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Climate change, agriculture, and global security

Climate change models generally suggest that rising temperatures and seas, fresh-water shortages, desertification, and weather extremes will severely affect developing countries. Under global warming scenarios, cereal grain yields and quality in many developing countries are expected to decline, nitrogen leaching and soil erosion could intensify, and land and water resources for food production will degrade. Policies promoting biofuels in industrialized nations are leading to increases in international food prices, reduced food security, and heightened pressure on natural resources in developing countries. Governments, farmers (particularly smallholders), and poor consumers will have trouble coping.

CIMMYT is working with partners worldwide to mitigate these and other effects of climate change on the poor in developing countries. The efforts will help maize and wheat farmers to increase productivity using tomorrow’s limited land and water resources and to deal with environmental and market instabilities.

The weather forecast? Harvests drizzle, prices heat up
Climate vulnerability in developing world regions like Africa is already high (see figure below). Studies for major maize and wheat production areas in key parts of the developing world suggest that changes in temperature, growing season length, and rainfall patterns will significantly reduce crop yields, challenging farmers’ ability to make a living and affecting regional food security and livelihoods.

Maize in sub-Saharan Africa and Latin America. In their 2003 study,1 CGIAR scientists Peter G. Jones and Philip K. Thornton took outputs from leading climate simulation models and data from various sources, including the Intergovernmental Panel on Climate Change and the Food and Agriculture Organization world soil maps, to simulate the growth, development, and yield of maize crops over sub-Saharan Africa, Central America, and South America. The results showed an aggregate yield decline by 2055 for smallholder rainfed maize production of 10%, representing an annual economic loss on the order of US $2 billion. Even more critical for poverty, the authors say this figure masks enormous regional and local variation in subsistence farming systems, particularly in the many settings where maize stover is fed to livestock in the dry season. Follow-up research for sub-Saharan Africa,2 based on projected temperature increases and changes in rainfall patterns, suggests that by 2050 the cropping season will shorten in many parts of the region. Under one of the study’s scenarios—that of rapid economic growth and globalization driving a continued, significant rise in temperature—drought becomes ever more likely by mid-century, causing failed crops and making maize farming untenable in key maize production areas of eastern and southern Africa.

Wheat in the heat. If maize, which evolved under tropical conditions, will be challenged by rising temperatures, researchers are saying that wheat, a crop which traces its origins to temperate climes, will suffer even more serious effects. In fact, this is occurring even now. Studies in the Yaqui Valley3 of northern Mexico have demonstrated that high wheat yields in tropical areas are strongly associated with low average temperatures—especially minimum temperatures—and high radiation levels around the time the crop flowers. Rising world temperatures would make many current, important wheat areas too hot for the crop.

A recent CIMMYT study4 details possible climate shifts in the Indo-Gangetic Plains of South Asia, a region of 13 million hectares that extends from Pakistan across northern India, Nepal, and Bangladesh. The area is home to more than one-fifth of humanity and accounts for 15% of the world’s wheat production. Much of the region is currently classed as an irrigated, high-potential wheat production environment. According to the study, by 2050 more than half of its area may become heat-stressed for wheat, with a significantly shorter season for the crop. If farmers continue to use current wheat cultivars and farming practices, the region’s productivity will drop dramatically. Dwindling water supplies for South Asia, the North China Plain, and many other irrigated wheat zones worldwide will make the situation even more critical.

Harvesting energy or food? Faced with the high economic, political, and environmental costs of petroleum products, China, Europe, India, Japan, the USA, and other states have committed to ambitious targets for using biofuels to meet future energy needs. Bioethanol accounts for nearly 90% of biofuel production. Most comes from maize grain or sugarcane,but producers will increasingly use cellulose, such as straw, stover, and other crop biomass. Price hikes forbiofuel crops, plus the displacement of food and feed crops, is driving up basic food grain costs. This creates opportunities for some cereal producers, but risks for consumers, including small-scale farmers in developing countries. Over the last year, the world prices for maize and wheat have soared. It takes 240 kilograms of maize grain— roughly equivalent to the average yearly per capita consumption of the crop in Malawi—to produce enough ethanol (100 liters) to fill the tank of a single sports utility vehicle. In Mexico escalating maize tortilla prices spurred a fierce public outcry. Food price inflation affects everyone, but the poor suffer most, as they spend a large portion of their income on food. Whereas increasing use of biofuels may reduce greenhouse gas emissions, intense biofuel cropping could also threaten water tables and degrade soils in many areas. Who will win and who will lose from biofuel expansion requires further study.

A basis for hope?
The above serves to illustrate how the world’s food production and environmental trends could lead to widespread crises and instability. Researchers in many quarters are working to better understand climate change, finding and promoting ways to slow the rise in temperatures and to mitigate negative impacts. CIMMYT helps resource-poor maize and wheat farmers secure food and livelihoods in changing economies and environments, developing resilient, resource-conserving cropping systems and practices, maize and wheat varieties that withstand heat and drought, risk reducing livelihood strategies for people who grow those crops, and support to partners worldwide in related work.

Stress tolerant crop varieties. Improved maize varieties that tolerate drought, heat, and low soil fertility will help maize farmers in stress-prone areas to obtain better harvests under dry conditions and higher temperatures. The Center earned the 2006 King Baudouin Award for its work on stress tolerant maize with partners in sub-Saharan Africa. Efforts there are based on a method developed over a decade at CIMMYT in Mexico, with support from the United Nations Development Program.5 Rather than selecting exclusively under well-fertilized, well-irrigated conditions, as was done previously worldwide, CIMMYT and national breeders prioritized the major stresses found in farmers’ fields—drought, low soil fertility, insect pests, acid soils—and replicated them on breeding stations. In southern Africa alone, enough seed of new, stress tolerant varieties has been produced to sow two million hectares. The work has received added impetus through funding in 2006 from the Bill & Melinda Gates Foundation, and is being extended to Asia and Latin America.

The Center has also developed wheats that are better at using available water to produce grain. Experimental varieties derived from crosses between wheat and goat grass, one of wheat’s wild relatives, produced up to 30% more grain than their wheat parents, in tests over two years under tough dryland conditions.6 In more recent experiments, this type of wheat outyielded its pure wheat parents by 18% under both irrigated and droughted conditions, due in part to an increased ability to take up water from greater depths, superior water use efficiency, and, possibly, improved early vigor that increases ground cover and thereby conserves soil moisture.7 These wheat varieties can help farmers in irrigated areas, where water is growing scarce, as well as resourcepoor farmers who grow the crop under rainfed conditions for food, income, and livestock fodder. They are being used in breeding programs worldwide, and their derivatives are being released to farmers in China and highland Ecuador. Meanwhile, CIMMYT scientists are seeking and testing new sources of drought tolerance from gene bank collections and other wheat or grass species, including wheat landraces brought to Mexico by Spanish colonizers and grown for centuries under dry conditions.

CIMMYT breeders have worked for nearly two decades to develop heat tolerant wheat. They have identified key physiological traits associated with higher yields in heatstressed environments, including low canopy temperatures and high leaf chlorophyll content during grain filling.8 Partly as a result of the development and release of improved, stress tolerant varieties by CIMMYT and partners, wheat yields improved 2-3% per year in dry and heat stressed environments in developing countries during 1979-1995.9

Saving soil, water, money. Fundamental changes in farming practices will be central to getting maximum benefits from improved maize and wheat and to addressing and mitigating climate change. CIMMYT has studied and fostered testing and adoption by farmers of various resource-conserving practices—including conservation tillage and keeping a crop residue cover on the soil—to save food production costs and resources, and maintain or improve soil quality. A long-term field experiment begun in 1991 in Mexico’s central highlands involves maize and wheat rotations and varied tillage and residue management methods, all under entirely rainfed conditions. Results suggest considerable benefits from zero-tillage, if residues from preceding crops are kept on the soil.10

The Rice-Wheat Consortium (RWC) for the Indo-Gangetic Plains, an award-winning partnership organized by CIMMYT, has fostered the adoption of conservation tillage to sow wheat after rice by farmers on nearly 2 million hectares in South Asia. The practice results in a net savings of 50 liters or more of diesel per hectare, greatly reduced water use, and lower CO2 emissions. These and other practices being tested by farmers (for example, sowing on permanent, raised beds) provide a better soil cover, moderate soil temperatures, and reduce the evaporation of irrigation water.

Fertilizer is another resource whose efficient use can improve crop productivity and reduce greenhouse gas emissions and other damage to the environment. With the Center’s help, wheat farmers in irrigated zones of Latin America and South Asia are testing use of infrared sensors to fine-tune fertilizer amounts, timing, and application methods. This saves money for farmers and cuts emissions of nitrous oxide, a gas with some 300 times the greenhouse effects of carbon dioxide. Research to date also supports the hope of using wheat’s grassy relatives as a source of genes to inhibit soil nitrification and the associated release of nitrous oxide.

For maize, CIMMYT is promoting conservation tillage and residue retention with smallholder maize farmers in Mexico and sub-Saharan Africa to improve soil health and to capture and preserve precious rainfall. In Africa, work focuses on Malawi, Tanzania, Zambia, and Zimbabwe; countries where smallscale, maize-based farming systems provide food and livelihoods for millions but degrade soils. Farmers have tested the improved practices for several years and generally like the cost savings and improved soil moisture. There are still multiple challenges to adoption—for example, livestock are often a key part of livelihood strategies in Africa, and crop residues fetch a better price as cattle fodder than as a soil cover. Experts also predict that a move to biofuels based on cellulose will eventually raise the price of maize and wheat stalks and straw, giving farmers greater reason to remove and sell those crop residues. Studies are needed to determine the precise amounts of residues required to maintain soil quality and, conversely, how much can safely be removed in either irrigated or rainfed settings.

Socioeconomic research, knowledge-sharing. Resource efficient crop varieties and knowledge-intensive, conservation agriculture farming practices must be properly tested by scientists and with farmers. Participatory and socioeconomic research by CIMMYT supports such efforts, as in the case of the RWC or work on stress tolerant maize for sub-Saharan Africa. It also elucidates economic and policy issues relating to climate change and developing world agriculture. For example, a recently-completed series of studies on maize production in marginal areas of seven Asian nations is serving as a baseline against which to gauge changes and devise interventions.11 Addressing new climate conditions will require complex policies and adjustments at many levels in developing country agriculture. Many players in maize and wheat market chains could benefit from reliable information on the economic opportunities and risks associated with biofuel expansion. Socioeconomics knowledge will help guide the use of Center resources best to catalyze relevant change among a wide range of stakeholders and partners.

CIMMYT can develop and share information dissemination products/systems about climate change for farmers, policy makers, and others in agricultural market chains. This will be crucial, given that farmers will need to apply knowledge-intensive practices such as increased cropping diversification, use of rotations to manage pests and pathogens, and generally more robust systems that provide insurance against risks and shocks from climate extremes.

Information technology and monitoring systems. Building on linkages within the center’s global maize and wheat nursery systems and geographic information system capacity and partnerships, it will be possible to form networks that allow researchers to follow and anticipate the movement of pathogens, pests, and invasive species and share the information with relevant stakeholders. For example, CIMMYT characterizations of heat-stressed wheat environments are being refined using spatial analysis and climatic factors identified through multi-location trials in those environments.

No security without food security. It is already clear that the security and quality of life of affluent nations are closely tied to conditions and events in the developing world. A 2007 report by the German Advisory Council on Climate Change,12 states that “…without resolute counteraction, climate change… could result in destabilization and violence, jeopardizing national and international security to a new degree.” Falling agricultural yields would block development and heighten poverty, thereby increasing the risk of conflicts. Decades prior to that report, CIMMYT wheat breeder and 1970 Nobel Peace Laureate, Norman Borlaug, said roughly the same thing in these terms: “If you desire peace, cultivate justice, but at the same time cultivate the fields to produce more bread; otherwise there will be no peace.”

Now and in the future, CIMMYT contributes to global security and peace by improving the food security and livelihoods of those who depend on maize and wheat farming in developing countries.

See also:

Science to benefit the disadvantaged: Flagship products

Trustees and principal staff (PDF version 260kb)

Financial Overview and Contact information (PDF version 602kb)

 

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