I have some questions for the people who think CO2 emissions need to be regulated.

1. What would happen if CO2 could be completely scrubbed from the atmosphere?

2. What fraction of CO2 in the atmosphere is the result of burning fossil fuels?

3. What was the CO2 concentration in the atmosphere when the Earth suffered its worst ice-age?

4. How did the Carbon in fossil fuels get there in the first place?

5. Can you prove that changes in the concentration of CO2 in the atmosphere, usually measured in parts per million, impact global temperatures?

6. In past interglacial periods, CO2 concentrations rose as the planet emerged from the previous ice age. Why didn’t these increased levels of CO2 stop the Earth from plunging back into the next ice age?

7. How come global temperatures have been dropping over the last decade, even though CO2 emissions continued to increase?

That’ll do for now. Click more for my answers.
My answers:

1. Life as we know it would cease.

2. 4%. (At least 96% of the current atmospheric CO2 comes from non-fossil-fuel sources, i.e. natural marine and juvenile sources. Hence for the atmospheric CO2 budget marine degassing and juvenile degassing from e.g. volcanic sources must be much more important, and burning of fossil-fuel and biogenic materials much less important, than hitherto assumed. (http://www.co2web.info/hawaii.pdf))

3. 12x more (Late Ordovician Period was also an Ice Age while at the same time CO2 concentrations then were nearly 12 times higher than today– 4400 ppm. (http://www.geocraft.com/WVFossils/Carboniferous_climate.html))

4. Ancient atmospheric CO2

5. Probably not. Research suggests that CO2 concentrations lag temperatures changes.

6. Could it be that CO2 has little impact on climate compared to other sources, such as a nearby star?

7. See 6. Maybe lower solar activity, as measured by sun spot activity, is a factor.