Last updated October 25, 2018 at 2:39 pm
Hopes of turning Mars into an Earth-lite are unlikely due to the opposite CO2 problem.
Mars is a freezing world devoid of a significant atmosphere, but by releasing trapped carbon dioxide it can be terraformed into a second home for plants and humans. At least that was the hope but, as the latest research in Nature Astronomy shows, there’s simply not enough of the greenhouse gas available to do the job.
Carbon dioxide has a significant public relations issue on Earth where too much of this greenhouse gas is trapping evermore of the Sun’s energy and driving climate change. Yet as Mars shows not having enough of the gas can also be an issue as temperatures plummet.
The solution beloved in science fiction films is to release the frozen carbon dioxide ice at the Poles to the atmosphere, where it will have the effect of thickening the atmosphere, trapping heat from the Sun to raise temperatures, and allowing water to remain on the surface of the planet, making it more hospitable for human colonies and plants to live on the surface. Even Elon Musk got into the spirit, suggesting we ‘nuke’ the Poles to release their frozen gases. The scientists calculated that could double the atmospheric pressure, but it would still be over 66 times too low for those of us who have evolved with ~1 bar of atmosphere.
There is potentially just as much carbon dioxide locked into surface layer rocks known as carbonates, yet even the unfeasible idea of heating most of this material to 300 degree Celsius to release that gas will only create triple what we got from the ice on the Poles. Again, far too little in total.
However there is a potential ‘deep’ layer of carbonates that may, or may not, exist below 100m depths. Hypothetically this could have enough carbon dioxide to attain 1 bar of atmospheric pressure, but reaching this is beyond feasible technology. Even redirecting asteroids to crash into the surface to release gases from depth would still need to occur across most of the planet to significantly change the atmosphere.
Even if future colonists released enough carbon dioxide to make the atmosphere more to our liking, the challenges would not stop. They would still have to contend with the stripping of the atmosphere by the solar wind – the cause of Mars losing its atmosphere in the first place.
Researchers estimated that in a best case scenario releasing all available carbon dioxide both above, and below, the surface could raise temperatures by at most 10 degree Celsius and only triple Mars’ atmosphere, which is barely a fiftieth of the air pressure required by us.
Unfortunately the findings suggest that terraforming the Red Planet will remain science fiction not science fact, meaning the hope for humanity rests in restricting carbon dioxide production on Earth rather than raising it on Mars.