[gamblor956]

Mars is not a viable safety hatch for continued human existence. It will simply be too dependent on resupply from the Earth for the foreseeable future (on a timescale measured in generations).

All of the following are easier to accomplish than colonizing Mars: solving global warming, colonizing the ocean floor, colonizing the Moon. Indeed, the technologies we would need to terraform or colonize Mars to a sufficient level to be an escape hatch would necessarily involve solving all of those first.