P5: Reducing uncertainty in predictions of climate change impacts on agricultural crop production in Ethiopia

Crop models are the most common tools for assessing the threat of climate change to local and regional crop productivity. However, numerous studies have shown that models used to predict crop yields are highly uncertain when predicting how crops respond to changes in temperature, annual precipitation amounts and distribution, and increasing carbon dioxide concentrations. It was also shown that simulations differ across crop models and that a significant proportion of the uncertainty in climate change impact projections is due to differences in the structure of these models. Hence, applications of multi-model ensembles have been suggested to reduce uncertainty in simulation of crop response to future climate.

The aim of this project is to reduce uncertainty in predictions of climate change impacts on productivity of wheat, maize and sorghum in Ethiopia. The agro-ecosystem simulation tool box Expert-N is used to setup a multi-model ensemble composed of four different crop growth models combined with different water regime and nitrogen turnover models. The single ensemble members are run for different locations in Ethiopia taking into account the country-specific management strategies and climate inputs. Simulation results are tested against recent and historic yield data. Uncertainties in model predictions due to the different model structures are quantified. Bayesian techniques are applied to calculate model weights accounting for the predictive power of each model combination. Only models with relevant predictive power (relevant weights) will finally be used for predicting crop productivity in Ethiopia during the next 20-30 years resulting in more reliable estimations of future yields, which may aid developing practicable mitigation strategies.

Involved persons

Prof. Dr. Thilo Streck
Dr. Sebastian Gayler
PhD Scholar Fasil Mequanint Rettie

Involved institutions

Institute of Soil Science and Land Evaluation (310)    
Chair of Biogeophysics (310d)
Food Security Center (791)