The impacts of climate change on global potato agriculture

It is vital that we develop our understanding of how crops will respond to climate change given the likely need to increase food production by 2050. The contribution of potatoes to the global food supply is increasing - consumption more than doubled in developing countries between 1960 and 2005. Analyses of climate impacts on potato compared to other major crops are relatively rare. Studies involving biotic stresses in crop modelling are also comparatively rare - around 70% of models do not incorporate pest and disease damage. This thesis simulated abiotic and biotic impacts of climate change to 2050 to identify risks and opportunities for global potato agriculture. The GLAM crop model is used to assess abiotic impacts and the SimCastMeta model is used to assess the impacts of the most important global disease of potato, late blight Phytophthora infestans. A further analysis uses pesticide data as a proxy for pest pressures, showing that warming leads to pesticide increases in temperate areas. GLAM is evaluated for potato simulation in two contrasting climates using data from Colombian regions and Aberdeen, UK. The model shows skill in simulating observed weather-yield relationships. National yield data are then used to test a global parameter configuration. Results show realistic planting dates and crop growth. Skill is low due to insignificant observed weather-yield relationships. Regional results show higher skill than global results, primarily due to more parameter detail. Global model results show skill in reproducing observed yields in Europe. Elsewhere, correlations are generally positive but low. Future climate simulations show that yields are expected to increase in most cases, primarily as a result of CO2 fertilisation, although the magnitude of increases are uncertain due to the uncertainties around future climate and CO2 fertilisation. Temperature increases in some regions result in shorter durations and reduce yield increases. Late blight is predicted to increase more in temperate regions, particularly if adaptation to climate change is considered. Taken together, abiotic and biotic impacts show potential opportunities for potato agriculture in temperate latitudes providing pests and diseases can be sustainably managed.