Geography of Climate Change Adaptation in US Agriculture

ABSTRACT Geography is a salient feature in agricultural adaptation to a warming climate. Facing heterogeneous natural‐resource and climatic endowments, farmers in different locations choose adaptive strategies that are best suited to their environments, resulting in inhomogeneous adaptation across space. We provide novel evidence of this explicitly spatial heterogeneity in heat sensitivity of US crop yields and their adaptation thereto. We generalize a popular long‐differences approach by explicitly incorporating geographic information of crop‐producing counties in a semiparametric fashion, using local kernel averaging. This lets us control for spatially clustered local heterogeneity that may be non‐neutral in that it moderates climate effects on agriculture. Obtained measurements of historical adaptation are also more granular and account for local contexts, as do projected yield changes due to climate change. We find that corn and soybean adaptation to overheat mainly occurred in the Northern Great Plains and Upper Midwest. There is a geographic bifurcation in expected climate change effects by the mid‐century, with some regions projected to experience large yield declines and others to benefit from significant yield gains. Considering the net offset potential of this bifurcation, our average yield impact projections are generally smaller relative to traditional approaches.