Extreme Weather Conditions and Climate Change Account for 40% of Global Wheat Production Variability

European Commission's Joint Research Center (JRC) scientists have proposed a new approach for identifying the impacts of climate change and extreme weather on the variability of global and regional wheat production. The study analyzed the effect of heat and water anomalies on crop losses over a 30-year period.

JRC scientists studied the relative importance of heat stress and drought on wheat yields between 1980 and 2010.  They developed a new Combined Stress Index in order to better understand the effects of concurrent heat and water stress events.

The study 'Wheat yield loss attributable to heat waves, drought and water excess at the global, national and subnational scales' was published in Environmental Research Letters earlier this month.  It finds that heat stress concurrent with drought or water excess can explain about 40% of the changes in wheat yields from one year to another.

One finding is that in contrast to the common perception, water excess affects wheat production more than drought in several countries.  Excessive precipitation and greater cloud cover, especially during sensitive development stages of the crop, are major contributors to reduced yields, as they help pests and disease proliferate and make it harder for the plants to get the oxygen and light they need.

In 2010 wheat contributed to 20% of all dietary calories worldwide.  It therefore has a major role in food security worldwide, some countries being particular reliant on it .  As climate change is increasing the duration, frequency and severity of extreme weather events, it has become increasingly urgent to identify their effects and provide early warnings, in order to ensure market stability and global food security.

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