Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences

    Water security is a defining challenge for society, science and policy in the twenty-first century. The World Economic Forum has identified water supply crises among the top global risks for three years running. Recognizing the need for interdisciplinary science to respond, the University of Oxford Water Network organized the first international conference on Water Security, Risk and Society in April 2012. The conference convened over 200 thought leaders from science, policy and enterprise in 30 countries to take stock of the scientific evidence on water security risk and prioritize future interdisciplinary research.

    The agenda-setting papers in this Theme Issue engage multiple dimensions of water security, ranging from drinking water, food production and energy to climate risks and economic growth. Risk provides the basis for a unifying framework to bridge across multiple disciplines and science–policy divides.

    Fifteen papers are organized in three broad sections to

    — Frame the policy challenges of and science responses to water security from a risk perspective. Three editorials outline: water security policy challenges to guide science agendas in the twenty-first century (led by Prof. David Grey and leading water practitioners in five countries), the role of science and partnerships as catalysts for innovation (former UK Government Chief Science Advisor, Prof. Sir John Beddington), and technological responses to improve water security (Prof. Ian Thompson).

    — Take stock of the scientific evidence about the status and driving forces of water security challenges. Review articles examine risk-based principles to achieve tolerable levels of water-related risk (Hall), implications of land surface–atmosphere interactions (Dadson), monitoring and management approaches to improve drinking water security (Bradley, Hope) and the governance dimensions of water security (Bakker).

    — Examine the responses to water insecurity at multiple scales. Research articles address the water security risks and responses associated with food production and water scarcity (Falkenmark), flood events (Vorosmarty), water quality (Whitehead), politics of hydropower development (Verhoeven), hydroclimatic risks and transboundary water allocation (Garrick), river basin management (Wheater) and relationship between climate hazards and economic growth (Brown).

    The papers characterize the unprecedented and growing scale of water security risks to society. For example, over 45% of the global population is projected to be exposed to water shortages for food production by 2050 (Falkenmark), and South American cities have experienced a doubling of risks associated with extreme rainfall from 1960 to 2000 (Vorosmarty). Modelling demonstrates that climate hazards are an impediment to national-level economic growth (Brown).

    The contributions provide a rounded perspective on complex, multi-scale water security risks. Taken together, these papers provide strong justification and strategic priorities for policy-driven science in the lead-up to new development goals in 2015 and beyond. The integration of natural and social science assessments is a priority for future research to diagnose major risks, investigate pathways to enhance water security and improve uptake of science into policy decisions and business investments.