Ecological Collapse

The thesis, in one sentence

Life on Earth has already crossed five global collapses; the sixth is underway and, for the first time, has a single identifiable species as its causal agent.

The five mass extinctions

• Ordovician-Silurian (~444 Ma) — global cooling and sea-level drop; ~85% of marine species lost.
• Late Devonian (~372 Ma) — pulses of ocean anoxia; ~75% of species gone.
• Permian-Triassic (~252 Ma) — the "Great Dying"; Siberian Traps volcanism, acidification and warming; ~96% of marine species extinct.
• Triassic-Jurassic (~201 Ma) — Central Atlantic Magmatic Province; ~80% of species lost.
• Cretaceous-Paleogene (~66 Ma) — Chicxulub impact combined with Deccan Traps volcanism; end of non-avian dinosaurs.

The Holocene extinction

• Rate — current extinction rates run 100 to 1,000 times the background rate estimated from the fossil record (Ceballos et al., Science Advances, 2015).
• Vertebrates — the Living Planet Report (WWF/ZSL, 2024) estimates an average 73% decline in monitored vertebrate population abundance since 1970.
• Insects — meta-analyses published in Biological Conservation report biomass declines above 75% in Central European monitored sites over three decades.
• IPBES (2019) — around 1 million animal and plant species at risk of extinction within decades.
• Dominant drivers — land-use change, direct exploitation, climate change, pollution and invasive species.

The nine planetary boundaries

• Climate change — transgressed.
• Biosphere integrity (genetic and functional loss) — transgressed.
• Land-system change — transgressed.
• Biogeochemical flows (nitrogen and phosphorus) — transgressed.
• Novel entities (plastics, synthetic chemicals, radionuclides) — transgressed (2022).
• Freshwater cycle — transgressed (2023 Stockholm Resilience Centre update).
• Ocean acidification — in the rising-risk zone.
• Atmospheric aerosol loading — regionally critical.
• Stratospheric ozone depletion — within the safe boundary (the only successful reversal, via the Montreal Protocol).

Ecosystem tipping points

• Amazon — savannization from combined deforestation, fire and drought; threshold estimated by Nobre and Lovejoy between 20% and 25% forest loss.
• Coral reefs — recurring mass bleaching above +1.5 °C; near-total loss projected above +2 °C.
• Permafrost — degradation releases CO₂ and CH₄, feeding further warming (positive feedback).
• Atlantic Meridional Overturning Circulation (AMOC) — observed weakening; a collapse would reshape North Atlantic climate and tropical monsoons.
• Ice sheets — Greenland and West Antarctica show signs of hysteretic instability.

Why this is systemic risk

Ecological collapse rarely appears as a single dated event. It shows up as the simultaneous loss of pollination, fisheries, regional climate stability, soil fertility, and coastal protection. Each of these functions underwrites production chains, food systems, and human settlements. That is why IPBES, IPCC, UNEP, and the World Economic Forum's Global Risks Report list biodiversity loss among the three top global risks of the decade.

Calibration, not panic

None of this implies a sealed fate. The recovery of the ozone layer shows that multilateral instruments work when there is evidence, political cost, and deadlines. The recovery of humpback whales, California condors, and European rewilded forests shows the curve can bend. The point is to recognize the scale: ecological collapse is not one environmental topic among others — it is the thermodynamic base of any economy and any national security.

Primary sources

• IPBES — Global Assessment Report on Biodiversity and Ecosystem Services (2019) and thematic reports.
• Stockholm Resilience Centre — Planetary Boundaries Framework (Rockström et al., 2009; updates 2015, 2022, 2023).
• IPCC — AR6, Working Group II (impacts, adaptation, vulnerability).
• Nature and Science — Ceballos et al. (2015, 2020); Barnosky et al. (2011) on the sixth extinction.
• WWF / ZSL — Living Planet Report (2024 edition).
• UNEP — Emissions Gap Report and Global Environment Outlook.
• Global Challenges Foundation — globalchallenges.org, global catastrophic risk analyses.