San Francisco Chronicle: California’s farmlands face dryer, hotter weather. Snowfall in the Sierra will be lighter. Wildfires and droughts will hit harder. Add to these predicted effects of global warming: Ever-rising sea levels that will flood coastal areas, with the Bay Area getting the worst of it. The rising ocean is the latest warning sign, say scientists detailing the damage that higher atmospheric temperatures will bring. It’s a future where walls will be needed to protect low-lying areas, steep cliffs …