Water supply has to be increased, not simply redistributed. Water tables are falling on every continent, 40% of humanity depends on international watersheds, agricultural land is becoming brackish, groundwater aquifers are being polluted, and urbanization is increasing water demands faster than many systems can supply. About 80% of all diseases in the developing world are water-related. Many are related to poor management of human excreta. Despite some recent improvements, 1.1 billion people still do not have access to safe drinking water and 2.6 billion people lack adequate sanitation, resulting in 1.7 million deaths per year from diarrhea and related diseases.

Many major rivers now run dry during part of the year before they reach the ocean. Water withdrawals from lakes and rivers have doubled in the last 40 years. UN agencies estimate that without major changes, by 2050 more than 2 billion people will live in water-scarce areas. Agriculture accounts for 70% of all human usage of fresh water, and it needs even more to feed the growing populations, while urban demands for water continue to grow and nature also needs sufficient water to be viable for all life support. More than 3,000 freshwater species are listed as threatened, endangered, or extinct. Future conflicts over trade-offs among agricultural, urban, and ecological uses of water are inevitable unless major political and technological changes occur. Previously, water-sharing agreements have occurred even among people in conflict and have led to cooperation in other areas.

Challenge 2 will be addressed seriously when the number of people without clean water and those suffering from water-borne diseases diminishes by half and when the percentage of water used in agriculture drops for five years in a row. WHO estimates that each $1 investment in increased water availability would yield an economic return of up to $34 and that the health-related costs avoided would reach $7.3 billion if global MDG water and sanitation targets are met. We need an integrated global water strategy, plan, and management system to focus knowledge, finances, and political will to address this challenge. It should apply the lessons learned from producing more food with less water via drip irrigation and precision agriculture, development of seawater agriculture on desert coastlines, rain-fed irrigation and watershed management, selective introduction of water pricing, new approaches to desalination like pressurization of seawater or its filtration via carbon nanotubes instead of more expensive reverse osmosis, and replication of successful community-scale projects around the world.

The plan should help convert degraded or abandoned farmlands to forest or grasslands; invest in massive desalinization, household sanitation, wastewater treatment, reforestation, water storage, and treatment of industrial effluents in multipurpose water schemes; and construct eco-friendly dams, pipelines, and aqueducts to move water from areas of abundance to scarcity. Water can also be conserved by using animal stem cells to produce meat tissue (without the need to create the animal) and by increasing vegetarianism around the world. Finally, use the UN’s 2005–15 Decade: Water for Life to get countries to commit to continually updating national and regional water plans.