EXTINCTION TIMELINE
Earth's Mass Extinction Events
Five catastrophic events reshaped life on Earth. The sixth is underway — driven not by asteroids or volcanism, but by human activity. Current species loss rates are 100–1,000× the natural background rate.
5+1
Mass extinctions
96%
Worst event (Permian)
48,646
Currently threatened
1,000×
Above background rate
THE BIG FIVE (+ NOW)
Species loss by extinction event
86%
species lost
444 Mya
Ordovician–Silurian
Glaciation and sea level drop
Severe glaciation locked water in ice sheets, dropping sea levels dramatically and destroying shallow marine habitats where most life existed.
Source: Barnosky et al. (2011), IUCN Red List
75%
species lost
372 Mya
Late Devonian
Ocean anoxia and cooling
A prolonged crisis spanning millions of years, driven by oxygen depletion in oceans and global cooling that devastated reef ecosystems and marine life.
Source: Barnosky et al. (2011), IUCN Red List
96%
species lost
252 Mya
Permian–Triassic
Siberian Traps volcanism and methane release
The worst extinction in Earth's history. Massive volcanic eruptions in Siberia released catastrophic greenhouse gases, causing ocean acidification and near-total collapse of marine ecosystems.
Source: Barnosky et al. (2011), IUCN Red List
80%
species lost
201 Mya
Triassic–Jurassic
Central Atlantic volcanism and CO₂ surge
Volcanic activity associated with the breakup of Pangaea released enormous quantities of CO₂, triggering rapid warming and ocean acidification.
Source: Barnosky et al. (2011), IUCN Red List
76%
species lost
66 Mya
Cretaceous–Paleogene
Chicxulub asteroid impact
A 10km asteroid struck the Yucatán Peninsula, triggering global firestorms, a years-long impact winter, and the end of non-avian dinosaurs.
Source: Barnosky et al. (2011), IUCN Red List
28%
species lost
Present day
Holocene (Ongoing)
Human activity
The current extinction crisis driven by habitat destruction, overexploitation, pollution, invasive species, and climate change. Species loss rates are 100–1,000× the background rate.
Source: Barnosky et al. (2011), IUCN Red List
How Much Life Was Lost?
Estimated percentage of species lost in each mass extinction event
* Holocene estimate reflects species assessed as extinct or threatened, not final projected loss · Source: Barnosky et al. (2011), Ceballos et al. (2015)
Threatened Species Are Increasing Rapidly
Number of species classified as threatened (CR + EN + VU) on the IUCN Red List, from 2000 to 2025
48,646
threatened species in 2025
+340%
since 2000
11,046
Threatened in 2000
48,646
Threatened in 2025
+37,600
Increase over 25 years
Note: Increases partly reflect expanded assessment coverage, not only worsening status
Source: IUCN Red List
Current Extinction Rate vs Natural Background Rate
How today's species loss compares to the natural “background” rate
Background Rate
0.1–1
species per million species per year
Current Rate
100–1,000×
above the natural background rate
Source: Ceballos et al. (2015), De Vos et al. (2015), IPBES Global Assessment (2019)