The recent food crisis, which saw crop prices sky rocket in 2007/08, demonstrated the fragile nature of the world’s food system. Coping with the short-term challenges of food price volatility is daunting, but the longer-term challenge of avoiding a perpetual food crisis due to global warming could be far more serious.
Temperatures in crop growing seasons across the world will exceed the most extreme seasonal temperatures on record by the end of the century, new research suggests.
Writing in the latest issue of Science, David Battisti at the University of Washington and Rosamond Naylor at Stanford University warn that unprecedented seasonal average temperatures will threaten global food security unless adaptations such as heat and draught tolerant crops, the creation of jobs outside of agriculture for those regions where farming will no longer be viable and appropriate irrigation systems are introduced.
In a new study, they use data from 23 global climate models produced for the Intergovernmental Panel on Climate Change’s 2007 scientific analysis to show that there is a 90% chance that the tropics, sub-tropics and temperate regions will experience unprecedented seasonal average temperatures by the end of the 21st century.
Their research looks at historical case studies of three regions – France, the Ukraine, and the Sahel in Africa – that have experienced extreme heat waves, to illustrate the size of the impact on food production. For example, France felt some of the greatest impacts of the 2003 heat wave in Western Europe, which saw temperatures rise to 32 -33°C in June to August – nearly 4°C higher than the country’s average historical temperature for those months. Over this period, production of maize fell by 30%, fruit harvests declined by 25% and wheat harvests dropped by 21%.
According to the study by Battisti and Naylor, by 2100 the temperatures experienced in the summer of 2003 will be the norm for the season in France.
Current strategies used to cope with food deficiencies in one part of the world by producing food surpluses in other areas, will be not be viable in future, says Naylor, an agricultural economist at Stanford.
“In the future, the world may not be able to rely on temperate regions for food supplies, as even mid-latitude crops will suffer at very high temperatures unless adaptations are pursued there. While temperate regions might benefit from some warming, the very high temperatures expected by the end of the century will lower yields even with CO2 fertilization effects unless heat tolerant varieties are developed,” says Naylor.
For the full story, see Nature News.
Natasha Gilbert is a staff reporter with Nature.
Image: Likelihood (in percent) that future summer average temperatures will exceed the highest summer
temperature observed on record for 2050. For example, for places shown in red there is greater
than a 90% chance that the summer-averaged temperature will exceed the highest temperature on
record (1900–2006). Courtesy of Science/AAAS