What's its carbon footprint? Just askin'..
It's burning RP1 (kerosene), so in terms of fuel burnt it's going to be fairly terrible. On the other hand, re-usability will save the impact of building a new rocket each time, which is a welcome innovation.
The BFR will be designed around liquid methane propellant instead, because that's practical to make on Mars from carbon dioxide and water. Elon makes the valid point that if you can make fuel from carbon dioxide, water and solar power on Mars, you could potentially do the same thing on Earth. So the BFR wouldn't be tied to fossil fuels in the long term.
On that basis I'm half expecting economically viable synthetic gas to be another commercial spinoff of Elon's Mars obsession. Assuming of course that Special Circumstances don't catch up with him first.
