Adaptation to climate change is the subject of increasing interest and research efforts. As a result, large amounts of information, studies and reports are available about topics such as climate projections, vulnerability assessment or practical adaptation options. However, there is a lack of guidance for decision makers at the local level who wish to proactively prepare for and adapt to climate change. Missing is also single ‘home’ for this information.

Building upon the wealth of knowledge within ICLEI, IWA and UNESCO-IHE as well as the vast quantity of information that has been or will be assembled during the SWITCH and PREPARED projects, this handbook – and its accompanying web pages – aims to be that home. The handbook will provide local governments and utilities with up-to-date information as well as access to resources and good practice examples. This will enable them to increase their awareness of how the potential impacts of climate change will affect their urban water systems and to build their capacity to develop a long-term strategy for adaptation in the water sector.

Climate change will disproportionately affect cities since these concentrate populations and economic activity and are mostly located in climate-sensitive areas such as floodplains and coastal zones. The urban water system – which includes water supply, wastewater and stormwater – is particularly at risk because climate change will mainly manifest itself through alterations in the water cycle. More variability and the increased occurrence of extreme weather events are predicted with a reasonable amount of confidence, in spite of some uncertainty. Some of these changes are already happening, and require cities to take urgent action.