5 ms·

You need to remove 30 gigatons per year to eliminate all the CO2 humans generate. This is the "what if humans disappeared" baseline you mentioned. If we elimin

You need to remove 30 gigatons per year to eliminate all the CO2 humans generate. This is the "what if humans disappeared" baseline you mentioned. If we eliminated 30 gigatons annually, yes the earth would recover at the rate you describe. If we increase above 30 gigatons or reduce emissions, we shorten the time dramatically. Growing trees or grasses, pyrolizing them into syngas and biochar, and sequestering the char could, in theory, supplement natural processes. It's a process that can be run with an energy surplus, but it does require a lot of labor and land. You'd need hundreds of thousands of square miles wholly dedicated to the effort. DACCS facilities are expensive, but achievable. You'd need roughly three major industrial DACCS facilities for every coal fire plant worldwide, which would be incredibly challenging but not impossible.

robomartin 6y ago
I think where some of these ideas run afoul of reality is that they ignore the scale of energy and resources necessary to make them happen. And the probability distribution of each idea being realizable at scale. It's a planetary scale problem, which means the numbers are very large no matter what anyone suggests. I have no clue how much CO2 t-shirt manufacturing produces when you consider the entire supply chain and human footprint. If you add-up t-shirt manufacturing world wide, the number likely isn't trivial. And yet, even if we stop making t-shirts the need for clothing does not evaporate. I would be willing to bet that t-shirt manufacturing is now optimized almost as far as one could go and the providing an alternative form of clothing to billions of people around the world would be dirtier and consume more resources than just making t-shirts. This is frustrating to me because I can't find a path. The minute one includes the pesky little reality of conservation of energy things become real. I can't think of a single problem --regardless of the domain-- that can be fixed with less energy than that which created it in the first place. And so, if that's true --and I think it is true without dispute-- this idea of being able to control atmospheric CO2 concentration at a planetary scale is in a range between hubris and lunacy. Another way to put it is: We cannot fix it by subtraction. This means we cannot fix it by simply going down to zero CO2 generation, no matter what the approach might entail. That, at best, gets us to 100K years for a 100ppm reduction in CO2. I admit, this is a defeatist view. Yet, I believe this is reality and what is being pushed out there is fantasy. My fear is that, yes, we need to start doing a number of things to make human life better (the planet will do fine without us) but none of this work will begin until we frame it from a truthful baseline. As I have said before, there are tons of reasons to cleanup our act globally --and we should-- but let's not lie to ourselves and pretend that this is to save the planet or reverse climate change. We can't. We won't. And we won't because, even if we go to zero CO2 the planet itself will not cooperate. If you look at the charts for the 800,000 year ice core sample CO2 data one of the questions should be: How did CO2 increase, we were not around to make it happen? The answer is, for the most part, massive continental scale fires. So, we go CO2 neutral and cover the planet with trees. And then fires, massive fires, fires we cannot control, contribute more CO2 to the atmosphere than we ever contributed before with our non-carbon-neutral technologies. Just look at what happened this year in California alone: https://news.mongabay.com/2020/09/off-the-chart-co2-from-california-fires-dwarf-states-fossil-fuel-emissions/ https://news.mongabay.com/2020/09/off-the-chart-co2-from-cal... It is hubris to think we can control this at a planetary scale. We can't control it in a US state that recently surpassed the entire United Kingdom to become something like the fifth largest economy in the world...and we can't stop massive forest fires. From the article: "The fires have already generated more than 91 million metric tons of carbon dioxide, which is about 25% more than the state’s annual emissions from fossil fuels." I wish I had answers. All I am able to do is point out that we are lying to ourselves in hopes that, if enough people stop to think and understand this reality we will switch tracks and empower our scientific community to look at this from a different perspective. Maybe then someone with a unique perspective might discover a way to deal with it. We don't need to fix it, I don't believe we can, we need to understand how humanity can survive the cycle we are on. Thanks for engaging.
- mrlinx 6y ago
  no, thank you for explaining it so well.
- philipkglass 6y ago
  This is frustrating to me because I can't find a path. The minute one includes the pesky little reality of conservation of energy things become real. I can't think of a single problem -- regardless of the domain -- that can be fixed with less energy than that which created it in the first place. Accelerated silicate weathering is one approach that takes less energy than turning carbon dioxide back into carbon and oxygen [1]. Natural silicate weathering has a low thermodynamic cost but is kinetically hindered. Accelerated silicate weathering only spends energy to accelerate the kinetics of natural silicate weathering and needs much less energy than combustion-in-reverse. Iron ocean fertilization is also possibly another case where the required human energy input for drawdown could be much smaller than reversing combustion. I say "possibly" because it has not been tested with enough rigor and scale yet. You can see from my comment history that I agree with you about how slowly natural processes alone can bring atmospheric CO2 levels back down to pre-industrial levels: https://news.ycombinator.com/item?id=24297363 https://news.ycombinator.com/item?id=24297363 [1] e.g. Project Vesta https://projectvesta.org/ https://projectvesta.org/
  - robomartin 6y ago
    > Accelerated silicate weathering > Iron ocean fertilization The real question is what it will cost in terms of energy and CO2 to mine, produce, prepare, deploy and manage such processes. I have a very hard time accepting that we can use less energy to reverse something than the energy it took to create it. I have to admit it would take a lot of research on my part to fully break down these processes and quantify them from start to finish. I am just going to trust physics and say that I suspect perpetual motion machines are still impossible. What truly scares me about ideas like iron ocean fertilization is the massive potential for causing a disaster that could damage sea life and ecosystems for hundreds of years. It's one thing to run an experiment on one beach or two. It's quite another to do this at a scale sufficient enough to affect things at planetary scale. That's where, frankly, my brain short circuits a bit. I can't imagine some of these things done at a planetary scale without expending massive amounts of resources and producing equally massive amounts of pollution, CO2 and potential ecosystem damage. Now, here's a twist. If the thought is that we can deploy any one of X approaches and deliver results a thousand times faster than the natural rate of change (100KY/100ppm) we have to be truly scared about what the unintended consequences might be. It's almost like that story about when they detonated the first nuclear weapon and thought there was some probability of the entire atmosphere igniting. I am not sure if the story is true, but it illustrates the point well enough. I think we (and anyone who truly stops to look at the data and apply critical thinking) agree that this is a difficult problem that is being made far more complex by a narrative that is patently false (or distorted) all both extremes. This is a sad reality. Science should not work this way. Scientists should be free from political forces.

robomartin 6y ago

I think where some of these ideas run afoul of reality is that they ignore the scale of energy and resources necessary to make them happen. And the probability distribution of each idea being realizable at scale. It's a planetary scale problem, which means the numbers are very large no matter what anyone suggests. I have no clue how much CO2 t-shirt manufacturing produces when you consider the entire supply chain and human footprint. If you add-up t-shirt manufacturing world wide, the number likely isn't trivial. And yet, even if we stop making t-shirts the need for clothing does not evaporate. I would be willing to bet that t-shirt manufacturing is now optimized almost as far as one could go and the providing an alternative form of clothing to billions of people around the world would be dirtier and consume more resources than just making t-shirts. This is frustrating to me because I can't find a path. The minute one includes the pesky little reality of conservation of energy things become real. I can't think of a single problem --regardless of the domain-- that can be fixed with less energy than that which created it in the first place. And so, if that's true --and I think it is true without dispute-- this idea of being able to control atmospheric CO2 concentration at a planetary scale is in a range between hubris and lunacy. Another way to put it is: We cannot fix it by subtraction. This means we cannot fix it by simply going down to zero CO2 generation, no matter what the approach might entail. That, at best, gets us to 100K years for a 100ppm reduction in CO2. I admit, this is a defeatist view. Yet, I believe this is reality and what is being pushed out there is fantasy. My fear is that, yes, we need to start doing a number of things to make human life better (the planet will do fine without us) but none of this work will begin until we frame it from a truthful baseline. As I have said before, there are tons of reasons to cleanup our act globally --and we should-- but let's not lie to ourselves and pretend that this is to save the planet or reverse climate change. We can't. We won't. And we won't because, even if we go to zero CO2 the planet itself will not cooperate. If you look at the charts for the 800,000 year ice core sample CO2 data one of the questions should be: How did CO2 increase, we were not around to make it happen? The answer is, for the most part, massive continental scale fires. So, we go CO2 neutral and cover the planet with trees. And then fires, massive fires, fires we cannot control, contribute more CO2 to the atmosphere than we ever contributed before with our non-carbon-neutral technologies. Just look at what happened this year in California alone: https://news.mongabay.com/2020/09/off-the-chart-co2-from-california-fires-dwarf-states-fossil-fuel-emissions/ https://news.mongabay.com/2020/09/off-the-chart-co2-from-cal... It is hubris to think we can control this at a planetary scale. We can't control it in a US state that recently surpassed the entire United Kingdom to become something like the fifth largest economy in the world...and we can't stop massive forest fires. From the article: "The fires have already generated more than 91 million metric tons of carbon dioxide, which is about 25% more than the state’s annual emissions from fossil fuels." I wish I had answers. All I am able to do is point out that we are lying to ourselves in hopes that, if enough people stop to think and understand this reality we will switch tracks and empower our scientific community to look at this from a different perspective. Maybe then someone with a unique perspective might discover a way to deal with it. We don't need to fix it, I don't believe we can, we need to understand how humanity can survive the cycle we are on. Thanks for engaging.

mrlinx 6y ago
no, thank you for explaining it so well.
philipkglass 6y ago
This is frustrating to me because I can't find a path. The minute one includes the pesky little reality of conservation of energy things become real. I can't think of a single problem -- regardless of the domain -- that can be fixed with less energy than that which created it in the first place. Accelerated silicate weathering is one approach that takes less energy than turning carbon dioxide back into carbon and oxygen [1]. Natural silicate weathering has a low thermodynamic cost but is kinetically hindered. Accelerated silicate weathering only spends energy to accelerate the kinetics of natural silicate weathering and needs much less energy than combustion-in-reverse. Iron ocean fertilization is also possibly another case where the required human energy input for drawdown could be much smaller than reversing combustion. I say "possibly" because it has not been tested with enough rigor and scale yet. You can see from my comment history that I agree with you about how slowly natural processes alone can bring atmospheric CO2 levels back down to pre-industrial levels: https://news.ycombinator.com/item?id=24297363 https://news.ycombinator.com/item?id=24297363 [1] e.g. Project Vesta https://projectvesta.org/ https://projectvesta.org/
- robomartin 6y ago
  > Accelerated silicate weathering > Iron ocean fertilization The real question is what it will cost in terms of energy and CO2 to mine, produce, prepare, deploy and manage such processes. I have a very hard time accepting that we can use less energy to reverse something than the energy it took to create it. I have to admit it would take a lot of research on my part to fully break down these processes and quantify them from start to finish. I am just going to trust physics and say that I suspect perpetual motion machines are still impossible. What truly scares me about ideas like iron ocean fertilization is the massive potential for causing a disaster that could damage sea life and ecosystems for hundreds of years. It's one thing to run an experiment on one beach or two. It's quite another to do this at a scale sufficient enough to affect things at planetary scale. That's where, frankly, my brain short circuits a bit. I can't imagine some of these things done at a planetary scale without expending massive amounts of resources and producing equally massive amounts of pollution, CO2 and potential ecosystem damage. Now, here's a twist. If the thought is that we can deploy any one of X approaches and deliver results a thousand times faster than the natural rate of change (100KY/100ppm) we have to be truly scared about what the unintended consequences might be. It's almost like that story about when they detonated the first nuclear weapon and thought there was some probability of the entire atmosphere igniting. I am not sure if the story is true, but it illustrates the point well enough. I think we (and anyone who truly stops to look at the data and apply critical thinking) agree that this is a difficult problem that is being made far more complex by a narrative that is patently false (or distorted) all both extremes. This is a sad reality. Science should not work this way. Scientists should be free from political forces.