***Rather I think we should first terraform Mars. The atmosphere can easily now be turned to Methane which when frozen is a decent rocket fuel. The large gas planets also have a lot of methane and H2. ***
If the atmosphere is converted to methane, how do we get off the planet without igniting the entire atmosphere? Or is it already in frozen form, so we wouldn't have to worry about that. Please clarify. =)
I did a brief google search for NASA methane, and a fellow has a plan to make a smallish industrial plant to make Methane, and bottle it.
A rocket generally has to provide a fuel and an oxidizer, and dumps reaction products out the back end. Only if you dumped your expensively created methane into the atmosphere would you have a fire hazard.
I understand that current theory has it that living things excreted oxygen until it got to the current (or higher) concentration. Earth was once a different place.