That's an interesting proposition, but how realistic is it really?
If we're talking about something like a huge asteroid colliding with the earth and/or a huge volcanic episode that would trigger a mass instinction, wouldn't the pale blue dot still be more hospitable than Mars? We have access to technology the dinosaurs didn't have, our chances of survival would probably be much better overall.
Even in case of man-made devastation, such as mass pollution or a nuclear winter I think it's safe to assume that Earth would still be more habitable than Mars.
How about something even more destructive? Maybe something like a gamma ray burst? Well then Mars is probably not far away to put it out of harm's way, although maybe they would be more likely to be unaffected by it if it hit the other side of the planet due to its very thin atmosphere? I'm not sure.
If an event happened that caused the Earth's atmosphere to not be breatheable in a number of hours, would anyone survive? We may have the technology but do there already exist any artificial independent self-sustaining human habitats on Earth that would survive? We could try to build such habitats now -- it would probably be cheaper than going to Mars -- but I think we would have trouble forcing ourselves to spend the money and effort on it and have trouble keeping it honest (avoiding any cheats where it's mostly independent but still dependent on the Earth's ecosystem for some specific uses) without a separate goal (being on another planet) and a hard forcing factor (an environment that doesn't allow any cheats).
If we're talking about something like a huge asteroid colliding with the earth and/or a huge volcanic episode that would trigger a mass instinction, wouldn't the pale blue dot still be more hospitable than Mars? We have access to technology the dinosaurs didn't have, our chances of survival would probably be much better overall.
Even in case of man-made devastation, such as mass pollution or a nuclear winter I think it's safe to assume that Earth would still be more habitable than Mars.
How about something even more destructive? Maybe something like a gamma ray burst? Well then Mars is probably not far away to put it out of harm's way, although maybe they would be more likely to be unaffected by it if it hit the other side of the planet due to its very thin atmosphere? I'm not sure.