The International Union for Conservation of Nature (IUCN) is an international nature conservation organization whose members include governments and environmental organizations from around the world. It was established on October 5, 1948, in Fontainebleau, France, and is headquartered in Gland, Switzerland. The IUCN assesses how close the plants and animals on Earth are to extinction and produces the Red List. As of 2026, it has more than 1,600 members. Of these, 209 were countries and government agencies as of October 2025, while most of the remainder were private environmental organizations. The IUCN is distinctive in bringing governments and private organizations together to determine the direction of nature conservation.
The World Conservation Congress, held every four years, is where these diverse members determine the organization’s direction. In September 2012, South Korea hosted the congress in Jeju, the first such gathering in Northeast Asia. At the most recent congress, held in Abu Dhabi, United Arab Emirates, in October 2025, 148 resolutions were adopted, along with a long-term vision for the next 20 years and a program of work for 2026 through 2029.
The IUCN has also played a major role in the development of international environmental norms. It provided scientific foundations during the creation of major conventions, including the Ramsar Convention on wetland conservation and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which regulates international trade in endangered plants and animals, and the Convention on Biological Diversity(CBD). In 1999, it obtained observer status at the United Nations General Assembly, allowing it to attend and express opinions at the General Assembly even though it is not a member state.
The organization’s scientific role is best illustrated by the Red List, which it first created in 1964. The Red List places species into nine categories according to their level of extinction risk. In descending order of risk, seven categories are Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, and Least Concern; Data Deficient and Not Evaluated are separate categories. Species classified as Critically Endangered (CR), Endangered (EN), or Vulnerable (VU) are collectively called “threatened species.” The latest edition, released in July 2026, assessed 175,909 species—3,289 more than the previous edition’s 172,620—and classified 49,505 as threatened species. This means nearly three out of every 10 species assessed, approximately 28%, face a risk of extinction.
The most notable change in the latest edition appeared in the depths of the ocean. Of the 201 mollusk species—including snails and clams—that live only around hydrothermal vents, openings on the seafloor where hot water emerges, 125 (62%) were listed as threatened species. Deep-sea mining to extract valuable minerals was identified as the greatest threat. At its 2021 congress, IUCN members had already adopted a motion stating that deep-sea mining should be halted if marine ecosystems cannot be properly protected. This is a case in which the warning that competition for minerals could lead to biodiversity loss has been confirmed by the numbers.
The IUCN’s role lies in linking scientific assessment with international norms. It measures species’ extinction risks through the Red List, proposes directions for action through resolutions adopted jointly by government and private members, and conveys the underlying evidence to discussions on international conventions. However, IUCN resolutions are not legally binding. Even after a resolution calling for an end to deep-sea mining was adopted, many hydrothermal-vent species were assessed as threatened species. Whether the IUCN’s assessments and resolutions lead to actual conservation results depends on how fully national governments and international organizations reflect them in their policies.