Union-Tribune: Lake Mead, one of the West’s linchpin reservoirs, could go dry in 15 years if climate and water use trends don’t change, researchers at Scripps Institution of Oceanography said Tuesday. Without the reservoir, residents in Southern California and Nevada would be highly vulnerable to yearly changes in rainfall and water deliveries would become "highly unstable," said climate experts Tim Barnett and David Pierce at Scripps, which is part of UC San Diego. The two scientists …