We also don't have the luxury to withdraw from the Paris climate accord. Elon Musk is not the only person who could improve the likelihood of us surviving on th

We also don't have the luxury to withdraw from the Paris climate accord. Elon Musk is not the only person who could improve the likelihood of us surviving on this planet. The clue about having a self-sustaining colony on Mars would be that it protects humanity from almost any danger that happens to humanity on Earth. Even if an asteroid protection system were cheaper, it would only protect from one low probability danger. But it is likely not to be cheaper, as you would have to install lots of surveillance satellites over the solar system to detect all those small asteroids we can't yet detect from Earth or detecting much too late for anthing to do. Also, you would need to reach those asteroids quickly enough to do countermeasure (nuking an asteroid a few thousands kilometers from Earth like in the movies either wouldn't work at all or be a stupid thing to do). Which is technology in the same ballpark as lifting one million people to Mars. Synergistic effects would apply with a thriving private space travel industry.