Global freshwater resources are threatened by rising demands from many quarters. Growing populations need ever more water for drinking, hygiene, sanitation, food production and industry. Climate change, meanwhile, is expected to contribute to droughts.
Policymakers need to figure out how to supply water without degrading the natural ecosystems that provide it.
Existing low-tech approaches can help prevent scarcity, as can ways to boost supplies, such as improved methods to desalinate water.
But governments at all levels need to start setting policies and making investments in infrastructure for water conservation now.