But don't pack your bags yet. It will take 100,000 years, give or take a thousand or two, to turn Mars habitable, with a (minimum requirement) breathable atmosphere, for humans, let alone a cosmic vacation destination. But, scientists say, it could be “warm, wet and ready for (primitive) life” in about a century. "Mars: Making the New Earth," a part of NatGeo's Expedition Week series, is a step-by-step guide on how to reanimate a foul, nasty planet with an average temperature of -80 degrees and an atmosphere made up of deadly ultraviolet and cosmic radiation, a place that has been dead as a cosmic doornail and frozen solid for 3.5 billion years.
As with any big project, you start with baby steps. First, get there, necessarily with a small, expeditionary force. Then start cooking the atmosphere, setting up little factories, which, of course, would have to be built from scratch, and make use of super greenhouse gasses like sulfur and florine, thousands of times more potent from a planetary warming point of view, than fossil fuels and both present on the planet. Slightly warmer temperatures would set off natural processes that would get the greenhouse ball rolling. After 100 years, liquid water would exist. The atmosphere would thicken, turning the Martian sky blue. Although much of the planet would remain icy, like above the Arctic Circle, life would be possible. Lichen and mosses would be introduced. The primitive life forms would break rock down into soil, paving the way, so to speak, for grass and shrubs. Then high-altitude fir trees, possibly genetically engineered, would be introduced. This would improve the soil and atmosphere, making it possible for more complex life forms — humans — to exist, if we don't wipe out the species by ourselves.
Terraforming represents "planetary engineering on an almost inconceivable scale," the documenary admits. "It sounds crazy, but it's a scientifically credible idea," says Davis, 59, whose previous documentaries include “The Curse of T-Rex” in 1996, and “Mars Dead or Alive” in 2005, and who is currently chasing an American Experience deadline for his documentary on the so-called “bone wars,” a knock-down/drag-out battle between paleontologists Charles Marsh and Edward Cope. But why do it, other than to show off how clever we are? Our survival may depend of it. In the distant future, our sun will grow larger and burn hotter, a process that cannot be stopped; the closest planets will burn first. The only future, long long term, will be to escape to the farther reaches of the galaxy. To do that, we, if we exist, will have to know how to build a better planet. But, in the here and now, the reason to do this, beyond the fact that it is in our nature to explore, is knowledge: how planets work, how to keep them alive.