Multi-year prediction of drought and heat stress to support decision making in the wheat sector

Unfavorable and extreme climate events such as drought and heat stress affect wheat production and food security globally. Predicting such climate events in the next decade is of great interest for decision-makers, as this time horizon coincides with the strategic planning of many stakeholders in the wheat sector. To address this, we assess the forecast quality in predicting the evolution of drought and heat stress conditions using two proxy user-oriented drought and heat stress indicators: Standardized Potential Evapotranspiration Index (SPEI6) and Heat Magnitude Day Index (HMDI3) on a multi-annual timescale (forecast years 1 to 5). In particular, we present the probabilistic skill and reliability of decadal forecast to predict these indices for the months preceding wheat harvest on a global spatial scale. We use decadal forecasts from the Community Earth System Model Decadal Prediction Large Ensemble (CESM-DPLE), which contributes to the Decadal Climate Prediction Project (DCPP) of CMIP6. Following this, we demonstrate the potential applicability of these forecasts to enhance the adaptation and mitigation activities in the wheat sector by presenting the forecast of multi-year averaged SPEI6 and HMDI3 based on categorical events for the period 2016-2020 along with the corresponding observational values.