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We need to save the Amazon, but not for the sake of oxygen
Sou | 2:13 AM
There's been a crazy meme circulating in the media about oxygen. Let's fix that.
To their credit, quite a number of media outlets have been writing about the apparent reversal of the decline in the destruction of the Amazon rainforests.
Okay, that was a mouthful. Back in past decades the Amazon rainforest was being destroyed at a phenomenal pace. Local people became concerned and eventually they were heard around the world. Finally there was an turnaround or, I should say, the rate of destruction slowed substantially. Now it's picking up again and this is a very bad thing.
The problem with many of the reports is that they include a phrase(sometimes a headline): "The Amazon is often referred to as the planet's lungs, producing 20% of the oxygen in the Earth's atmosphere". That's way wrong!
It's not just wrong, it's wrong in so many ways. First of all, the Amazon produces nothing close to 20% of the oxygen in Earth's atmosphere. What it does is contribute something close to 6% of the amount of oxygen put into the air each year from the biosphere. Not only is the number 20% quite wrong, the 6% is only the amount put into the air each year from the biosphere - that's much less than the total amount of oxygen in the air. (It's not adding to the air overall, it's an exchange. Oxygen goes in and out of the air. The oxygen in the air isn't increasing.)
Correction, perhaps: Peter Cox, who has also done research on the subject, says that a carbon stable biome does not have a net impact on O2 in the air. It's a net zero O2 exchange and just recycles the oxygen. I will have to do more research on the subject. It's not easy to find. At the plant level it's easy enough, but not at the level of individual forests or grasslands or deserts etc. [Sou - a few hours later.]
Think about it. Probably half the oxygen exchange is over land and half over ocean. The total amount of oxygen (as O2) in the air is around 1,200,000 billion tonne. That's a lot of oxygen. Around 300 billion tonne is exchanged in and out of the air each year ( according to Wikipedia - I know, I don't have time to follow up original sources, but that's probably about right as long as I counted the zeros properly).
Now not only does that mean that total destruction of the rainforest would take a long time to have an effect on oxygen levels, it's likely that other plants would grow in its place (pasture for the cattle) and photosynthesis would continue.
So - be concerned, be very concerned about the destruction of the Amazon rainforest and river, but be concerned for the right reasons. Burning the forest releases CO2. Burning the forest destroys plants, wildlife, microorganisms, soil and entire ecosystems. It's a very bad thing, but you won't run out of oxygen.
I just thought I'd better put that out there. Others will do the same, and probably do a better job - but this'll do for the time being.
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