[patrickaljord]

Some people may have said this before Polio vaccine was discovered:

"Almost everything about the plan to help Polio victims, especially about creating a "polio vaccine" is uncertain. Compare that to the current, immediate suffering and lost potential that is caused by poverty and disease."

See how this works?

[hencq]

Polio is a disease that that's causing immediate suffering and lost potential. And it was even more so before discovery of the vaccine, so I'm not sure what you're trying to say here.

[saraid216]

The only specific alleviation that colonizing Mars yields is that people who don't want to live on Earth don't have to live on Earth.

There are some very good reasons to pursue the colonization of Mars, mostly in the form of advancing science. A backup population is not one of these good reasons.