Expanding access to safe wastewater treatment and improving our existing systems could cumulatively reduce at least 0.5 GT of CO2-equivalent greenhouse gasses per year by 2030.
Since this went out, Global Water Intelligence has put out an excellent and thorough report synthesizing the GHG footprint of global water and wastewater, based on the latest IPCC emission factors. https://www.globalwaterintel.com/water-without-carbon
Finally I made a mistake the number here for current energy-related emissions. It should be closer to 0.3 GT than 0.6 GT, and the savings possible from "quick wins" closer to 0.2 GT than 0.4 GT.
Daly here!
Since this went out, Global Water Intelligence has put out an excellent and thorough report synthesizing the GHG footprint of global water and wastewater, based on the latest IPCC emission factors. https://www.globalwaterintel.com/water-without-carbon
However, it's likely that IPCC emission factors are still underestimating the impact of methane and nitrous oxide, based on research from the past 2 years: https://engineering.princeton.edu/news/2023/02/28/wastewater-sector-emits-nearly-twice-much-methane-previously-thought
Finally I made a mistake the number here for current energy-related emissions. It should be closer to 0.3 GT than 0.6 GT, and the savings possible from "quick wins" closer to 0.2 GT than 0.4 GT.
How does greywater or septic systems fit in this model? Both of these system treat the water locally and require little to no electricity.