KQED Science: An immediate and growing threat. Thats how Californias lead environmental agency and the Governors office describe climate change in the latest in a series of periodic reports on the subject. The report cites already discernible impacts of climate change and attempts to pinpoint the main drivers no pun intended. In California, nearly 40 percent of greenhouse gas emissions come from the transportation sector trains, planes and automobiles, and the last in particular. According to...