The environmental dimensions of universal access to safe water

The world faces a major challenge in adapting to a future where demand for water is accelerating, but supply remains essentially fixed and increasingly variable. Meeting this challenge is central to achieving the Sustainable Development Goals (SDGs) as water is a common denominator linking health, food security and nutrition, clean energy, sustainable cities, climate action, gender equality and the protection of ecosystems. The overall framing of the SDGs, and Goal 6 specifically, marked a desire to unite the hitherto polarised spheres of environment and development, recognising the need to both develop water resources for domestic and productive uses, and to protect them for current and future generations (1, 2). Against this background, Goal 6 ‐ Ensuring availability and sustainable management of water and sanitation for all by 2030 – represents a hard ‐ won marriage of environmental and developmental objectives. But can we ‘have our cake and eat it?’ Unlike energy, where tradeoffs between energy expansion and environmental degradation can be negated through renewables, extending access to water without a commensurate increase in ‘efficiency’, or reallocation from another use/user, may increase pressure on a finite resource. In a 2050 world of almost 10 billion people 1 requiring food, energy and drinking water, demands and trade ‐ offs will increase