Nobody thought terraforming Mars was going to be easy. But now, a new in Nature Astronomy suggests that with current technology, transforming the Red Planet into a verdant oasis would actually be impossible.
It has been suggested that if you were able to release enough carbon dioxide into the air on Mars, the planet could form an Earth-like atmosphere. Producing abundant oxygen, warm weather, and arable land on the Red Planet has been the stuff of science fiction going back to Edgar Rice Burroughs—and it seems the idea is destined to stay fiction for now.
"Mars does not retain enough carbon dioxide that could practically be put back into the atmosphere" to terraform the planet, NASA said in a on the new study.
While the Martian atmosphere is carbon dioxide, that atmosphere is extraordinarily thin and cold compared to Earth: only 0.6 percent of our planet's atmospheric pressure. Using the spacecraft (MAVEN), NASA was able to get a better understanding of what that atmosphere looks like. Over time, much of the Martian atmosphere was blown out into space due to solar winds.
"Our results suggest that there is not enough CO2 remaining on Mars to provide significant greenhouse warming were the gas to be put into the atmosphere; in addition, most of the CO2 gas is not accessible and could not be readily mobilized," says Bruce Jakosky of the University of Colorado, Boulder, Principal Investigator of MAVEN and lead author of the new study. "As a result, terraforming Mars is not possible using present-day technology."
There is carbon dioxide ice in the polar caps of Mars, and vaporizing these sources of CO2 could double the pressure of the Martian atmosphere. However, all that effort would only result in a planet with an atmospheric pressure 1.2 percent that of Earth's at sea level. Releasing carbon dioxide from every mineral on the planet could boost pressure to 7 percent that of Earth—significantly stronger than 0.6 percent, but for heating and terraforming the planet, it's still not nearly enough.
The ancient atmosphere of Mars once likely made the planet a vibrant world of flowing water, but that thick air has been stripped away. While this means visions of terraforming, like Kim Stanley Robinson's Red Mars trilogy, will likely remain fiction, it does not preclude the possibility of building a pressurized base on Mars. We may colonize the Red Planet yet, but it's not going to be as easy as releasing the carbon dioxide trapped in the planet.