Quantifying the Yield Sensitivity of Modern Rice Varieties to Warming Temperatures: Evidence from the Philippines

This study examines the relationship between yields of modern rice varieties and warming temperatures. Data from a long-running farm-level survey in the Philippines, with rich information on planted rice varieties, allow us to estimate fixed effect econometric models of rice yields. We find that increases in temperature, especially minimum temperatures, have statistically significant negative impacts on rice yields. Point estimates of the marginal effect of higher temperatures on rice yields indicate that early modern varieties bred primarily for higher yields, pest resistance, and/or grain quality traits (i.e., not necessarily abiotic stress tolerance) tend to be more resilient to heat events than traditional rice varieties. Moreover, the marginal effect point estimates also suggest that more recent rice varieties bred for better tolerance to abiotic stresses are likely more resilient to warming than both traditional varieties and early modern varieties. Notwithstanding the heat resilience pattern suggested by these point estimates, we are unable to find statistically significant differences in the marginal yield response to warming across these three rice varietal groups. These results provide suggestive evidence that rice breeding efforts have improved resilience to warming temperatures and point to several interesting future research directions