Founded in 1964 and headquartered in Gland, Switzerland, the International Union for Conservation of Nature (IUCN) Red List of Threatened Species is the world’s most comprehensive inventory of extinction risk.
Overview
The Red List provides a standardized, science‑based system for categorising species according to their probability of extinction. It is maintained by the IUCN Species Survival Commission and supported by the Red List Partnership IUCN Red List – About. Assessments cover plants, animals, fungi and selected protists, with more than 172,600 species evaluated in Version 2025‑2
IUCN Red List – Summary Statistics.
Categories and Criteria
Species are placed in one of nine categories: Extinct (EX), Extinct in the Wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD) and Not Evaluated (NE) IUCN Red List – Main Site. The assignment follows quantitative criteria A–E, each with explicit thresholds such as a ≥90 % population decline over ten years or three generations for CR (Criterion A)
IUCN Red List Categories and Criteria – PDF. Criteria cover population reduction, restricted range, small population size, quantitative analysis, and observed declines.
Assessment Statistics
Version 2025‑2 records over 172,600 assessed species, of which more than 48,600 are classified as threatened (CR, EN, VU). Threat levels vary by taxonomic group, with especially high percentages for reef‑building corals (44 %), amphibians (41 %) and sharks & rays (38 %) IUCN Red List – Summary Statistics.
Red List Index and Policy Use
The Red List Index (RLI) aggregates category changes to track global biodiversity trends and is a key indicator for the Convention on Biological Diversity, the United Nations Sustainable Development Goals, CITES, the Ramsar Convention and IPBES Red List Index – IUCN. Governments and NGOs use the index to evaluate progress toward the Kunming‑Montreal Global Biodiversity Framework targets.
Governance and Partnerships
The assessment process is driven by more than 11,000 volunteer experts in the Species Survival Commission and coordinated through the Red List Partnership, which includes BirdLife International, BGCI, Conservation International and other major biodiversity organisations Species Survival Commission
IUCN Red List – Partners.
Licensing and Citation
Data are provided under the IUCN Red List Terms of Use v3.1 (June 2024) permitting non‑commercial reuse for conservation, education and scientific research IUCN Red List – Terms of Use. The recommended citation format is: IUCN. 2025. The IUCN Red List of Threatened Species. Version 2025‑2.
https://www.iucnredlist.org.