[RedDevil]

Originally Posted by litesong

Can I take lots of CO2 to help warm the planet? Yes, even I see the need for warmth on Mars. Problem is, so much CO2 will be needed to warm Mars, that, even with good quantities of nitrogen & oxygen, necessary CO2 levels will poison us.

Sure, take what you need
Actually the atmosphere of Mars contains about 93% CO₂. It is much more abundant there than here. Even so, its atmosphere as a whole has just a fraction of our density.

I don't think it will ever be possible to live on the surface of Mars.
It is too small, its gravity is too low, it would lose its atmosphere especially when the sun gets brighter (and even in 2 billion years from now, it will be nowhere bright enough). Cosmic radiation would cause big trouble. And the soil, if you can call it that, is highly toxic.

If you want to survive on Mars you need to tunnel deep. Martians (of human descent) will be cave dwellers.

We can practice on the Moon. There's a giant lava cave, in its extremities the temperature is fairly constant.
As a moon 'day' takes almost a month the days are hot enough to melt some metals and the nights are cold enough to freeze gases like oxygen. Thermal stresses on any structure are extreme. Also moon dust is extremely abrasive and penetrates everything. And we have cosmic radiation, the Earth's magnetic field is too weak at that distance to provide meaningful protection like it does for the ISS.
So you really don't want to be on the surface of the moon. Start in the cave and tunnel from there, that's the only way.

Tunneling is tiresome work though. Maybe we should start on ice-ball moons or asteroids or such, that should be relatively easy.

Meanwhile we should buy ourselves some time by poisoning our own planet less fast.