Development and use of agronomic weather indices in assessing intra-seasonal climate change risks to rainfed cropping systems

To answer the fundamental question of “adapt to what” within the context of climate-smart agriculture investments, staff and partners of the Food and Agriculture Organization of the United Nations (FAO) have developed and applied a set of 69 agronomic weather indices to identify trends in the frequency and intensity of intra-seasonal weather events associated with climate change. These indices, when applied to daily historical and downscaled projected temperature and precipitation data, provide a robust, empirically-driven means of identifying the principal attributes of climate change to which crop agriculture must adapt. Research completed with national teams in Malawi and Zambia used the indices with the daily weather station records from the National Meteorological and Hydrological Services and gridded climate data. Individually, and in combination, the indices allow the identification of important trends in seasonality, the crossing of critical crop tolerance thresholds, extreme weather events and the responsiveness of some adaptation options. The projection of these trends into the near-term future helps to guide climate-smart agricultural investments in research programmes, extension field activities and climate change adaptation efforts more broadly. Using daily temperature and precipitation data, the established indices can be used with any crop for which a basic physiological understanding exists, covering spatial scales ranging from individual weather stations to national and regional coverage.