4 ms·

> Over 75% of life on earth is behind us (4.2bn years) What do you mean by this? Are you predicting that life on earth can only last for another 1.4 billion ye

> Over 75% of life on earth is behind us (4.2bn years) What do you mean by this? Are you predicting that life on earth can only last for another 1.4 billion years? What extinction event is so certain in the next 400m-800m years?

r3trohack3r 4y ago
Less than 1.4Bn. AFAIK the carbon cycle grinds to a halt in 400M-800M years: https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future
- deleted 4y ago
  [deleted]
- Rury 4y ago
  That whole thing is highly dubious, and reads like a slippery slope argument. Like one, there's a limit on how much water can exist as vapor in our atmosphere, (which is far, far less than what the earth's oceans hold), up until the point of boiling. This is conventionally known known as the saturation point, which is 100% relative humidity. Anytime you try to go above this limit, forces the water to condense and drop down back to the oceans as liquid. So the oceans aren't going to evaporate out to being dry like it predicts unless global temperatures rise by an extreme amount - quite likely requiring boiling temperatures, but in any case, extreme enough that life would likely be dead from the temperature alone. So its subsequent reasoning on how photosynthesis and life ends is not likely how it will play out. Additionally, it ignores that CO2 is made by animals, and O2 is made by plants, and therefore, the entire possibility of having a natural carbon cycle without volcanism. Never mind the fact that we currently have climate change tech that produces CO2 already, and if we survive that long, could easily prevent photosynthesis from ending in such a way.
galangalalgol 4y ago
The increased output of the growing sun will (ironically) sequester all the co2 due to weathering processes of certain rocks. Then there will be no plants. It won't take long after that.
- twoodfin 4y ago
  There isn’t that much CO2 in the atmosphere. This is obviously a WAG, but I’d suppose that the planet-scale geoengineering required to maintain plant-friendly CO2 levels in that changed solar environment would be at least as feasible as developing a sustainable, coherent interstellar civilization.
  - XorNot 4y ago
    See this great article of wikipedia[1] (warning: potentially depressing). The problem is that it's not just one problem, it's a whole bundle of them happening simultaneously. It's not just that CO2 is being taken out of the atmosphere and into rocks, it's that the oceans are evaporating entirely at the same time. Though you are quite right that this is potentially solvable for us: lagrange point sunshields to manage solar incidence would buy us a lot of extra time. But it's still hundreds of millions of years - not billions. 500 million years from now, we're fighting a losing battle against the sun's death. [1] https://en.wikipedia.org/wiki/Timeline_of_the_far_future https://en.wikipedia.org/wiki/Timeline_of_the_far_future
    - 867-5309 4y ago
      sorry, but in a millennium or two we will possess the technology to travel at an appreciable percentage of the speed of light in the next million years (let alone hundreds) humans will have populated most of the galaxy that is, if we survive climate change
      - Andrew_nenakhov 4y ago
        There is an absolute certainty that climate change will not make human race extinct. If we die out, it'll be because of some other disaster.
        Tagbert 4y ago
        The largest risk to humans of climate change is the stress it will put on civilizations and the potential for war from that. If that stress triggered an all out nuclear war, it could make humans extinct.
dheera 4y ago
The sun will be 10% brighter in 1 billion years, which is enough to evaporate all the oceans. Life will be gone MUCH earlier than that, unless we can terraform the Earth to not contain all that heat. And that's without any human-created CO2.

r3trohack3r 4y ago

Less than 1.4Bn. AFAIK the carbon cycle grinds to a halt in 400M-800M years: https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future

deleted 4y ago
[deleted]
Rury 4y ago
That whole thing is highly dubious, and reads like a slippery slope argument. Like one, there's a limit on how much water can exist as vapor in our atmosphere, (which is far, far less than what the earth's oceans hold), up until the point of boiling. This is conventionally known known as the saturation point, which is 100% relative humidity. Anytime you try to go above this limit, forces the water to condense and drop down back to the oceans as liquid. So the oceans aren't going to evaporate out to being dry like it predicts unless global temperatures rise by an extreme amount - quite likely requiring boiling temperatures, but in any case, extreme enough that life would likely be dead from the temperature alone. So its subsequent reasoning on how photosynthesis and life ends is not likely how it will play out. Additionally, it ignores that CO2 is made by animals, and O2 is made by plants, and therefore, the entire possibility of having a natural carbon cycle without volcanism. Never mind the fact that we currently have climate change tech that produces CO2 already, and if we survive that long, could easily prevent photosynthesis from ending in such a way.

galangalalgol 4y ago

The increased output of the growing sun will (ironically) sequester all the co2 due to weathering processes of certain rocks. Then there will be no plants. It won't take long after that.

twoodfin 4y ago
There isn’t that much CO2 in the atmosphere. This is obviously a WAG, but I’d suppose that the planet-scale geoengineering required to maintain plant-friendly CO2 levels in that changed solar environment would be at least as feasible as developing a sustainable, coherent interstellar civilization.
- XorNot 4y ago
  See this great article of wikipedia[1] (warning: potentially depressing). The problem is that it's not just one problem, it's a whole bundle of them happening simultaneously. It's not just that CO2 is being taken out of the atmosphere and into rocks, it's that the oceans are evaporating entirely at the same time. Though you are quite right that this is potentially solvable for us: lagrange point sunshields to manage solar incidence would buy us a lot of extra time. But it's still hundreds of millions of years - not billions. 500 million years from now, we're fighting a losing battle against the sun's death. [1] https://en.wikipedia.org/wiki/Timeline_of_the_far_future https://en.wikipedia.org/wiki/Timeline_of_the_far_future
  - 867-5309 4y ago
    sorry, but in a millennium or two we will possess the technology to travel at an appreciable percentage of the speed of light in the next million years (let alone hundreds) humans will have populated most of the galaxy that is, if we survive climate change
    - Andrew_nenakhov 4y ago
      There is an absolute certainty that climate change will not make human race extinct. If we die out, it'll be because of some other disaster.
      - Tagbert 4y ago
        The largest risk to humans of climate change is the stress it will put on civilizations and the potential for war from that. If that stress triggered an all out nuclear war, it could make humans extinct.

dheera 4y ago

The sun will be 10% brighter in 1 billion years, which is enough to evaporate all the oceans. Life will be gone MUCH earlier than that, unless we can terraform the Earth to not contain all that heat. And that's without any human-created CO2.