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> Are we really supposed to expend as much energy as we expended in the entire industrial age just to remove the excess CO2 in the atmosphere? Basically, yeah!

> Are we really supposed to expend as much energy as we expended in the entire industrial age just to remove the excess CO2 in the atmosphere? Basically, yeah! The last IPCC described the need for carbon removal in their last report[1]. The gist of it is that we'll need to decarbonize virtually everything, and use removal for the last 5-10% of residual emissions. That ends up being like six billion tons per year by 2025. [1] https://www.ipcc.ch/sr15/faq/faq-chapter-4/ https://www.ipcc.ch/sr15/faq/faq-chapter-4/

rhelz 3y ago
But....I mean, for that 5-10%, we have to spend MORE THAN DOUBLE the energy we get from burning carbon....wouldn't we just be better of not burning the carbon? It doesn't compute. I mean, you get my point, right? That 5-10%, supposedly we couldn't get it from some renewable source....we could only get it from burning fossils fuels. So where is the energy going to come from to suck the CO2 back out of the air again? By hypothesis, we didn't have any more renewable energy to use. But you can't clean the air by burning fossils fuels--thermodynamics says that you will always release more C02 than you could recapture.
- graeme 3y ago
  You’re correct, but: 1. Just stopping burning carbon isn’t enough. We need to take the existing excess carbon from the atmosphere. 2. It would be rational to move on an emergency basis to renewables + nuclear and burn less carbon in order to save future energy. But….well that’s difficult and we need energy now and humans aren’t famous for being rational all the time or having great long run planning in groups So either we figure out how to eventually do it with renewables, nuclear or some other method, or we fail
  - rhelz 3y ago
    > Just stopping burning carbon isn’t enough. We need to take the existing excess carbon from the atmosphere. Yeah, I just don't see that happening. E.g. suppose we only wanted to take the CO2 out of the air that we put in last year. It would take more energy to do that than we got from burning fossils fuels last year. I don't remotely see how that would at all be feasible. I mean, yeah, 100 thousand of years of plants doing photosynthesis--taking that energy slowly but surely from the sun--would do it. But the shorter of a timeframe you want it done, the more energy you are going to need--and since energy is conserved, that will eventually end up as waste heat and heat up the earth anyways.
    - graeme 3y ago
      That’s correct, except consider the alternative, not doing it. Then we either: * Let the temperature rise so fast that plants and animals will struggle to adapt. Within this century, or * Do some sort of geoengineering that limits the amount of solar radiation entering earth and manually manage the planet’s temperature. #1 is the default and is doom. #2 seems what we’ll likely try. The barriers there are: 1. We somehow have to manage it globally. 2. It will let us continue emitting carbon, thus acidifying the oceans and leaving those ecosystems unable to adapt It’s still the best option, hopefully we can actually do it. If we want to avoid it we need a surplus of energy and a way to store the excess carbon in a reasonable cost effective way. But it will almost certainly take more energy than was produced by burning it in the first place. Animals and plants have fairly narrow bands of acceptable temperature and don’t have air conditioning. Mass extinction is hypothesized at ~5 degrees of warming from pre industrial levels. Note that land warming will be higher than average warming, as the average includes the oceans.
      - rhelz 3y ago
        > consider the alternative, not doing it....Let the temperature rise so fast... Sounds like the obvious choice...but can you put some numbers to it? 1. How much C02 do we need to take out of the air to prevent your doomsday scenario, 2. How fast do we need to take it out of the air? 3. How much energy would it take to do that? 4. What are the side effects of generating that much energy, and expending it according to the timeframe of #2? HellifIknow the answers, but I can do a bit of Fermi-style estimation, and no matter what numbers I plug in, it just doesn't make any sense. Depending upon the answer to #2, we might not even be able to: 1. convert 100% of our energy generation to carbon-neutral sources, 2. Install 2.5-3x (depending upon how efficient carbon capture can become) the amount of power generating capacity we already have--again, all from carbon neutral sites 3. And then start extracting C02 out of the atmosphere at the same rate we put it in. #1 alone seems like it will take decades, to say the least. #2 says that doing #1 is going to be 2.5-3x harder. We will have to not only supply our current power budget, but also the energy needed to power these global scrubbers. And is the rate in #3 even enough? > Animals and plants have fairly narrow bands of acceptable temperature and don’t have air conditioning. Yeah, unless I'm very mistaken, they are screwed. It might not even be physically possible to do steps #1 through #3 in time to save them.
- hackerlight 3y ago
  > wouldn't we just be better of not burning the carbon? Of course, just like we'd all be better off not overfishing, but tragedy of the commons dilemma makes it hard to coordinate to stop that from happening. Not to mention, renewables have only become cheap recently, but we've been emitting for a long time.
  - rhelz 3y ago
    no, even if you are a greedy kapitalist pig, we'd be better off not burning the carbon...because: 1. You can't scrub the air using energy from burning fossils fuels--it puts more C02 into the atmosphere than it yields energy to take it back out again, and 2. In the scenario described, we were only able to provide 90-95% of our energy using carbon-neutral sources. That and #1 above means that we would not have the energy needed to scrub any C02 from the atmosphere. Burning fossils fuels at that point would be a net loss in power.
- zamfi 3y ago
  Gasoline and other oil-derived products are fantastic storage of energy. They're liquid, shockingly easily transportable for the amount of energy contained, etc. For things like long-distance flights, jet fuel is way more fantastic energy storage than any kind of electrification can sustain. It may make sense to spend 2x that energy sucking CO2 out of the air. The issue isn't "total energy production" it's "storing energy in a small metal box and releasing it over 13 hours". Of course, producing that jet fuel in a carbon-neutral way (e.g., from plant biomass) is probably a better solution than sucking the CO2 out of the air, but we'll need the latter anyway...
- sn9 3y ago
  Not only can we get it from renewables, but there are startups actively working on using solar specifically to capture CO2 and convert it to synthetic fuels to displace fossil fuels [0]. [0] https://caseyhandmer.wordpress.com/2023/01/09/terraform-industries-whitepaper-2-0/ https://caseyhandmer.wordpress.com/2023/01/09/terraform-indu...

rhelz 3y ago

But....I mean, for that 5-10%, we have to spend MORE THAN DOUBLE the energy we get from burning carbon....wouldn't we just be better of not burning the carbon? It doesn't compute. I mean, you get my point, right? That 5-10%, supposedly we couldn't get it from some renewable source....we could only get it from burning fossils fuels. So where is the energy going to come from to suck the CO2 back out of the air again? By hypothesis, we didn't have any more renewable energy to use. But you can't clean the air by burning fossils fuels--thermodynamics says that you will always release more C02 than you could recapture.

graeme 3y ago
You’re correct, but: 1. Just stopping burning carbon isn’t enough. We need to take the existing excess carbon from the atmosphere. 2. It would be rational to move on an emergency basis to renewables + nuclear and burn less carbon in order to save future energy. But….well that’s difficult and we need energy now and humans aren’t famous for being rational all the time or having great long run planning in groups So either we figure out how to eventually do it with renewables, nuclear or some other method, or we fail
- rhelz 3y ago
  > Just stopping burning carbon isn’t enough. We need to take the existing excess carbon from the atmosphere. Yeah, I just don't see that happening. E.g. suppose we only wanted to take the CO2 out of the air that we put in last year. It would take more energy to do that than we got from burning fossils fuels last year. I don't remotely see how that would at all be feasible. I mean, yeah, 100 thousand of years of plants doing photosynthesis--taking that energy slowly but surely from the sun--would do it. But the shorter of a timeframe you want it done, the more energy you are going to need--and since energy is conserved, that will eventually end up as waste heat and heat up the earth anyways.
  - graeme 3y ago
    That’s correct, except consider the alternative, not doing it. Then we either: * Let the temperature rise so fast that plants and animals will struggle to adapt. Within this century, or * Do some sort of geoengineering that limits the amount of solar radiation entering earth and manually manage the planet’s temperature. #1 is the default and is doom. #2 seems what we’ll likely try. The barriers there are: 1. We somehow have to manage it globally. 2. It will let us continue emitting carbon, thus acidifying the oceans and leaving those ecosystems unable to adapt It’s still the best option, hopefully we can actually do it. If we want to avoid it we need a surplus of energy and a way to store the excess carbon in a reasonable cost effective way. But it will almost certainly take more energy than was produced by burning it in the first place. Animals and plants have fairly narrow bands of acceptable temperature and don’t have air conditioning. Mass extinction is hypothesized at ~5 degrees of warming from pre industrial levels. Note that land warming will be higher than average warming, as the average includes the oceans.
    - rhelz 3y ago
      > consider the alternative, not doing it....Let the temperature rise so fast... Sounds like the obvious choice...but can you put some numbers to it? 1. How much C02 do we need to take out of the air to prevent your doomsday scenario, 2. How fast do we need to take it out of the air? 3. How much energy would it take to do that? 4. What are the side effects of generating that much energy, and expending it according to the timeframe of #2? HellifIknow the answers, but I can do a bit of Fermi-style estimation, and no matter what numbers I plug in, it just doesn't make any sense. Depending upon the answer to #2, we might not even be able to: 1. convert 100% of our energy generation to carbon-neutral sources, 2. Install 2.5-3x (depending upon how efficient carbon capture can become) the amount of power generating capacity we already have--again, all from carbon neutral sites 3. And then start extracting C02 out of the atmosphere at the same rate we put it in. #1 alone seems like it will take decades, to say the least. #2 says that doing #1 is going to be 2.5-3x harder. We will have to not only supply our current power budget, but also the energy needed to power these global scrubbers. And is the rate in #3 even enough? > Animals and plants have fairly narrow bands of acceptable temperature and don’t have air conditioning. Yeah, unless I'm very mistaken, they are screwed. It might not even be physically possible to do steps #1 through #3 in time to save them.
hackerlight 3y ago
> wouldn't we just be better of not burning the carbon? Of course, just like we'd all be better off not overfishing, but tragedy of the commons dilemma makes it hard to coordinate to stop that from happening. Not to mention, renewables have only become cheap recently, but we've been emitting for a long time.
- rhelz 3y ago
  no, even if you are a greedy kapitalist pig, we'd be better off not burning the carbon...because: 1. You can't scrub the air using energy from burning fossils fuels--it puts more C02 into the atmosphere than it yields energy to take it back out again, and 2. In the scenario described, we were only able to provide 90-95% of our energy using carbon-neutral sources. That and #1 above means that we would not have the energy needed to scrub any C02 from the atmosphere. Burning fossils fuels at that point would be a net loss in power.
zamfi 3y ago
Gasoline and other oil-derived products are fantastic storage of energy. They're liquid, shockingly easily transportable for the amount of energy contained, etc. For things like long-distance flights, jet fuel is way more fantastic energy storage than any kind of electrification can sustain. It may make sense to spend 2x that energy sucking CO2 out of the air. The issue isn't "total energy production" it's "storing energy in a small metal box and releasing it over 13 hours". Of course, producing that jet fuel in a carbon-neutral way (e.g., from plant biomass) is probably a better solution than sucking the CO2 out of the air, but we'll need the latter anyway...
sn9 3y ago
Not only can we get it from renewables, but there are startups actively working on using solar specifically to capture CO2 and convert it to synthetic fuels to displace fossil fuels [0]. [0] https://caseyhandmer.wordpress.com/2023/01/09/terraform-industries-whitepaper-2-0/ https://caseyhandmer.wordpress.com/2023/01/09/terraform-indu...