Carbon dioxide is only one of many greenhouse gases, a major one is methane (from livestock). Currently the carbon dioxide i use comes from carbon capture techniques used in power stations, if cars could stop producing it or store it then that would have a major slowing effect on global warming.
I would have to give the money to mechanical engineers to find a way to trap the CO2 before it left the exhaust pipe, or to make hydrogen cars safe and cheap as they will product water not CO2.
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