With the possibility of catastrophes hitting Earth and current problems such as global warming and an exploding population becoming worse, colonizing Mars could be humanity's option to continue sustaining life.
The U.S. is already going after a manned mission to Mars in the future, and missions to the Red Planet, such as the Mars Global Surveyor, Mars Pathfinder, Viking and the Phoenix Mars Lander, have already gathered valuable data about the planet, which can be used to assess the sustainability of living in a Martian environment.
Still, there continue to be problems that humanity needs to solve in order to colonize Mars. Here are some of them:
Mars One, which plans to land humans on Mars in 2025, aims to provide drinking water for the colony by baking Red Planet soil that contains water ice, but the technology required for this won't be ready yet to be flown on a space mission.
Food is essential for survival. However, there is yet no clear idea on how it is possible to produce food in Mars, which means that a settlement on the Red Planet would have to rely on food shipments that come from Earth.
Terraforming a planet involves deliberately changing its climate and surface so it could have an environment that is hospitable to humans and make colonization possible. Things, however, could go wrong with attempts to terraform Mars. Experts, for instance, estimate that the approach might take 100,000 years to make the atmosphere breathable. Altered biological cycles could also possibly go in a direction that would turn out harmful. Organisms, for instance, could evolve on a transformed Mars and could become hazardous.
Radiation on the surface of Mars is more than twice the one experienced at the International Space Station. Solar particle events also occur without warning and bombard the place. Something needs to be done to address the radiation problem because it would mean that colonists would have to live short and sickly lives.
Space Suit Limitations
Colonists would have to use spacesuits in Mars but these could also fail. Accidents that damage the spacesuit could be fatal. Once spacesuits fail, the colony can also only do some repairs but will be unable to produce these suits.