The majority of the mass (72%) of CO2 is oxygen, not carbon. By convention, the "tons" generally quoted in climate literature are carbon-dioxide, not pure carbo

The majority of the mass (72%) of CO2 is oxygen, not carbon. By convention, the "tons" generally quoted in climate literature are carbon-dioxide, not pure carbon. Using $418/ton of oil: $418 * (1-0.72) = $117, in striking range of the $100 target. Where renewables match or exceed hydrocarbon fuel, $100 would appear to be a reasonable price.