Science Blogs: Four weeks after a wildfire began in the Canadian province of Alberta, thousands of structures in Fort McMurray have been destroyed, over 100,000 people have been evacuated, and 2200 square miles have gone up in smoke. The fire has also shut down commercial extraction of tar sands, a source of fossil fuel and the reason for Fort McMurrays prosperity. Greg Laden points out the perverse cause and effect of it all: tar sands contribute to global warming, global warming contributes to weather variation...