[GeronL]

If CO2 were cut in half, life as we know it on this planet would cease to exist

[Ben Ficklin]

There have been 3 SCOTUS decisions on CO2: 2007, 2011, & 2014. So you need to consider each of these decisions, and how/what they apply to.

Then you need to consider that there are 2 sources of CO2: mobile sources such as tailpipes and stationary sources such as power plants. These 2 sources are being regulated in different ways.

Then you need to recognize that the stationary sources are being regulated based on being either a new source or an existing source.

Once you have it broken out into the various components, then you can analyze it qualitatively and quantitatively