Re-posted from the 2020 Mauna Loa CO2 thread:

Thank you Stephan. Since you are regularly updating several GHG readings, would it be possible to add a CO_{2e} figure?

In that way we'll have the cumulative GHG effect updated. I know it depends on assumptions but you can put those in.

nanning,

I will do it in the next time. I have the monthly reading of four gas concentrations (CO_{2}, CH_{4}, N_{2}O and SF_{6}) on my PC, in different files, and I can put them together.

I did it, but the sum differs from what I saw from gerontocrat's posting further upthread where he provides NOAA's annual table.

I took the monthly concentrations (beginning from 2000 on, before that date I do not have all the four gases) and multiplied CH

_{4} with the factors 85 (20 years) and 28 (100 years), N

_{2}O with 264 (20 & 100 years), and finally SF

_{6} with 17500 (20 years) and 23500 (100 years), using the conversion factors from the later IPCC report. Then I looked up the definition of these CO

_{2} equivalents, which are not given in moles, but in kg and converted the numbers by taking their molecular weight.

I end up with the latest data (Sep 2019) with the following values (100 years equivalent):

CO

_{2}: 408.54

CH

_{4}: 19.05

N

_{2}O: 87.65

SF

_{6}:

0.78sum: 516.01

This sum is higher than the CO

_{2} eq given further upthread. Also the proportions of the ratio CH

_{4} to N

_{2}O differs completely from NOAA's table. Where is the error?