Book excerpt: In line with COP21 agreements, state-led climate change mitigation and adaptation actions are being undertaken to transition to carbon-neutral, green economies. However, the capacity of many countries for action is limited and may result in a ‘boomerang effect’, defined as the unintended negative consequences of such policies and programmes on local communities and their negative feedbacks on the state. To avoid this effect, there is a need to understand the policy drivers, decision-making processes, and impacts of such action, in order to determine the ways and means of minimizing negative effects and maximizing mutually beneficial policy outcomes. This book directly engages the policy debates surrounding water resources and climate actions through both theoretical and comparative case studies. It develops the ‘boomerang effect’ concept and sets it in relation to other conceptual tools for understanding the mixed outcomes of state-led climate change action, for example ‘backdraft’ effect and ‘maldevelopment’. It also presents case studies illustrative of the consequences of ill-considered state-led policy in the water sector from around the world. These include Africa, China, South Asia, South America, the Middle East, Turkey and Vietnam, and examples of groundwater, hydropower development and forest hydrology, where there are often transboundary consequences of a state's policies and actions. In this way, the book adds empirical and theoretical insights to a still developing debate regarding the appropriate ways and means of combating climate change without undermining state and social development.