Two problems with this idea (and to some extent the proposal in the article), all related to this idea of engineering the climate: 1. The state of the Earth 10

Two problems with this idea (and to some extent the proposal in the article), all related to this idea of engineering the climate: 1. The state of the Earth 100 years ago was just a decade before the "dirty 30s" dustbowl years: extended droughts for the whole decade across the USA and Canada. There's no particular reason to aim for that climate! 2. The way CO2 interacts with the climate is too poorly understood to aim for any particular target temperature by adding or removing it. This is true on Earth, at least, but Mars is hardly studied at all. Yes, some climatologists / journalists / politicians claim otherwise but read their papers and you'll find they don't agree on the function that maps CO2 levels to temperature changes: there are lots of different values for the key variable of climate sensitivity used in production models, those models tend to overshoot, observation-based values are lower than the modelling based values they often use and assumed ECS values have been getting wider over time instead of narrower. So if we don't know how to map CO2 changes to temperature changes on Earth, it seems kinda premature to assume we can predict the effects on Mars. Whilst in some senses the Martian atmosphere and climate is simpler than Earth's we don't really know how removing things like water clouds affects things (because we don't really understand their effects at home either).