Climate Variability Differentially Impacts Rice Production Systems in the Philippines Depending on Temporal and Spatial Scale.

Changes in crop yield and production over time are driven by a combination of genetics, agronomics, and climate. Disentangling the role of these various influences helps us understand the capacity of agriculture to adapt to environmental change. Here we explore the impact of climate variability on rice yield and production in the Philippines from 1987-2016 in both irrigated and rainfed production systems at various scales. Over this period, rice production is predominantly affected by variations in soil moisture, which are driven by the El Niño – Southern Oscillation (ENSO). We found that the climate impacts on rice production are strongly seasonally modulated and differ considerably by region, with higher spatial and temporal resolution (i.e. regional and quarterly) providing significantly more information than lower resolution (i.e. national and yearly). Rainfed upland rice production systems are more sensitive to soil moisture variability than irrigated paddy rice. About 10% of the variance in rice production on the national level is explained by soil moisture changes, which in turn are strongly negatively correlated with the Niño3.4 index. Our results show that while temperature variability is of limited importance today, future climate projections suggest that by the end of the century, temperatures will regularly exceed known limits to rice production if warming continues unabated. The differential impacts across various spatio-temporal scales that we identify here, drive regional food security and policy decisions.