Including ozone increases estimated global crop and economic benefits of carbon neutrality policies

Climate change and ozone change are two major channels through which climate policies influence agricultural production, yet most studies assess climate or ozone in isolation, which can limit the accuracy of estimated climate policy effects. Here we use an integrated model to quantify how carbon neutrality policies pledged by 153 countries affect yields of maize, rice, soybean and wheat and the associated economic outcomes. We show that excluding ozone change may understate the benefits of existing carbon neutrality policies for the four main crops, by up to 38.7%. By including the combined effect of ozone and climate, carbon neutrality policies can prevent 0.5-41.5% in losses, and more than 70% of the crop area would experience crop gains compared with the no policy scenario. For countries that still experience agricultural losses, we discuss options to reduce food security risks in terms of mitigation policies, adaptation measures and agricultural trade agreements.