I discuss some of this literature in my recent paper on air capture:

http://sciencepolicy.colorado.edu/admin/publication_files/resource-2716-2009.03.pdf

That’s a very informative page. Is 50% adsorption reasonable assumption? Thanks Mike

The 2.13 comes from ORNL, see Table 3 here:

http://cdiac.ornl.gov/pns/convert.html

I get 255 Gt CO2, which is what I assume you get.

To convert to C divide by 3.7, giving about 69 Gt C.

Using your 50% for airborne fraction, that leaves 34.5 Gt C.

To convert to PPM divide by 2.13, giving about 16 ppm.

When you total all of the emissions 1949-2007 you come up with 250GT. Using your 2.13GT=1PPMV this equates to adding 120 PPM. Assuming half is absorbed that leaves 60PPM for the US alone from just fuel. Since this can’t be right what’s wrong with my calculation?

Mike McHenry

You are correct. The graph shows commercial US CO2 emissions, not total. I have updated the post to make this clear, and also added a new graph showing total US CO2 emissions, which jibes with your numbers. Thanks for the close read.

FYI, the CO2 data that I used is here:

http://www.eia.doe.gov/oiaf/1605/ggrpt/excel/historical_co2.xls

-6-Curt

Yes

Can you give a more precise link to the CO2 data that were used in the chart? According to my reading of the numbers for energy-related CO2 emissions in the EIA table, these are given as 5991 m. tons in 2007, which is only 2.75 times the level of emissions in 1949 – not the ratio of 4.0 that appears to be shown on the vertical axis of your chart. Am I misunderstanding your analysis?

Yes