The report found that droughts and extreme heat had reduced cereal harvests by between 9% and 10% on average in affected countries. Researchers examined the effects of 2,800 weather disasters from 1964 to 2007 to determine how much production was lost to extreme weather, and how it varied across the globe.
They discovered that countries with advanced agricultural systems were hit far harder by a drought than developing countries – with production in North America, Europe and Australasia down 19.9% on average. In contrast, production declined 12.1% in Asia, 9.2% in Africa, and there was no significant effect in Latin America and the Caribbean.
Differences in farming methods
This figures may reflect differences in scale and methods of farming in wealthier countries compared with the developing world, said researchers.
In North America, for example, crops and methods of farming are uniform across huge areas, and if a drought hit in a way that damages crops, the impact would be widespread, added report lead author Corey Lesk of McGill University. Developing countries are likely to have smaller fields with a more diverse mix of crops.
Passing on extra costs
“Lower-income countries may better resist drought because smallholders tend to use risk-minimizing strategies compared to the yield-maximizing ones prevalent in higher-income countries,” said Lesk.
When a drop in supply pushed up prices, bakers were forced to make difficult decisions such as how much of the extra cost to pass onto customers, or whether to switch ingredients or sources.
“As the global climate warms into the future, extreme weather disasters will likely become more frequent and intense, so bakers may have to face these pressures more often,” Lesk said.
And as more farmers adapted their crops to a changing climate, the suitability of their grains for certain breads and pastries could shift, he added. “Bakers may therefore need to update their techniques to keep their loaves light.”
Lesk predicted farmers may substitute different varieties of wheat to adapt to the changing climate, which could affect the protein and enzyme content of flour.
“Bakers may need to add enzymes and protein to get consistent products if flour quality changes,” he said.
Source: Nature 529, 84-87 (January 7 2016)
‘Influence of extreme weather disasters on global crop production’
Authors: Corey Lesk, Pedram Rowhani, and Navin Ramankutty