"Radiation is one of the important factors in evolution. It causes mutation, and some level of mutati..." — David Grinspoon

What we should really be thinking about is what it would look like for a truly intelligent technological species to be interacting with their planet's atmosphere.

Mars does not have an atmosphere and does not have a magnetic field today, so the planet doesn't have the protection from radiation that our atmosphere and magnetic fields provide us on Earth.

I'm an astrobiologist, and I come from a planetary science background, so in a very broad sense, I study the evolution of planetary environments.

Earth is going to lose its oceans in the future, just as Venus did in the past. How long planets retain their oceans is a function of distance from the sun, all other things being equal.