Global warming and local air pollution have reduced wheat yields in India

We use regression analysis on data from 208 districts over the period 1981–2009 to examine the impact of temperature and solar radiation (affected by pollution from aerosols) on wheat yields in India. We find that a 1 °C increase in average daily maximum and minimum temperatures tends to lower yields by 2–4% each. A 1% increase in solar radiation increases yields by nearly 1%. Yields are estimated to be about 5.2% lower than they would have been if temperatures had not increased during the study period. We combine the estimated impacts of weather on yield with the estimated impacts of aerosol pollution (measured by moderate resolution imaging spectroradiometer sensor in terms of aerosol optical depth, aerosol optical depth (AOD) in 2001–2013) on weather to compute the net impact of reducing aerosol pollution on wheat yields. A one-standard-deviation decrease in AOD is estimated to increase yields by about 4.8%. Our results imply reducing regional pollution and curbing global warming in the coming decades can counter wheat yield losses.