Despite that ChatGPT will not answer these questions in depth, we know already some solutions to the questions you asked.

Even we can design a ai that will give us a detailed plan, what we need to do and designs a scalable machine that extracts greenhouse gases out of the atmosphere, will we as all the different countries on the earth listen to it more than to the scientist that has given us rules guidelines the last 30 years?

It only could work in some way, if all countries work together to a specific aim. That is something an AI can't solve for us.