Can We Make Mars Earth-Like Through Terraforming?
Mars has more abundant sources of carbon dioxide, such as those locked in the martial soil and tightly bonded carbon in minerals. But based on 20 years of NASA and ESA satellite data, researchers estimate that even if we mine Mars’ entire surface for carbon dioxide, the atmospheric pressure would still only be about 10-14% of Earth’s. This would correspond to an average temperature rise of about 10 degrees Celsius––not nearly enough to sustain liquid water.
To put this all into perspective: we would need more carbon dioxide to meaningfully warm up Mars than humans have released throughout our entire history on Earth. Terraforming Mars is therefore a daunting endeavor that doesn’t seem possible with current technology.
With future technological advances, we might be able to excavate minerals deep in the Martian crust that may hold significantly more carbon dioxide and water. But the extent of these buried deposits isn’t currently known or evidenced by satellite data. We could also artificially introduce heat-trapping gases that are superior to carbon dioxide, like chlorofluorocarbons. These gases are short-lived, though, so the process would need to be repeated on a large scale to keep Mars warm.
Another idea is to import gases by redirecting comets and asteroids to hit Mars. However, this isn’t exactly practical, as it would require an inordinate amount of impacts to make any meaningful difference.
Breathing on Mars
Another challenge is making Mars’ atmosphere breathable. The MOXIE experiment on NASA’s Perseverance rover aims to convert carbon dioxide from Mars’ atmosphere into oxygen. If it works, future human explorers could use this kind of technology to generate oxygen for their habitats. However, doing this for the entire planet may not be feasible. This is why some researchers suggest turning to forms of life that have already transformed Earth’s atmosphere.
On Earth, cyanobacteria were responsible for converting, via photosynthesis, our atmosphere of methane, ammonia and other gases around 2.5 billion years ago into the oxygen-rich one of today. Since Mars receives less than half the sunlight as Earth—and has a global dust storm problem that makes visibility worse—researchers have suggested that we introduce special microorganisms on Mars that photosynthesize in low-light to create breathable air for humans. When paired with other organisms, an entire life cycle could be created on Mars with a favorable blend of gases.