[stcredzero]

And if it becomes that common, in 150 years time, New York will be under water.

If it becomes that common, it will be well within the major power's ability to block 1.5% of the sunlight that hits the Earth by posting sunshades at L1.

Surely burning a country's worth of rocket fuel every time you want to travel long distance is not sustainable?

It doesn't take that many airliner flights to match that power output.

[snrplfth]

Indeed, a Falcon 9 takes only the amount of fuel used by 2 long-distance 747 flights. BFR might be, say, five to seven times that, though it's a different fuel (natural gas instead of kerosene.)