Highlights: Most San Franciscans (87%) believe global warming is happening. Few (5%) believe it is not. Two in three (67%) believe that if global warming is happening, it is caused mostly by human activities. San Franciscans think global warming is important and are worried about it. Nine in ten (89%) say the issue of global warming is at least somewhat important to them personally. And three in four (77%) are at least somewhat worried about it...