Climate and Air Pollution Impacts on Indian Agriculture, 1979-2009

The impacts of climate change on agricultural production have important ramifications for food security and policy from local to global scales. Recent research investigating these impacts has focused on the roles of temperature and precipitation (including extremes) on yield, using historical panel data and statistical models to tease out the effects of weather deviations on productivity. These studies have shown that India is one of the regions that has already been most negatively affected by climate change. Indian rice and wheat yields are several percent lower than they otherwise would be, based on temperature and precipitation changes alone over the last 30 years (Lobell et. al, 2011). However, regional climate and crop productivity changes in India are likely due to both global emissions of long-lived greenhouse gases (GHGs) as well as regional emissions of short-lived climate forcers (SLCFs) like aerosols and ozone precursers, which can impact crop production indirectly, by altering surface radiation and precipitation dynamics (aerosols), and directly, by damaging plants (ozone). Existing estimates of the effects of these short-lived climate forcers on crop yields have been drawn from field experiments and cultivar-specific dose-response relationships. Some work has been done to incorporate radiation changes into a statistical panel model for rice production (Auffhammer et. al. 2006, 2011), but no research has as yet simultaneously examined the roles of both longer-run trends and short-lived climate forcers. We present results from a statistical model of the impact of temperature, precipitation, and short-lived climate forcers on rice and wheat yields in India over the past 30 years. This is the first such analysis fully combining effects of SLCFs including ozone, and shows that yield gains from addressing regional air pollution could help offset expected future losses due to rising temperatures and T & P extremes. This new insight into the relative importance of these climate and air pollution factors can help inform both climate policy discussions and agricultural adaptation efforts in this critical food security region.