The Arab Climate Change Assessment Report — Main Report presents a comprehensive picture of the impact that climate change is expected to have on freshwater resources in the Arab region until the end of the century and how this will affect the vulnerability of water resources, agriculture, natural ecosystems, human settlements and people. The results are based on the outcome of a region-specific integrated assessment that generates regional climate modelling and hydrological modelling projections for the Arab region and for selected subdomains, including some of the region’s major shared surface water basins. These outputs are then used to inform an integrated vulnerability assessment that considers how exposure to climate change over time will affect the vulnerability of five key sectors and nine subsectors in the Arab region, in the absence of adaptation or any mitigating measures. Case studies findings examining flood frequency, droughts, crop productivity and human health are also summarized in the report. This publication is complemented by a Technical Annex and forms the core part of the series of RICCAR publications.