When the Amazon is gone we'll have 40% less atmospheric oxygen

Posted in: Comment, New Publications, News and Updates

I received an email Network Link newsletter from UNESCO UK the other day, and was pleased to see that it contained a number of references to education, including two focused on sustainability.  One was about ESD in Practice:

To raise the visibility of Education for Sustainable Development (ESD) in the lead up to the Rio+20 conference this month UNESCO published a series of ESD success stories from around the globe.  With the help of the UKNC, the WWF project "School's Global Footprint" in Scotland was covered as an excellent example of ESD in practice.

When you click on the link it takes you to a feature on Lawthorn primary school, Ayrshire, which begins with this statement:

When the Amazon is gone we will have 40 per cent less atmospheric oxygen."

This quote is from a ten‐year‐old boy who’s a member of the school's eco‐committee.  The article then details the school's many achievements, including 4 green flags.  Happily, it also says how useful the UNESCO website has been:

The school say that the UNESCO website has been a huge help, providing resources and giving suggestions which have sparked the children’s imagination and encouraged them to conduct their own research online.  Several speakers have visited the school, from UNESCO and other organisations.  As [principal teacher] Ms Milne says, “It allows the children to do research, to see where they all fit in to the world, and to bring all the information together.”

Just so.  I guess this is where the idea came from that our oxygen levels are going to drop to 13% (from the current 21%) if the Amazon forests are cut down?   For example, this easily-found  website simply says that:  "Tropical rainforests produce 40% of Earth's oxygen".

But this notion of "production" is a problem as it confuses the net production of oxygen with its turnover, as any organism that is photosynthesising (where there is oxygen production) will also be respiring (where there's oxygen use) and so, whilst the turnover may be substantial, any net production may well be much lower, and this appears to be the case with rain forests, and a significant component of net oxygen comes out of the oceans courtesy of phytoplankton and cyanobacteria photosynthesis.  The boy's conclusion also ignores the interconnectedness of systems as rain forests, and what happens there, are not isolated from the rest of the biosphere, which is probably the more serious point. [1]  [2]

Whilst I can understand that the boy might not know this, or many of the undoubted subtleties involved (which I don't understand either), why didn't his teacher recognise nonsense when (s)he saw, and how come UNESCO editors didn't spot it?  Can this really be, as UNECO says, "an excellent example of ESD in practice"?  Either way, it does raise questions (again) about what's being taught (or learned at any rate) in schools about ecological / systems issues. Enthusiasm is not enough. [3]  [4]


[1] That said, the % of atmospheric oxygen does seem to be falling rather faster than the CO2 increase would suggest – around 6–10 ppm/year.  Given the existing concentration is around 209 460 ppm, it will be a while before we get to 13% (130 000 ppm).  However, it's clear that we humans would be past caring long before this.

[2] And, just to complicated matters further, the loss of (rain)forests will likely have some effect on oxygen / carbon dioxide transport and turnover – just nowhere near what the boy thinks.

[3] I'm told that this error (a misconception, I guess) has been around for some time, though I'd not come across it.  Memo: shold get out more ...

[4] Whilst I immediately saw the problem with the boy's 40% statement, I subsequently found it very difficult to pin down the ins and outs of net oxygen production – even to the very limited extent that I did.  Perhaps some of Mr Gradgrind's "facts" might have come in handy here.

Posted in: Comment, New Publications, News and Updates


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