3 ms·

It's basically too late to stay under 1.5 by just cutting emissions. By the time we do eliminate emissions, we're going to need air capture already scaling up.

It's basically too late to stay under 1.5 by just cutting emissions. By the time we do eliminate emissions, we're going to need air capture already scaling up. Fortunately, it's possible for civilization to do more than one thing at a time.

Zigurd 4y ago
Some sequences of events make sense: It is not possible to benefit from direct carbon capture cleanly before dirty energy sources are replaced. It would just add to the problem, mainly in the carbon cost of building appropriate energy sources for capture. No free lunch. In this case doing "more than one thing at a time" amounts to trying to have one's cake while feeling good about baking it with coal-generated electricity.
blueflow 4y ago
Its not emissions that are the problem, its the extra carbon that we dig out and insert it into the existing capture - emissions cycle. And since no technologies exist that can do permanent recapture to undo that at a useful scale (and probably never will because its a conservation of energy problem), its a debt we'll never be able to pay back.
- worldsayshi 4y ago
  It should be possible if we gain access to "almost infinite" energy right? It would be absurd to assume it but if we really get fusion energy going and then if we get serious cost reductions in space based solar. Sure it's all (hard) science fiction but I feel like we're giving up on realistic near term solutions anyway.
  - mrguyorama 4y ago
    As long as electricity generation is a profit making endeavor, it doesn't matter what the source is, generating companies will never build enough of it to significantly drop costs. "Energy too cheap to meter" was always a lie. Capitalism always makes it more profitable to make too little of something rather than too much.
- krisoft 4y ago
  > probably never will because its a conservation of energy problem But we have this gravitationally contained fusion reactor in the neighbourhood literally radiating energy at us. (I'm talking about the sun, if it is not clear.) That is the thing which powered the previous capture. How would it be impossible to do it again? (I'm not talking about "practical" or "fast" those are questions after we established that it is possible, which it seems we disagree on.)
  - Avicebron 4y ago
    If you're referring to planting more biomatter, I fully agree it's not impossible, I think the sticking point really is the scale, can we theoretically leverage this to capture at a rate that matters while simultaneously not giving up our current lifestyles. ( I think the main crux of these solutions imply this even if they don't deliberately state it, the solution has to not impact people's lives "negatively' to be viable).
  - blueflow 4y ago
    The question is the scale. How much space do you need for plants to capture a gigaton of carbon? Does earth even have that much suitable surface? And how do you put it into the ground so it can't decay and be re-processed into carbon dioxide?
    - krisoft 4y ago
      > The question is the scale. Ok, but that means the question is not the energy balance. That is my whole point. > How much space do you need for plants to capture a gigaton of carbon? Plants are only one of the possibilities. All I am arguing is that it is not impossible on account of the principle of energy conservation. Not arguing how easy or hard it is. > Does earth even have that much suitable surface? Of course. It happened once.
      - blueflow 4y ago
        I know where you are going, but human technology is energy intensive, wasteful and won't save us.
- DennisP 4y ago
  We can't turn CO2 back into fuel without an input of energy, but we can store CO2 for the long term without turning it back into fuel. For example, we can pump it into deep basalt formations, where it will turn into rock. And of course when we do want to turn CO2 into hydrocarbons we can use solar and nuclear energy sources, in which case the hydrocarbons play the role of a battery rather than primary energy source. We can also use non-fossil energy to concentrate CO2 from the air; in theory at least that takes quite a bit less energy than hydrocarbons release when burned.
slashdev 4y ago
Staying under 1.5 is a fantasy. If we want to stay under 3 we’d better get some real effort behind ending coal as soon as possible. While it is possible to do more than one thing at a time, our politicians are trying to plug a leak while ignoring a giant gaping hole just around the corner. It’s like they’re incompetent morons or something.
- bryanlarsen 4y ago
  OTOH, I used to have lots of people tell me that it would be almost impossible to stay under 5 degrees of warming. Landing at about 3 degrees of warming is substantially better than many of the scenarios laid out in the past. I'm still optimistic we can stay below 2 degrees of warming.
- DennisP 4y ago
  We absolutely should end coal as soon as possible, along with oil and natural gas. We should also develop and scale methods for pulling CO2 back out of the atmosphere. Just ending emissions avoids the worst outcomes but still leaves us with a bad outcome. If politicians were not incompetent morons then we could have solved the problem a lot sooner without having to pull CO2 back out of the air, but here we are. Also, there are some applications, like long-haul jets, that will be very difficult to electrify, and DAC gives us a way to make liquid hydrocarbons for them without any net emissions. Biofuel is another way in theory, but not always in practice, and it takes a lot more land area.

Zigurd 4y ago

Some sequences of events make sense: It is not possible to benefit from direct carbon capture cleanly before dirty energy sources are replaced. It would just add to the problem, mainly in the carbon cost of building appropriate energy sources for capture. No free lunch. In this case doing "more than one thing at a time" amounts to trying to have one's cake while feeling good about baking it with coal-generated electricity.

blueflow 4y ago

Its not emissions that are the problem, its the extra carbon that we dig out and insert it into the existing capture - emissions cycle. And since no technologies exist that can do permanent recapture to undo that at a useful scale (and probably never will because its a conservation of energy problem), its a debt we'll never be able to pay back.

worldsayshi 4y ago
It should be possible if we gain access to "almost infinite" energy right? It would be absurd to assume it but if we really get fusion energy going and then if we get serious cost reductions in space based solar. Sure it's all (hard) science fiction but I feel like we're giving up on realistic near term solutions anyway.
- mrguyorama 4y ago
  As long as electricity generation is a profit making endeavor, it doesn't matter what the source is, generating companies will never build enough of it to significantly drop costs. "Energy too cheap to meter" was always a lie. Capitalism always makes it more profitable to make too little of something rather than too much.
krisoft 4y ago
> probably never will because its a conservation of energy problem But we have this gravitationally contained fusion reactor in the neighbourhood literally radiating energy at us. (I'm talking about the sun, if it is not clear.) That is the thing which powered the previous capture. How would it be impossible to do it again? (I'm not talking about "practical" or "fast" those are questions after we established that it is possible, which it seems we disagree on.)
- Avicebron 4y ago
  If you're referring to planting more biomatter, I fully agree it's not impossible, I think the sticking point really is the scale, can we theoretically leverage this to capture at a rate that matters while simultaneously not giving up our current lifestyles. ( I think the main crux of these solutions imply this even if they don't deliberately state it, the solution has to not impact people's lives "negatively' to be viable).
- blueflow 4y ago
  The question is the scale. How much space do you need for plants to capture a gigaton of carbon? Does earth even have that much suitable surface? And how do you put it into the ground so it can't decay and be re-processed into carbon dioxide?
  - krisoft 4y ago
    > The question is the scale. Ok, but that means the question is not the energy balance. That is my whole point. > How much space do you need for plants to capture a gigaton of carbon? Plants are only one of the possibilities. All I am arguing is that it is not impossible on account of the principle of energy conservation. Not arguing how easy or hard it is. > Does earth even have that much suitable surface? Of course. It happened once.
    - blueflow 4y ago
      I know where you are going, but human technology is energy intensive, wasteful and won't save us.
DennisP 4y ago
We can't turn CO2 back into fuel without an input of energy, but we can store CO2 for the long term without turning it back into fuel. For example, we can pump it into deep basalt formations, where it will turn into rock. And of course when we do want to turn CO2 into hydrocarbons we can use solar and nuclear energy sources, in which case the hydrocarbons play the role of a battery rather than primary energy source. We can also use non-fossil energy to concentrate CO2 from the air; in theory at least that takes quite a bit less energy than hydrocarbons release when burned.

slashdev 4y ago

Staying under 1.5 is a fantasy. If we want to stay under 3 we’d better get some real effort behind ending coal as soon as possible. While it is possible to do more than one thing at a time, our politicians are trying to plug a leak while ignoring a giant gaping hole just around the corner. It’s like they’re incompetent morons or something.

bryanlarsen 4y ago
OTOH, I used to have lots of people tell me that it would be almost impossible to stay under 5 degrees of warming. Landing at about 3 degrees of warming is substantially better than many of the scenarios laid out in the past. I'm still optimistic we can stay below 2 degrees of warming.
DennisP 4y ago
We absolutely should end coal as soon as possible, along with oil and natural gas. We should also develop and scale methods for pulling CO2 back out of the atmosphere. Just ending emissions avoids the worst outcomes but still leaves us with a bad outcome. If politicians were not incompetent morons then we could have solved the problem a lot sooner without having to pull CO2 back out of the air, but here we are. Also, there are some applications, like long-haul jets, that will be very difficult to electrify, and DAC gives us a way to make liquid hydrocarbons for them without any net emissions. Biofuel is another way in theory, but not always in practice, and it takes a lot more land area.