Volcanoes can affect climate
Volcanic eruptions can temporarily cool the planet by injecting sulfur aerosols into the stratosphere, but they emit far less CO₂ than human activities and can also cause severe side effects like crop failures and ozone impacts. Commenters explore whether mimicking this effect through geoengineering—such as stratospheric SO₂ injection or altering fuels—could buy time against global warming, while warning about risks, unintended consequences, and the need for continual intervention. Most agree that such measures, if used at all, can only supplement deep decarbonization rather than replace it.
Volcanic CO₂ vs Human Emissions
- Multiple comments stress that volcanoes emit far less CO₂ than humans.
- One cites estimates that humans emit ~100× more CO₂ annually than all volcanoes combined.
- The 1991 Mount Pinatubo eruption is mentioned: ~0.05 GT CO₂, roughly equal to ~12 hours of current human emissions.
- Explanation that subducted carbonates (e.g., limestone) are a volcanic CO₂ source.
- Some initially assume “large eruptions must dominate,” but others counter that even very large eruptions are small next to ongoing human output.
Volcano-Induced Cooling and Historical Impacts
- Mount Tambora’s 1815 eruption and the “Year Without a Summer” are cited: rapid global cooling, crop failures, and famine.
- Krakatoa and Tambora are used as examples of why deliberately triggering major eruptions is likely a bad idea.
- Comments note that volcanoes can cool for months–years via aerosols, while their CO₂ impact is comparatively minor and long-term.
Sulfur, Aerosols, and Geoengineering Proposals
- Discussion of stratospheric aerosol injection and “volcanic winter” as a template for solar geoengineering.
- Ideas include sulfur cannons (as in fiction), extra sulfur in jet fuel, marine cloud brightening, and ship emissions as de facto “sulfur sprayers.”
- Some argue stratospheric injection gives strong cooling with less acid rain than tropospheric sulfur.
Risks, Uncertainties, and Ethical Concerns
- Concerns: crop losses from reduced sunlight, acid rain, ocean acidification compounding CO₂ effects, ozone impacts, regional weather disruption.
- Debate over how well volcanic analogs generalize: some say sulfur physics is well understood; others say complex climate feedbacks make extrapolation risky.
- A key worry: sulfates are short-lived, so stopping injections after delaying decarbonization could cause rapid “catch‑up” warming.
- Counterpoint: short lifetime is seen as a safety feature—if harmful, effects decay in 1–2 years.
- Fears of “cowboy geoengineering” by states or billionaires, with no global governance.
Climate Policy, Decarbonization, and Activism
- Strong theme: geoengineering cannot substitute for drastic CO₂ reduction; at best it buys time.
- Debate over whether temporary cooling is valuable (to bridge generational and technological transitions) or just postpones inevitable crises.
- Skepticism that global economic restructuring will occur before major catastrophes in rich countries.
- Side discussion on nuclear vs renewables, China’s trajectory, and the limited effectiveness of current activism and offsets (e.g., tree planting).
Miscellaneous
- Brief curiosity about underwater volcano climate impacts (left unanswered/unclear).
- Thread includes humor framing volcanoes as “exhaust ports/pipes” and sarcastic “news at 11” reactions.