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I admit that this is not a genuinely earth sience question, but since there is no stack exchange site genuinely devoted to general ecology, I dare to ask it here:

From a table in the German Wikipedia article on emissions trading I've learned that the global warming potential of nitrous oxide is 298 times as high as that of carbon dioxide, and that it makes 7.9% of the humans caused greenhouse gases:

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Given these numbers nitrous oxide seems to contribute roughly 30 times more heavily to climate change than carbon dioxide does.

Why is nevertheless carbon dioxide the gold standard of greenhouse gases and humans caused climate change?

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  • $\begingroup$ you are confusing potential contributor with actual contributor. $\endgroup$ – John Jul 22 '19 at 16:37
  • $\begingroup$ I believe the comments at your cross-post should have clarified your wrong assumptions. $\endgroup$ – Roland Jul 23 '19 at 6:50
  • $\begingroup$ They did, thank you! $\endgroup$ – Hans-Peter Stricker Jul 23 '19 at 7:09
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There isn't enough nitrous oxide in the atmosphere to make a major contribution to global warming, which in some ways is a pity, because we'd all bee in a much jollier mood if there was (N2O is sometimes known as laughing gas). It also depletes the ozone layer if it gets up that high, though depleting ozone at ground level, where it is harmful, is a good thing. Compared to N2O, there are vast quantities of CO2 in the atmosphere, enough to create millions of tons of wood and other plant materials every year. The whereabouts of N2O in the atmosphere, whether it is high up or low down, probably has some bearing on the matter.

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Two things to think about:

Nitrous oxide is extremely scarce in the atmosphere, less than 1 ppm. Compare with carbon dioxide that (unfortunately) is now greater than 400 ppm.

Also consider the lifetime of the gases in the atmosphere: nitrous oxide has a much shorter lifetime than carbon dioxide. If we'd stop emitting greenhouse gases now, nitrous oxide would be gone much quicker than carbon dioxide.

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Specifically regarding the table in your question, the last column compares the emissions not by mass but by CO2-Eqivalent mass. That means that the number already takes into account that the global warming potential of N2O is much higher, so every emitted molecule of N2O counts like 298 molecules of CO2.

In other words, when the table says 7.9% is N2O, it doesn't mean 7.9% of the mass or the number of molecules. The actual fraction is much less.

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