Imagine building reservoirs and desalination plants in Monterey County during the 1970s because we knew there would be a drought of the magnitude we are experiencing today? No need to imagine, because we did know.

That was the message delivered Tuesday during the Salinas Rotary Club meeting at the National Steinbeck Center. The messenger: Rebecca Costa, best-selling author of “The Watchman’s Rattle,” a look at why leaders, corporations and even nations stumble even when they have solutions to problems staring them in their collective face.

For example, the world has known for decades that climate change will negatively affect water supplies and exacerbate droughts. When did we act? Three weeks ago when the state issued an emergency drought declaration. Why?

“Because policy is based on unproven beliefs and opinion makers,” Costa said. “We have 1.5 billion temperature readings from around the world, yet 65 percent of the U.S. population believes there is no climate change.”