Environmentalism has gone off the deep end.
To me, it doesn't really matter if CO2 is a greenhouse gas or not, most of the proposed solutions do nothing to fix things even if it were. Eliminating the internal combustion engine and replacing it with electric motors is not going to happen because of economic constraints. There are reasons why the ICE is used to the extent it is: it is relatively lightweight, is a heat engine, it can use easily stored and refilled liquid fuels, is relatively cheap and the infrastructure is already in place for it to be useful.
More of an issue in my opinion than CO2 is the dropping energy return on energy invested (EROEI) of fossil fuels. I've seen estimates as low as 1 to 5: of every 5 barrels of oil equivalent produced, on of those barrels covers the cost of getting it out of the ground. When oil was easy to get, 1-to100 was not uncommon and has an overhead of 1%. At 1-to-5 you are are 20% overhead and getting worse fast. At 1-to-1, there is no energy return and no energy reason for getting oil out of the ground. Petroleum is used as a chemical reagent in the production of many products, and even at below 1-to-1 these don't really have a replacement.
I am more supportive of things like Fischer-Tropsh and other gas to liquids processes. These can use any organic feedstock to produce many of the chemicals found in petroleum, allowing the existing, already paid for infrastructure to be used. Because they use syn-gas (a mixture of hydrogen and carbon monoxide) any material that can be burned can be gasified and used as a feedstock. Institute source separation of garbage to remove high-liquid materials like foods to feed to anerobic digestion, and to remove problematic materials like Polyvinyl-chloride (PVC). Add in cogeneration by siting the refineries close enough to downtown centers to make district heating and cooling economical, and the combined efficiencies can reach upwards of 85-90%, producing liquid fuels, chemical feedstocks, electricity, and hot and cold water for space heating and cooling.
I am also highly skeptical of solutions that require large-scale government interference. I would rather that people take personal responsibility for ensuring they don't poison their environment than be forced by government. Oppressed people will always be looking for ways to get around their oppression. Better ideas are to promote recycling, waste to energy, composting, local sustainable agriculture and industry (reduce the need to transport goods), public transportation (reduce the cost of transporting people), feeding food waste to chickens and pigs are all going to be more effective than worldwide carbon sequestration at helping the environment because it can be implemented piecemeal and doesn't require an all-in commitment, so it is more likely to happen.
If CO2 really bothers you, start planting trees and biomass crops. Some of these crops, like Miscanthus, can fix 5-6 tons of carbon per acre per year, and the biomass energy can be used to offset fossil fuel usage. Biochar can sequester carbon in soils for many decades and boosts soil fertility in the process. Building with wood rather than metal when it makes sense also sequesters carbon for the lifetime of the building, at which time it can be burned for energy.
