Exploring climate change impacts and adaptive capacity of agricultural systems: Integration of risk assessment and agro-hydrological modelling

Global agendas are converging to address the overlapping challenges related to climate change, disaster risk reduction and sustainable development. Thus, the respective research communities, that until a few years ago were working separately, should take the opportunity to further share and integrate knowledge and approaches. This would be particularly useful when dealing with water since its management involves multiple stakeholders, often with different opinions about its use. Indeed, water scarcity, which occurs when water supply fails to satisfy water demand, and water shortage, a lack of water supply of acceptable quality, caused either by climatic, infrastructural, or hydrological factors, are two of the main global challenges which will be likely worsened by climate change, hampering food security in many countries of the world. This thesis revolves around four manuscripts that investigate the research topics in two study areas. I first apply the approaches of the disaster and climate research communities in Central and Southern Tuscany, Italy, starting with a drought risk assessment, in the first manuscript, and continuing with a climate change impact assessment, also evaluating the adaptive capacity of agricultural systems, in the second and third manuscripts, by applying the Soil and Water Assessment Tool + (SWAT+). In this study area, I also analyze the uncertainty in future climate aridity due to climate models and the vegetation responses to CO2. Furthermore, I assess the impact of agricultural adaptation strategies on hydrological fluxes, an aspect which is often neglected. As a second case study, I selected the Juba and Shabelle catchments in Somalia, an area which is highly exposed to extreme events and with a population mainly composed of small-holder agro-pastoral communities. In this fourth manuscript of the thesis, I integrate both approaches including indicators obtained after simulations of the SWAT+ agro-hydrological model in a climate risk assessment framework. In this way, the representation of climate change hazard and resilience, defined as the combination of coping, adaptive and transformative capacities, is improved. Combining climate change impact and risk assessment, I provide useful information to be used by local decision-makers in Italy and Somalia to better tackle water-related, agricultural climate change challenges. Furthermore, in the four manuscripts of the thesis, I highlight specific issues and uncertainties of these methodologies and explore solutions to address them. Finally, I propose an example framework to combine the approaches to show how the integration is beneficial and helps to deliver a clear and robust message to achieve greater policy impact for a better water management.