Terraforming Mars: Enough CO2, a misunderstanding
A supposed debate broke out earlier this week amongst NASA and Elon Musk about the possibility of terraforming Mars. NASA scientists suggested that there isn't enough CO2 on Mars to terraform the planet with today's technologies. Elon Musk replied (on Twitter, of all places) that it was indeed terraform-friendly with the CO2 trapped in the planet's soil, using heat. Then people started to lose their minds, arguing one side or the other, when in reality there wasn't much of an argument in the first place, only a matter of a couple of different perspectives.
Today, not Tomorrow
NASA's release on July 30th suggested that "Mars terraforming not possible using present day technology." They made clear – in the title of the article about the study they were writing about – that they were talking about technology available right now, here, today. Bruce Jakosky, University of Colorado, Boulder, lead author of the study at hand, spoke on the subject as follows:
"Carbon dioxide (CO2) and water vapor (H2O) are the only greenhouse gases that are likely to be present on Mars in sufficient abundance to provide any significant greenhouse warming," said Jakosky. "[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. As a result, terraforming Mars is not possible using present-day technology."
The full study can be found under title "Inventory of CO2 available for terraforming Mars" in Nature Astronomy published July 30th, 2018. That's Nature Astronomy volume 2, pages 634–639 (2018), in the paper authored by Bruce M. Jakosky & Christopher S. Edwards.
ABOVE: A video clip referenced in the study – of Elon Musk. Imagine that!
Misunderstanding or Quick Trigger Finger
Elon Musk took to Twitter to issue a rebuttal to part of the study – the part that said terraforming Mars wasn't possible – without acknowledging the several disclaimers. Musk suggested the following:
"There's a massive amount of CO2 on Mars adsorbed into soil that'd be released upon heating," said Musk. "With enough energy via artificial or natural (sun) fusion, you can terraform almost any large, rocky body."
Musk's comment was a reply on Twitter to a Tweet for an article from Discover Magazine with the comment "Sorry, Elon. There's not enough CO2 to terraform Mars." So Musk replied – sort of directly to Discover Magazine, more than the original research paper and authors. Discovery Magazine issued a sort of rebuttal in the article: No Seriously, Elon. You Can't Just Nuke Mars (We Asked).
There, Jakosky spoke up once more, responding to Musk's reply, agreeing with Musk – sort of. As mentioned in the research paper, there is indeed CO2 in the soil, but – again – getting it out with today's technology isn't possible.
"When you're thinking about a technology far into the future, you can think about anything you like and imagine it's feasible," said Jakosky. "That's why we stuck with today's technology — things we actually know how to do."
A Renewed Conclusion
The amount of CO2 available on the surface of Mars – in the soil – is not enough to terraform Mars. It's only with technologies advanced well beyond what's possible now that we'd be able to access any CO2 found well below the surface, generally only brought up by non-human-made means.
With the amount of CO2 available in the rock on the surface of Mars, even by optimistic appraisal, you'd not reach the amount needed to terraform. You'd not be able to get the greenhouse gas you need to get Earth's air pressure at sea level, aka a bar. "You [could] get some significant warming and significant pressure," said Jakosky, "[but] you would still fall well short of a bar."
So yes and no, there's not enough CO2 right now, on the surface, to terraform Mars. But there might be enough CO2 below the surface of Mars – we just need to figure out how to get it out.