Terraforming Mars: Mass, Forcing, and Industrial Throughput Constraints

TL;DR

This paper evaluates the physical and industrial constraints of terraforming Mars, highlighting the immense scale, energy, and time required to achieve habitable conditions, and suggesting regional strategies are more feasible than global ones.

Contribution

It provides a quantitative analysis of the planetary, atmospheric, and industrial requirements for Mars terraforming, emphasizing the scale and feasibility challenges involved.

Findings

Mars requires exaton-class atmospheric inventories for pressure buildup.

Endogenous CO2 is a limited resource, insufficient for significant warming.

Achieving habitable temperatures demands large-scale reflector deployment.

Abstract

Terraforming Mars can be evaluated with a set of system-level constraints linking (i) target pressures & compositions to required atmospheric inventories, (ii) target surface temperatures to the required radiative control, (iii) inventories & climate agents to sustained industrial throughput & power over a build time, (iv) persistence against collapse, escape, geochemical sinks. We use order-of-magnitude scalings to compare endogenous CO2 release, synthetic super-greenhouse gases, CO2-H2 collision-induced absorption, engineered aerosols/nanoparticles, orbital mirrors, regional paraterraforming. We find: (1) human-relevant pressures imply exaton-class inventories, because Mars requires 3.89 x 10^15 kg of atmosphere per mbar of global mean surface pressure; (2) accessible endogenous CO2 is best treated as ~10s of mbar resource, with a 20 mbar case yielding <10 K warming under present insolation; (3) mean surface temperatures of 250-273 K require either effective IR opacity of ~2-4 or direct absorbed-solar forcing of ~100 W/m^2, implying reflector areas of ~10^{13}-10^{14} m^2 together with large deployment, control, durability, replacement burdens; (4) breathable open-surface endpoints are dominated by O2 and N2 inventories and by a minimum oxygenation work exceeding 10^{25} J, implying average build rates of 10^7-10^8 kg/s and average power from multi-100 TW to PW for century-to-millennial build times before inefficiencies and sink filling. We conclude that regional habitability via paraterraforming/covered-area strategies are plausible on near-term industrial scales, whereas no credible open-atmosphere pathway is identified to a Mars permitting pressure-unassisted human exposure or a breathable surface atmosphere without exaton-class volatile supply, multi-century planetary industry, + sustained climate actuation, retention, durability management, replacement against sinks and loss.