Climate Change Will Worsen Hunger, Study Says

India, wheat, climate changeClimate change is expected to lower grain yields and raise crop prices across the developing world, leading to a 20-percent rise in child malnutrition, a new study finds.

The total calories available in 2050 will be lower than in 2000, the International Food Policy Research Institute (IFPRI) estimates, increasing malnutrition rates in South Asia and sub-Saharan Africa in particular.

"Farmers will have reduced yields, but it will vary by region, vary by crop, and vary by management system," said Gerald Nelson, an IFPRI senior research fellow and lead author of the report, released today.

Higher temperatures are expected to reduce crop yields, allow damaging weeds and insects to spread, and shift precipitation patterns worldwide. While some agricultural regions are expected to benefit from climate change, overall production will decline for the world's rice, wheat, maize, millet, and sorghum harvests, the report said.

The report, released as international climate negotiators discuss a successor agreement to the Kyoto Protocol, is the first to combine climate and agricultural models to measure the effects of climate change on the global food supply.

Most severely affected will be the wheat-growing regions of South Asia, Europe and Central Asia, and sub-Saharan Africa, where production is projected to decline by 46, 47, and 35 percent, respectively. Also under threat are Middle Eastern rice paddies, where production is expected to fall by 36 percent.

The regions that would benefit from climate change would experience relatively smaller changes. The analysis estimates that wheat production in Latin America will grow by 13 percent and that millet production will increase in the East Asia and Pacific region and in Latin America and the Caribbean, by 6 and 8 percent, respectively.

The expected changes vary for irrigated and rain-fed fields. Irrigated rice yields are projected to decline by more than 16 percent in developing countries, whereas rain-fed rice would decline by less than 1 percent. Likewise, irrigated wheat yields are projected to decline by more than 31 percent in developing countries, and rain-fed wheat would increase by more than 1 percent.

Rising concentrations of greenhouse gases may, however, encourage some plants to waste less water and grow more quickly, a process known as carbon dioxide fertilization. If so, the total calories available in developing countries may increase by nearly 6 percent by 2050, the study said. But Nelson cautioned that these gains may be negated by the rise in pest populations.

"There's an ongoing debate in the scientific community about the effectiveness of carbon dioxide fertilization," Nelson said. "We provide both sides of the story."

With the human population projected to reach 9 billion by 2050, more people eating meat and dairy products, and biofuels demanding more farmland, overall food production will need to increase by some 70 percent more than the 2005-07 output, according to a United Nations Food and Agriculture Organization (FAO) report released last week.

The FAO expects that enough land and water resources will be available in 2050 for chronic malnourishment to be reduced to 5 percent, a major drop from the 16 percent observed throughout the developing world in 2003-05. But production increases alone will not ensure that food becomes more available, said UN Secretary-General Ban Ki-Moon at a food security event last week.

"Our goal is to initiate a new era for agricultural development - a revolutionary approach that will support smallholder farmers, especially women, a transformation of markets, and trading systems so they work better for the poor," Ban said.

Although the FAO estimates do not factor in climate change, a forum of government experts will meet in Rome next month to discuss food policy strategies; investments to adapt to climate change will be part of the agenda.

The IFPRI report recommends that at least $7 billion be set aside annually to help developing countries adapt to the agricultural effects of climate change. The funds would support agricultural research, improve irrigation systems, and expand rural roads.

The World Bank estimates in its 2010 World Development Report that $75 billion will be needed each year to adapt to the effects of climate change, such as sea-level rise, tropical diseases, and agricultural decline. 

Adaptation costs are highly uncertain due to the unpredictability of climate change, said Rosina Bierbaum, co-director of the Bank report. As much as half of the estimated funds required for adaptation could be applied for immediate projects, but the costs for many of these projects are still unknown.

"It's not completely clear what we should be including," Bierbaum said. "We're not coping with the climate shocks of today, nonetheless of tomorrow."

Still, given the threats many developing countries are likely to face due to climate change, Oxfam International climate advisor Antonio Hill said that financial resources should be provided sooner rather than in the distant future.

"Prevention is cheaper than cure," Hill said. "Unless developing countries receive enough support in the short term, costs in 2045 will be to compensate for actual damages, not to prevent them."

International leaders gathered on Monday in Bangkok, Thailand, for the fourth round of international climate negotiations this year. The climate change summit this December in Copenhagen, Denmark, will address funding adaptation, lowering global emissions, and developing new carbon sequestration strategies.

Ben Block is a staff writer with the Worldwatch Institute. He can be reached at

This article is a product of Eye on Earth, Worldwatch Institute's online news service. For permission to reprint Eye on Earth content, please contact Juli Diamond at