"As a young planet, Venus was losing hydrogen rapidly to space. The oceans boiled off, and after some..." — 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.

Radiation is one of the important factors in evolution. It causes mutation, and some level of mutation is actually good for evolution.

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.