It's not the technology to tackle environmental issues that is lacking, it's the political will. Not going to space doesn't magically solve the problem of entrenched carbon-emitting interests having the power to block a short-term mandatory transition to renewable energy.

Given that, it absolutely makes sense to colonize space, as Mars can't be ruined in the same way that we're ruining Earth, and the petroleum mining industry won't be coming along for the ride.