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This is the letter for week 33 of a weekly climate strike that went on for 4 years in front of San Francisco City Hall, beginning early March 2019. For more context, see this story. For an annotated table of contents to see topics for all the strike letters, see this story.
STRIKE FOR THE PLANET
Because now all the greenhouse gases (GHGs) are bad news.
This week’s topic is Other GHGs.
Can you name all the greenhouse gases (GHGs)?
Sure, you know about CO2 and CH4, but do you know there are other GHGs we have to cut back on?
- Water vapor makes up roughly 95% of all GHGs, accounts for 60-70% of the greenhouse effect, and increases due to temperature increases, creating a warming positive feedback loop.1
- Nitrous oxide (N2O) is the 3rd most long-lived GHG, produced primarily by bad practices involving agricultural and human sewage.
- Ozone (O3) is created by human-caused ground level pollution.
- CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) destroy stratospheric ozone (the kind we need to block UV) and are wickedly efficient GHGs.
- All covalently bonded fluorine compounds (SF6, CF4, C2F6, NF3) absorb radiation in frequencies where the atmosphere is supposed to be transparent to infrared, creating a super greenhouse effect.2
Why should we care about these other GHGs?
Because they are heating up the atmosphere.
(left vertical axis) The heating imbalance in watts per square meter relative to the year 1750 caused by all major human-produced greenhouse gases: carbon dioxide, methane, nitrous oxide, chlorofluorocarbons 11 and 12, and a group of 15 other minor contributors. Today's atmosphere absorbs about 3 extra watts of incoming solar energy over each square meter of Earth's surface. According to NOAA's Annual Greenhouse Gas Index (right axis) the combined heating influence of all major greenhouse gases has increased by 43% relative to 1990. NOAA Climate.gov graph, based on data from NOAA ESRL.3
Methane from farming and livestock represents 8% of our total GHG emissions.4 Nitrous oxide is released by modern agricultural practices; a single molecule of nitrous oxide has 298 times the global warming potential of a CO2 molecule. HCFCs have 1,430 to 14,800 times the global warming potential of a CO2 molecule. SF6 has 22,800 times the global warming potential of CO2.5 Water vapor in the atmosphere is a function of temperature and roughly doubles the amount of CO2 warming.6 And ozone causes net radiative forcing of approximately 0.35 watt per square meter.7
So what actions must SF take regarding these other GHGs?
Actions that are bad for life on the planet are bad in multiple different ways; actions that are good for life on the planet are good in multiple different ways. The actions to take on GHGs turn out to be actions that have multiple other ecosystem benefits as well. For example:
- Water vapor is temperature dependent but can be controlled if it’s bound up in biological and inorganic systems. Increase surface permeability throughout the city. Plant native trees and shrubs. Eliminate all non-permeable surfaces. Legislate living roofs and eliminate paved over yards and curb areas.
- Human-caused N2O is produced by bad waste practices. That’s why we have to plant and maintain our parks and farms according to regenerative agriculture, and make deals with agricultural suppliers around SF to help them move to regenerative ag practices. And we obviously need blackwater recycling in SF asap.
- Tropospheric ozone is caused by internal combustion engines and power plants. So get rid of internal combustion engines in SF, and take over control of our utilities to switch them entirely to renewable energy.
- Eliminate the manufacture, use, and sale of all covalently bonded fluorine compounds in SF and in dealings between SF and outside agencies and businesses. Other chemicals that can be used for refrigeration and air-conditioning include CO2, glycol, and water-cooled loops.8 Truly inert gases such as N2 and CO2 can be used as blowing agents, in foams and fire extinguishers9, and different ideas about how to extinguish fires lead to much safer solutions.10 SF6 can be replaced in high temperature insulation, and the need for high temperature insulation can be reduced.11
What’s the timeline for action?
It hasn’t changed, except you’ve lost another week in which to act. We are still increasing the amount of GHGs being dumped into the atmosphere every year. If we are going to hit zero emissions by 2030, we have to start acting immediately.
58 weeks left.12
FOOTNOTES
1. “It’s Water Vapor, Not the CO2”. ACS Climate Science Toolkit / Narratives. 2019. https://www.acs.org/content/acs/en/climatescience/climatesciencenarratives/its-water-vapor-not-the-co2.html.
2. Melanie Hall. “Banning the ‘super’ greenhouse gas”. DW.com. 17 October 2016. https://www.dw.com/en/banning-the-super-greenhouse-gas/a-36044849.
3. LuAnn Dahlman. “Climate Change: Annual greenhouse gas index”. NOAA Climate.gov. 26 September 2019. https://www.climate.gov/news-features/understanding-climate/climate-change-annual-greenhouse-gas-index.
4. Lisa Friedman, Kendra Pierre-Louis, Somini Sengupta. “The Meat Question, by the Numbers”. The New York Times. 25 January 2018. https://www.nytimes.com/2018/01/25/climate/cows-global-warming.html.
5. “Carbon Dioxide, Methane, Nitrous Oxide, and the Greenhouse Effect”. Land Trust Alliance. 2019. https://climatechange.lta.org/get-started/learn/co2-methane-greenhouse-effect/.
6. John Cook. “Explaining how the water vapor greenhouse effect works.” Skeptical Science. July 2015. https://skepticalscience.com/print.php?r=44.
7. “Surface level ozone and other compounds”. Encyclopaedia Britannica. 2019. https://www.britannica.com/science/global-warming/Surface-level-ozone-and-other-compounds.
8. “Fluorinated greenhouse gases”. EU Action. https://ec.europa.eu/clima/policies/f-gas_en.
9. Mark Robin. “Halocarbons in fire suppression”. International Fire Protection. 10 March 2018. https://ifpmag.mdmpublishing.com/halocarbons-in-fire-suppression/.
10. Anton Riecher. “Carbohydrates replace fluorine as basis for new AFFF substitute: Sweet Smell of Success”. Industrial Fire World. Winter 2014. http://www.solbergfoam.com/getattachment/8bf831ab-f717-4b82-bbd0-2e2cb14c34ff/Sweet-Smell-of-Success.aspx.
11. Yannick Kieffel, Francois Biquex, Philippe Ponchon. “Alternative Gas to SF6 For Use In High Voltage Switchgears: g3”. CIRED. 15-18 June 2015. https://pdfs.semanticscholar.org/8f23/7bba890a33ccc3c9e7cbbd56a4c3b9decaa0.pdf.
12. Based on the 2018 IPCC report that world emissions need to peak by 2020 in order to change our path from 3°C (or more) increase to 1.5°C. There are only 420 gigatons of CO2 remaining to be used in total before we pass that goal. And this goal only give us a chance of not shooting beyond 1.5°C. And 1.5°C temperature increase is already devastating; more is probably unlivable.