This is one of those things which is around and about true even if not exactly so – Brazilian termite mounds have been found covering an area about the size of Great Britain. They likely emit greenhouse gases to something like the amount of Great Britain too. Yes, of course, the amount emitted by the UK is in addition to the natural cycle, the termites part of it, but it’s still an interesting enough comparison. And we might also note that natural doesn’t mean either good or harmless – as deadly nightshade tells us.
This part of it is certainly fun:
For some 4,000 years, termites have been building a massive and magnificent structure in northeastern Brazil, and until recently, it’s been a well-kept secret.
Scientists have uncovered tens of millions of mysterious cones made of soil, each standing 6 to 13 feet high and 30 feet across at the base, in a largely undisturbed region of Brazil, according to a new paper in Current Biology.
One useful reaction would be to ship some anteaters – yes, I know, but they do eat them – in stat. Another would be to compare that land size to something else we have in our heads:
Researchers have recently uncovered evidence of a 4,000-year-old construction site in northeastern Brazil. Stretching over an area the size of Britain is a cluster of 200 million mounds, some as high as 10 feet tall, that were painstakingly raised over the centuries by generations of extremely ambitious builders—termites.
But there’s an interesting thought here. Human emissions are some 50 billon (we’re rounding here) tonnes a year of CO2. Britain is responsible for some 500 million, or 1% or so. And termites?
So which data does he have to back up that they are ‘the biggest contributors’? Because looking at some papers, they do contribute methane, but the exact amount is species-specific (and there are 3000 species) and depends on the estimation methods used (because nobody counted all the termites in the world and measured how much methane they produce). There is a very old paper that calculated that termites contribute to 27-47% of methane production per year, but it was highly speculative because the lab conditions they used and the generalization of one species for all thousands of termites species make for a very crude estimate. A lot of methane is also reabsorbed by the soil before it exits the termite nest. Current estimates are closer to <3 % of global emissions.
Note that’s methane emissions only and the 3% is all termites globally. But then so is the older estimate of 47% too. Rather more than cows that is. And yes, it really is true that termites emit methane:
Their ability to degrade lignocellulose gives termites an important place in the carbon cycle. This ability relies on their partnership with a diverse community of bacterial, archaeal and eukaryotic gut symbionts, which break down the plant fibre and ferment the products to acetate and variable amounts of methane, with hydrogen as a central intermediate.
That’s not a million miles away from what the cows do to grass thus the methane emissions there.
At which point we get to go into a truly vast argument about sums. Termites produce 3 to 47% of global methane. We’ve just found an area of termites the size of Britain. Do the termites emit more than Britain?
Well, that’s left as an exercise for the reader. But could be, could be. Natural emissions are very much larger than human, everyone knows that. The problem is that we humans are in addition to what we think is a balanced system. Worth noting here that no, the ecosystem isn’t always balanced. The first life killed itself quite efficiently by having oxygen as the output of their metabolism, the oxygen which poisoned them and then left the space open for the lines which led to us and our present world. So there’s no surety that “natural” means “don’t worry.”
So, in theory, termite emissions could be higher than UK. But of course the termites covering just an area the size of the UK could well be emitting much less than the UK. Except, the termite emissions are methane, in the short to medium term some 20 times – sometimes, if people want to scare us about fracking, 100 times – worse for climate change than CO2. And the British emissions are CO2 or CO2 equivalence.
So, umm, work it out or yourself. But it is still at least possible that this lovely discovery of lots of termites the size of Britain is emitting more greenhouse gases than Great Britain’s humans. Which would be interesting, wouldn’t it?