I've always been interested in this theory.

Could we not nuke the hell out of it to cause global warming and warm the planet up? Would it not be reusable in 90 years or so?

Originally posted by Claudius
Terraforming of mars is a hypothetical process in which the climate of mars is
made suitable for human habitation.

We'll probably do it eventually if Mars is uninhabited.

But if Mars is inhabited, then it belongs to the martians. I'm surprised the Wiki article doesn't address the ethics of this aspect of terraforming.

We really don't yet know if there are some kind of martian lifeforms living in the martian soil, so we need to determine that before we start terraforming.

But creating a human colony somewhere off Earth is nearly essential for human survival, as it seems there is likely to be another impact like the one that killed the dinosaurs again. The question is when, not if it will happen. And when it happens again, we don't want to be a one-planet species.

Personally, I'd rather put my effort into colonizing Venus. Collecting comets and introducing them to the planet would give it the planet the much-needed hydrogen boost it needs. There is already plenty of carbon and oxygen on the planet.

The other major hurdle (for either Mars or Venus) lies in the lack of a large and stable magnetic field for either - something rather interesting and critical to us on Earth.

It's theorized that the severe storms on Venus provide enough of a magnetic field to shelter the planet - but changing the climate by bombarding the planet with hundreds of comets would likely make it so we could not rely on that.

The magnetic field would probably have to be generated artificially - or the 'natural' process Earth has would have to be somehow replicated.

In either case - both planets will take hundreds - perhaps thousands of years or more to engineer into a suitable climate. Building artificial platforms in space would be far more practical and worth the effort. Terraforming would be more of a luxury project done for the sentiment.