Sunscreen for the Planet
14 hours ago
- #stratospheric-aerosols
- #climate-change
- #geoengineering
- The world is warming faster than emissions can be cut, with 15 countries setting national temperature records in 2024.
- Global CO2 emissions rose by 0.8% in 2024 despite reductions in Europe and the US.
- Permanent carbon removal techniques currently extract only tens of thousands of tons of CO2 annually, far less than the billions needed.
- Methane, fluorinated gases, and nitrous oxide contribute significantly to atmospheric heating alongside CO2.
- Air pollutants from industrial processes cause around 7 million premature deaths each year.
- Historical sulfur dioxide emissions have unintentionally cooled the planet by reflecting sunlight, masking some global warming.
- Volcanic eruptions like Mount Pinatubo in 1991 demonstrated the cooling effect of stratospheric sulfur dioxide.
- Deliberate stratospheric aerosol injection (SAI) could offset global warming but poses risks and uncertainties.
- Potential risks of SAI include ozone depletion, uneven cooling, and impacts on agriculture and solar energy.
- A phased approach to testing SAI, similar to clinical trials, is proposed to minimize risks.
- Phase 1 would involve small-scale sulfur dioxide releases to study aerosol formation and dispersion.
- Phase 2 would scale up to measure regional climate impacts like temperature and rainfall patterns.
- Phase 3 would test sustained cooling effects and operational scalability.
- Full deployment of SAI could require 20 million tons of sulfur dioxide annually by 2100, delivered by specialized aircraft.
- The cost of large-scale SAI is estimated at $70 billion per year, but less than the damage from extreme weather events.
- International cooperation is essential for SAI research and deployment to ensure political legitimacy.
- SAI is not a substitute for emissions reductions but could complement efforts to mitigate climate impacts.