Climate Change Threatens Smallholder
Rainfed Maize Production in the Tropics

‘Norham Castle, Sunrise’, by J.M.W. Turner, © Tate, London, 2002

Climate change poses a grave threat to the livelihoods and food security of poor farmers of the tropics. Scientists have recently mapped the impacts of climate change in Africa and Latin America on maize yields five decades from now. This assessment, carried out at high resolution to disclose impacts at the household level, indicates profound changes for tens of millions of smallholder crop-and-livestock farmers who rely on rainfed maize production to feed their families and livestock.











In some regions, such as eastern Brazil, maize yields are predicted to decrease moderately, up to 25%, if there are no changes in current production practices. In this case, scientists think that farmers will be able to maintain if not increase their current production levels by applying different maize breeding and agronomy practices.

Elsewhere, such as in the Ethiopian highlands around Addis Ababa, smallholder rainfed maize production may benefit from climate change, with yields in some areas as much as doubling.

In other regions, maize yields may decline drastically, almost to zero. Such precipitous declines, which could displace human populations altogether, can be addressed only by making major changes to the current agricultural system.

Overall, maize yields in three-quarters of the countries of Africa and Central and South America, particularly in dry tropical environments, will decrease to 2055 as a result of a warming climate and changing rainfall patterns and levels. This future reduction is about 10% of the total maize production on these continents in 2000. Although serious, we can expect this decrease to be compensated for by plant breeding and farmer adoption of technological interventions in the intervening period.

However, this aggregate figure of 10% hides enormous variability. In many areas, the decrease in maize yields will be much greater and rural life will be considerably disrupted. Where subsistence agriculture is the norm—where, for example, maize stovers that remain after harvesting keep farm animals, and thus people, fed during the dry season—lives as well as livelihoods will be at stake.

Alternative production systems need to be found for farmers in these most-affected areas, while maize production is shifted to wetter areas. Research on adaptive and ameliorative options for the farmers in these regions needs to begin immediately, as a matter of urgency.

This study was funded by members of the Consultative Group on International Agricultural Research. It was conducted by scientists at two Future Harvest Centres, the Africa-based International Livestock Research Institute (ILRI) and the Colombia-based International Center for Tropical Agriculture (CIAT).

INTERNATIONAL LIVESTOCK RESEARCH INSTITUTE
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Research in animal agriculture to reduce hunger, poverty and environmental degradation in developing countries.
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