ONE-SIXTH of humanity is suffering from hunger – the UN Food and Agriculture Organisation (FAO)’s most recent estimates are that 105 million more people were pushed into hunger in 2009, bringing the total number of hungry to a shameful 1.02 billion.

Food prices remain stubbornly high. Although international prices have climbed down from their record highs in 2008, they have yet to drop to pre-food-crisis levels, and the risk of volatility continues. According to FAO, average food prices in May 2009wereabout 24% higher than they were in 2006.

Add climate change to these statistics, and the situation looks decidedly gloomy. A recent report by the International Food Policy Research Institute (Nelson et al., 2009) warns that unchecked climate change will have major negative effects on agricultural productivity, with South Asia forecast to be particularly hard hit. The analysis suggests that there will be 20% more malnourished children in 2050 due to climate change.

The Intergovernmental Panel on Climate Change (IPCC) had earlier projected that crop productivity would increase slightly at mid- to high latitudes for local mean temperature increases of up to 1-3C (depending on the crop), but would decrease beyond that in some regions (IPCC, 2007). More significantly, for many developing countries, at lower latitudes, especially in the seasonally dry and tropical regions, crop productivity is projected to decrease for even small local temperature increases (1-2C). This would increase the risk of hunger.

On a global scale, the potential for food production is projected to increase with increases in local average temperature over a range of 1-3C, but above this it is projected to decrease (IPCC, 2007). Given that warming by the end of the 21st century (2090-2099) will be worse than expected and that the best estimates project a rise of 1.8-4C, and a likely range of 1.1-6.4C, the world is likely to see a decline in food production.

For developing countries, including where some of the poorest people live and farm, the projections of climate change’s impacts on agriculture are dire (see box on p.22). Climate change will cause yield declines for the most important crops and result in additional price increases for the world’s staples – rice, wheat, maize and soybeans (Nelson et al., 2009).

While different challenges may emerge for different regions, the general indications are that climate change will adversely affect agriculture and human well-being (Nelson et al., 2009). Moreover, it is the majority of the world’s rural poor who live in areas that are resource-poor, highly heterogeneous and risk-prone, who will be hardest hit by climate change. For these vulnerable groups and subsistence farmers, even minor changes in climate can have disastrous impacts on their lives and livelihoods (Altieri and Koohafkan, 2008).

The relationship between climate change and agriculture is however a two-way one; climate change in general adversely affects agriculture and agriculture contributes to climate change in several major ways.

Agriculture releases into the atmosphere a significant amount of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), amounting to around 10-12% of global anthropogenic greenhouse gas emissions annually (Smith et al., 2007); mostly methane from livestock raising, biomass burning and wet cultivation practices, and nitrous oxides from the use of synthetic fertilisers. If indirect contributions (e.g., land conversion to agriculture, fertiliser production and distribution and farm operations) are factored in, some scientists have estimated that the contribution of agriculture could be as high as 17-32% of global anthropogenic emissions (Bellarby et al., 2008).