"No matter what assumptions are used for the amount of or increase in fossil fuel generated CO2 in the US, from small amounts to very large ones, complete elimination of all fossil fuels in the US immediately would only restrict any increase in world temperature by less than one tenth of one degree Celsius by 2050, and by less than one fifth of one degree Celsius by 2100.
What? Say that again. If the US eliminated all fossil fuel use tomorrow, it would have virtually no measurable impact on world temperature.
So, this means that if the US developed some kind of carbon tax that would reduce fossil fuel use by, say, 50% by 2050, it would have even less of an impact on world temperature than if all fossil fuel use were elimininated immediately."