A December 2012 CNN article reported

Last year, all the world's nations combined pumped nearly 38.2 billion tons of carbon dioxide into the air from the burning of fossil fuels such as coal and oil, according to new international calculations on global emissions published Sunday in the journal Nature Climate Change.

Wolfram Alpha tells me that that mass

≈ 0.35 × estimated mass of all oil produced since 1850 (upper limit) ( 1×10^11 t )


≈ 0.4 × total biomass on Earth (≈ 8×10^13 kg )

which seems pretty high.

Was the total CO2 added to the atmosphere in 2011 (or a similar year)?

3 Answers 3


Wolfram Alpha tells me that that mass

 ≈ 0.35 × estimated mass of all oil produced since 1850 (upper limit) ( 1×10^11 t )

You're forgetting two things here: Oxygen and coal. While there are other sources of this apparent discrepancy, these are the two main sources of your skepticism.

Carbon dioxide comprises one molecule of carbon and two of oxygen. By mass, carbon dioxide is 27.3% carbon and 72.7% oxygen. The other factor is coal. In 2011, only a third (33.2%) of the carbon dioxide produced by mankind came from the burning of oil-related products. About 63% of the remaining 2/3 came from burning coal. Using these two qualifier (12/44 and 0.332) to refine the Wolfram Alpha query in the question yields a more relevant comparison:

≈ 0.76 × world oil production mass in 2004 (≈ 4.15×10^12 kg )

Not quite 100%, for two reasons. Some oil is used for purposes other than producing carbon dioxide, and some of the mass of oil is in the form of hydrogen.

Was the total CO2 added to the atmosphere in 2011 (or a similar year)?

Yes. This amount is consistent with other estimates. For example, the Emissions Database for Global Atmospheric Research says global emissions of carbon dioxide were 33865904 kilotons in 2010, 35865277 in 2013. (Note: Those overly precise are exactly what's on that web site. I've left them as-is.) Converting to customary units yields 37.3 billion tons for 2010, 39.5 billion tons for 2013. The Global Carbon Project says that 9.5±0.5 petagrams of carbon were released in 2011; multiplying by 44/12 to get the CO2 equivalent and converting to short tons yields 38.4 billion tons. Several other sources provide estimates consistent with these.

  • 2
    Well done. The "oil" vs coal and oil comparison jumped out at me, but I neglected, as well, to consider the oxygen added to the mix via combustion. Mar 5, 2019 at 22:39
  • Some of this was in my original post, before Oddthinking cleaned it up. I underestimated the amount of coal and other fossil fuels that were being used, and I'm still stunned that we're burning a mass of fossil fuels equal to the amount of biomass on the planet every few years.
    – prosfilaes
    Mar 6, 2019 at 1:20

That looks about right. Here is a link to data for global emissions, as well as individual nations, going back to 1990. The global numbers are in the range you cite.

Keep in mind the these values are CO2 emissions, not carbon alone. The carbon component is 12/44 of the CO2 mass, or about 27%. So (assuming the Wolfram Alpha numbers are correct), the total carbon emitted in 2011 is about 0.27 * 0.35 * all oil produced since 1850, or roughly 10%. The comparison to biomass is about the same.

  • 1
    And that includes carbon added from coal combustion, as well. Mar 5, 2019 at 22:37

Was the total CO2 added to the atmosphere in 2011 (or a similar year)?

It depends on what you mean by "added to the atmosphere". Skeptical Science says:

  • 29 billion tons produced by human activity (they chose a different year, so doesn't match the 38.2).
  • 439 - 450 = 11 billion tons absorbed by land plants.
  • 332 - 338 = 6 billion tons absorbed by oceans.

That's a net increase of 12 billion tons added to the atmosphere.

So if the question is if 38.2 billion tons was the increase in atmospheric carbon dioxide in 2011, then the answer is no. It's just the portion due to human activity. The cycle excepting human activity is negative. We can estimate that about half of that was absorbed by other activity.

That said, 20 billion tons may be better than 38.2 billion tons, but it's still not zero.

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