Agreed, but climate change is a monumental issue and even if we assume the government can act in a timely manner to shift the economic model to one that is more environmentally friendly, that won't be enough to fix the problem. I don't think this should be viewed as a cop out, or an alternative to economic change, but rather as something that augments it and moves us in the right direction.
IMO the problem here is the leap of faith you are making by believing an untested technology, operating on a planet scale, will help.
We only have one planet here, so instead of betting on a massive terraforming technology to suck the CO2 out of the air, I'd rather use a more conservative approach such as massive reforestation - something that is low-tech, can be done by anyone, anywhere, and improve the resilience of the ecosystem rather than kicking its balance again.
