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It's a race between nuclear, batteries, and using direct air capture to make up for remaining fossil fuels, concrete and other corner case greenhouse gas emissi

by hedora 2y ago

It's a race between nuclear, batteries, and using direct air capture to make up for remaining fossil fuels, concrete and other corner case greenhouse gas emissions. I think direct air capture is going to be the technology that gets us over the finish line, simply because it's the only one that has a path to net-zero. Nuclear, renewables and batteries all make carbon capture more affordable, so the ultimate answer is probably "all of the above".

mjhay 2y ago
Direct air capture is really about the least realistic of popular geoengineering proposals. The atmosphere is huge. We didn't get into this situation overnight - it took almost two centuries and oodles of factories, vehicles, concrete plants, etc. It's vastly cheaper just not to output more CO2 in the first place. Thermodynamic constraints mean that tremendous amounts of energy are required to do DAC in the first place, not to mention the knock-on biosphere effects of the production required to build that hitherto-unseen scale of capability. We can't magic-tech our way out of this situation. It will take huge effort, and more importantly, sacrifice of the unthinking low-value abundance we have. Nuclear power is hard, but it is still much more realistic than unproven wundertech like DAC.
- thehappypm 2y ago
  Yep. We basically doubled the amount of CO2 in the atmosphere. If we had a machine that could take some volume of air and scrub all the C02 out, we’d need to pass half of the atmosphere through it to cut the CO2 in half.
- ElevenLathe 2y ago
  I think the point is that even if we can scale up DAC to work, we need some carbon-free source of energy to power it. Fixing the atmosphere essentially means we need enough non-emitting energy to run civilization since 1850 in reverse, and preferably much faster than 1x.
nojvek 2y ago
Trees are technically “direct air capture”. Trees capture C02 + H20 + sunlight into glucose/wood + O2. So if we can reduce our C02 output, and preserve the rain forests, they’ll do their job. Even getting to zero carbon electricity in top economies is going to be a huuuuge deal.
- mjhay 2y ago
  No argument from me. Trees work. Stopping forest loss is an absolutely low-hanging fruit, but one that we still cannot achieve. Rewilding of massive areas must be a primary goal. If we can't do that, we certainly can't do DAC. In general, the Earth's homeostasis (and thus, thus homeostasis of human civilization) depends on continued, robust functioning of the biosphere. The biosphere is resilient and adaptable. However, it has never faced intelligence before. Humans - more and more unfettered by their own physical limitations - will seek (as always) to bend their environment to their own particular wills - even when it conflicts with the interests of humanity as a whole. Even in a decaying and impoverished environment, people may still seek out ever more marginal benefits at greater and greater social costs. I hope I'm wrong, but we may be at the great filter.
  - WorldMaker 2y ago
    Right now most of our cities are directly dealing with the problems of the "Heat Island effect". It's dangerous and causing very real, very scary death statistics. We know the easy fixes: add more trees to parking lots. Replace more parking lots with trees. We know exactly why that is an unpopular solution: most parking lots are privately owned and trees don't pay parking fees. Also, our cities are so car-centric parking is "important" and removing any parking spaces is seen as hurting surrounding businesses because fewer people will commute there from the suburbs/exurbs. "Ban cars and reforest parking lots" is a joke of an extremist take, but also both one of the easiest solutions and one of the hardest solutions, to the Heat Island effect specifically, but also as a microcosm of the things we need to do to solve climate change issues in general.

by hedora 2y ago

mjhay 2y ago

Direct air capture is really about the least realistic of popular geoengineering proposals. The atmosphere is huge. We didn't get into this situation overnight - it took almost two centuries and oodles of factories, vehicles, concrete plants, etc. It's vastly cheaper just not to output more CO2 in the first place. Thermodynamic constraints mean that tremendous amounts of energy are required to do DAC in the first place, not to mention the knock-on biosphere effects of the production required to build that hitherto-unseen scale of capability. We can't magic-tech our way out of this situation. It will take huge effort, and more importantly, sacrifice of the unthinking low-value abundance we have. Nuclear power is hard, but it is still much more realistic than unproven wundertech like DAC.

thehappypm 2y ago
Yep. We basically doubled the amount of CO2 in the atmosphere. If we had a machine that could take some volume of air and scrub all the C02 out, we’d need to pass half of the atmosphere through it to cut the CO2 in half.
ElevenLathe 2y ago
I think the point is that even if we can scale up DAC to work, we need some carbon-free source of energy to power it. Fixing the atmosphere essentially means we need enough non-emitting energy to run civilization since 1850 in reverse, and preferably much faster than 1x.

nojvek 2y ago

Trees are technically “direct air capture”. Trees capture C02 + H20 + sunlight into glucose/wood + O2. So if we can reduce our C02 output, and preserve the rain forests, they’ll do their job. Even getting to zero carbon electricity in top economies is going to be a huuuuge deal.

mjhay 2y ago
No argument from me. Trees work. Stopping forest loss is an absolutely low-hanging fruit, but one that we still cannot achieve. Rewilding of massive areas must be a primary goal. If we can't do that, we certainly can't do DAC. In general, the Earth's homeostasis (and thus, thus homeostasis of human civilization) depends on continued, robust functioning of the biosphere. The biosphere is resilient and adaptable. However, it has never faced intelligence before. Humans - more and more unfettered by their own physical limitations - will seek (as always) to bend their environment to their own particular wills - even when it conflicts with the interests of humanity as a whole. Even in a decaying and impoverished environment, people may still seek out ever more marginal benefits at greater and greater social costs. I hope I'm wrong, but we may be at the great filter.
- WorldMaker 2y ago
  Right now most of our cities are directly dealing with the problems of the "Heat Island effect". It's dangerous and causing very real, very scary death statistics. We know the easy fixes: add more trees to parking lots. Replace more parking lots with trees. We know exactly why that is an unpopular solution: most parking lots are privately owned and trees don't pay parking fees. Also, our cities are so car-centric parking is "important" and removing any parking spaces is seen as hurting surrounding businesses because fewer people will commute there from the suburbs/exurbs. "Ban cars and reforest parking lots" is a joke of an extremist take, but also both one of the easiest solutions and one of the hardest solutions, to the Heat Island effect specifically, but also as a microcosm of the things we need to do to solve climate change issues in general.