This article is essentially an opinion article. It is paywalled, and the Abstract contains no actual quantitative data on which to judge the contents. It uses "

This article is essentially an opinion article. It is paywalled, and the Abstract contains no actual quantitative data on which to judge the contents. It uses "today's technology" as some sort of viability deteriminant, but this is really kind of tautological: we haven't really perfected the art of sending large payloads to Mars, yet. We struggle to do about one ton. So of course current technology is insufficient. They speak of CO2 greenhouse effect not being sufficient to cause sufficient warming... But that's kind of obvious, isn't it? Because if it was sufficient with easily accessible reservoirs, that'd imply Mars is in some sort of unequilibrium state that could randomly trigger into a partial runaway greenhouse effect (to terraform the planet, not make it like Venus) without even our intervention. And another thing, warmth is fairly easy to address. What's critical is pressure. I'm much less interested in the amount of CO2 to heat the whole planet by itself than I am in the amount of CO2 needed to exceed the Armstrong Limit (0.9psi, the minimum pressure you can survive without a pressure suit and only a forced air oxygen mask) at the lowest points on Mars (like Hellas Basin). That's not addressed in the abstract at all, and I'm not about to pay for an article that doesn't even bother to answer such a basic question in the abstract as what mass of CO2 exists in these reservoirs (from which one can easily determine the pressure... Mars needs about 6e16kg of additional volatiles added to its atmosphere to reach the Armstrong Limit in Hellas Basin... Mars' atmosphere is currently 2.5e16kg). Every terraforming proposal I've seen does something like this: 1) Increase albedo of surface via dust on the poles or black powder. 2) Increase greenhouse effect by industrial production of super greenhouse gases that are far more effective (>20,000?) than CO2. 3) Increase insolation of Mars via giant orbital mirrors (more realistic than you might think, as you can use micron-thick solar sail type material). 4) Adding more volatiles from exterior sources like comets or asteroids or moons. 5) Vaporize very deep reservoirs of volatiles using fission or fusion or geothermal or sunlight or impact energy, reservoirs not considered here. Many of these require "new" technology, but the principles behind each one are pretty well understood. ...it's simply impossible to have a serious discussion of this paper as it's paywalled and contains no quantitative information in the public abstract. Instead, it serves as just a conversation piece for what people already think about Mars terraforming.