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On October 21 2019 Australian Federal MP Malcolm Roberts posted an image to his Facebook feed claiming termites produce 10 times more CO2 than humans in a year. Is there a factual basis to this?

Screen shot of post for reference:

Malcom Roberts: "TERMITES Produce 10 x more CO2 than MAN in the Whole World in a YEAR!"

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    I trust a good answer will consider CO2e and not just dismiss the claim on the grounds that termites emit CH4 rather than CO2. – Oddthinking Oct 27 at 10:09
  • The global emissions of methane and carbon dioxide are 19.7 ± 1.5 and 3500 ± 700 Mt yr−1, respectively (1 Mt = 1012 g). These emissions contribute approximately 4% and 2%, respectively, to the total global fluxes of these gases. I don't know how much humans produce, and if we include human caused emissions such as fires. – daniel Oct 27 at 10:14
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Leaving aside the fact that termite CO2 production is on few, if any, secondary school syllabuses, its more complicated than that.

  1. Termites are not burning fossil fuels. The carbon they produce comes from decomposing wood. This carbon came from the atmosphere, and as the wood rots this carbon will wind up back in the atmosphere whether termites eat it or not. Over the lifespan of a tree this is a carbon neutral process, and is accordingly treated as a net zero in global CO2 accounting. So from a global climate point of view the statement is flat wrong.

  2. Termites produce a mixture of methane and CO2. Methane is a much more potent greenhouse gas than CO2, but is much less persistent in the atmosphere. For global climate purposes the various greenhouse gasses are counted as the equivalent mass of CO2, but for termite emissions the amounts vary greatly between wet and dry seasons. We don't have good estimates for the global amount, and it would also need to be set against the balance of CO2 and methane that would be produced by other decomposition processes. Complicating this even further is the fact that bacteria in the termite mounds seem to be oxidising anything from 20% to 80% the methane into CO2. So if you are comparing the tailpipe emissions of termites with human industry without regard to the source of the carbon then the answer is "we don't know".

  3. Termites are spreading into new areas due to anthropogenic climate change, and places where they are endemic can also see increases in populations due to tree cutting. So some termite gas production is an indirect result of human activity.

Leaving aside all the questions about exactly how much methane and CO2 comes out of termite mounds, the real issue is that we are burning fossil fuels, and hence introducing new carbon into the global carbon cycle, while termites, along with fungi and all the other decomposition processes, merely move the same carbon around the cycle. If all our CO2 came from burning wood or biofuels then we wouldn't have a problem with global warming regardless of the termite population. So the implied statement that termites have a much bigger impact on global climate than human industry is simply wrong.

  • True. I'll edit to define the time frame. – Paul Johnson Oct 27 at 14:40

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