Essentially we can measure man-made emissions reasonably well, but we can’t measure the natural emissions and sequestrations of CO2 at all precisely — the error bars are huge. Humans emits 5Gt or so per annum, but the oceans emit about 90Gt and the land-plants about 60Gt, for a total of maybe 150Gt. Many scientists have assumed that the net flows of carbon to and from natural sinks and sources of CO2 cancel each other out, but there is no real data to confirm this and it’s just a convenient assumption. The problem is that even small fractional changes in natural emissions or sequestrations swamp the human emissions.
Read the rest herehttp://joannenova.com.au/2011/08/blockbuster-planetary-temperature-controls-co2-... There goes another “fingerprint”…
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It’s not just that man-made emissions don’t control the climate, they don’t even control global CO2 levels.
Judging by the speech Murry Salby gave at the Sydney Institute, there’s a blockbuster paper coming soon.
Listen to the speech: “Global Emission of Carbon Dioxide: The Contribution from Natural Sources”
Professor Murry Salby is Chair of Climate Science at Macquarie University. He’s been a visiting professorships at Paris, Stockholm, Jerusalem, and Kyoto, and he’s spent time at the Bureau of Meterology in Australia.
Over the last two years he has been looking at C12 and C13 ratios and CO2 levels around the world, and has come to the conclusion that man-made emissions have only a small effect on global CO2 levels. It’s not just that man-made emissions don’t control the climate, they don’t even control global CO2 levels.
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“It is often asserted that we can measure the human contribution of CO2 to the air by looking at the ratio of C12 to C13. The theory is that plants absorb more C12 than C13 (by about 2%, not a big signature), so we can look at the air and know which came from plants and which came from volcanos and which came from fossil fuels, via us. Plants are ‘deficient’ in C13, and so, then, ought to be our fossil fuel derived CO2.
The implication is that since coal and oil were from plants, that “plant signature” means “human via fossil fuels”. But it just isn’t that simple. Take a look at the above chart. We are 5.5 and plants are putting 121.6 into the air each year (not counting ocean plants). There is a lot of carbon slopping back and forth between sinks and sources. Exactly how closely do we know the rate of soil evolution of CO2, for example?”
Chiefio also found some interesting quotes pointing out that corn (a C4 plant) absorbs more C13, and our mass fields of corn might just muck up the stats… (it’s a good post).
Read the rest herehttp://joannenova.com.au/2011/08/blockbuster-planetary-temperature-controls-co2-... 
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