Abstract:
Using a panel of 74 countries that spans nearly 60 years, this paper investigates the effects of climate change on global soybean yields. In alignment with previous research, we find a global non-linear relationship between growing season average temperature and yield growth—a parabola that minimizes around 24.9◦C. It indicates that effects of warming change from being beneficial to harmful, and reach to the most damaging at the optimum temperature; however, beyond the optimum, warming becomes less detrimental probably due to adaption of local crop variety to heat at countries that have been persistently hot. However, by incorporating regional dummies to our empirical model, we find significant heterogeneity in different regions. For example, in contrary to the global response function that opens upwards, the opposite direction, a downward open response function, is found for Southeast Asia, such that crop yield growth maximizes at 24.23◦C. We also demonstrate precipitation has non-linear effects on soybean yields. In contrast to the large heterogeneity in temperature effects, the regional response functions for precipitation are more consistent over the world. Except for regions not sensitive to precipitation changes, areas such as Southeast Asia, Eastern Europe & Central Asia, and Sub-Saharan Africa all show a downward open parabolic response curve to precipitation. In addition to temperature and precipitation, we highlight the importance of diurnal temperature range (dtr) in assessing climate change impacts on crop yields. We find dtr is a statistically significant factor to soybean yields—an additional 1◦C dtr will slow global soybean yield growth by 4.1 percentage points.
Citation:
Yuan, M. (2021), 'Heterogeneity in the Effects of Climate Change on Soybean Yields', Working Paper, https://my1396.github.io/images/Crop_yield_0309.pdf