"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 the things you read in the popular press are at best skimming the surface and at worst outright misleading due to grabbing onto one obscuring factoid instead of the most important pieces of information. Per Gell-Mann, I only see this in tech and science reporting, but that makes me really unreasonably suspicious of political reporting, too.
FTR, this article is doing exactly that. Like, they a) divert your attention with the CO₂<->O₂ conversion (which doesn't change relative numbers in percentages of photosynthesis at all - you multiply both sides of the equation). And b) then proceeds to pretend that the Amazon eats up most of the Oxygen it produces, but the rest of the world apparently doesn't. Like, if a tree re-metabolizes 40% of the O₂ it produces, then that's also true for the 91% of O₂ produced outside the Amazon, so we still end up with the same 9% figure of all O₂ produced in the Amazon.
The article ends with the "CO₂ emission is more important". Which, again, fair. But Photosynthesis is presumably a pretty important mechanism by which CO₂ is removed from the air. So a reduction of O₂ production is equivalent to a reduction of CO₂ absorption (though you have to multiply with 2.67, don't forget!), which seems to… be a bad thing for CO₂ concentration in the air.
The gist of the article is pretty much "if you don't round and take into account maritime photosynthesis, the Amazon only produces 9% of all O₂". Which is fair. The rest is noise. It doesn't add to the argument and is just fueling the "MSM is bad!" cries…
> 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.
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 that in turn produce half of the worlds breathable O2 and fixes carbon right in the ocean.
This is a case where a literal point is incorrect but it does not decrease the importance of the rainforest to our globe.
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.
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.
That's a fair point. The IPCC gives an estimate of 109 tonnes per acre of tropical forest. Which is about an order of magnitude higher than my original estimate.
But even with those numbers, deforestation is basically a rounding error compared to fossil fuel emissions. The Bolsonaro admin has increased deforestation rates by 278%, or an annual rate increase of 4500 sq km. Using the IPCC numbers, that's 110 million tonnes of Carbon per year.
That's less than one week of America's carbon emissions. Less than one day of global carbon emissions. The point is that from a climate standpoint, current rates of deforestation are largely inconsequential compared to fossil fuel emissions. It's almost certainly more effective to spend political and economic capital on energy efficiency and renewables.
Trees are not the only part of the amazonian ecosystem, but I'm pretty sure trees outweigh other parts of the amazonian ecosystem by a significant ratio. I think the calculation probably suffices as a back of the envelope estimation.
> 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.
Removing tropical rainforest would be disastrous, but not because of impact on global CO2 levels. (Its effects on CO2 levels would not be helpful but wouldn't be among the worst consequences). Among other reasons, it would significantly alter global weather patterns and cause massive damage to ecosystems across the globe.
I think the point is that even an ecosystem as massive and influential as the amazon can't even make a dent in the amount of CO2 that is being produced by human activity.
In temperate ecosystems, there's net long-term storage of biomass and nutrients in soil. Mainly roots of dead plants. But also stuff that accumulates faster than it can decompose. Tundra and taiga are extreme examples.
But mature tropical ecosystems are pretty much in equilibrium, with ~zero net impact on the soil or atmosphere. Pretty much all mineral nutrients are locked up. And everything that dies gets recycled very quickly.
BTW, that's kind of the entire point of a site like HN. Experts from different fields (and hobbyists and laypersons) get together and exchange knowledge. Sorry to go on about this, but I've been seeing too many responses saying to go Google things.
I know nothing about the topic, but literally just Googled Drugs from the Amazon , and the very first example of the very first search result I came across was Quinine. 
Given the option between not commenting at all or offering some variant of JFGI, I'll strongly prefer the former. "You don't have to attend every fight you're invited to", or comment on every post. But if you do, try to land solid punches. Even if you're not Mohammed Ali.
(I've frequently learned things, and more than once entirely changed my mind, in researching to answer comments.)
has been isolated the alkaloid d-turbocuarine, which is used to treat such diseases as multiple sclerosis, Parkinson's disease and other muscular disorders.
It’s a muscle paralyzing agent used in surgery. It’s not use in MS or Parkinson’s.
I wonder what else is wrong in the article.
No need to wag your finger.
And it doesn’t seem that it will get higher. My impression of modern pharmaceutical research is that instead of focusing on natural medicinal compounds, it is more focused on discovering the exact mechanisms behind various disease processes and synthesizing molecules that either slow down or speed up key pathways along those processes.
but thats also how you end up on a geocities site about anti vaxxing because big pharma doesn't want you to know about the amazon and yell "exactly, I knew it all along!"
But why should this be? Physics, and similar hard sciences, are deep and complex fields. There's plenty of math, jargon, and a long literature. Of course inaccurate simplifications happen when writing about it for a popular audience. Add in the weird incentives of mass media and the lack of scientific expertise among most journalists, and it makes sense that popular physics news is not so accurate.
In contrast, other newspaper topics like politics, sports, business, etc. are often literal reporting of what people do. I'm not saying any of these areas is necessarily simple, but they are at the root level about human actors, not abstract quantities that most people have 0 intuition for. So I expect that it's actually easier to do good reporting on those topics.
But people don't even have a good handle on the "what" of a lot of science (what are these new particles? what is p vs np?) which is why we get all these analogical half understandings.
And backtracking slightly to my grandparent comment, Gell-Mann was coined by Michael Creighton who in the same quote compared Murray Gell-Mann's knowledge of physics to Creighton's knowledge of show business. The "what you know well enough to spot errors" can be anything as can the "what you blindly trust the reporter on out of your own ignorance."
Where would you get that idea? It is definitely the other way around.
In hard sciences at least you can easily construct experiments and find out truths with time, which while complex, are basically predictable. In human sciences everything is much more complex and chaotic effects and problems with definitions and inherent unpredictability of humans make everything more complicated.
I was once in a local paper for my participation in a sports team. Well, my picture was. The name given to me in the article and caption was fabricated. Such a name didn't even belong to anybody else in my school, let alone on the same team!
I assume the 'reporter' was too drunk to remember my name and too embarassed to ask somebody, so he just made one up.
I sort of understand the misgendering. Most visible street people are male. But the fabricated quote made me feel like "They think they can just do anything they want because I'm so poor." That felt like intentionally shitty behavior.
If you are in public and the photo is “newsworthy” your image can be printed in a newspaper without your consent.
“Use of someone's name or likeness for news reporting and other expressive purposes is not exploitative, so long as there is a reasonable relationship between the use of the plaintiff's identity and a matter of legitimate public interest.” - http://www.dmlp.org/legal-guide/using-name-or-likeness-anoth...
Like, when a journalist quotes you in print, it is often not a real direct quote, but rather the journalists interpretation of what you said (which can be way off). Always insist to "check quotes" or you could get a surprise when you read your interview.
This comment should be preserved for all time and cited in the Gell-Mann Effect entry. Do you really think physics is infinitely more complicated than finance or politics?
The paper runs articles on politics every single day. The characters and issues don't change too quickly: Quimby was the mayor last week; next week, he'll be the same mayor, dogged by the same scandals and trying to enact the same politics too. A lot of the facts are easy to check, if someone cared to do so. The reporters may have a background in political science or history, or something somewhat related.
In contrast, the science section is pretty small. Maybe it runs once a week and has one or two main reporters, who cover everything from Astronomy to Zoology. No one has a background in all of that, and many reporters don't have a technical background at all. You can try to fact check it, but the experts themselves don't always agree and it's hard to tell whether Dr. So-and-So is really an expert on the topic anyway.
And, despite all that, the science reporting I see does a pretty good job. One of my papers got a bit of media coverage, and pretty much everyone got the broad strokes right. One place made me sound a little too exuberant about the immediate ramifications; another made me sound a bit too negative, but neither was egregiously bad.
And despite this, most of the media got the two of the most significant political happenings of the last 5 years (US elections and Brexit) completely wrong.
By saying "most of media gets it wrong" without any examples, everyone agrees, and noone needs to think about what the media said or what happened at all. Everyone reading can be right and everyone else can be wrong at the same time.
Less snarkily - what media narrative are you referencing specifically? What do you believe occured instead? There was much media covering many angles on both of these issues.
From discussions with my wife, who is board certified in infectious diseases, newspaper coverage of the following topics are simplified to the point of losing the main point: antimicrobial resistance, any tropical disease from malaria to Ebola, organ rejection.
I think the problem is universal not specific.
> Fig. 4 summarizes the annual averaged global O2 budget from year 1990 to 2005, with the mass of O2 in gigatonnes (Gt) listed in each sink and for each process mentioned above (see Section 2.5). The inputs of O2 to the atmosphere by land and outgassing from oceans are quantified as 16.01 and 1.74 Gt/a, respectively. ....
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 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 there's no light, plants do absorb oxygen and give off carbon dioxide in order to continue respiration -- but the amount of oxygen given off during the day is typically ten times greater than the quantity of oxygen consumed at night.
> This reminds me, as we should all be reminded on a regular basis, the bulk of the things you read in the popular press are at best skimming the surface and at worst outright misleading due to grabbing onto one obscuring factoid instead of the most important pieces of information.
Similarly, we should all be reminded that when skimming blogs and comments you're likely to come across misleading and inaccurate content. Scientifically inaccurate content like this gets posted on HN and blindly upvoted all the time.
I think you may not have read the article closely enough:
>> Plants produce oxygen through photosynthesis (green arrow). However, the the same plants consume the equivalent of over half the oxygen they produce in their own respiration ... my own team's research suggests this is more like 60%
>> The remaining 40% of the Amazon oxygen budget is consumed mainly by microbes breaking down the dead leaves and wood of the rainforest, a natural process called heterotrophic respiration
> Similarly, we should all be reminded that when skimming blogs and comments you're likely to come across misleading and inaccurate content
The "blogger" who wrote this article is "Professor of Ecosystem Science, University of Oxford" and "Founding Director, Oxford Centre for Tropical Forests" and probably knows more about this than you or I. This is not a peer reviewed paper, but it is probably more accurate than science journalism by a non-ecologist on this topic.
My point was he hasn't cited that research - if it is concluded ? published? reviewed?
He seems to be just having a technical rant about a contextual phrase while giving the impression that forests in general, or at least the amazon or equatorial forests do not help maintain the atmospheres oxygen content. That would certainly be a maveric proposition at this stage in Earth sciences.
I am far more willing to take the word of an established and respected expert who understand the subject mater than a random internet person with a poorly contextualized citation. You can find the author's published papers on this and related subjects quite easily at the top of the article.
> He seems to be just having a technical rant about a contextual phrase while giving the impression that forests in general, or at least the amazon or equatorial forests do not help maintain the atmospheres oxygen content. That would certainly be a maverick proposition at this stage in Earth sciences.
He is a scientist clarifying a technical subject that has been being misconstrued. There has already been plenty of damage done by people throwing around fake facts and pictures.
Here is a recent work which substantiates matters that Amazons practical involvement in the planets atmospheric oxygen/carbon levels is really not as the professor felt like putting it as "effectively zero".
> Abstract: The response of the Earth’s land surface to increasing levels of atmospheric CO2 and a changing climate provide important feedbacks on future greenhouse warming6,7. One of the largest ecosystem carbon pools on Earth is the Amazon forest, storing around 150–200 Pg C in living biomass and soils8. Earlier studies based on forest inventories in the Amazon Basin showed the tropical forest here to be acting as a strong carbon sink with an estimated annual uptake of 0.42–0.65 Pg C yr−1 for 1990–2007, around 25% of the residual terrestrial carbon sink3,4. There is, however, substantial uncertainty as to how the Amazon forest will respond to future climatic and atmospheric composition changes. .... Here we analyse the longest and largest spatially distributed time series of forest dynamics for tropical South America. .... Our data show that mature forests continued to act as a biomass sink from 1983 to 2011.5, but also reveal a long-term decline in the net rate of biomass increase throughout the census period. The decline in net biomass change is due to a strong long-term increase in mortality rates, and occurred despite a long-term increase in productivity. While mortality increased throughout the period, productivity increases have recently stalled showing no significant trend since 2000. ....
Published in Nature: 18 March 2015 : "Long-term decline of the Amazon carbon sink"
I couldn't agree more. A bunch of people are coming away from reading that article believing that forests have no impact on global carbon sequestration and oxygen production. In attempting to make a contrarian technical point and refute mass media figures, the author has done a disservice to furthering public understanding of the issue.
Sure, a mature forest can come into equilibrium with regard to carbon/oxygen production and consumption. A forest could even be a net contributor of atmospheric carbon by means of an insect or fungus overpopulation. However:
1. Studies show that's not true for the Amazon rainforest (annually it is still a carbon sink).
2. Over the lifetime of the forest the effect is clearly a massive gain in oxygen and massive sequestration of carbon as evidenced by all the biomass (e.g., trees) and dirt you find in forests.
If you were really concerned about people misunderstanding the article, you would not make up claims and attribute them to the author. Instead you would quote the relevant parts of the article to demonstrate what is actually being said.
The author in no way claims that the Amazon is in equilibrium, (probably because as one of the foremost global experts on rainforest carbon cycles, he knows it isn't.)
The claims are quite specific:
1) The amazon provides ~9% of the global O2 production.
2) The amazon consumes most of the O2 it produces through tree metabolism and wood decomposition.
3) There is way, way more O2 in the atmosphere than CO2 so the effects all human activity (or ecosystems) on global O2 levels are miniscule compared to their effect on global CO2 levels.
Burning down the entire amazon rainforest would be a bad for a number of reasons (release of CO2, changes in global weather patterns, loss of bio-diversity, etc), but impact on global atmospheric O2 levels is NOT one of those reasons.
Fear mongering about a non-issue with made up facts only serves to provide ammunition to anti-science skeptics.
What on Earth are you referring to?
> The author in no way claims that the Amazon is in equilibrium
Yes he does. As I already explained to you, the author asserts that the O2 produced by the Amazon rainforest ecosystem is equal to the amount of O2 consumed by the Amazon rainforest ecosystem -- that is a perfect example of what it means to be in equilibrium. He literally says it in big bold letters:
> the net contribution of the Amazon ECOSYSTEM (not just the plants alone) to the world's oxygen is effectively zero.
Did he use the word equilibrium? No. Did he describe an equilibrium? Yes!
I am done arguing with you on this point -- it has truly devolved into semantics and has become unnecessarily inflammatory. At this point all I can do is refer you to a dictionary.
> Fear mongering about a non-issue with made up facts only serves to provide ammunition to anti-science skeptics.
Fear mongering? Now you've truly lost me. If asserting that forests net sequester carbon and produce O2 makes me a fear monger, then I'm guilty as charged...
The paper you cited as "disproving" the author's argument for "prefect equilibrium" was co-authored by the author.
Indeed, in the comments on the article, the author explains further:
>> [net carbon sequestration] is not related to the total amount of photosynthesis, but to where organic matter is being buried and removed from atmosphere and biosphere. This occurs in places like swamps, peat bogs and in particular deep ocean sediments. Material from the Amazon probably plays some role in this (e.g. organic material being swept out into the ocean and being buried in deep sediment), but this process is not strongly related to the amount of photosynthesis in any given area. I suspect the burial of a tiny fraction ocean plankton in deep sediments play a dominant role here.
> Fear mongering? Now you've truly lost me. If asserting that forests net sequester carbon and produce O2 makes me a fear monger, then I'm guilty as charged...
Sorry, I am talking about making claims like "the amazon produces 20% of our oxygen." and I was doing so to justify what you called "nitpicking"
The point I was trying to make (and clearly did a poor job with) is summarized by the author in one of his responses to attacks like yours and strainers:
>> No ecosystem scientist I have spoken disagrees with the science in this post: it simply highlights a long-established scientific understanding that oxygen angle is a myth. Just like no serious climate scientist denies the seriousness and importance of human-caused made climate change. If you choose to be selective about which science to choose to hear you fall into the same trap as the climate deniers, construct your own alternative facts universe and you betray your scientific training. The also open yourself the other, more accurate arguments being discredited as a package when the scientific truth emerges
Why are you still conflating O2 and CO2?
Edit: You do realize that "Y. Malhi", one of that authors of that paper, is the same "YADVINDER MALHI" who wrote this blog post.
That should be obvious. Any evidence of amazon sequestering carbon is evidence of amazon liberating oxygen. If you cant bear that in mind you have been distracted by the artificial separation proposed here, between "a strong carbon sink" sinking carbon and the respiring of O2, they are very effectively both expressions of the same process.
> one of that authors of that paper, is the same "YADVINDER MALHI" who wrote this blog post
Correct and it puts into stark contrast the co-authors private blog advice that "the net contribution of the Amazon ECOSYSTEM (authors emphasis) to the world's oxygen is effectively zero". That misjudged statement which is even highlighted in the article now, is in plain contradiction to that paper he took part in, which is also about the Amazon ECOSYSTEM and the Amazon can not physically be "a strong carbon sink" and at the same time have zero contribution to the worlds atmospheric oxygen system.
The claim is wrong, and hangs only on the ambiguities of what "effectively zero" could be argued to mean that is in reality documented to be very far from zero indeed.
The Amazon has been known for decades as great "lung" of the planet, SINKING Carbon and RELEASING O2. Malhi has himself taken part in work which describes it "greatly" doing so. If its personal credentials you put faith in you could regard Sir David Attenboroughs describing it the same, for many years, in finished and award winning works, as opposed to a professors conversational web article.
Malhi's advisory 9% figure (that is then subsequently reduced to zero?!) is not even necessarily more final or uncontestable as the supposedly terrible global media outbreak of 20% reports. And since (even that work Mahli took part in reveals) that the amazon is recently in serious flux, such figures are technically speaking conditional.
The point of publicity figure is to be defensible and educate the fact that the Amazon has had and can have major effects on the atmospheres important constituents. That whether it is currently in equilibrium or a great carbon sink or grave carbon emitter - is a very grave matter because by its size and history it is capable of all those things.
But the effects on global atmospheric composition are not equivalent as has already been explained to you. The fact that you seem to choose to deliberately not understand this does not speak well of you.
> The claim is wrong, and hangs only on the ambiguities of what "effectively zero" could be argued to mean that is in reality documented to be very far from zero indeed.
There are no ambiguities, the caveats of that statement are quite clearly stated in the article.
> Malhi's advisory 9% figure (that is then subsequently reduced to zero?!) is not even necessarily more final or uncontestable as the supposedly terrible global media outbreak of 20% reports.
Nobody ever said it was final or uncontestable (that's not how science works). It is a fairly rough estimation, but even as such it is FAR more accurate and its precision is sufficient for popular discussion.
> The point of publicity figure is to be defensible and educate the fact that the Amazon has had and can have major effects on the atmospheres important constituents. That whether it is currently in equilibrium or a great carbon sink or grave carbon emitter - is a very grave matter because by its size and history it is capable of all those things.
Neither I nor the author dispute the importance of the amazon. What is disputed is the bad science that is being spread by the well-intentioned but misinformed.
Atmospheric O2 levels are not a problem, atmospheric CO2 levels are.
What do you think you are accomplishing by attacking environmental scientists and spreading misinformation? Are you really trying to help spread accurate knowledge about climate change? How does this help with that?
I did read the article closely :)
The author is stating that the Amazon rainforest is in perfect equilibrium without citing any studies or evidence. There are plenty of studies that indicate otherwise, such as this 30 year survey involving 100 researchers: https://www.nature.com/articles/nature14283
> While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation.
But even if we accept the author's argument that today the Amazon is in perfect equilibrium -- I think it was misleading of the author not to clarify that in order for any forest to grow, it must be a net carbon sink and net oxygen producer up to that point in the forest's lifetime.
Now the comment that I originally replied to said something different. That comment argued that forests cannot be net producers of oxygen because there aren't "ever growing [piles of wood]" and then he provided the Wikipedia article for photosynthesis as evidence supporting that. That's wrong as I explained above.
You can have forests that are net carbon sinks and net producers of oxygen and you don't need "ever growing [piles of wood]" in order for that to happen.
The author argued no such thing, You are making up claims adn attributing them to the author, so perhaps an even closer reading of the blog post would be beneficial.
>> 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. The same is pretty much true of any ecosystem on Earth, at least on the timescales that are relevant to humans (less than millions of years).
The paper you cited is talking about carbon dioxide, not oxygen. The net effect on global O2 levels of carbon sequestration is minimal and not significant on human time scales. That same carbon sequestration has a significant impact on global CO2 because there is much less CO2 in the atmosphere.
Please go read the article again. That's exactly what he's saying. He is saying that Amazon rainforest O2 production and consumption are in equilibrium.
> The paper you cited is talking about carbon dioxide, not oxygen. The net effect on global O2 levels of carbon sequestration is minimal and not significant on human time scales. That same carbon sequestration has a significant impact on global CO2 because there is much less CO2 in the atmosphere.
For heaven's sake, please read the study. If you'd rather not read the study, then just Google until you find a satisfactory source that explains that net O2 production and net CO2 sequestration strongly correlate with one another.
> net O2 production and net CO2 sequestration strongly correlate with one another.
yes, but we have ~500 times more O2 than CO2 in the atmosphere so the effects on atmospheric composition are not anywhere close to equivalent.
edit: Let me put it another way. We have so much oxygen that if we were to use any significant amount (say 1%) of that oxygen burning sequestered carbon (rainforests, oil, etc) we would have increased the carbon dioxide in the atmosphere by something like ~2000% (and would already be totally screwed in many, many ways)
Either way I'm done with this tangent.
Y. Malhi, one of the authors of that paper, is also the author of this blog post. That makes sense since he a preeminent rainforest ecologist who publishes lots of papers on the carbon cycle.
Short answer: Because the article doesn't contradict the study at all.
1) The rainforest is a carbon sink: It holds carbon that would otherwise be present in the atmosphere as CO2.
2) The rainforest is currently a net carbon sink: As an ecosystem it takes in more CO2 than it releases.
3) The rainforest (like most ecosystems) operates fairly close to equilibrium: The amounts of CO2/O2 consumed and produced tend to be pretty close.
4) Major ecological net carbon sinks depend less on the amount of photosynthesis in the ecosystem than they do on the sequestration of bio-matter into the ground.
5) There is ~500x more O2 than CO2 in the atmosphere. This means that the effects of the carbon cycle on atmospheric O2 are far less pronounced than on CO2.
6) net oxygen production of the amazon is effectively 0 (millions of years before a significant impact) because of 5) and 3)
In what way do any of these points contradict eachother?
The major reason (carbon cycle related, excluding biodiversity & global weather patterns & cooling etc) to care about about the amazon is to avoid releasing the CO2 already there. Purely in terms of net carbon sinking ecosystems, we should be paying more attention to our oceans as they do a much better job of sequestering that carbon into the ground.
Oxygen in the atmosphere is simply not an issue because we have so much of it.
But that carbon is all released back as it decomposes after its death.
On a "whole forest/whole year" perspective, there is normally an equal mass of plants growing and being decomposed, and thus the net oxygen effect is zero.
> On a "whole forest/whole year" perspective, there is normally an equal mass of plants growing and being decomposed, and thus the net oxygen effect is zero.
Sure, if you're talking about a timespan of one hour, one month, one year, etc then it's definitely possible for biological processes in a forest to expel carbon in the form of CO2 in equal volumes that were sequestered by plants. You could even have an overpopulation of some kind of insect or fungus cause a forest to temporarily become a net contributor of atmospheric carbon.
But over the lifetime over the forest, the net effect is obviously massive CO2 sequestration and massive O2 production. If the net carbon impact was zero over the lifetime of a forest, then forests would have no soil. But we know that not to be the case. Forests grow, they accumulate soil, etc.
Despite constant heavy rains and erosion, soil in the Amazon rainforest is often several meters deep and spans an area of over 2 million square miles. That's a lot of carbon sequestration!
I assume it reaches an equilibrium after some time, and that the Amazon soil has remained the same "several meters" deep for many millions years.
But I'll admit I don't know that, and you may have a valid point. If real, this effect has to be quite small though.
Yep definitely and in part because CO2 only makes up ~0.04% of our atmosphere. Photosynthesis processes slow when CO2 levels fall and increase when CO2 levels rise. But as well as know atmospheric CO2 levels are rapidly on the rise and is outstripping the ability of large forests to sequester it.
Regarding sequestration: the carbon goes into the trunk, branches, roots and leaves of the tree. Leaves fall off the tree, rot and become soil. The tree eventually dies, rots and becomes soil.
Some carbon will be given off by various decomposition processes, but the overall net effect is by far a carbon sink.
BurningFrog said the carbon from CO2 goes into plants. Since plant matter isn't accumulating, carbon can't be accumulating, and therefore oxygen can't either. You replied, "This is just plain wrong".
So you're saying the part that is sequestered goes into the soil. That means some significant fraction of the 20 billion tonnes of carbon the Amazon photosynthesizes each year is turning in to soil. You're claiming the amount of soil increases by this amount each year, correct?
Correct. That fraction is obviously reduced when the forest is burned.
The soil does not need to be millions of meters deep in order for the forest to be both a net carbon sink and net positive oxygen producer -- it can slowly acrue over time.
And even if biological respiration processes in the forest began to equal carbon sequestration processes -- the forest would still be a massive carbon sink over its lifetime given the massive quantites of plant matter and soil present.
Yes, the rainforest has been a massive carbon sink over its 30+ million year lifetime - because of the carbon it sequestered while it was first growing and expanding.
Yes, it could be producing very, very tiny amounts amounts of oxygen each year so that the rise in soil level isn't noticeable. If the rainforest was still slowly sequestering carbon in soil at a rate of about 1 meter of soil depth per 30 million years, then you're talking about it sequestering about 0.00005% of the carbon it captures through photosynthesis. If you're calling the article "completely wrong" over that, I'm not sure what to say.
And it's not just the yearly rate of oxygen production that must be negligible. The total oxygen produced over the Amazon's lifetime is negligible. As the article points out, if you burned the entire Amazon rainforest, releasing all the sequestered carbon, it would only decrease atmospheric oxygen from about 20.95% to 20.93%.
The biomass of the Amazon is not, for the most part, sinking into very salty water.
If 3kg of carbon sequestration per year per square meter were accumulating as soil, and the rainforest has existed at least 30 million years, the soil would be over 2,000,000 meters deep (with rich organic soil being about 9% carbon). If even 1% of the carbon captured through photosynthesis was sequestered in soil, we should still have much, much deeper soil.
All carbon in your body was once sequestered by plants.
As the total biomass of insects isn't growing, the carbon they consume is balanced by the carbon released by decomposition of (otherwise) unconsumed insects; the same applies for animals up the food chain - if at the end of 2019 the total weight of insects and animals in the Amazon is not larger than at the end of 1919, then zero carbon has been sequestered in these insects and animals over a hundred years.
The plants can't be net collecting carbon each year unless the Amazon contains more and more plant matter each year.
It takes place at a lower intensity than our burning of fossil material and forests in recent history. Regrowing forest, usefully captures carbon and releases oxygen more rapidly than mature forest, but of course not rapidly enough to make up for burning them down.
> Under the Representative Concentration Pathways (RCPs) RCP8.5 scenario, approximately 100Gt (gigatonnes) of O2 would be removed from the atmosphere per year until 2100, and the O2 concentration will decrease from its current level of 20.946% to 20.825%.
2018 209460 ppm
2100 208250 ppm
From Stolper et al. (2016) A Pleistocene ice core record of atmospheric O2 concentrations:
> We present a record of Po2 reconstructed using O2/N2 ratios from ancient air trapped in ice. This record indicates that Po2 declined by 7 per mil (0.7%) over the past 800,000 years, requiring that O2 sinks were ~2% larger than sources.
That's 7000 ppm decrease over 800000 years, or 0.009 ppm per year. And so yes, atmospheric oxygen concentration is dropping lots faster now. But TFA's point that it's slow, and regulated by long-term processes, is still valid.
"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 timeframes, the plant life they contain is the reason we have any oxygen to breath. And if the amazon currently amounts to about 20% of the plant life on earth now, its not wrong to teach that it is doing 20% of the oxygen maintaining.
The fact that long term maintenance is obscured by shorter term dynamics including our modern industrial activity, does not make a lie of the understanding and respect that forests are lungs of the planet.
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.
If you destroy the forest then you will reduce the capacity to remove the CO2 from the atmosphere and produce oxygen or do you disagree with this?
> If you destroy the forest then you will reduce the capacity to remove the CO2 from the atmosphere and produce oxygen or do you disagree with this?
The linked article explains this isn't true. The rainforest is in equilibrium. It doesn't remove CO2 overall. It's a carbon stockpile.
If you were to burn the forest, it would release the stockpiled carbon into the atmosphere as CO2.
About 1/2 of the oxygen produced is produced by Phytoplankton, which are not plants (though they are similar).
> And if the amazon currently amounts to about 20% of the plant life on earth now
The amazon accounts 16% of the photosynthesis on land.
> its not wrong to teach that it is doing 20% of the oxygen maintaining.
It is wrong. If you want to provide a nice round, reasonably accurate number you should use 10%.
> does not make a lie of the understanding and respect that forests are lungs of the planet.
Forests are important and and a significant part of the respiration of them planet, but they are less important than our oceans. Our oceans are the true lungs of the planet (edit: and they are not in great shape, atmospheric oxygen may not be an issue, but oxygenation of the ocean is more variable).
The advice that amazons contribution is "zero", hedged under this safety-net word "effectively" is false to the understanding of geophysics and natural history. I hope the professor will clarify his language after consideration.
But we should be worried about it because of the impact on global biodiversity. Not because we'll be running out of oxygen. Having ~20% oxygen in the atmosphere reflects a long-term equilibrium of biologic and non-biologic processes.
If advocates focus on the oxygen issue, adversaries can easily point to negligible changes, and argue that there's nothing to worry about.
And, as I said, to the extent that oxygen is an issue, we ought to worry even more about the oceans. They are by far the major oxygen source, and arguably more vulnerable to catastrophic collapse.
The blogger does professional work on the subject. The article makes it pretty clear that the net positive production of oxygen the the Amazon is so close to zero that it is only relevant on the time scale of millions of years.
First of all oxygen is constant. Oxygen is currently not the problem. And it's a good thing that it's constant because we don't want more of it either.
The problem with Amazon is that on Earth it's all interconnected and while there's plenty of room for failure, there is a tipping point, scientists have only disagreed on where that tipping point is. Once we are there however we will no longer be able to stop the chain reaction.
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.
Especially when on fire ...
If it is the latter, then we will see decreased oxygen levels as the forest decreases is size.
If it burns,there will be leftover life that will no longer be supported by the amazon. Causing a significant increase in net Oxygen consumption.
1% uncomoemsated consumption doesn't sound like much but it will remain that way or worse whic means total O2 will continue to deplete.
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?
It may be a click-bait factoid, but it's not like that factoid isn't an important one.
And I'm not qualified to answer what happens when you burn down an entire millenia-old ecosystem. Seems plausible that it might not go straight back to its old self in a human-relevant timeframe.
That’s not obvious to me. Most plants are C2 plants, but grass is a C4 so it captures sunlight more efficiently.
Not to say burning the Amazon isn’t a terrible idea.
Not that any of this is a valid excuse for burning down the Amazon.
Like most of what you hear in the big press, it comes with an agenda. It's not the case that a 'zero' was mispelled or enough info was not available, thus the erroneous reporting. You won't win the argument that way. The piece simply has another purpose from the one it is claiming to have, in this case, that future generations will say that the fires wiped out the entire human civilization in all it's glory at the hand of the Brazilian president. Ergo, he has to go until it's not too late.
Also, what you call average is only the average over the past few years, which means: illegal loggers and ranchers burning the forest on purpose.
The true long-term average is a healthy forest with very few fires.
> only the average over the past few years
That only reinforces in the point; if the numbers changed from the average a few years ago, why the sudden massive response just now?
Indeed, people are burning more this year than they did in the past few years – any burning at all has always been unacceptable, but if the current spike is what it takes to finally create some international outrage and put pressure on Bolsonaro, then I'll gladly take it.
It's a traditional farming practice that has been used all over the word https://en.wikipedia.org/wiki/Slash-and-burn
The idea is that you can burn a small place, cultivate it for a few years and then abandon it so the natural grow of the forest regenerate it. And some years later repeat the cicle.
When the population is small it's fine because the time between burn and burn was enough for the soil and forest to recover. When the population increase the time gets too small and the forest has not enough tome to recover, and after a few cicles you have problems like reduction of fertility, erosion and desertification.
Those are images of fires to illustrate people's message, they convey the greater concept that we should be aware of the Earth as a global shared system. No one is saying 'look at this picture of the Amazon burning right now' (not even in the Macron's tweet).
Regarding "the Amazon provides 20% of our oxygen", I guess it could be debated, and the biodiversity would probably have been a better argument.
I think it is flat out wrong and not really debatable. Also, focusing on oxygen is not the right thing to talk about because we have so much more oxygen than carbon dioxide.
Before we manage to consume significant amounts of our oxygen, we will have released so much carbon dioxide that a slight dip in O2 will not be a concern.
The red regions are largely tropical rainforest. Exceedingly highly productive, but not particularly viable for human agricultural activity.
What stands out are the regions which I'm aware are highly agriculturally productive, indicated in green and cyan: the eastern half of the US, generally, the Argentine and Brazillian Pampas regions, the Sahel, Europe (particularly western Europe -- England, France, and Germany), and south and East Asia. A small patch of Central America.
Notably contrasting: the western US, other than a thin strip (the central valleys of California and Oregon), the Australia, other than the extreme south-eastern band, the Sahara, virtually all of Russia, western South America, and most of Canada. And of course, the Sahara and Antarctica.
We're feeding 7.7 billions of souls on those regions of green and light blue. Those are also the regions in which the great civilisations of the past have developed -- compare with a time-lapse of human population such as:
In my experience people listen to people who can explain things, not just claim that something is wrong/false.
Anyway, the geological history of oxygen is pretty wild:
Naturally, this includes some marketing to support the message and to try to persuade as many people as you can.
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 for a forest to capture carbon would be to accumulate an ever-increasing layer of it under the forest floor. That would be a lot of combustible material accumulated over millions of years that Amazon was around, and I'm pretty sure it isn't there (otherwise certain people would be mining it already).
Amazon is not scrubbing carbon out of the air, and neither does any other forest of static size. The carbon has to go into the ground to remain sequestered.
As you indicate, those people are incorrect. But a forest may contain a lot of C02, such that burning it all at once increases the amount in the atmosphere noticeably.
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.
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.
it's just less accessible but I'm pretty sure like any forest on the face of the earth, portions of dead animal and plant matter is getting sequestered into the ground while another portion is getting exhaled by animals eating the leaves or other animals eating the animals.
The stuff that's getting sequestered though is probably miniscule. At the timescale of our lifetime it may be negligible but I wouldn't know as I'm not an expert. Perhaps someone with the actual data can fill us in?
> A final point to make is that the atmosphere is awash with oxygen, at 20.95% or 209,500 ppm (parts per million). Carbon dioxide, by comparison, is around 405 ppm and rising by around 2-3 ppm per year, over 500 times less. Human activity (around 90% of which being fossil fuel combustion) has caused this concentration to drop by around 0.005% since 1990, a trivial amount. In parallel, the same activities have caused carbon dioxide concentrations to rise by by 37 ppm since 1990, or 10%. This is a much more substantial percentage because there is so little carbon dioxide in the atmosphere to begin with, so human activities can make a major difference. This is why we need to worry about the increase of carbon dioxide in the atmosphere (and its resulting impact on climate), and why we don't need to worry about running out of oxygen.
The 3 order of magnitude difference is the relevant bit of info.
So while it takes millions of years for the amazon to have an impact on )2 levels, impacts on CO2 levels happen on the time scale of thousands of years.
This is also why it makes more sense to be concerned about the CO2 being released by burning the Amazon than the oxygen consumed by the fire.
Additionally tectonic plates move, 55 million years ago the amazon probably wasn't even there. Additionally oil found on land could've been produced by biomass under the ocean and vice versa it's all moving around all the time. Likely the oil found underneath the amazon could have been produced at a time where that tectonic plate was under water.
This is confusing for many people, I know.
Ecosystems tend to increase its complexity with time. From lava field to savanna to forests. This is how it works. Life fills the gaps.
If untouched, forests aim for the higher state of organisation possible, the so called "climax": A big forest, with huge old trees. Plants accumulate water, big plants accumulate big water, plants make water also (Is a by-product of this respiration)...
...therefore the climax is a humid forest of some kind (a rainforest, a bamboo cloudforest, a laurisilva, a scottish caledonian rainforest, a sequoia forest)
A place full of spongy fungus and plants accumulating water, a place that creates its own climate and make rains that collect in streams and then in rivers for the people benefit. They do not need fire to work at all. Wildfires are scarce and self-contained events. Such places would need a lot of energy to start burning.
The young forest is vulnerable to fire. For decades the fire risk increases. This is that people remember, but sadly they do not see the second part. After a thousand years, the risk start decreasing and then the entire area is fire-proof. Wildfires stop often when reaching an old forest.
The tragedy is that before to reach this state of full healing, the forest is burned again BY MAN (>90% of wildfires are caused by man). Is called "necessary management" or "reducing the risk", but life does not need human management. Has evolved to sustain maximum amount of life possible. We need "Management" is another way to say we want "nature explotation". Is the "groundhog day" film with trees.
Nobody is trying to restore it and return the water to Mediterranean or to California because... it would need two or three human generations to show results and it would need much smarter humans.
There are also parts of this science that deal with the study of stress in ecosystems. A low or medium source of stress can increase the biodiversity. A mix of healed and degraded ecosystems can provide habitats for different types of life beings. A big source of stress otherwise will distroy all the job done by time and simplify the ecosystem. Moreover, the damage can be so deep that the new state of organisation enters in a loop. The remain is just too flammable to advance and the only species surviving benefit from fire so they need fire to keep competitors at bay, germinate and survive. And they make fire creating flammable structures. Fire triggers water quiting the area and will distroy soil organic structure. Without water the future of the area enters in a reverse path, to savanna, then arid, finally desert. Is happening in California for example.
For climate change figthing purposes, the closer to the ecological climax, the better chance for long-term human survivorship.
Climate change will actively distroy climactic ecosystems also (more hurricans, etc), so the problem is more complicated that "just stop chopping trees and damaging coral reefs with tourist cruises". We can expect a lot of problems and extinction cascades in the future.
To increase net oxygen levels in the atmosphere and reduce CO2 levels we would also have to eliminate a lot of the microorganisms that help recycle dead trees and go back to the Paleozoic era and before when these organisms didn't exist and the Earth witnessed several glaciation events.
Adding more stable forests to the world does not reduce CO2 levels or increase oxygen levels (relative to after it becomes a stable forest). It just speeds up the carbon cycle.
If trees sequester carbon in their trunks and release oxygen, what do they use the oxygen for at night, and how come they are oxygen-neutral, do they store it somehow?
Also, if the Amazon is a carbon sink today, what about if there was dieback? It would turn into a carbon source, but how? Don’t the “unit economics” of trees remain the same?
(Notes about the oversimpliplification: Wood is made of cellulose that is a carbohydrate and sugar is algo a carbohydrate, they are quite similar chemically. Also, plants produce and "burn" other compounds.)
“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.
Does the Amazon provide 20% of our oxygen?
is equivalent to
Does the Amazon remove 20% of our waste carbon dioxide?
The main part of the "lungs" of the planet is the phytoplankton in the sea.
Quote: "The Amazon Basin is critical to help mitigate climate change due to its trees absorbing around a quarter of the CO2 released each year from the burning of fossil fuels."
The specific quote is talking about trees in the rainforest, not the rainforest itself. The rainforest is an ecological system that also produces CO2 (mainly through microbes breaking down wood) and you can't ignore the rest of the system.
Which is not to say that the Amazon doesn't play a significant in the global environment and weather systems.
Though i have to admit to bring skeptical of his analysis that suggests the rainforest is a net zero on oxygen production.
But the article totally misses the issue of carbon capture.
Burning that carbon to CO2 requires oxygen, which will deplete the atmospheric reservoir to some degree.
Burning cellulose (poly-C6 H10 O5) to CO2 and H2O would require (for each molecule): 12O (for 6CO2) and 5O (for 5H2O). This is a total of 17O.
Cellulose contains only 5O, so 12O (or 6O2) would be required for a full stoichiometric burn of cellulose.