This negative effect on wheat yield is particularly evident in humid rain-fed and irrigated areas of major wheat-producing countries, including the USA, France, India, China and Russia.
Demand for wheat, which provides 20% of human dietary protein and caloric intake, has doubled globally since 1980. Increasing yield production to meet this demand and achieve the United Nations' Sustainable Development Goal 2 (SDG2 – Zero Hunger) leads to greater pressures on water supplies to irrigate crops.
However, this article shows that increased irrigation actually exacerbates the negative effects of ozone. This implies that the beneficial effects of increasing irrigation in response to the effects of climate change (rising temperatures, water shortages and drought) could actually be reduced due to rising concentrations of ozone.
How ozone affects crops
Ozone is a gaseous pollutant that is absorbed by plant leaves. It damages sensitive crops such as wheat, rice and soybeans by diffusing into the leaves and eliciting defense mechanisms that divert resources away from growth and seed production. Its concentration is increasing, particularly in rapidly developing countries.
The authors estimate that 85 million tonnes of grain were lost due to ozone between 2010-2012, reducing wheat yields by 9.9% in the northern hemisphere and 6.2% in the southern hemisphere.
Losses due to ozone in developing countries receiving development assistance are 50% higher than those in developed countries. Unless suitably ambitious air pollution control measures are taken, rising ozone concentrations may push the achievement of the SDG2 (Zero Hunger) further out of reach, particularly in a world faced with growing populations and food demand, and increasing temperatures.
However, all is not lost. The authors show that international efforts to mitigate air pollution could play an important role in achieving SDG2, while also contributing to other SDGs on human health and well-being, ecosystems and climate change.