Deutsche Bank has launched a "carbon counter" (click here) that displays the running total amount of long-lived greenhouse gasses in the earth's atmosphere, measured in metric tons.
It hums along there pretty fast. You can even download a widget here to put on your computer's desktop if you're into that kind of thing. One person who has seen it has likened it to "watching a car crash in slow motion, but we're in the car." Happy driving!