Terraforming, aka the process of creating an environment resembling that of Earth on a different planet, has been proposed as one solution for enabling long-term colonization on the Red Planet.
By doing so, it's hoped that enough carbon dioxide would be released into the Martian atmosphere to create a protective covering that could warm the planet. Unfortunately, Mars doesn't currently retain enough carbon dioxide to make that scenario possible -- not given Earthlings' current technological capabilities, says a report from the National Aeronautic and Space Administration (NASA).
Even though the atmosphere on Mars is made up largely of carbon dioxide, it's too thin and cold to support water in liquid form -- something that's required to sustain life.
Still, hope abounds for thickening the atmosphere by releasing greenhouse gases that would boost the temperature until liquid water shows up as stable on the surface of Mars.
Potential sources of additional CO2 include the planet's polar ice caps, which could be vaporized by scattering dust to absorb more solar radiation. Explosives might also do the trick. Still, the amount of CO2 released would still fall far short of what's needed.
Another possible source would be CO2 fused with dust particles in the Martian soil; heating up the dirt could release the gas. And this would provide about 4 per cent of the pressure needed. Still another source is mineral deposits, but which are estimated to hold less than 5 per cent of the needed pressure.
Scientists have even theorized about re-directing asteroids or comets to collide with Mars, though that would require thousands of occurrences.
As a result, terraforming Mars won't happen until, as NASA says, "very far into the future".