The Economist reports that America’s West is in the grip of a 22-year megadrought that is the second-worst in the past 1,200 years.
Drought refers to a dry period that eventually ends. But now two longer-term trends are at work: climate change, which is making the region hotter and drier, and population growth, as Americans move west. Most of the fastest-growing cities are in the south-west. Phoenix, which gets 18 cm (7 inches) of rain a year, grew faster than any other big us city over the past decade.
What can be done? Proper pricing would help. For pricing to work, the West’s outdated system of water rights will need an overhaul.
Agriculture slurps up 70 per cent of the water that flows down the Colorado River, which serves 40 million people across the south-west.
But in many states, farmers or ranchers forfeit their water rights if they don’t use them. Such “use it or lose it” clauses mean that the reward for conservation can be the loss of one’s livelihood.
A law passed recently in Arizona will let people leave water in rivers without jeopardising their rights. Similar schemes are cropping up around the region. Water trading also shows promise. Physically moving water is tricky, but trading within basins, as Australia does, could benefit farmers and cities.
Policymakers must accept that a few wet seasons won’t bail them out. One reason water-rationing for the Colorado River basin could be so painful is that rights were allocated based on overly optimistic assumptions about the river’s flows.
Some officials would still rather plan for more dams or aqueducts than reckon with the reality of shrinking reservoirs. Instead they should focus on reducing water consumption. In Las Vegas each person uses 47 per cent less water than in 2002, reducing overall usage even as the population increased.
America is rich enough to recycle water and to look after its watersheds. That will help mitigate the effects of climate change. But drought is not a problem unique to the American West. The World Health Organisation estimates that water scarcity afflicts 40 per cent of the global population.