Increased ozone concentrations reduce global food production in average by 10%. Most hit: China and India

The increased concentration of ozone in the atmosphere has reduced crop yields. That is shown in a worldwide study in which University of Gothenburg researchers and others have investigated how tropospheric ozone affects global food production.

The researchers have compiled and analysed worldwide data from field experiments with ozone and scaled up the effects to the global level. The results show that plant uptake of tropospheric (ground-level) ozone sharply reduces the size of harvests.

The most important global crops – wheat, rice, maize and soybeans – are all sensitive to ozone, but ozone also seriously affects other crops. Ozone causes estimated global crop losses of 7 per cent for wheat and as much as 12 per cent for soybeans.

Tropospheric ozone has a negative impact on crops comparable to parasitic infestations or extreme drought.

“Climate-related effects rightly attract quite a lot of attention, but our study shows that widespread air pollution on a large scale also has a significant effect on global food production,” says Håkan Pleijel, professor of environmental sciences at the University of Gothenburg.

The results also indicate that there are large differences among different regions of the world. Food production is most vulnerable in Asia, especially in China and India.

Strategies for improvement

The best strategy to reduce the problem of ground-level ozone is to strongly reduce the emissions of ozone forming substances. Since this is likely to take time, another strategy for reducing the impact of ozone involves developing more robust crops. A further approach is to change crop management approaches, such as planting or irrigating at the right time in relation to the highest ozone concentrations, thus avoiding excessive ozone uptake by the crops.

“For example, if farmers have good forecasts of ozone peaks, they can refrain from irrigating in connection with them. When plants have plenty of water, the stomata in their leaves are wide open and their uptake of ozone is especially large,” Uddling says.

 

 

(Release by University of Gothenburg)

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