Re: Climate change?
"which I'm guessing will find their way into the Falcon boosters before long."
EXTREMELY unlikely. That would involve a ground up redesign for Falcon 9, which doesn't make economic sense. Nor can the F9 really use the (much more powerful) Raptor engines as they can't be throttled down as much in general, and using fewer more powerful engines means you can't just shut a few down and use only a single engine for landing. Using Raptor on F9 would mean giving up re-usability.
Theoretically it MIGHT be possible to redesign the Merlin to run on liquid methane, but that would still be a massive effort that they don't really need. I'd find it more likely they'd invest in making synthetic liquid fuel from methane that the Merlin 1D can run on without modification (which is proven to be possible, just currently not economically viable).