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> Relying on carbon dioxide removal and so-called negative emissions technologies to lower greenhouse gases in the atmosphere over several decades is too risky

> Relying on carbon dioxide removal and so-called negative emissions technologies to lower greenhouse gases in the atmosphere over several decades is too risky to contemplate. Author is saying to not even think about all solutions? Unprompted, on a post ostensibly sharing research findings? Sounds a bit dogmatic and politically motivated. I don’t trust their results.

thrown_22 4y ago
The energy budget needed for CO2 removal makes all our energy consumption done to this point a rounding error.
- twawaaay 4y ago
  There are possibilities for removal mechanisms that do not require proportionate input in energy directly. For example, you could perfect growing algae and let the algae extract energy from sunlight on its own. We would just have to ensure good transfer of CO2 from atmosphere to water. Another I have seen is crushing rock -- as silicate is weathering it will naturally extract CO2 and the question is how efficiently you can powder rock. Another possible solution would be finding a process that will remove CO2 as a byproduct. If you have to put a lot of energy into it, at least get some part of it back.
  - mjhay 4y ago
    You're describing small systems being scaled up millions of times. It reminds me of the doomed and misguided Ocean Cleanup Project. Where would you grow all this algae? It would take a great deal of area (easily multiple thousands of square miles) because it relies on photosynthesis. You can't build it at sea, because it would be destroyed be storms. The crushing rock works very slowly - that part of the carbon cycle takes ages. Any significant speedup of that would also be an environmental disaster - again too much rock crushing, and it would have to be spread over large areas. Even worse, this will all need to be done in an already deteriorated planet, with almost assuredly worse political stability and real economic output than we have now.
    - twawaaay 4y ago
      > You're describing small systems being scaled up millions of times. What you are describing is how technological progress works usually. We first typically learn to do something at small scale, then learn to solve problems that are necessary to scale it up. The problem isn't really whether we can do it but whether we can get people to be willing to do it. > The crushing rock works very slowly Yes, it does. But once you crush the rock the rest happens on its own while you are crushing even more of it. Which means after some time the removal will asymptotically reach the speed at which you are able to crush the rock (and supply the air).
      - mjhay 4y ago
        I don't think you are grasping the full, physical scale here. This is a lot of CO2, and you need a lot of crushed rock. This is not like integrated circuits or anything - it would be an enormous heavy industrial operation the likes of which the world has never seen. The main problems aren't really even technological - but economic, physical, and ecological. This isn't an area where Silicon Valley can invent some magic silver hammer that they always think is around the corner.
        twawaaay 4y ago
        I did not say crushed rock is the solution. I just used it as an example that solution may not require us to supply the amount energy from the grid that we would normally get from emitting the CO2 in the first place. Also, I think you are just flat wrong about how unprecedented this operation would be. Digging oil and coal from under the sea or thousands of meters below ground is certainly more difficult than crushing rock that is readily available on the surface basically everywhere. I think the bigger issue is figuring out what to do with that crushed rock so that it has contact with air so that it can actually perform the reactions we want (this might not be solvable). We can use crushed rock to some extent. For example, I use powdered basalt in my garden. It improves the soil and provides nutrients over long periods of time. But I think we would quickly run out of agricultural soil to fertilise this way.
  - thrown_22 4y ago
    >For example, you could perfect growing algae and let the algae extract energy from sunlight on its own Yes, we only need to produce more fertilizer than we ever have and keep doing that year on year forever. >as silicate is weathering it will naturally extract CO2 and the question is how efficiently you can powder rock. We only need to mine an Everest worth of stone each year for a millennium or so. Yes. Such achievable goals. The only ones that come close to being reasonable is dispersing aerosols in the upper atmosphere and reducing the sunlight that reaches the ground directly. That has the problem that we need sunlight for such pesky things like photosynthesis.
mjhay 4y ago
"Negative-emissions" carbon-capture technologies have essentially intractable problems scaling up, including basic thermodynamics; that isn't even talking about the massive resource inputs to build a system capable of meaningfully reducing CO2. It's a lot easier to to not emit as much in the first place. Even barring these severe problems, the precautionary principle is the right thing to apply here. If "negative emission" tech has even a 90% chance of working, we still should focus on reducing emissions, because that tail risk is bad. It's like why people have fire insurance even though most people's houses never catch on fire.
11235813213455 4y ago
the solutions are not technological, they are just about people reducing each drastically their footprint, and creating more natural super efficient carbon sinks, also called forests, permacultures, and more vegetation overall
- 11235813213455 4y ago
  I expected downvotes in a place where Elon Musk must be considered a god / savior against global warming (while cars with 500kg of batteries can't certainly be a good idea) but that's still the truth that someone highly knowledgable like https://en.wikipedia.org/wiki/Jean-Marc_Jancovici https://en.wikipedia.org/wiki/Jean-Marc_Jancovici would explain in more details, there are many aspects, not just carbon
potsandpans 4y ago
and what are your qualifications?
THENATHE 4y ago
If this, hypothetically, isn’t the solution, then what is? It is literally not possible to get everyone to stop emissions. If reducing emissions by planting trees and building carbon banks isn’t enough, will anything be enough? Seems kinda fatalist to just say “ah, we’re fucked”
deleted 4y ago
[deleted]

thrown_22 4y ago

The energy budget needed for CO2 removal makes all our energy consumption done to this point a rounding error.

twawaaay 4y ago
There are possibilities for removal mechanisms that do not require proportionate input in energy directly. For example, you could perfect growing algae and let the algae extract energy from sunlight on its own. We would just have to ensure good transfer of CO2 from atmosphere to water. Another I have seen is crushing rock -- as silicate is weathering it will naturally extract CO2 and the question is how efficiently you can powder rock. Another possible solution would be finding a process that will remove CO2 as a byproduct. If you have to put a lot of energy into it, at least get some part of it back.
- mjhay 4y ago
  You're describing small systems being scaled up millions of times. It reminds me of the doomed and misguided Ocean Cleanup Project. Where would you grow all this algae? It would take a great deal of area (easily multiple thousands of square miles) because it relies on photosynthesis. You can't build it at sea, because it would be destroyed be storms. The crushing rock works very slowly - that part of the carbon cycle takes ages. Any significant speedup of that would also be an environmental disaster - again too much rock crushing, and it would have to be spread over large areas. Even worse, this will all need to be done in an already deteriorated planet, with almost assuredly worse political stability and real economic output than we have now.
  - twawaaay 4y ago
    > You're describing small systems being scaled up millions of times. What you are describing is how technological progress works usually. We first typically learn to do something at small scale, then learn to solve problems that are necessary to scale it up. The problem isn't really whether we can do it but whether we can get people to be willing to do it. > The crushing rock works very slowly Yes, it does. But once you crush the rock the rest happens on its own while you are crushing even more of it. Which means after some time the removal will asymptotically reach the speed at which you are able to crush the rock (and supply the air).
    - mjhay 4y ago
      I don't think you are grasping the full, physical scale here. This is a lot of CO2, and you need a lot of crushed rock. This is not like integrated circuits or anything - it would be an enormous heavy industrial operation the likes of which the world has never seen. The main problems aren't really even technological - but economic, physical, and ecological. This isn't an area where Silicon Valley can invent some magic silver hammer that they always think is around the corner.
      - twawaaay 4y ago
        I did not say crushed rock is the solution. I just used it as an example that solution may not require us to supply the amount energy from the grid that we would normally get from emitting the CO2 in the first place. Also, I think you are just flat wrong about how unprecedented this operation would be. Digging oil and coal from under the sea or thousands of meters below ground is certainly more difficult than crushing rock that is readily available on the surface basically everywhere. I think the bigger issue is figuring out what to do with that crushed rock so that it has contact with air so that it can actually perform the reactions we want (this might not be solvable). We can use crushed rock to some extent. For example, I use powdered basalt in my garden. It improves the soil and provides nutrients over long periods of time. But I think we would quickly run out of agricultural soil to fertilise this way.
- thrown_22 4y ago
  >For example, you could perfect growing algae and let the algae extract energy from sunlight on its own Yes, we only need to produce more fertilizer than we ever have and keep doing that year on year forever. >as silicate is weathering it will naturally extract CO2 and the question is how efficiently you can powder rock. We only need to mine an Everest worth of stone each year for a millennium or so. Yes. Such achievable goals. The only ones that come close to being reasonable is dispersing aerosols in the upper atmosphere and reducing the sunlight that reaches the ground directly. That has the problem that we need sunlight for such pesky things like photosynthesis.

mjhay 4y ago

"Negative-emissions" carbon-capture technologies have essentially intractable problems scaling up, including basic thermodynamics; that isn't even talking about the massive resource inputs to build a system capable of meaningfully reducing CO2. It's a lot easier to to not emit as much in the first place. Even barring these severe problems, the precautionary principle is the right thing to apply here. If "negative emission" tech has even a 90% chance of working, we still should focus on reducing emissions, because that tail risk is bad. It's like why people have fire insurance even though most people's houses never catch on fire.

11235813213455 4y ago

the solutions are not technological, they are just about people reducing each drastically their footprint, and creating more natural super efficient carbon sinks, also called forests, permacultures, and more vegetation overall

11235813213455 4y ago
I expected downvotes in a place where Elon Musk must be considered a god / savior against global warming (while cars with 500kg of batteries can't certainly be a good idea) but that's still the truth that someone highly knowledgable like https://en.wikipedia.org/wiki/Jean-Marc_Jancovici https://en.wikipedia.org/wiki/Jean-Marc_Jancovici would explain in more details, there are many aspects, not just carbon

potsandpans 4y ago

and what are your qualifications?

THENATHE 4y ago

If this, hypothetically, isn’t the solution, then what is? It is literally not possible to get everyone to stop emissions. If reducing emissions by planting trees and building carbon banks isn’t enough, will anything be enough? Seems kinda fatalist to just say “ah, we’re fucked”

deleted 4y ago

[deleted]