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Another similar myth is that the air we breathe comes from trees. 2/3 of the air we breath also comes from plankton. Trees are mostly net zero in regards to o

Another similar myth is that the air we breathe comes from trees. 2/3 of the air we breath also comes from plankton. Trees are mostly net zero in regards to oxygen. What they release during their lifetime they take back when they die and decay.

bnegreve 5y ago
If by air you mean (di)oxygen, it kinda does come from the plants, but prehistoric ones rather than modern ones. E.g. see [1] "The growth of these forests removed huge amounts of carbon dioxide from the atmosphere, leading to a surplus of oxygen." [1] https://www.nationalgeographic.com/science/article/carboniferous https://www.nationalgeographic.com/science/article/carbonife...
- pfdietz 5y ago
  The timescale for O2 to be stripped from the atmosphere (by reaction with reduced chemicals exposed by erosion, weathering, and emitted from volcanoes) is only about 10 million years, so the current composition of the atmosphere is due to recent conditions, not ancient conditions. There is an open question of why atmospheric O2 has been relatively stable (varied by a factor of several) in the Phanerozoic. This may just be anthropic selection: if it ever fell too far, higher life would have been wiped out, and we wouldn't be here. This has implications for the existence of extraterrestrial intelligence: it might be that most life-bearing worlds suffocate themselves before ETs can evolve.
  - bnegreve 5y ago
    Hum, I'd like to read more about this. I find hard to believe that the current atmospheric conditions are completely unrelated to the rise of oxygen attributed to photosynthesis, and that they can only be explained by anthropic selection (which is always a possible explanation anyway).
    - pfdietz 5y ago
      Oxygen has cycled many times through the crust and back out again since the GOE (or even since the Neoproterozoic Oxygenation Event) so I don't see why you think any sort of "memory" of those ancient events would remain in the system.
      - bnegreve 5y ago
        Ok, I'm not saying that the exact same molecules of O2 from the GOE were preserved until today, rather that the presence of O2 in the atmosphere is related to the emergence of plants and photosynthesis. This is what I meant by "O2 comes from prehistoric plants". For the record, the "memory" if you want to call it like this, would be the (unoxidized) carbon buried underground and/or segregated in the plants body.
        pfdietz 5y ago
        There is unoxidized carbon buried underground, but the bulk of the Earth has vastly more reducing capacity than relatively piddling amounts of buried organic carbon. Fully oxidized, the Earth could consume orders of magnitude more oxygen than exists in the atmosphere. Simply oxidizing all the minerals in the crust down to a couple of hundred meters would use all the atmosphere's O2, and then there's thousands of kilometers of mantle loaded with ferrous iron and sulfides, and then the iron core.
        bnegreve 5y ago
        I see, it's actually a bit scary. But if oxidation doesn't happen fast enough (no matter why) the O2 surplus can still be explained somewhat indirectly by the emergence of photosynthesis billions years ago. Or maybe by something else. Anyway, I finally got your point, interesting.
        pfdietz 5y ago
        The atmosphere is like a leaky boat. Oxygen leaks out when rocks are eroded and weathered and when volcanoes release reduced gases, and burial of photosynthesized material pumps it back in. The troubling part is that there's no obvious reason why these two processes have to be balanced over periods much longer than the time constant of the system.
TheFreim 5y ago
All of these myths I learned in school make me think it was an even bigger waste of time than I originally though.
- rabuse 5y ago
  Our public education in the U.S. is a travesty. There's really no incentive to remain up-to-date on information, and it seems to be getting worse.
  - mncharity 5y ago
    An educator suggests[1], in the context of preK science education, that students have a human right to make sense of their world "now". That's very not the focus of current science education content. PreK-13. But what if were? What might that look like? Status quo is students being told the Sun is yellow, from preK on through to the most common intro astronomy college textbooks, with only a few of them getting an "oops, nope, our bad" decades later, in astronomy graduate school discussion of common misconceptions in astronomy education. We've known Sun color for a century, had detailed limb darkening and tint numbers for decades, and now years of intensive effort on stellar atmospheres in support of occultation and exoplanet work. Also years of hemispherical-camera daytime-sky surveys. And science education content manages to remain decoupled from all of that. A startup pivoted from supporting learning of English in Japan, because the market there turned out to be for performance on English proficiency exams, not for English fluency. And a teacher remarked that it seemed the societal objective was English accessibility for work, while avoiding the fluency which could contaminate culture. Similarly, an truly excellent briefing on biology would necessarily be pervasively steeped in evolution... and thus be less than entirely welcome in the US. Not that Europe or Russia, or China, India, or Brasil, have incentivized its creation either. It seems neither the science research nor science education communities are set up to pursue it. [1] https://scholar.google.com/scholar?q=Larimore+Vision+2020 https://scholar.google.com/scholar?q=Larimore+Vision+2020
- ptr2voidStar 5y ago
  This is precisely my thoughts, as I scroll through the comments - jaw on the floor.
tomtomtom777 5y ago
I think it's a bit odd to call this "net zero". If there are more trees, there's more oxygen. Sure, if a tree dies this is eventually reverted but it also makes room for a new tree (unless humanity claims the land).
ptr2voidStar 5y ago
Has anyone bothered to point this out to tree huggers out there? Some citations on this would be very powerful antidote to the misinformation out there. I'm speechless

bnegreve 5y ago

If by air you mean (di)oxygen, it kinda does come from the plants, but prehistoric ones rather than modern ones. E.g. see [1] "The growth of these forests removed huge amounts of carbon dioxide from the atmosphere, leading to a surplus of oxygen." [1] https://www.nationalgeographic.com/science/article/carboniferous https://www.nationalgeographic.com/science/article/carbonife...

pfdietz 5y ago
The timescale for O2 to be stripped from the atmosphere (by reaction with reduced chemicals exposed by erosion, weathering, and emitted from volcanoes) is only about 10 million years, so the current composition of the atmosphere is due to recent conditions, not ancient conditions. There is an open question of why atmospheric O2 has been relatively stable (varied by a factor of several) in the Phanerozoic. This may just be anthropic selection: if it ever fell too far, higher life would have been wiped out, and we wouldn't be here. This has implications for the existence of extraterrestrial intelligence: it might be that most life-bearing worlds suffocate themselves before ETs can evolve.
- bnegreve 5y ago
  Hum, I'd like to read more about this. I find hard to believe that the current atmospheric conditions are completely unrelated to the rise of oxygen attributed to photosynthesis, and that they can only be explained by anthropic selection (which is always a possible explanation anyway).
  - pfdietz 5y ago
    Oxygen has cycled many times through the crust and back out again since the GOE (or even since the Neoproterozoic Oxygenation Event) so I don't see why you think any sort of "memory" of those ancient events would remain in the system.
    - bnegreve 5y ago
      Ok, I'm not saying that the exact same molecules of O2 from the GOE were preserved until today, rather that the presence of O2 in the atmosphere is related to the emergence of plants and photosynthesis. This is what I meant by "O2 comes from prehistoric plants". For the record, the "memory" if you want to call it like this, would be the (unoxidized) carbon buried underground and/or segregated in the plants body.
      - pfdietz 5y ago
        There is unoxidized carbon buried underground, but the bulk of the Earth has vastly more reducing capacity than relatively piddling amounts of buried organic carbon. Fully oxidized, the Earth could consume orders of magnitude more oxygen than exists in the atmosphere. Simply oxidizing all the minerals in the crust down to a couple of hundred meters would use all the atmosphere's O2, and then there's thousands of kilometers of mantle loaded with ferrous iron and sulfides, and then the iron core.
        bnegreve 5y ago
        I see, it's actually a bit scary. But if oxidation doesn't happen fast enough (no matter why) the O2 surplus can still be explained somewhat indirectly by the emergence of photosynthesis billions years ago. Or maybe by something else. Anyway, I finally got your point, interesting.
        pfdietz 5y ago
        The atmosphere is like a leaky boat. Oxygen leaks out when rocks are eroded and weathered and when volcanoes release reduced gases, and burial of photosynthesized material pumps it back in. The troubling part is that there's no obvious reason why these two processes have to be balanced over periods much longer than the time constant of the system.

TheFreim 5y ago

All of these myths I learned in school make me think it was an even bigger waste of time than I originally though.

rabuse 5y ago
Our public education in the U.S. is a travesty. There's really no incentive to remain up-to-date on information, and it seems to be getting worse.
- mncharity 5y ago
  An educator suggests[1], in the context of preK science education, that students have a human right to make sense of their world "now". That's very not the focus of current science education content. PreK-13. But what if were? What might that look like? Status quo is students being told the Sun is yellow, from preK on through to the most common intro astronomy college textbooks, with only a few of them getting an "oops, nope, our bad" decades later, in astronomy graduate school discussion of common misconceptions in astronomy education. We've known Sun color for a century, had detailed limb darkening and tint numbers for decades, and now years of intensive effort on stellar atmospheres in support of occultation and exoplanet work. Also years of hemispherical-camera daytime-sky surveys. And science education content manages to remain decoupled from all of that. A startup pivoted from supporting learning of English in Japan, because the market there turned out to be for performance on English proficiency exams, not for English fluency. And a teacher remarked that it seemed the societal objective was English accessibility for work, while avoiding the fluency which could contaminate culture. Similarly, an truly excellent briefing on biology would necessarily be pervasively steeped in evolution... and thus be less than entirely welcome in the US. Not that Europe or Russia, or China, India, or Brasil, have incentivized its creation either. It seems neither the science research nor science education communities are set up to pursue it. [1] https://scholar.google.com/scholar?q=Larimore+Vision+2020 https://scholar.google.com/scholar?q=Larimore+Vision+2020
ptr2voidStar 5y ago
This is precisely my thoughts, as I scroll through the comments - jaw on the floor.

tomtomtom777 5y ago

I think it's a bit odd to call this "net zero". If there are more trees, there's more oxygen. Sure, if a tree dies this is eventually reverted but it also makes room for a new tree (unless humanity claims the land).

ptr2voidStar 5y ago

Has anyone bothered to point this out to tree huggers out there? Some citations on this would be very powerful antidote to the misinformation out there. I'm speechless