Extreme Temperatures and Crop Yields in Karnataka, India

The recent literature shows that extreme temperatures have an adverse effect on the yield of major crops in different parts of the world. This paper investigates the impact of exposure to extreme temperature on crop yields of a range of crops cultivated in the State of Karnataka, India. The crops examined in this study are rice, sorghum (jowar), finger millet (ragi), and pigeon pea. We use a taluk-level fixed effects panel data model to study the impact of exposure to extreme temperatures, measured in terms of extreme degree days, on crop yields. Crop yields are the dependent variables and total seasonal rainfall, growing degree days (GDD) and extreme degree days (EDD) are the independent variables used in this model. The paper finds an inverse linear relationship between yield and extreme degree days. The impact of extreme temperature on yields (EDD) was greater than the impact of rainfall and GDD. The regression coefficients were checked for robustness using quantile regression methods. For most crops, the sign of the coefficient of EDD was consistent for the 25, 50, and 75 per cent quantiles of estimation. This suggests that the inverse relationship between EDD and crop yield holds for the different quantile levels. This study is perhaps the first of its kind in southern India and for crops other than wheat. It focuses on climate and climate variability, and clearly shows that exposure to extreme heat is the most important effect of climate change on agriculture that can be currently observed in Karnataka.