Correct me if I’m mistaken, but the ultimate point of your comment appears to be climatic sensitivity to tropospheric CO2, rather than the simple percentage of C02 and what human activities may be contributing. I think this is an important distinction because the former may or may not be directly and linearly related to the latter. Therefore, it’s premature to state that “A reduction in emissions that has insignificant reduction in the total amount of both natural and man made CO2 is not worth doing.”, since, with current estimates between a 1.5 & 4 DC average temperature increase for a doubling of CO2, I think it’s fair to state that no one really knows. It could be a non-problem; it could be a big problem.

As I commented above (and elsewhere), I too have serious doubts about the threat posed by increased CO2, and the wisdom of diverting precious resources to what may very well be a non-problem. But I also think it’s a good idea to fully consider the magnitude of the task we might face – both because it could be a real problem, and because there seem to be a lot of people out there who haven’t thought through what “an X% reduction by 2050” really means. Roger has done this – very thoroughly, clearly, and dramatically. I really don’t see how anyone could object.

I also think it’s a good idea to do some serious engineering studies on capture technology, and perhaps a few pilot projects. I’m perfectly willing to admit that I could be wrong, and that we may need these technologies.

As someone who works in industry, where only the whole truth on a project leads to progress, you need to work on a more honest presentation. When you show the growth in CO2 emissions, you need to show this in relationship to the total amount of CO2 in the atmosphere. A reduction in emissions that has insignificant reduction in the total amount of both natural and man made CO2 is not worth doing.

The bio-fuel industry is based on this type of incomplete analysis. There apparently is a net increase in CO2 emissions from farming more marginal land, with little gain in energy out vs. energy in. Meanwhile death due to malnutrition is increasing because of increased worldwide grain prices.

Your work has consequences. Look at the results of banning DDT based on incomplete analysis.

Overall, I think it’s a very well organized & effective overview of the challenges and opportunities for de-carbing facing us in the next half-century. I’m still not convinced that de-carbing is a good idea, or rather, that increased atmospheric CO2 is a bad thing, but a relatively modest investment in “backstop” technologies, as you call them, seems like a senisble precaution.

Assuming that de-carbing is desirable, then on the face of it, France seems like a model approach; but I remember reading John McPhee’s “The Curve of Binding Energy” as an undergrad, and it scared the hell out of me. If the nuclear option is solidly on the table, I sure hope we’ll have a lot better cradle-to-grave tracking of fissionables this time.

As a nit, I couldn’t understand the graph on slide 11 – it was too fuzzy to make out the details.

Finally, you’ve been to Britain & Oregon in the last several weeks, Roger. Is your carbon trekking-boot print getting a bit large? (or do you insist on Pielke-matic carbon capture units on any plane you take?)(insert smiley face here)