-Views are my own and are not endorsed by present or past employers or affiliates.-
Possible calamities on Earth aren’t the only compelling reason to colonize.
Space exploration develops a lot of astoundingly useful technology out of necessity for survival in a new environment. We’ve benefited from that already. Space colonization, by necessity, must develop a lot of technology to make us more efficient at resource utilization, whether by managing energy sources (solar, wind, hydrocarbons and fossil fuel, nuclear), recycling necessities (oxygen, waste water, carbon dioxide), or producing food.
If a Mars colony had to grow its own food because it was too expensive to ship, how many people in Africa or on the streets of New Orleans could have enough to eat?
If a ten-person outpost on Mars had enough oxygen, clean water, food, power, and heat, how much more so an Earth village with wind energy, twice the solar energy, water they didn’t have to carry on 470 times as much fuel, and soil suited to growing plants without a pressurized greenhouse?
Yes, space is expensive.
But that payoff can both provide technology for cleaning water, producing energy, and feeding the hungry AND drive down the cost of doing so.
Invest in the future’s humanity. Invest in space colonization.
PS. Mars One folks are still a little crazy.