Assessment of El Niño and La Niña impacts on China: Enhancing the Early Warning System on Food and Agriculture

Assessing crop production variations is of great importance for agriculture and food security worldwide. The impacts of El Niño and La Niña events are particularly critical for understanding these variations. Besides the individual El Niño and La Niña event, newly-identified El Niño and La Niña dominant cycles also add another dimension into the analysis. As the world largest food producer and importer, China has endeavored to increase its agricultural production while reducing climate risks over time. By using satellite-based indicators, ENSO (El Niño-Southern Oscillation) indices and grain yield statistics for China, the characteristics of ENSO events, as well as their relationships with crop-growing conditions and yields at different administrative levels are analyzed. The results show that the evaluation of agricultural impacts of an El Niño/La Niña event should consider both the dominant cycle in which the event occurs and the characteristics of the event itself, combined with local crop phenology. Additionally, county and prefectural level analysis shows that over the long term, in China, La Niña events tend to have net positive impacts on grain productivity compared to the effects of El Niño events. The analysis and methods presented can be extended to other countries in the world and help better understand the local agricultural impact of El Niño and La Niña phenomena. This, in turn, would improve the agriculture and food security related early warning capacities of countries to issue and trigger targeted and timely response and climate risk reduction measures.