Making the Red Planet Green

Our planet is the only one known to be able to support life. But what if we had to leave, make a new home on another planet? Our two closest neighbors are Venus and Mars. They are about the right distance from the sun to house life. Venus, unfortunately, has poisonous gases in its atmosphere, making it  a poor choice for a home. However, Mars does not. Would we be able to turn it into a home, if we had to?

To make the red planet green, we would need an atmosphere that could support life. There are large amounts of carbon dioxide in Mars's polar ice caps. If we could raise the temperature of the planet, it would start to melt. Hey, we've managed to do it here - why not on Mars, too? If the temperature of Mars went up, water in the planet would start to melt. We would need this water, since the price of shipping would be huge if we wanted it from Earth.

Another problem is the amount of nitrogen in the atmosphere. Earth has 70%. Mars has 3%. Nitrogen is essential to life. We would have to bring nitrogen in. This could be done by taking rockets out to the asteroid belt and selecting certain ones with plenty of nitrogen, then driving them back. This, however, turns an already incredibly ambitious project into a near impossibility. In the best case scenario, if everything went well, after this was done, it would take a hundred years to complete. Growing plants on Mars, which would be necessary, is made difficult by radiation.

If everything went smoothly and we could grow plants, the oxygen levels might be enough to just barely survive on Mars in a thousand years. Then there would have to be volunteers who would move to Mars. But, if we ever actually could terraform Mars, we would probably find a way to clean up Earth, which would be easier anyhow.