Inaugural Article: Case study of the effects of atmospheric aerosols and regionalhaze on agriculture: An opportunity to enhance crop yields in Chinathrough emission controls?

摘要

The effect of atmospheric aerosols and regional haze from air pollution on the yields of rice and winter wheat grown in China is assessed. The assessment is based on estimates of aerosol optical depths over China, the effect of these optical depths on the solar irradiance reaching the earth’s surface, and the response of rice and winter wheat grown in Nanjing to the change in solar irradiance. Two sets of aerosol optical depths are presented: one based on a coupled, regional climate/air quality model simulation and the other inferred from solar radiation measurements made over a 12-year period at meteorological stations in China. The model-estimated optical depths are significantly smaller than those derived from observations, perhaps because of errors in one or both sets of optical depths or because the data from the meteorological stations has been affected by local pollution. Radiative transfer calculations using the smaller, model-estimated aerosol optical depths indicate that the so-called “direct effect” of regional haze results in an ≈5–30% reduction in the solar irradiance reaching some of China’s mostproductive agricultural regions. Crop-response model simulationssuggest an ≈1:1 relationship between a percentage increase (decrease)in total surface solar irradiance and a percentage increase (decrease)in the yields of rice and wheat. Collectively, these calculationssuggest that regional haze in China is currently depressing optimalyields of ≈70% of the crops grown in China by at least 5–30%.Reducing the severity of regional haze in China through air pollutioncontrol could potentially result in a significant increase in cropyields and help the nation meet its growing food demands in the comingdecades.