California’s current drought is in its fourth year, but research indicates that the state and the rest of the West had ancient megadroughts that lasted decades and sometimes two centuries. Credit Matt Black When Gov. Jerry Brown of California imposed mandatory cutbacks in water use earlier this month in response to a severe drought, he warned that the state was facing an uncertain future. “This is the new normal,” he said, “and we’ll have to learn to cope with it.” The drought, now in its fourth year, is by many measures the worst since the state began keeping records of temperature and precipitation in the 1800s. And with a population now close to 39 million and a thirsty, $50 billion agricultural industry, California has been affected more by this drought than by any previous one. But scientists say that […]