If you believe in Capitalism:
Step 1: Assign a cost for CO2 emissions.
Step 2: Let the market deal with the costs.
Step 3: Asses if the cost was at the right amount. Adjust if necessary and repeat.
If you don't believe in Capitalism:
Step 1: Change the governmental system to a system of your liking.
Step 2: Find a way in this new system to control what companies do. e.g. state planned economics, regulations, etc.
convince people to stop using their IPhones, stop using your PC, stop driving cars, stop using electricity. Bam, problem solved. Or try to overthrow corporations with big carbon monoxide signatures. Yeah, I didn't think so.
It is an immensely complex problem that has no easy solution, and people talking about it is not gonna do much, or is it??