nutrition-related drivers of food systems, impact pathways, and policy and program interventions to find win-wins for positive health and nutrition.