The $10 per gram for "cooling credit" is mentioned in the original MIT technology review news....
On Wed, 28 Dec 2022, 15:52 Reiss Jones, <reiss1...@gmail.com> wrote: > Thanks both for sharing these calculations on this. > > Bala, where did you get your $10 per gram number from? That would be > $1,000,000 per tonne of SO2, when in reality it costs on average $9,000 > per tonne of SO2 <https://www.pharmacompass.com/price/sulfur-dioxide> - > 99.1% cheaper. Using this figure it would only cost $36 billion per year. > > Best, > Reiss > > *Reiss Jones* > *Climate + Engineering + Synbio* > *Inventions* <https://www.synthetic-rabbit.com>* Linkedin > <https://www.linkedin.com/in/reiss-jones-b78520174/> **Blog* > <https://reissjones.substack.com/?utm_source=substack&utm_medium=web&utm_campaign=substack_profile> > > On 28 Dec 2022, at 06:42, Govindasamy Bala <bala....@gmail.com> wrote: > > this is all good and well-known, but the cost of this commercial venture > (as per the news) is way too high. > > For a 2deg offset, the calculations show ~4 TgSO2 of injection per year > which translates to ~ 40 Trillion dollars per year at a rate of $10 per > gram of SO2. Cost estimates have gone through the roof into the > stratosphere from a few billion dollars to trillions of dollars. Well, > looks this is what commercialization would do. At this rate, the cost of > stratospheric aerosol geoengineering could be similar to the cost of > mitigation.... > > Bala > > On Wed, Dec 28, 2022 at 5:07 AM Andrew Lockley <andrew.lock...@gmail.com> > wrote: > >> https://makesunsets.com/blogs/news/calculating-cooling >> >> >> DECEMBER 27, 2022 >> Share >> Calculating Cooling >> >> How do we know how much cooling we're creating with our "clouds," and how >> does this compare to warming from carbon dioxide emissions? >> Fortunately, much smarter people have studied this for decades. Let's >> review some of their work and calculate our climate cooling impact. >> >> Radiative Forcing? >> >> Radiative forcing is the key concept here. This is how much energy enters >> the atmosphere vs. leaves it. An increase in radiative forcing leads to >> warming, and a decrease causes cooling. Here's a more detailed explanation. >> Measured in watts per square meter (W/m^2), we're over 3.1 W/m^2 of >> increased radiative forcing since 1750. >> >> >> Reflective Clouds >> >> How much reflectivity can we get from our clouds? Here's the summary >> we're working from: >> >> >> >> This number isn't pulled from thin air. As the author explains: "This >> sulfate efficacy value differs from that used in Smith and Wagner (2018) >> (which considered only incoming radiation) and falls towards the center of >> the values present across recent literature (Ferraro et al 2012, Pope et al >> 2012, Kuebbeler et al 2012, Pitari et al 2014, Kleinschmitt et al 2017, Dai >> et al 2018)." >> >> The key number here: >> -.62 W/m2 radiative forcing created for a year by injecting 1 Tg of sulfur >> >> But, we're using SO2. So, SO2/S mass ratio means we get half as much >> cooling per Tg: >> -.62/2 = -.31 W/m2 radiative forcing per Tg SO2/year >> >> CO2's Warming >> >> How much does carbon dioxide warm the planet? I was surprised about the >> uncertainty band here. IPCC says between .27 and .63 C per 1000 gigatons >> co2: >> >> >> >> So: 1000 gigatons CO2 = +.45C >> >> Converting Units >> >> Now we've got all the information we need to do our math. First, a >> conversion: temperature to radiative forcing. From the first table above, >> .7C per W/m2 >> >> So, we'll convert our radiative forcing per Tg SO2 to temperature change: >> -.31 W/m2 * .7C per w/m2 = -.217 C per Tg SO2/year >> >> Residence Time >> >> How long do these particles create cooling? 1-3 years. For our purposes, >> we'll go with 2.1 years (although further particle optimization, higher >> injection altitudes, and other changes may eventually result in much >> greater residence time). >> >> So, 2.1 years particle life * -.217C per TG SO2/year = -.4557 C per Tg >> SO2 launched for 1 year >> >> Putting It All Together >> >> So, how many grams of "cloud" to offset 1 ton of co2's warming impact for >> a year? >> 1000 gigatons co2 = +.45C >> 1 Tg SO2 = -.4557C >> 1000 gigatons co2 ~ 1 Tg SO2 >> 1 gigaton = 1,000 Tg, so: >> 1,000*1,000 = 1,000,000 Tg co2 = 1 Tg SO2 >> dividing both sides by 1T: >> 1,000,000 g co2 = 1 g SO2 >> 1 metric ton = 1,000,000 g: >> 1 metric ton co2 = 1 g SO2 >> >> So, with uncertainty bands on all of this, a gram offsets a ton: one gram >> "cloud" offsets 1 ton of co2's warming impact for a year. >> >> Here's the spreadsheet I used to calculate this, with links to sources. >> >> There are arguments to compare this in different ways (joules, etc.); >> many of these have strong merits. Because buyers of voluntary carbon >> credits are focused on co2 equivalence, we've gone this route. >> >> As with all our work here, please let us know if you think we've made a >> mistake and we'll correct! >> >> (image via Lexica) >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "geoengineering" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to geoengineering+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/geoengineering/CAJ3C-06OwAfeYPF%3DLwJ3X2nYdGvtq5gPj%3DNvRTGKnbO7sOR_hw%40mail.gmail.com >> <https://groups.google.com/d/msgid/geoengineering/CAJ3C-06OwAfeYPF%3DLwJ3X2nYdGvtq5gPj%3DNvRTGKnbO7sOR_hw%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > > > -- > With Best Wishes, > > ------------------------------------------------------------------- > G. Bala > Professor > Center for Atmospheric and Oceanic Sciences > Indian Institute of Science > Bangalore - 560 012 > India > > Tel: +91 80 2293 3428; +91 80 2293 2505 > Fax: +91 80 2360 0865; +91 80 2293 3425 > Email: gb...@iisc.ac.in; bala....@gmail.com > Google Scholar <https://scholar.google.com/citations?user=eurjQPwAAAAJ> > ------------------------------------------------------------------- > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/CAD7fhVmyf8gXFy48N_4VsUgf%2BF-CE1ar4mwQpVA9zhy7FNFyaA%40mail.gmail.com > <https://groups.google.com/d/msgid/geoengineering/CAD7fhVmyf8gXFy48N_4VsUgf%2BF-CE1ar4mwQpVA9zhy7FNFyaA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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