Climate change is likely to first hurt developing countries which could become almost too hot to successfully grow essential crops, international experts told a conference Wednesday.
World Bank Vice President for Sustainable Development Katherine Sierra told a scientific conference in Canberra that "heat stress" from global warming posed a serious threat to food supply.
"Rising temperatures will create heat stress in some species of livestock, less stable crop yields and lead to more frequent outbreaks of pests and disease," said Sierra, who also chairs the Consultative Group on International Agricultural Research. "Developing countries are likely to suffer the earliest, and the most, from climate change."
Sierra said these problems were being compounded by "stagnating" support for agricultural research in the past decade, the consequences of which had become dramatically evident in recent months with a global food prices crisis.
Trevor Nicholls, chief executive of CAB International, a group involving 45 governments which focuses on agricultural and environmental research, said extreme weather events had already become more intense and more frequent with increasingly destructive results on crops.
"Although these extreme events have very visible destructive impacts, climate change will also have much more subtle impacts but much more drastic impacts on crops," Nicholls told the conference.
He said while crop yields could benefit in the short term from rising temperatures, they are predicted to shrink significantly with a 5 degree Celsius (9 degree Fahrenheit) increase which the United Nation's Intergovernmental Panel on Climate Change forecasts could happen by 2050.
"Most disturbingly, the biggest increases are ... predicted to impact on the tropics where crops such as maize and rice are already near the upper limits of their optimum temperatures for growth," Nicholls said.
He said climate change was likely to be most extreme in the tropical regions of Asia, Latin America and sub-Sahara Africa where countries were already struggling to feed growing populations.
Climate change was also influencing the range and prevalence of crop diseases and pests, creating a "continuing biological arms race" for farmers, he said.
Bananas and plantain, staples across India, Africa and the Caribbean, are particularly susceptible to pests and diseases.
The fungal disease black sigatoka originated in Fiji but is now appearing throughout the tropics, Nicholls said. Banana weevil also has become widespread, and banana bacterial wilt has spread from Africa, he said.
Australian Agriculture Minister Tony Burke told the conference that genetically modified crops will be necessary to meet global food shortages.