Normally, where that CO2 comes from would not matter and there are much cheaper sources than air capture.

ECONOMIST: Combating climate change

As for the timescale, fusion certainly wouldn't be available in the short-term, but the problem of providing viable energy sources is not going to get easier even if conservation, CO2 sequestration, fission and renewables are more widely used, and there are currently no other large-scale options beyond the 20-50-year timeframe.

BBC: VIEWPOINT

Here's the problem: According to the Clean Air Act, once the EPA regulates greenhouse gas emissions for autos, it must do so for so-called "stationary sources" that emit the equivalent of more than 250 tons of CO2 per year.

FORBES: Regulations

For plants that don't report emissions, the site relies on industry sources, precise engineering and fuel specifications and statistical models, to estimate CO2 releases.

NPR: Web Site Tracks Carbon Emission Sources

He argues that the EPA relied heavily on secondary sources in producing its endangerment finding and that the agency has "absolutely no evidence" linking increases in CO2 to adverse health effects.

FORBES: Climate