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Biodiversity loss and the "sixth mass extinction" debate

Gerardo CeballosFangliang HeStephen HubbellMark Vellend

This page delivers no verdict; it presents claims and evidence with their sources. No theory in science is absolute. Method

For everyone

The 2019 global assessment of IPBES, a UN-linked body, estimated that around one million animal and plant species face extinction. Some researchers argue that today's extinction rate is far above the natural rate and that Earth has entered a sixth mass extinction. Others show that estimates of extinction rates depend heavily on the methods used and that species numbers are not declining everywhere at local scale. The debate is less about whether loss is happening than about its rate and scale.

For specialists

In the five past mass extinctions roughly three-quarters of species disappeared within short geological spans. Documented extinctions today do not yet approach this proportion, but the ratio of the current extinction rate to the background rate is estimated to be very high. Estimates based on the species–area relationship have been shown to overstate extinctions caused by habitat loss. At local scale species numbers can stay constant while composition changes and global diversity declines.

Claims

Evidence

Supporting

Statistics / meta-analysis

Even under conservative assumptions, the extinction rate of vertebrate species since 1900 was calculated to be tens of times the background rate.[2]

Challenging

Theoretical argument

It was shown mathematically and empirically that the widely used species–area method for estimating extinction from habitat loss systematically overstates extinction rates.[3]

Statistics / meta-analysis

A meta-analysis of more than 16,000 vegetation plots from 168 studies found no net decrease in species numbers at local scale on average.[4]

Open questions

Connections

Parent

Biology

Related

The ecosystem concept and ecologyPresent-day global warming and its causes

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Sources

  1. ReportIPBES (2019). Global Assessment Report on Biodiversity and Ecosystem ServicesDOI 10.5281/zenodo.3831673archive
  2. ArticleCeballos, G.; Ehrlich, P. R.; Barnosky, A. D.; García, A.; Pringle, R. M.; Palmer, T. M. (2015). Accelerated modern human–induced species losses: entering the sixth mass extinction. Science Advances 1(5), e1400253DOI 10.1126/sciadv.1400253archive
  3. ArticleHe, F.; Hubbell, S. P. (2011). Species–area relationships always overestimate extinction rates from habitat loss. Nature 473, 368–371DOI 10.1038/nature09985archive
  4. ArticleVellend, M. et al. (2013). Global meta-analysis reveals no net change in local-scale plant biodiversity over time. Proceedings of the National Academy of Sciences 110(48), 19456–19459DOI 10.1073/pnas.1312779110archive

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Cite this page

APA

Athena contributors. (2026). Biodiversity loss and the "sixth mass extinction" debate. Athena: The tree of human knowledge. Retrieved November 1, 2026, from https://latifkedi.github.io/athena/en/d/biyocesitlilik/

BibTeX
@misc{athena_biyocesitlilik,
  title        = {Biodiversity loss and the "sixth mass extinction" debate},
  author       = {{Athena contributors}},
  year         = {2026},
  howpublished = {\url{https://latifkedi.github.io/athena/en/d/biyocesitlilik/}},
  note         = {Athena: The tree of human knowledge. Accessed: 2026-11-01}
}

Added: September 28, 2026 · Last changed: September 28, 2026 · Page history

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