Well, i saw on Ripleys that there are actualy some people somewhere in the world that are actualy living underground in there own underground houses and they have there own comunity there. lol
On other planets that still have a vast supply of natural resources. Our natural resources are running out, so how is moving undergound going to help? Our Ozone Layer is depleting due to pollution, thus allowing deadly ultraviolet rays from the sun to pass through our atmosphere so how is moving closer to the sun going to help? And, this could potentially vaporize our oceans when the ultraviolet rays become deadly enough so how is living in the oceans going to help?
Under the oceans is a rediculous notion to begin with, as you're drilling into the Earth's crust to find a new house, so I'm not even going to address that with a response.