The ‘endangered scale’ evaluates species’ extinction risk and the scope of life disappearing from our planet. This concept provides a framework to understand the accelerating loss of biodiversity, which refers to the variety of life on Earth. Recognizing this scale helps appreciate the severity of the global biodiversity crisis and its implications.
Categorizing Species at Risk
The International Union for Conservation of Nature (IUCN) assesses and classifies species by their extinction risk. Its Red List of Threatened Species is the globally recognized standard, informing conservation actions and policy worldwide. This inventory helps inform conservation actions and policy worldwide by providing data on species’ populations, habitats, threats, and conservation needs.
The IUCN Red List uses categories to describe a species’ conservation status, from least concern to extinct. “Threatened” species fall into three main categories: Vulnerable (VU), Endangered (EN), and Critically Endangered (CR). Vulnerable means a high risk of extinction in the wild, Endangered signifies a very high risk, and Critically Endangered denotes an extremely high risk, meaning the species is in a particularly dire state.
The Red List also includes Extinct in the Wild (EW), for species surviving only in captivity or outside their native range, and Extinct (EX), for species no longer extant. These classifications are determined by scientific criteria, including population size, decline rate, and geographic range.
The Global Picture of Decline
Species endangerment shows a severe and accelerating decline in biodiversity. A report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) highlights that nature is declining at unprecedented rates. This assessment indicates approximately 1 million animal and plant species are now threatened with extinction, many within decades.
At least 680 vertebrate species have been driven to extinction since the 16th century. The IPBES report estimates over 40% of amphibian species, almost 33% of reef-forming corals, and more than a third of all marine mammals are currently threatened. Available evidence suggests about 10% of insect species may also be threatened.
This decline impacts all ecosystems and regions. The average abundance of native species in most major land-based habitats has fallen by at least 20% since 1900. The global biomass of wild mammals has decreased by an estimated 82% due to human impact. These statistics underscore biodiversity loss, which poses grave impacts on people worldwide.
Primary Threats to Species Survival
Human activities are the primary drivers pushing species towards endangerment and extinction. Changes in land and sea use are the leading threat, often stemming from agriculture, urbanization, and deforestation. Converting natural habitats fragments ecosystems, reduces living space, and isolates populations, making them more vulnerable.
Climate change also contributes to species loss by altering weather patterns, increasing extreme events, and causing sea-level rise. These changes disrupt ecosystems, shift species’ geographic ranges, and can exceed a species’ ability to adapt, leading to declines or localized extinctions. For example, a 2°C global warming could threaten an estimated 5% of Earth’s species.
Overexploitation, including unsustainable fishing, logging, and the illegal wildlife trade, directly reduces species populations. When species are harvested faster than they can reproduce, their numbers dwindle. Pollution, such as plastics, chemicals, and pesticides, contaminates air, water, and soil, harming species directly or indirectly by damaging their food sources and habitats. Invasive alien species, introduced intentionally or unintentionally, can outcompete native species, disrupt food webs, and introduce diseases, leading to further biodiversity loss.
Broad Approaches to Conservation
Combating species endangerment requires a multifaceted approach. One strategy is establishing and managing protected areas, such as national parks and wildlife reserves. These areas safeguard habitats and provide havens for threatened species, allowing populations to recover.
International agreements and policies coordinate global conservation efforts. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulates the international trade of wild animals and plants to prevent overexploitation. The Convention on Biological Diversity (CBD) aims to conserve biodiversity, promote its sustainable use, and ensure the fair and equitable sharing of benefits from genetic resources.
Habitat restoration projects rehabilitate degraded ecosystems, helping rebuild species populations and improve ecological health. Promoting sustainable resource management in agriculture, forestry, and fisheries reduces the human footprint. Raising public awareness and education fosters understanding of biodiversity’s value and encourages actions that support conservation. These efforts involve collaboration among governments, non-governmental organizations, scientific communities, and local communities to achieve lasting conservation outcomes.