With the recent rampant burning of rainforest in Brazil, and the Amazon rainforest being called by media “the lungs of the planet,” I wanted to ask if things went to their unchecked conclusion - say the Brazilian rainforest is ***all ***gone and wiped out one day; does the entire rest of the planet begin to experience a reduction of O2 in the air, so much so that we all start to get some oxygen-deprivation symptoms?
That’s what they’re called. It’s brilliant marketing, but it doesn’t mean it’s true.
While the forests and rainforests of the world provide a non-insignificant amount of oxygen to the atmosphere, most of it (70%) comes from marine plants: phytoplankton, kelp, and algal plankton.
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“Lungs of the planet” is a metaphor. It’s a media-savvy metaphor, but that doesn’t make it a bad metaphor.
I guess it would be more accurate if one said “The Amazon rainforest constitutes one important lobe of the planet’s lungs, while most of the other lobes are under water.”
That’s a little more accurate but a lot less catchy. Still, no metaphor is perfectly accurate; any perfectly accurate metaphor is a literally true description and thus isn’t a metaphor in the first place.
Lungs absorb oxygen, not produce it. Calling the Amazon Rain Forest the Lungs of the Planet is like calling like the Great Lakes the Heart of the Planet. You know because of all the water going in and of the Great Lakes, just like blood goes in and out of a heart.
20% of the world’s oxygen comes from the Amazon rainforest. That’s still pretty significant.
Right, that’s what I meant. If the oxygen in an enclosed room were reduced by 20%, people would be suffering some ill effects. I was wondering if that applied on a planet-wide scale.
From the body’s perspective, lungs get rid of CO2 and make O2 available. The lung does for the body what forests do for the planet.
Amazon rain forest - lungs of the planet
Great lakes - heart of the planet
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Columbus, OH - the armpit of the planet
Pessimist: Numbers are numbers. When we lose oxygen-generating capacity, oxygen-breathing things start to die until supply and demand balance out. There are no magic oxygen reserves waiting to be triggered. There are a whole lot of greenhouse gas reservoirs waiting to be triggered.
Optimistic case: All the extra CO2 might stimulate more plant growth elsewhere, making up the O2 balance.
Realistic case: We’re dicking around with complex systems that we don’t fully understand, and it’s best not to. The earth may eventually heal itself, but likely not in human timescales.
Depends on where the room is.
This calculator says that air pressure is 80% of sea level at about 6500ft elevation.
So, we’d definitely notice the difference, but the vast majority of people at sea level would probably not suffer ill effects. People with compromised lungs, or who already live at substantial altitude, might be in trouble.
We probably wouldn’t be setting any new athletic records for a while either.
From the BBC:
Many claim on social media that the Amazon produces about 20% of the world’s oxygen. It’s widely quoted - by campaign groups and well-known figures, including Emmanuel Macron and footballer Cristiano Ronaldo.
But academics say this is a very common misconception, and that the figure is less than 10%.
Oxygen is released by plants during the process of photosynthesis, where sunlight and carbon dioxide are converted into energy in the form of carbohydrates.
A large proportion of the world’s oxygen is produced by plankton, explains Professor Malhi. He says of the oxygen produced by land-based plants, about 16% comes from the Amazon.
But this isn’t the whole story. In the long run, the Amazon absorbs about the same amount of oxygen as it produces, effectively making the total produced net zero.
https://www.bbc.com/news/world-latin-america-49450925
Professor Jon Lloyd from Imperial College London says although the Amazon produces a lot of oxygen during the day through photosynthesis, it absorbs about half of it back through the process of respiration to grow. Further oxygen is used up by the forest’s soil, animals and microbes.
The plants which provide the oxygen that animals (or fires) need are the same ones which provide the food that animals (or fires) need.
Which means the animals in the Amazon rainforest will die out along with the trees. Therefore both the production and the consumption of oxygen will decrease. The world’s oxygen level will not change much.
And the Amazon forest is not as old as first thought. Certainly not pre historic. There are cities and civilisations underneath.
The earth functioned very well before the Amazon forests were firmed.
That just means that there are some portions that are (relatively) new growth. Most likely, when those civilizations were thriving, they were surrounded by jungle, and were built on the site of what had been jungle before the city-builders cleared it.
The reason people are burning the Amazon rainforest is not to produce barren earth; it is to create farms growing soybeans, etc. So you need to compare oxygen production and usage of rainforests vs that of modern agriculture.
I’m not sure if it’s true; but I think a better way to express this statement would be: “The total carbon sequestered as biomass in the Amazon rainforest would be enough to convert 20% of the atmosphere’s oxygen into carbon dioxide”.
Or in other words, if all of the rainforest burned at once, the oxygen content in the atmosphere would suddenly jump downwards by 20%, and then (if all else remained equal) it would remain at that new, lower number.
Of course, all else wouldn’t remain equal, but the changes would be unpredictable. Most living things could survive the lower oxygen levels, but that’d come with a corresponding increase in carbon dioxide, and the impact of that would be huge. In addition to the considerable greenhouse effect, that level would be more than enough to poison a great many animals, us included.