Step 2 Build the Space Colonies in Lunar Orbit to build the solar Generating Stations which would beam electricity to eartn. No more burning fuel in the atmosphere. Sen Harrison Schmitt suggests mining HE3 on the moon, fueling fusion generators and beaming electricity to eartn. another Green solution.
Step Three. Move all heavy industry off planet, (von braun suggested this in the mid 50s).
Step Four gather food from the sea per Arthur Clarke and let the land grow green!
Step Five enjoy a man built Eden!
Liberals find it cheaper and easier to prevent anyone else from breeding, freeing up the land and getting rid of ugly industry.