The cracked and desiccated shoreline of Lake Mendocino made a telling backdrop for California Governor Gavin Newsom’s message at a news conference last week: Drought conditions are here, and climate change makes the situation graver.  But water supplies vary across regions, which is why the governor limited a drought emergency declaration to just two northern counties. In fact, highly urbanized Southern California has a record 3.2 million acre-feet of water in reserve, enough to quench the population’s needs this year and into the next.