As the world's climate warms, droughts are increasingly common — and severe. Without water, crops wither, wells dry out, and people are saddled with strict water-saving measures. In California's recent drought, more than 5,000 people lost running water, while others were prohibited from washing their cars or watering their lawns.
"Many cities across the globe are facing water scarcity, which is intensifying in the face of a warming climate and growing population," says Pouya Vahmani, a postdoctoral fellow at Lawrence Berkeley National Laboratory and an expert on urban climates.
While there's no reliable way to prevent long dry spells, scientists are identifying new ways to predict drought and mitigate its effects. One new study conducted by Vahmani and Andrew Jones, Deputy Director of the Climate Readiness Institute at the lab, suggests that a highly effective way to conserve water across broad areas involves so-called "cool roofs," which use reflective materials to limit absorption of the sun's rays.
It's long been known that cool roofs — which can be anything from a coat of white paint to shingles or tiles treated with a reflective coating — can help keep buildings cool and reduce energy costs. But the study — which used satellite climate data for 18 counties in California — showed that if more businesses and residences switched to reflective roofs, ambient temperatures in the area would fall significantly. And, according to the study, lower temperatures could save up to 15 gallons of water per person per day — that's as much water as the typical washing machine uses for a load of laundry.
That may not sound like much, but it's likely enough to make things a bit easier for people facing water-saving restrictions. During the California drought, for instance, the state mandated a 25 percent cut in water consumption.
So given our climate woes, don't be surprised if you see more cool roofs in California and other places with warm, sunny weather.