It's not the outgassing...
Hello Jacob -
Its that given the radiation, you end end up with the water forming about every type of toxic substance around in quantity...
Its that no type of agriculture would be possible, as the radiation would kill just about any plant...
It's that you couldn't wander around the surface and lead any kind of normal life...
I'm actually hoping Eby can come up with some kind of solution, at least enough of one to make manned Mars flight possible... otherwise I've got a massive re-write to do...
EP