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Post by David B. Benson on Mar 20, 2020 18:23:07 GMT 9.5
The right dose of geoengineering could reduce climate change risks 2020 Mar 19 Phys.org m.phys.org/news/2020-03-dose-geoengineering-climate.htmlAdding atmospheric aerosols is a highly contentious subject, in part due to uncertainty of regional effects. This study attempts to remove that uncertainty.
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Post by engineerpoet on Mar 21, 2020 0:34:13 GMT 9.5
Sooner or later (and probably sooner) it's going to be undeniable that we have passed a climate "tipping point" causing positive feedbacks in the system. The only way to offset the effects will be aggressive measures to block heating, remove GHGs or both in order to push the system back toward stability. Since even CO2 removal is deemed to be geoengineering, it's definitely going to be in our future.
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Post by engineerpoet on Mar 27, 2020 8:01:54 GMT 9.5
Some very rough calculations on the olivine enhanced weathering solution to excess atmospheric CO2: ~500 billion tons CO2 removal required to return to 350 ppm. 1.25 tons CO2 removed per ton olivine weathered: www.researchgate.net/profile/Oliver_Tickell/publication/48321940_Enhanced_weathering_of_olivine_to_capture_CO2/links/5694e75a08ae820ff0747619/Enhanced-weathering-of-olivine-to-capture-CO2.pdf~400 billion tons dunite required $15/ton dunite = $6 trillion total material cost Assuming all cost is for electric power @ $0.05/kWh (very rough estimate): 300 kWh/ton dunite, 1.2e14 kWh total energy required Spread over 20 years, that's 684.5 GW average power. This number could be high by a factor of 2; if energy at the reference mine costs $0.10/kWh instead of $0.05, the power requirement would fall to 342 GW average. Or there could be other costs which increase it somewhat. I'd bank on the number being within a factor of 2. Another thing: A 60% efficient combined cycle plant burns 6 MJ of gas per kWh. At 50 MJ/kg LHV, that's 0.12 kg of gas which burns to 0.330 kg of CO2. Producing 300 kWh in such a plant generates 99 kgCO2 (call it 100). If it takes 300 kWh to mine and crush 1 ton dunite and it removes 1.25 tCO2 from the atmosphere, we can burn fossil fuel to power our CO2 removal systems and barely dent the positive effect. This would be a big job, requiring the mining of literally cubic kilometers of ultramafic rock and distributing it as fine particles so they would weather quickly. But it's doable. We CAN save the planet from our fossil fuel habit. But will we?
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Post by David B. Benson on Mar 27, 2020 8:57:11 GMT 9.5
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Post by David B. Benson on Mar 28, 2020 7:29:41 GMT 9.5
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Post by David B. Benson on Jun 9, 2020 2:54:50 GMT 9.5
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Post by David B. Benson on Oct 9, 2020 10:05:22 GMT 9.5
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Post by David B. Benson on Oct 31, 2020 9:44:52 GMT 9.5
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Post by David B. Benson on Nov 18, 2020 3:06:41 GMT 9.5
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Post by David B. Benson on Nov 25, 2020 8:01:58 GMT 9.5
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Post by David B. Benson on Dec 6, 2020 14:22:11 GMT 9.5
Direct mineralization of atmospheric CO2 using natural rocks in Japan Corey Myers & Takao Nakagaki 2020 Nov 27 Environmental Research Letters iopscience.iop.org/article/10.1088/1748-9326/abc217Most of the energy is used for comminution, i.e., crushing and grinding. h/t to nigelj and Engineer-Poet at Real Climate
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Post by David B. Benson on Dec 22, 2020 10:57:40 GMT 9.5
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Post by David B. Benson on Jan 17, 2021 2:22:03 GMT 9.5
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Post by David B. Benson on Jan 30, 2021 7:05:38 GMT 9.5
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Post by David B. Benson on Oct 2, 2021 2:13:59 GMT 9.5
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Post by David B. Benson on Sept 17, 2022 3:31:04 GMT 9.5
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Post by huon on Mar 7, 2023 13:47:48 GMT 9.5
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Post by David B. Benson on Aug 12, 2023 12:20:31 GMT 9.5
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Post by David B. Benson on Jan 8, 2024 12:45:00 GMT 9.5
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