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Does the Amazon provide 20% of our oxygen?

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Re: Does the Amazon provide 20% of our oxygen?

#181

Post by nearbuy »

eveningcoffee wrote: post #159
strainer wrote: post #152

Earlier quoted context omitted.

So that's where he is getting the context for his rant >> "So, in all practical terms, the net contribution of the Amazon ECOSYSTEM (not just the plants alone) to the world's oxygen is effectively zero." Practically, the reason why we have oxygen in the atmosphere is plant photosynthesis over long terms. We can quibble over the net annual product of every forest and ecosystem as he has - but over geological timeframe…

I am lately thinking that we are assigning too less value to this fact. We all need oxygen and we should have enough forests to produce it and this means that we should globally subsidize forest keeping. It is not a single country problem. It is a global problem.

1. The article explained this isn't true. Carbon dioxide is a problem. Oxygen depletion is not. Burning enough forests to decrease atmospheric oxygen by just 1% would increase CO2 by 5000%. We'd be dead long before we ran out of oxygen.

2. I'm not sure what you have in mind for "short term" vs "long term", but oxygen levels only change significantly over hundreds of millions of years.

3. Just like a stable sized forest doesn't produce any significant net oxygen, humans don't overall use up oxygen from breathing. The plants you eat (or if you're eating meat, the plants your food ate) released oxygen into the air when forming the carbohydrates and fats you eat. Your body then recombines these with an equal amount of oxygen to produce energy.

Re: Does the Amazon provide 20% of our oxygen?

#182

Post by dcolkitt »

chewbacha wrote: post #173
jefftk wrote: post #172

Earlier quoted context omitted.

The article is making a much stronger claim: > the net contribution of the Amazon ECOSYSTEM (not just the plants alone) to the world's oxygen is effectively zero If this is correct, then the entire Amazon could vanish without having any effect on CO₂ levels.

It could be correct and still have an impact on CO2 levels as it is still a massive sequester of carbon. Burning it down removes the sequester and adds it to the atmosphere. Also, just because it doesn’t produce the breathable O2 we need, that doesn’t mean it’s not part of a global system that produces and stabilizes our atmosphere. It actually is responsible for a massive silt run off that feeds the oceanic diatoms…

Some back of the envelope math... One tree in a tropical rainforest sequesters 50 pounds of carbon. The Amazon contains 390 billion trees. Since industrialization humanity has cumulative released about a trillion tons of carbon. So if the entire Amazon burned down it would increase atmospheric carbon by less than 1%.

This is just a rough estimate, and I'd encourage others to check my calculations. But intuitively this seems correct. Extracting fossil fuels releases all the carbon sequestered by organisms over 100 million+ years. Burning down a rainforest only releases the carbon sequestered by organisms currently living.

I don't see how it wouldn't be possible for fossil fuels not to contain orders of magnitude more carbon than forests. Which is of course why the switch from wood to coal precipitated the industrial revolution.

[1] https://medcraveonline.com/FREIJ/FREIJ-02-00040.pdf [2] http://mentalfloss.com/article/63519/how-many-trees-are-ther... [3] https://ourworldindata.org/co2-and-other-greenhouse-gas-emis...

Re: Does the Amazon provide 20% of our oxygen?

#183

Post by MuffinFlavored »

wcunning wrote: post #3

The basic gist of the article is found about 1/2 way in: "First, the phytoplankton in the oceans also photosynthesise [...] Therefore in terms of TOTAL global photosynthesis, photosynthesis in the Amazon contributes around 9%. [...] Second, a bigger point that is often missed is that the Amazon consumes about as much oxygen as it produces." This reminds me, as we should all be reminded on a regular basis, the bulk of…

> Second, a bigger point that is often missed is that the Amazon consumes about as much oxygen as it produces."

Does this mean that if the Amazon rainforest fell off of the map tomorrow, life as we know it would pretty much stay the same/be ok?

Re: Does the Amazon provide 20% of our oxygen?

#184

Post by Dumblydorr »

m0zg wrote: post #14
tcgv wrote: post #6

This subject has been treated so irresponsibly these past few days that not only people are making inaccurate statements such as "the Amazon provides 20% of our oxygen", but also high profile people such as Emmanuel Macron (France's President) and Cristiano Ronaldo (World famous soccer player) are sharing false information and photos[1] [1] http://translate.google.com/translate?hl=&sl=pt&tl=en&u=http...

All of US presidential candidates, democratic and republican alike, routinely and knowingly push blatant lies as a part of their platform and nobody blinks an eye. If you went through what they say with a fine toothed comb and removed all the lies, there'd be hardly anything left. People don't care about facts. They care about how a narrative makes them feel. Sad but true.

While it's true most politicians lie or bend facts or report them wrongly, you can not create a false equivalence between them all. Trump lies egregiously and far more than basically any non dictatorial politician. Your stance reminds me of those who said both 2016 candidates were bad, so they didn't vote or voted for the two clown third party candidates.

Re: Does the Amazon provide 20% of our oxygen?

#185

Post by navigatesol »

EB66 wrote: post #127
BurningFrog wrote: post #123

Earlier quoted context omitted.

Let's demystify how plants "produce oxygen". They do it by splitting CO₂ molecules. The oxygen part (O₂) goes into the air, and the carbon (C) part becomes the plant. So for the Amazon to continually produce surplus oxygen to the atmosphere, it must also continually produce an ever expanding amount of plant material ("wood") that would form an ever growing pile there. This is not happening. Because forests don't prod…

> This is not happening. Because forests don't produce surplus oxygen. Our atmosphere doesn't work that way. This is just plain wrong. The blogger is completely wrong on this point as well. In normal atmosphere conditions, photosynthesis does result in net oxygen gain. Plants do require oxygen for respiration, but they require far less oxygen than what they produce during photosynthesis. Furthermore, at night when th…

>The blogger is completely wrong on this point as well.

Classic HackerNews, right here.

His CV is public...and extensive.

>Scientifically inaccurate content

I'm sure Dr. Malhi'd be more than happy to debate you on the subject. Go post your arguments on his blog.

Re: Does the Amazon provide 20% of our oxygen?

#186

Post by chewbacha »

dcolkitt wrote: post #182
chewbacha wrote: post #173

Earlier quoted context omitted.

It could be correct and still have an impact on CO2 levels as it is still a massive sequester of carbon. Burning it down removes the sequester and adds it to the atmosphere. Also, just because it doesn’t produce the breathable O2 we need, that doesn’t mean it’s not part of a global system that produces and stabilizes our atmosphere. It actually is responsible for a massive silt run off that feeds the oceanic diatoms…

Some back of the envelope math... One tree in a tropical rainforest sequesters 50 pounds of carbon. The Amazon contains 390 billion trees. Since industrialization humanity has cumulative released about a trillion tons of carbon. So if the entire Amazon burned down it would increase atmospheric carbon by less than 1%. This is just a rough estimate, and I'd encourage others to check my calculations. But intuitively thi…

I agree that burning fossil fuels release more CO2 into the atmosphere. I was not trying to imply that the rainforest will halt global warming, obviously it can’t because it’s been there the entire time.

However, I do believe just multiplying trees by weight does not accurately describe what carbon sequestration is. Trees are not the only place carbon is sequestered in a forest. Soil sediment, animals, and other plants also sequester. It’s also a home of biodiversity and nutrient run off that assists other parts of our global ecosystem. In turn, Carbon sequestration occurs over time; and it’s these rich, biodiverse ecosystems that produce the fossil fuels that we are burning, without them the carbon would never sink into the earth as it does.

Eliminating the rainforest halts the engine that cleans the atmosphere and removes the carbon and cools the earth. It would also dump millions of more tones into the atmosphere (even by your calculations). It would also disrupt global food chains which do produce our global breathable oxygen.

I’m not sure what your point is that you are making other than you imply that we don’t need to save the tropics because fossil fuels are worse; but I heartedly disagree with that implication.

Re: Does the Amazon provide 20% of our oxygen?

#187

Post by bad_user »

BurningFrog wrote: post #126
Retric wrote: post #31

Earlier quoted context omitted.

There is no single tipping point. There are a vast number of different tipping points with different outcomes.

There is this idea that the ecological balance is very fragile and easily destroyed. This is true, in a way, but it doesn't mean nature will dies. It almost always just means that nature will find a new ecological balance.

If nature finds a new ecological balance that's incompatible with human life, does it matter?

Re: Does the Amazon provide 20% of our oxygen?

#188

Post by gdubs »

This thread feels politically toxic. The discussions seems to be heavily focused on a “gotcha”, exploiting a kind of Guilt By Association fallacy to minimize the disturbing event unfolding in the Amazon.

“The lungs of the world” is a poetic phrase. Trying to make it literal diminishes it, by giving cynics a small thread to pull on until it unravels — while in the process ignoring all the other ways in which the Amazon is important.

A vibrant discussion of the original post would be relevant — using the misaccounting as a cudgel against environmentalists and journalism as a whole is explicitly not the spirit of HN.

Re: Does the Amazon provide 20% of our oxygen?

#189

Post by DenisM »

Rebelgecko wrote: post #105
DenisM wrote: post #71

A few comments are saying that forests capture a lot of CO2. But how could that be? If a forest doesn't change over thousands of years it cannot be accumulating carbon in any significant quantity. Or else where would that material go? The Amazon trees are about as tall and wide today as they were 10,000 years ago, and only so many of them fit on a given area. If the amount of vegetation remains the same the only way…

Doesn't burning the forest down release a good portion of that CO2?

My point is that a standing forest doesn’t affect carbon levels. A growing forest or a burning forest does.

So a statement like “forests are scrubbing CO2 and help us against climate change” are false - a stationary size forest has no effect whatsoever.

For carbon to be sequestered it has to go into the ground and stay there.

Re: Does the Amazon provide 20% of our oxygen?

#190

Post by DenisM »

cmrdporcupine wrote: post #179
DenisM wrote: post #71

A few comments are saying that forests capture a lot of CO2. But how could that be? If a forest doesn't change over thousands of years it cannot be accumulating carbon in any significant quantity. Or else where would that material go? The Amazon trees are about as tall and wide today as they were 10,000 years ago, and only so many of them fit on a given area. If the amount of vegetation remains the same the only way…

Temperate forests sequester carbon over millions of years by leaving a layer of carbon rich top soil beneath them through leaf and other litter fall. Soil can hold a _lot_ of carbon per square foot. Carbon that is partially lost to the atmosphere when it is plowed. But my understanding is that tropical forests tend to have fairly carbon poor soils on the forest floor.

The only way it could work is for the top soil to grow thicker by the year, reaching huge depths over tens of millions of years. As I recall my temperate forests, the topsoil is skin-deep, relatively speaking.
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