Kyle,
Ironically, I think the amount of water that falls from the sky could significantly increase in the temperate regions. That'd lead to golf courses being "water sinks" that are able to absorb the additional water. Golf courses could also become "CO2 sinks".
All of a sudden, a mega box-store with its acres of non-porous parking lots seems to be a much worse environmental concern than a golf course.
And I think that many non-golfers will finally "get" the environmental advantages of a golf course as a greenspace.
But I think they key is public access. I think St Andrews has it right - shut it down once a week and give the land back to the people. (Golf's survival may depend on significant paradigm shifts at private clubs)