§6Terraforming

The CO₂ is not there. A new research community says local warming might be. Domes are what anyone will actually live in.

Terraforming is the one Mars question with a settled answer and a live footnote. The answer, from 2018, is that the planet does not hold enough carbon dioxide to do it. The footnote, from 2024 onward, is that warming Mars and giving it an atmosphere may be different problems, and the first might be tractable. The two are graded differently on this page because they are different claims.

The CO₂ ceiling

§6.1 Jakosky and Edwards (Nature Astronomy, 2018) inventoried all accessible CO₂ on Mars (polar caps, gas adsorbed in regolith, carbonate minerals) and concluded that releasing all of it would only about triple the current atmosphere. That is roughly 1/50th of what a ~1-bar atmosphere needs, and about 10 °C of warming against the 30 °C or more required for stable surface liquid water. Their verdict: “terraforming Mars is not possible using present-day technology.” It remains the consensus baseline. established

Warming without an atmosphere

§6.2 Ansari, Kite et al. (Science Advances, August 2024, “Feasibility of keeping Mars warm with nanoparticles”) showed that engineered conductive nanorods, about 9 µm long and made from Martian iron and aluminum, could warm the planet more than 5,000 times as efficiently as the best greenhouse gases. A sustained release of about 30 liters per second could raise the global temperature by 30 K or more over years to a decade, enough to begin melting ice. model output

Read the claim precisely. This is warming to enable liquid water and possibly microbial life. It is not a breathable atmosphere, which needs a nitrogen inventory Mars lacks in accessible form and an oxygen inventory on the order of 10¹⁹ times a MOXIE-scale demonstration. contested: plausible physics, no field test, and a different target than the word “terraforming” implies.

A community is coalescing around it: a 2024 and a larger 2025 terraforming workshop (Pioneer Labs, funded by the Astera Institute), a 2025 Nature Astronomy opinion piece, “The case for Mars terraforming research,” and follow-on studies of aerosols, silica-aerogel tiles, and biological warming. Aerogel tiles can create warm, UV-shielded microhabitats locally. Magnetic-shield concepts (an artificial magnetosphere at the Sun–Mars L1 point) exist only on paper.

Domes: the realistic path

§6.3 Paraterraforming, sealed domes and tunnels holding a breathable volume, is the only realistic near-to-mid-term path to habitable space on Mars. It is also, functionally, what the Weinersmiths and Kim Stanley Robinson’s own domed-city phases depict before any planet-wide change. The optimist and the skeptic agree on the architecture of the first century; they disagree about what comes after it.

Expedition or settlement?

§6.4 Terraforming is irrelevant to an expedition and, on the report’s reading, irrelevant to the first settlements too: full terraforming is speculative and multi-century at best. Track the new research community as legitimate early science, and hold the Jakosky–Edwards baseline while doing so.