Our planet probably has no more and no less water than it has ever had, but many more people use much more of it. Today, a billion people cannot get enough safe drinking water.
By 2050, 45% of humankind will live in countries chronically short of water. Water is scarce – but cheap (or free). It is valuable – but wasted and polluted. It is the stuff of life, but dirty water spreads disease: bad water and poor sanitation kill 5,000 children a day. Climate change is moving the available fresh water to different places, and new water systems are required to obtain it.
The biggest industrial use of water is for cooling thermal power stations, and carbon capture and storage systems would require vast amounts of water – two more reasons to move from carbon energy to renewable energy.
Two-thirds of all the water taken from nature is used to grow crops. This dries the landscape, empties wetlands, destroys fisheries and even alters the climate.
There are myriad solutions, both big and small. Sanitation systems that use little or no water are available. Drip irrigation, rather than flooding fields, can cut water use by 60% or more. Some Indian farmers make their own drip systems from plastic sleeves made to hold popsicles. If farmers are taught how to measure and evaluate their water use, they learn to use less of it. And effective water pricing can help people and businesses understand its value.
Many small dams are usually more effective than a few big dams, both in terms of irrigation water and hydropower. Water use must be systematized overall, as it has been in Singapore, where domestic water use has fallen in the last decade since the introduction of water tariffs and low-use taps and toilets.