Yes, which is exactly why we should terraform Mars: as a test run of a severe-case rebuilding scenario. If we can handle Mars even at its best (let alone its worst), then we can handle Earth in all but the most catastrophic events.
I personally feel that having a "fallback" in case something literally Earth shattering happens is compelling enough a reason to colonize other bodies in our solar system, Mars included.
I don't disagree. Ceres ain't that much further, and it's literally a giant ball of water and hydrocarbons.
That said, it's possible that even Mars' relatively low gravity is enough to stave off the health problems associated with prolonged microgravity/freefall, so that might be good motivation. If there's some lower bound on how high g needs to be in order for our bones to not become brittle, and Mars is above it while - say - the Moon is below it - then Mars is really the only option besides the moons of the gas/ice giants (and their respectively-giant gravity wells) or Venus (with its Earth-like gravity well and its hellscape of a surface).
So there's another scientific motivation: to measure the effects of low but existing gravity on human health.
The biggest problem to fixing earth is the people with politics that fly in the face of reality. Mars Doesn't have republicans, so I think it would be easier to terraform than earth.
Unless you're building better humans, we're going to have the exact same political problems on Mars that we do on Earth. Except in an environment where any small thing going wrong has the potential to kill everyone.
>Unless you're building better humans, we're going to have the exact same political problems on Mars that we do on Earth.
No, not immediately.
This isn't much different from other colonization missions in human history: humans from one place got sick of the people living there, and went somewhere (relatively) uninhabited so they could live the way they wanted without the political problems they had back home. Eventually, there were new political problems of course, but that took generations; for the initial travelers, it was a sensible move. And the political problems that came were likely different, as so much time had passed.
We could accidentally fire nukes, accidentally let a GM smallpox strain out, accidentally start WW3, we could do so much as it is. That is beside the point anyway.
Presumably the first people to go to Mars are going to be vetted for some level of education and skill. This will likely prevent the fear mongering, demagoguery and other forms of lying that allow some successful politicians argue against singularly true facts, at least for a little while. Likely until the mars colony is self sufficient.
Even then it seems unlikely you will get an anti-global warming lobby on Mars, because it is good for every business (presuming breathable air is government utility/service).
