Whether it is really possible, is a different question, but after you have an atmosphere, you could have engineered microorganism processing the soil etc.
To put it into perspective, we are effectively terraforming Earth today, though maybe not in a good way.
We have converted most of the land to agriculture and released maybe trillions of tons of greenhouse gas in the atmosphere, there are 8 billions of us working on it. And what did we do? Increased the global temperature 2 degrees? Made the sea level rise a couple of meters?
It may be bad for us, but compared to terraforming a planet like Mars, that's nothing, and we have the entire humanity industrial complex to do it while on mars, we need to build everything, starting from a hostile environment.
That's exactly my point. We don't have the manpower, the materials, the industry.
For mars this just isn't happening unless we ship half of Earth's people and resources over there. Who will have to live on a toxic planet.
But we can't even ship all that stuff there because we don't have enough fuel to do that (it requires many times the payload in fuel) and all the launches would make earth uninhabitable. Terraforming mars is therefore science fiction unless we break a lot of barriers like clean fusion, space elevators etc. And even then the material question will remain a problem.
I think even reverting climate change on earth, a much easier problem than terraforming a remote planet, is a pipe dream. If we're going to be going carbon capture at that global scale, we're going to need to extract so much material, manufacture so much equipment, transporter it all, deal with all the captured carbon, maintenance, power etc all stuff that's not possible to do completely carbon neutral, that we're just polluting a lot more. Especially if we want to do it at a timescale where it still matters.
It's just that terraforming will require a lot of materials that will have to be brought over from Earth. And every tonne of materials to Mars requires many tonnes of fuel to launch from Earth.
I don't think it is possible to ever transport enough to make this happen.
I wouldn’t go that far. It was pretty clear a long time ago that humans spending so much time filling the internet with content was going to eventually enable neural networks to pretend to communicate.
The advancements required to arrive at modern LLMs and the tech needed to get humans safely to Mars or live safely on the Moon are orders of magnitude in difference.
If you can kick off self-sustaining biological processes it’ll happen on its own eventually, but you’d just be looking at generational time scales to do it.
Of course you’ll probably have lots of side-effects.
How do we do that? I imagine dumping Earth life on Mars it will just die. What if we buried a terrarium at the Martian pole with a radio isotope and solar heater and controls so that it could try growing bacteria inside and controlled-leaking some outside into a nearby warm (liquid water) surroundings, and that could get many chances to evolve strains that could survive further away - analogous to ocean life around deep hydrothermal vents.
The closest thing I’ve heard of is genetically engineering some extremophile bacteria to seed some bacterial colonies with, and then building some domed habitats and dropping plants and fungi into it. And then you could allow some of that life to grow outside the dome and spread over time, slowly bulking up the oxygen levels. There are also proposals that you could have orbital focusing mirrors to beam additional heat at the planet and start to melt some of the water and frozen greenhouse gases.
Any effort is only temporary though, because Mars doesn’t have a magnetic field, so the sun is constantly stripping atmosphere off it. It’s not a renewable resource there like it is here.
> In that sense then the term "terraforming" is on equal footing with alchemy
NASA has proposed using "synthetic biology to take advantage of and improve upon natural perchlorate reducing bacteria. These terrestrial microbes are not directly suitable for off-world use, but their key genes pcrAB and cld...catalyze the reduction of perchlorates to chloride and oxygen" [1].
Whether it is really possible, is a different question, but after you have an atmosphere, you could have engineered microorganism processing the soil etc.