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Human fingerprint on atmospheric CO2

Posted on 23 August 2007 by John Cook

George Morrison points out the argument Human CO2 is a tiny % of CO2 emissions says nothing about carbon isotopes and how we know rising CO2 levels are due to human activity. The carbon atom has several different isotopes (eg - different number of neutrons). Carbon 12 has 6 neutrons, carbon 13 has 7 neutrons. Plants have a lower C13/C12 ratio than in the atmosphere. If rising atmospheric CO2 comes fossil fuels, the C13/C12 should be falling. Indeed this is what is occuring (Ghosh 2003) and the trend correlates with the trend in global emissions.

Many thanks to George for pointing out the oversight - I've updated the Human CO2 page.

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Comments 1 to 4:

  1. The contrarians' dismissal of the tiny percentage of anthropogenic CO2 as therefore automatically insignificant is shown to be completely fallacious by an interesting analogy drawn by Professor Andrew Pitman, Climatologist at UNSW.
    Professor Pitman reminds us that the Ebola virus, whilst undeniably microscopic is hardly insignificant to human health.
    This link is to an interview with Martin Durkin about his mockumentary The Great Global Warming Swindle.
    See the upper video at 06.18
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  2. What, then, is the total weight of Carbon dixide in the atmosphere and what weight is calculated to have been produced by burning fossil fuels? Does this method of analysis distinguish between CO2 released from burning fossil fuels and "old" CO2 produced from the decay of corals? In what proportion?
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  3. CO2 = 379 ppm or 0.000380, or 0.038% currently.
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  4. A chart here shows the percentages
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