Like it did last year, Google reported its 2011 carbon footprint yesterday morning on its Google Green site. In 2010 the company emitted 1.46 metric tons of CO2 and in 2011 that was up to 1.68 metric tons. Google continues to deploy power hungry data centers, though Google’s are among the most efficient in the world with a new best power usage effectiveness (PUE) rating of 1.13. And the company seems on track with its renewable energy goals, having sourced 33 percent renewable energy in 2011 with 13 percent coming from direct Google purchases and 20 percent already on the grid. Google reports that its carbon use per million dollars of revenue is declining at an annual rate of 10 percent. All in all, other companies (Apple) could learn a few things from Google’s aggressive transparency about its environmental footprint. And what would be even better would be seeing industries that hog energy like iron and steel manufacturing and the petrochemical industry having the same sense of global responsibility.