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Global climate change poses particular risks to poor farmers in developing countries, but there are steps that farmers, policymakers, and researchers can take to minimize losses and adapt to climate change.

Climate change, it appears, is now under way. Since 1900 the global mean temperature has increased by 0.7 degree Celsius. The Intergovernmental Panel on Climate Change (IPCC) has concluded that human activities that emit greenhouse gases into the atmosphere are responsible for most of the warming of at least the past 50 years.

Past emissions that are already in the pipeline mean that even if global emissions stopped today, the Earth's temperature would rise by about 0.5 to 1.0 degree Celsius over the next several decades. If global emissions stabilize at today's level, the temperature would increase by 2 to 5 degrees Celsius by the time it reaches equilibrium. And if emissions continue to grow at current rates, they would cause temperatures to rise by 3 to 10 degrees Celsius, not including climate feedback effects that could further exacerbate climate change in a vicious circle.

Awareness of climate change and its risks has now made it firmly onto the international agenda. Former U.S. vice president Al Gore recently released a documentary, An Inconvenient Truth, on the risks of global warming, and in October 2006 Sir Nicholas Stern, a U.K. Treasury official and former World Bank economist, published the "Stern Review on the Economics of Climate Change," a 700-page report arguing that the risks are large and the costs of acting now are relatively small.

"Climate change is rapidly emerging as one of the most serious threats that humanity may ever face," said Kenyan Environment Minister Kivutha Kibwana at the opening of the United Nations Climate Change Conference on November 6. The conference, of which Kibwana was president, brought together representatives of the 166 parties to the Kyoto Protocol for their second meeting.

Because it is linked so closely to natural resources and climate conditions, agriculture will keenly feel the effects of climate change through changes in both temperature and precipitation, and thus the availability of water for growing food. Scientists predict that the interiors of major continents will warm more quickly than the oceans. In addition, current weather extremes are likely to be exacerbated. It is likely that wet areas of the world will get even wetter, and dry areas will get drier. Thus, for example, monsoons in South Asia will intensify, while arid regions of Africa will become drier. Mark Rosegrant, director of IFPRI's Environment and Production Technology Division, points out, "Agriculture is the largest consumer of water globally, and as climate change alters the quantity and reliability of water supplies, it could threaten the welfare of millions of poor farmers."

Clearly, controlling and ultimately reducing greenhouse gas emissions are essential to minimizing the severity of global climate change and its harmful effects. Yet global warming has already begun, and given the levels of past greenhouse gas emissions, it will continue for decades.

According to Bob Watson, the World Bank's chief scientist and advisor for environmentally and socially sustainable development, "The Earth's climate is already changing, and further change is inevitable. Therefore we need to both mitigate climate change and to adapt to climate change. Clearly, the industrialized countries must take the lead in mitigating climate change by reducing greenhouse gas emissions, but large developing countries such as India and China will also have to start to reduce their emissions over the next 20 to 30 years, albeit with differentiated responsibilities. But for many countries, especially in Africa and small countries in Asia and Latin America, the challenge of the day is adaptation to current climate variability and climate change."

Of all the world's regions, Africa is likely to be hardest hit by the impacts of global warming. Climate models differ, but according to the U.K.'s Hadley Centre for Climate Change, a leading producer of global climate change estimates, temperature increases in parts of Africa could be double the global average increase. Given Africa's heavy dependence on agriculture—agriculture employs 70 percent of people in Africa—the effects of climate change could put millions of people there at greater risk of poverty and hunger.

Africa is particularly vulnerable to climate change because of its high proportion of low-input, rainfed agriculture, compared with Asia or Latin America, according to Siwa Msangi, an IFPRI researcher. The Food and Agriculture Organization of the United Nations (FAO) reports that rainfed agriculture is used on 95 percent of cropland in Sub-Saharan Africa. "This type of exposure to rainfall variability also extends to livestock, which mostly depend on range and grasslands that are affected by environmental shocks, such as climate change," says Msangi.

In addition, temperatures in Africa are already generally high and rainfall patterns often erratic, and climate change that exacerbates these conditions will thus create even more hardship. Most important, poverty is widespread in Africa, and governments typically face tight budget constraints, making it much harder for individuals and governments to invest in adaptations to climate change.

Moreover, Africa accounts for 30 percent of global land degradation, so farmers are already struggling to grow crops on land that contains inadequate nutrients and has little capacity to retain water. According to a November 2006 report from the United Nations Framework Convention on Climate Change (UNFCCC), climate models show that 80,000 square kilometers of agricultural land in Sub-Saharan Africa that is currently classified as water constrained will experience more rainfall with climate change. On the other hand, a much larger 600,000 square kilometers classified as moderately water constrained will become severely water limited. This will create even more challenges for African farmers, even for subsistence crops like millet, groundnuts, and sorghum.

Farmers in developing countries will clearly need to adapt to a climate that is changing and will change further. Farming practices will have to change in many regions. In the face of drier, hotter weather, farmers may need to switch the crops they grow. For example, farmers in some areas of Africa may switch from maize to sorghum, which requires less water. Or they may switch to more drought-resistant or heat-resistant varieties of the crops they already grow.

Before adaptation can be implemented at the farm level, farmers need to perceive a need to change. According to surveys conducted by IFPRI and its partners in Sub-Saharan Africa, 90 percent of farmers in South Africa's Limpopo basin have noticed increased temperatures and reduced precipitation levels over the past 20 years, while in the highlands of Ethiopia's Nile River basin, 53 percent have perceived increased temperatures and 61 percent noticed declining precipitation. Yet fewer than half of the farmers who perceived long-term changes in climate actually implemented adaptation measures. Farmers cited insufficient access to credit as the most important obstacle to adaptation in South Africa, and lack of access to information on climate as well as options for adaptation in the Ethiopian highlands. According to Claudia Ringler, an IFPRI research fellow, successful adaptation will require not only new crop technologies and increased investments in water security in rural areas, but also policy actions to give small-scale subsistence farmers better access to information, credit, and markets.

Work is already underway on developing heat- and drought-resistant varieties of staple crops. A project in Southern Africa, for instance, involving the International Maize and Wheat Improvement Center (CIMMYT) and partners in the region has released drought-tolerant maize varieties that yield 34 percent more than farmers' existing varieties in Malawi, South Africa, Tanzania, and Zimbabwe. According to Rodomiro Ortiz, director of resource mobilization at CIMMYT, farmers can benefit by changing not only what they grow, but how they grow it. CIMMYT scientists are working on developing wheat varieties that are well suited to zero-tillage farming, as well as heat-tolerant, for farmers in the Indo-Gangetic Plain of India. By drastically reducing farmers' manipulation of the soil, zero-tillage farming helps conserve water and nutrients for crops and, as an added benefit, reduces the amount of carbon dioxide released from the soil into the atmosphere, where it contributes to climate change. The Indo-Gangetic Plain is currently a highly productive, irrigated agricultural area, but climate models show that by 2050 as much as half of the region may be reclassified from a high-potential area to a heat-stressed area with a short growing season.

Regional cropping patterns will need to adjust to changing climates. A 2006 Texas A&M University study reached this conclusion when looking at the implications of climate change for food security in Mali. Currently, farmers in the region of Sikasso in relatively cool, wet southern Mali grow mainly maize and cotton, whereas farmers in Segou in hotter, drier northern Mali grow mainly sorghum and millet. As the climate of Sikasso becomes more like that of Segou, the farmers of Sikasso could benefit by growing the crops of Segou, the study found. As Segou becomes still hotter and drier, however, "its farmers may be left with few options," says Tanveer Butt, leader of the study. "The north will become more like the Sahara Desert."

So what are farmers to do if, despite their efforts to adapt, a drought or heat wave decimates their crops? One solution currently being tried in some areas is weather-indexed crop insurance. Insurance will not help farmers who confront permanent climate shifts that reduce the viability of agriculture, but it may be relevant for those who face more volatile weather events. Weather-indexed insurance pays out to farmers based not on their yield losses, but on specific, local weather-related benchmarks. But establishing effective crop insurance programs raises some challenges. Peter Hazell, formerly director of IFPRI's Development Strategy and Governance Division, cautions, "Insurance can be expensive and may not be affordable by the poor people who need it most. The cost is also likely to increase as the probability of more severe weather events increases. Simple forms of regionally indexed weather insurance may be most cost-effective but need government help getting launched. There may also be a case for subsidizing the insurance for the most vulnerable as an alternative to direct disaster assistance."

Food systems may also need to adapt to bear some of the burdens that poor households cannot bear themselves, adds Msangi. "We may need to revisit the design and governance of food distribution systems to stabilize food availability and to compensate for shocks that markets may not be able to absorb, especially where market-level imperfections and liquidity constraints exist." he says.

Agroforestry—that is, the cultivation of trees together with crops—can help farmers cope with several of the adverse consequences of climate change. The World Agroforestry Centre (ICRAF) has assessed the potential for agroforestry to help adapt to climate change. Researchers have found that planting trees between crops and in the boundaries around crops can help prevent soil erosion, restore soil fertility, and provide shade for other crops. The practice of improved fallow also holds great promise. By planting certain fast-growing shrubs on fallow land, farmers reduce soil loss and improve soil structure in ways that allow it to retain much more water. "Optimizing the use of increasingly scarce rainwater through agroforestry practices such as improved fallow could be one effective way of improving the adaptive capacity of systems to climate change," says Louis Verchot, principal scientist at ICRAF.

Agroforestry also has the benefit of contributing to climate change mitigation, because trees and shrubs tend to sequester more carbon than other crops. The IPCC reports that agroforestry has the potential to sequester nearly 600 million metric tons of carbon a year by 2040, compared with about 120 million metric tons for cropland. Given that deforestation and agriculture together account for 32 percent of greenhouse gas emissions, some argue that farmers in developing countries, who are so at risk from climate change, should be able to improve their livelihoods by participating in carbon emissions trading as part of the Kyoto Protocol's Clean Development Mechanism. Odin Knudsen, joint chief executive officer of the company IDEAcarbon and formerly senior manager of the Carbon Finance Unit of the World Bank, says that carbon payments to farmers could encourage them to change their farming practices in ways that benefit the globe while also helping to enhance their incomes. But to achieve these goals, the Clean Development Mechanism would need to change in several respects, says Knudsen. Agricultural land use change and forest preservation should be included as eligible activities, procedures for gaining payments for afforestation and reforestation should be simplified, and limits to payments in these categories should be removed. Then farmers' cooperatives, or even rural banks, could arrange for certifying the group's carbon sequestration, applying for carbon payments, and distributing funds back to farmers. "In the past, agriculture's task was mainly to increase production," says Knudsen. "It needs to switch to a new value proposition. Farmers will need to ask themselves, 'How do I get more value from this crop—not just as food or fiber, but as a carbon asset?'"

It would be easier for farmers to adapt to climate change if they knew what the weather was going to be like on their farms during the growing season. Africa in particular is in need of much better climate and weather information. The continent has about 1,150 world weather watch stations. That is one per 26,000 square kilometers—or eight times lower than the minimum density recommended by the World Meteorological Organization.

"Meteorological departments in Africa are often more aligned toward the aviation industry or the military than to development priorities in agriculture and other climate-sensitive sectors," says James W. Hansen, a research scientist at Columbia University's International Research Institute for Climate and Society. "In most African countries, realigning meteorological departments toward agriculture and development will require major shifts in policy and substantial investment in human capacity and in data."

Improving climate information is only half the battle—the other half is ensuring that farmers get the information in ways they can use to make farming decisions. "We understand why poor farmers in developing countries often find little use for currently available operational climate information products," says Hansen.

Part of the problem, he says, is that weather information is not provided on a narrow enough spatial and time scale, and little information is given to help farmers understand what weather forecasts might mean for their own particular plots. And it is often not made clear to farmers how certain or uncertain forecasts are. "Climate forecasts reduce but don't eliminate uncertainty," Hansen explains. "If risk-averse farmers are going to climate forecasts effectively, farmers must understand this uncertainty in a way that is consistent with how they understand and manage uncertainty in the absence of forecasts."

Projects in India and Zimbabwe have brought farmers together with climate and agricultural scientists over several seasons to help climate prediction better match farmers' needs, according to Hansen. This close interaction improved the farmers' use of climate information in making decisions like what varieties to plant and when, and increased use of climate information was in turn associated with better harvests.

Scaling up these kinds of highly interactive projects will be a challenge, says Hansen, but it can be done through extension or farm advisory services. "It shows that farmers can make good use of climate information if it is local, timely, relevant, and transparent, and if they hear it from people they already go to for advice," he says.

The world community, through the UNFCCC, has established two funds to help poor countries adapt to climate change, and a third, the Adaptation Fund, is being established. Yet funding for the two existing funds is meager—just US$43 million in 2005–06. And the Adaptation Fund is expected to receive only 2 percent of all funds invested in the Clean Development Mechanism. "Much more money is needed to fund adaptation," says Knudsen.

Funding will need to go to researching crop varieties that are resistant to drought, heat, and floods, that sequester more carbon, and that make better biofuels. Moreover, other sectors besides agriculture will need funds to adapt as well. According to a report entitled "Africa: Up in Smoke 2" produced by a consortium of development organizations known as the Working Group on Climate Change and Development, the overall cost of adapting to projected climate change is likely to be between US$10 billion and US$40 billion a year. And the longer the world delays, the more the costs of adapting will increase.

A new model of development is needed, the report says, to give greater urgency to coping with climate change. For every policy and project, the key question should be, "Are you increasing or decreasing people's vulnerability to the climate?"

What will it take to get developing-country governments and international organizations to start factoring climate change into their decisions? Clearer information on options may help. IFPRI is expanding an existing model of water and food projections to account for the impacts of climate change on both water and food security at a much more detailed scale than existing models. Understanding these impacts, says Mark Rosegrant, will help clarify the specific adaptations that both policymakers and farmers must make.

The challenge is making climate adaptation in poor countries a higher priority. James Hansen argues that the countries that are most vulnerable to future climate change tend to be most overwhelmed by immediate development concerns. "Understandably, poorer countries are unlikely to place a high priority on problems projected to occur 30–50 years down the road—problems imposed by relatively wealthy countries," he says. "We hope to gain the attention of policymakers with a different approach: Climate variability is a current development problem. It is one of several crucial challenges that already impede progress in agriculture, particularly in the vast marginal rainfed farming regions of Africa and South Asia, where the majority of the Earth's poor and food-insecure reside."

This means that addressing the difficulties that farmers in many areas already face—not only low and erratic rainfall and hot temperatures, but also inadequate infrastructure, lack of access to markets and credit, and other challenges—will contribute to current agricultural development and food security while building resilience to future climate change.