That is an interesting and surprisingly plausible pathway, given the apocalyptic title. Although, this will probably need a few rounds of peer review, some further research and a bit less science...
That is an interesting and surprisingly plausible pathway, given the apocalyptic title.
Although, this will probably need a few rounds of peer review, some further research and a bit less science communication to be credible. As in, there might be a lot of things interrupting that mechanism that we haven't thought much about yet that could interrupt it to our benefit. So let's do the science right. For once, it's not that urgent.
This result isn't exactly new -- I'm not sure what particularly differentiates this study, but similar predictions have been made before. In fact, just over a month ago I made a comment outlining...
This result isn't exactly new -- I'm not sure what particularly differentiates this study, but similar predictions have been made before. In fact, just over a month ago I made a comment outlining our apocalyptic future [1] (though I concentrated on CO2 levels instead of O2 levels, but they're obviously connected; in fact, the study in the OP explores disruptions to the carbonate-silicate cycle, which would be the catalyst for everything I described in my comment).
More on the nose, the Wikipedia article "Timeline of The Far Future" (probably my favorite Wikipedia article) has this to say regarding oxygen between 500-800 million years from now:
As Earth begins to rapidly warm and carbon dioxide levels fall, plants—and, by extension, animals—could survive longer by evolving other strategies such as requiring less carbon dioxide for photosynthetic processes, becoming carnivorous, adapting to desiccation, or associating with fungi. These adaptations are likely to appear near the beginning of the moist greenhouse. The death of most plant life will result in less oxygen in the atmosphere, allowing for more DNA-damaging ultraviolet radiation to reach the surface. The rising temperatures will increase chemical reactions in the atmosphere, further lowering oxygen levels. Flying animals would be better off because of their ability to travel large distances looking for cooler temperatures. Many animals may be driven to the poles or possibly underground. These creatures would become active during the polar night and aestivate during the polar day due to the intense heat and radiation. Much of the land would become a barren desert, and plants and animals would primarily be found in the oceans.
and this to say about oxygen a few hundred million years later:
Carbon dioxide levels fall to the point at which C4 photosynthesis is no longer possible. Without plant life to recycle oxygen in the atmosphere, free oxygen and the ozone layer will disappear from the atmosphere allowing for intense levels of deadly UV light to reach the surface. In the book The Life and Death of Planet Earth, authors Peter D. Ward and Donald Brownlee state that some animal life may be able to survive in the oceans. Eventually, however, all multicellular life will die out. At most, animal life could survive about 100 million years after plant life dies out, with the last animals being animals that do not depend on living plants such as termites or those near hydrothermal vents such as worms of the genus Riftia. The only life left on the Earth after this will be single-celled organisms.
Yes. Love it. I'm just saying, without even pretending to fully understand the geology involved here, that I find it hard to take such a prediction on faith. I'm not sure about the amount of peer...
the Wikipedia article "Timeline of The Far Future" (probably my favorite Wikipedia article)
Yes. Love it.
I'm just saying, without even pretending to fully understand the geology involved here, that I find it hard to take such a prediction on faith. I'm not sure about the amount of peer review that went into this, but with the general conditions of the situation (predicting a singular event 500 million years ahead of time that has not happened previously), I could easily see something about the prediction being wrong without us even knowing. Maybe some mechanism that will stabilise the carbonate-silicate cycle, maybe another cycle will pop up, I don't know. I just find it hard to believe that earth will become so rigorously uninhabitable just a relatively short while after humans/life pop up, and it's not because of said life, ya know? Kind of smells like self-sampling.
The tone in my first comment was a bit more combative than I'd like, so sorry about that. Still, I would push back against the narrative that this research is premature. Luckily I have access to...
The tone in my first comment was a bit more combative than I'd like, so sorry about that.
Still, I would push back against the narrative that this research is premature. Luckily I have access to the article through my university, so we can take a peak inside the article. From the introduction:
Previous work on the future lifespan of Earth’s biosphere has focused principally on the links between secular changes in solar luminosity, the stability of the carbonate–silicate geochemical cycle and the loss of surface water to space [16–20].
(Even without access, you can view the references here [1].) Notably, those references date from 1992, 1982, 2006, 2002, and 2013, suggesting this has been known for decades. Although I have admittedly no expertise here, I'd be willing to bet that "increasing solar luminosity will destabilize the carbonate-scilicate cycle" is an established fact in this field. The conclusion basically says as much:
In summary, our stochastic analysis suggests that the eventual deoxygenation of Earth’s atmosphere is a robust outcome of increasing solar luminosity, irrespective of large uncertainties in geophysical/biological boundary conditions [...]
Of course, you're correct that a billion years is a long time, and more generally there are unknown-unknowns that could disrupt our understanding of geoscience in unforeseen ways.
Fair enough. Was a cheap shot at a pop-sci article of my part to begin with. My thesis was less supposed to be "The science is wrong" but more "oh well, looks like we have a few million years to...
The tone in my first comment was a bit more combative than I'd like, so sorry about that.
Fair enough. Was a cheap shot at a pop-sci article of my part to begin with. My thesis was less supposed to be "The science is wrong" but more "oh well, looks like we have a few million years to make sure we did it right". That said, I do feel kind of strongly about science journalism because I think it's a) super important and b) seemingly no matter which scientist you talk to, science journalism gets that scientist's topic wrong, therefore gets every topic wrong.
To get back to my self-sampling point: I think it's curious that humanity decides to turn up after 500-1000 million years (Ma) of substantial amounts of oxygen in our atmosphere, only to find out that in another 500 Ma, the circumstances enabling human life would be gone. There is only about 500-1000 Ma worth of data on atmospheric oxygen, and we want to predict the future just as far? Also, with there only being 500 Ma years left to life on earth, that would mean that either we coincidentally showed up just before the effect that ends the world (carbonate-silicate cycle disruption) is noticable, or it is already noticable. If the latter, fair enough, but I don't really see it, I just see noise
On the other hand, ignoring any priors we might have for a moment, shouldn't we expect to be somewhere in the middle of an era where oxygen is plentiful? Wouldn't it be unusual for us to be near...
To get back to my self-sampling point: I think it's curious that humanity decides to turn up after 500-1000 million years (Ma) of substantial amounts of oxygen in our atmosphere, only to find out that in another 500 Ma, the circumstances enabling human life would be gone.
On the other hand, ignoring any priors we might have for a moment, shouldn't we expect to be somewhere in the middle of an era where oxygen is plentiful? Wouldn't it be unusual for us to be near one of the tails instead?
That is an interesting and surprisingly plausible pathway, given the apocalyptic title.
Although, this will probably need a few rounds of peer review, some further research and a bit less science communication to be credible. As in, there might be a lot of things interrupting that mechanism that we haven't thought much about yet that could interrupt it to our benefit. So let's do the science right. For once, it's not that urgent.
This result isn't exactly new -- I'm not sure what particularly differentiates this study, but similar predictions have been made before. In fact, just over a month ago I made a comment outlining our apocalyptic future [1] (though I concentrated on CO2 levels instead of O2 levels, but they're obviously connected; in fact, the study in the OP explores disruptions to the carbonate-silicate cycle, which would be the catalyst for everything I described in my comment).
More on the nose, the Wikipedia article "Timeline of The Far Future" (probably my favorite Wikipedia article) has this to say regarding oxygen between 500-800 million years from now:
and this to say about oxygen a few hundred million years later:
[1] (self-plug) https://tildes.net/~enviro/uun#comment-64tg
Yes. Love it.
I'm just saying, without even pretending to fully understand the geology involved here, that I find it hard to take such a prediction on faith. I'm not sure about the amount of peer review that went into this, but with the general conditions of the situation (predicting a singular event 500 million years ahead of time that has not happened previously), I could easily see something about the prediction being wrong without us even knowing. Maybe some mechanism that will stabilise the carbonate-silicate cycle, maybe another cycle will pop up, I don't know. I just find it hard to believe that earth will become so rigorously uninhabitable just a relatively short while after humans/life pop up, and it's not because of said life, ya know? Kind of smells like self-sampling.
The tone in my first comment was a bit more combative than I'd like, so sorry about that.
Still, I would push back against the narrative that this research is premature. Luckily I have access to the article through my university, so we can take a peak inside the article. From the introduction:
(Even without access, you can view the references here [1].) Notably, those references date from 1992, 1982, 2006, 2002, and 2013, suggesting this has been known for decades. Although I have admittedly no expertise here, I'd be willing to bet that "increasing solar luminosity will destabilize the carbonate-scilicate cycle" is an established fact in this field. The conclusion basically says as much:
Of course, you're correct that a billion years is a long time, and more generally there are unknown-unknowns that could disrupt our understanding of geoscience in unforeseen ways.
[1] https://www.nature.com/articles/s41561-021-00693-5#Bib1
Fair enough. Was a cheap shot at a pop-sci article of my part to begin with. My thesis was less supposed to be "The science is wrong" but more "oh well, looks like we have a few million years to make sure we did it right". That said, I do feel kind of strongly about science journalism because I think it's a) super important and b) seemingly no matter which scientist you talk to, science journalism gets that scientist's topic wrong, therefore gets every topic wrong.
To get back to my self-sampling point: I think it's curious that humanity decides to turn up after 500-1000 million years (Ma) of substantial amounts of oxygen in our atmosphere, only to find out that in another 500 Ma, the circumstances enabling human life would be gone. There is only about 500-1000 Ma worth of data on atmospheric oxygen, and we want to predict the future just as far? Also, with there only being 500 Ma years left to life on earth, that would mean that either we coincidentally showed up just before the effect that ends the world (carbonate-silicate cycle disruption) is noticable, or it is already noticable. If the latter, fair enough, but I don't really see it, I just see noise
On the other hand, ignoring any priors we might have for a moment, shouldn't we expect to be somewhere in the middle of an era where oxygen is plentiful? Wouldn't it be unusual for us to be near one of the tails instead?