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Originally Posted by Cato
Is ten years really an effective time frame to base geologic conclusions upon?
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Who said anything about geologic conclusions? I am simply pointing out that the current co2 rise seen year on year has an anthropogenic cause.
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Post hoc, ergo propter hoc.
CO2 concentrations fluctuate naturally. Therefore, there must be some mechanism by which CO2 concentrations increase naturally. Therefore, it is possible that CO2 concentrations are increasing naturally. Definitive statements like the one I quoted are therefore false.
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co2 concentrations can increase naturally, but in this case there is good evidence it is an anthropogenic cause.
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Furthermore, you're arguing that CO2 concentrations are increasing because humans are emitting CO2. You argue that nature sequesters more CO2 than it emits, and further claim that this is because there is "extra" CO2 in the atmosphere. You then conclude, erroneously, that were there no human emissions, CO2 concentrations would fall. This conclusion does not follow from your premises.
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Yes it does because it is only when you include human emissions that co2 sources worldwide are more than co2 sinks worldwide. Take out the human source and co2 sinks will then be absorbing more than the sources are emitting.
Global co2 emissions per year (nature and man): X + 28
Global co2 absorption per year (just nature): X + 13
(X+28) - (X+14) = +15 (rise of 15 tons co2 per year in atmosphere)
Now take away the human source (the 28), and you get:
X - (X+14) = -14 (loss of 15 tons co2 per year in atmosphere)
How can co2 in the atmosphere continue rising if human emissions stopped, when nature is absorbing more than it emits?
And notice that unlike other sources in nature, the human source has only appeared significantly in the past 200 years, correlating with the co2 rise..The evidence is more than compelling.
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If the only reason nature is absorbing more CO2 than it emits is because humans are emitting CO2, and you took humans out of the equation, then nature would not be absorbing more CO2 than it emits. CO2 concentrations would remain stable. Yet, CO2 levels have not remained stable (in any real geologic sense) for the entire history of this planet.
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Nature would still be absorbing more co2 than it emits. It's absorbing more co2 than it emits because there is an abundance of co2 in the atmosphere. Turn off human co2 emissions tommorow and you still have that same abundance in the atmosphere. The rate of co2 absorption by nature will be the same. It will only lower over time as the co2 is absorbed. But in no way is co2 going to continue rising without human emissions.
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In reality, you can't say with any certainty why CO2 concentrations are increasing, nor whether removing human emissions would have either a positive or negative net effect.
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There's just too much evidence that the rise is man caused:
-co2 levels today are about 35% higher than at any point in the 700,000 years of ice core records available.
-the co2 rise has been exponential, just like human co2 emission trends
-the co2 rise correlates in time with human co2 emission trends
-preceeding the co2 rise levels were relatively flat at 280ppm for hundreds of years
-carbon isotope ratios in the atmosphere are compatible with the source of co2 being from fossil fuels, while ruling out some other sources
-humans emissions more than explain the rate of co2 rise observed year on year
Any one of many of these points can be argued as a coincidence. But the chance of so many coincidences... Especially the last one there which alone is enough. It's simply unexplainable how a 28 billion ton/year emission rate cannot be the cause of a 15 billion ton/year co2 rise.