East Asian aerosol cleanup has likely contributed to global warming

Original Article ↗ Hacker News Discussion ↗

Aerosols masking warming & East Asian cleanup

  • Commenters note that sulfate aerosols from coal and shipping have been significantly cooling the climate, temporarily offsetting greenhouse warming.
  • Cleaning up these pollutants in East Asia (mainly China) and in global shipping has revealed “hidden” warming rather than newly causing it.
  • Aerosols are short‑lived (months to a couple of years), while CO₂ persists for centuries, so the recent spike is framed as a one‑time adjustment, not a permanently higher trend.
  • Some highlight that local air quality and health gains remain unambiguously positive, even if global temperatures rise faster in the short term.

Geoengineering: sulphates, CaCO₃, clouds

  • There is active debate on deliberate aerosol injection (SO₂ or CaCO₃) and marine cloud brightening as “plan B” to buy time.
  • Supporters argue it looks technically cheap, fast‑acting, and reversible at the physical level; opponents stress systemic risk, unknown second‑order effects (on rainfall, crops, ecosystems), and moral hazard.
  • A recurring “termination shock” concern: if sulfate injections mask rising greenhouse gases and then suddenly stop (e.g., due to politics or recession), rapid catch‑up warming over a few years could be catastrophic.
  • Several argue such tools might only be acceptable alongside a credible path to net‑zero CO₂, used narrowly to avoid specific tipping points (e.g., permafrost melt).

Politics, bans, and distrust

  • Many point to growing US state‑level efforts to ban geoengineering and even small‑scale tests (cloud seeding, salt‑spray trials), often framed by conspiracy‑tinged narratives.
  • Others see these bans as aligned with fossil‑fuel interests that also attack climate science and Earth‑observation budgets (e.g., attempts to cut NASA Earth science satellites).
  • Some stress that any large‑scale climate engineering would trigger geopolitical tension, possibly even war, if done unilaterally.

Carbon emissions, responsibility & economics

  • Thread splits between those who want to “just stop using oil and gas” and those who see this as politically unrealistic without strong carbon pricing or making renewables cheaper.
  • Carbon pricing is viewed by some as effective and already in use; others call it a grift or note difficulties in global coordination.
  • Discussion of China and India:
    • China is the largest absolute emitter and has driven major aerosol reductions while still building coal plants, but also leads in renewables and pollution control.
    • Per‑capita and consumption‑based metrics shift much responsibility back to richer Western countries, whose demand drives much of Chinese manufacturing emissions.
    • India is portrayed as rapidly expanding solar but also heavily reliant on low‑quality coal and struggling with grid reliability and broader development challenges.

CO₂, health, and cognition

  • One subthread asks if high atmospheric CO₂ directly harms cognition.
  • Some cite indoor‑air studies and a meta‑analysis suggesting measurable declines in complex task performance above ~1000 ppm, especially in poorly ventilated spaces.
  • Others counter with submarine/spacecraft data and older studies showing no clear cognitive harm at much higher levels, and argue new studies may have methodological flaws and publication bias.
  • Consensus in the thread: direct CO₂ health effects are uncertain and likely secondary to its climate role, but rising outdoor CO₂ makes controlling indoor levels harder.

Climate physics and denial arguments

  • A prolonged exchange revisits radiative transfer and whether CO₂’s greenhouse effect is “saturated.”
  • One side cites mainstream work (e.g., line‑by‑line calculations, HITRAN, water vapor and methane feedbacks) and decades of peer‑reviewed climate physics.
  • The other leans on a small set of contrarian analyses claiming strong saturation and minimal additional warming from more CO₂; critics point out issues with those papers and their fossil‑fuel‑linked sponsors.
  • Overall thread sentiment leans toward established climate science while acknowledging logarithmic forcing, but not saturation at current concentrations.

Doom, adaptation, and multiple levers

  • Some commenters share extremely pessimistic scenarios (billions dying or population collapsing this century); others challenge these as unsupported or exaggerated compared to mainstream projections.
  • A more moderate view holds that climate change will cause significant harm (heat deaths, migration, agricultural shifts, instability) but agriculture will adapt and impacts will be uneven, not pure global collapse.
  • Several stress that “everything is climate engineering”: continuing fossil use is itself an uncontrolled experiment.
  • Many conclude that realistic pathways must combine rapid decarbonization, massive low‑carbon build‑out (solar, wind, etc.), potential CO₂ removal, local adaptation, and at least serious research into geoengineering—while recognizing its political and ethical minefields.