Biodiversity crisis or sixth mass extinction?: Does the current anthropogenic biodiversity crisis really qualify as a mass extinction?: Does the current anthropogenic biodiversity crisis really qualify as a mass extinction?

Abstract

Human actions have caused an increasing number of species to go extinct. Do the available data support concerns about a new mass extinction event?

Figure 1. Anthropogenic extinctions, last 500 years

Taxonomic distribution of the 900 species that have gone extinct since 1,500, according to the IUCN Red List of threatened species (https://www.iucnredlist.org/, retrieved 16 October 2021).

Figure 2. The Big Five mass extinctions of the Phanerozoic

The five mass extinctions of the Phanerozoic, as defined by the percentage of extinct genera of marine animals. Each mass extinction is highlighted by a red number (1–5) and the percentage of extinct species with respect to the total. The orange line represents the background extinction rates (note that not all extinction bursts above background rates are considered mass extinctions). Geological periods: O, Ordovician; S, Silurian; D, Devonian; C, Carboniferous; P, Permian; Tr, Triassic; J, Jurassic; K, Cretaceous; Pg, Paleogene; N, Neogene. Based on Raup and Sepkoski (1982).

Figure 3. Map of currently threatened species

World map of threatened species (vulnerable, endangered and critically endangered). Terrestrial species are in green, and marine species are in blue. The intensity of the colors is proportional to the number of endangered species. Modified from IPBES (2019).