Weather extremes slash cereal yields
Wheat and other cereal crops in developed countries such as Australia have been decimated. Image: CSIRO via Wikimedia Commons
LONDON, 8 January, 2016 – Climate change may have already begun to take its toll of agriculture. New research suggests that drought and extreme heat in the last 50 years have reduced cereal production by up to 10%. And, for once, developed nations may have sustained greater losses than developing nations.
Researchers have been warning for years that global warming as a consequence of rising levels of carbon dioxide in the atmosphere – in turn, a pay-off from increased fossil fuel combustion – will result in a greater frequency or intensity in extremes of weather.
They have also warned more recently that weather-related extremes could damage food security in Europe, Africa and India.
Global cost
But a study in Nature journal by Navin Ramankutty, professor in global food security and sustainability at the University of British Columbia in Canada, and colleagues is perhaps the first to identify the global cost of weather-related disasters in the last half of the 20th century.
The researchers looked at 2,800 extreme hydro-meteorological disasters – floods, droughts and extremes of heat and cold – reported between 1964 and 2007 from 177 countries, and matched the data with production figures for 16 cereal crops.
They could detect no significant influence from floods or ice storms, but they found that drought and extreme heat reduced average national cereal production by between 9% and 10%.
Drought reduced both cereal yield and the area under harvest, while heat mainly affected yield. This is likely to be a consequence of different timescales: droughts can last for years, but heatwaves tend to be counted in no more than weeks.
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