East Bay Express: Now that President Barack Obama has blocked construction of the Keystone XL pipeline, the Bay Area has emerged as a new battleground in the struggle to keep dirty tar sands oil in the ground a goal that scientists say is critical to avoiding a climate change catastrophe. In fact, even before the defeat of the Keystone XL, Canadian oil investors desperate to get their landlocked crude to market were already planning an "invasion" of tar sands oil to the West Coast, according to a report issued...