Animal Extinction

Compiled by: Yan Vana

For as long as species have been evolving, they have been going extinct. It is estimated that 99.9% of all species that have ever lived are now extinct.

The rate of extinction is far from constant, but as new species evolve to fit ever changing ecological conditions, older species naturally fade away.

At least a handful of times in the last 500 million years, 75 to 90 per cent of all species on Earth have disappeared within a relatively brief geological period, in catastrophes we call mass extinctions.

To date there have been five mass extinctions and most experts believe that we are now in the midst of a sixth.^[1] The difference this time is that the sixth mass extinction event will be a direct result of human overpopulation and human behaviour.

Habitat loss is one of the biggest causes of animal extinction.

Currently, 40 per cent of all land on earth has been repurposed for food production to support human population growth.^[2] Agriculture is also responsible for 80 per cent of global deforestation and accounts for 70 per cent of the planet’s freshwater use, devastating the species that inhabit those places by significantly altering or destroying their ecosystems.

It is also evident that where and how food is produced is one of the biggest anthropogenic threats to ecosystems and the species within them. Unsustainable agricultural practices, such as monoculture farming, degrade soil fertility, increase erosion, and pollute waterways, making it harder for species to survive in areas that had previously sustained them.^[3]

The degradation of habitats alter the ‘health’ of landscapes to such an extent that animals are often no longer able to survive, forcing extinction of entire species. This may occur by direct effects, such as the environment becoming toxic, or indirectly, by limiting a species’ ability to compete effectively for diminished resources.

Thousands of species are already being impacted by anthropogenic climate change, and its rapid onset is limiting the ability of many species to adapt to their changing environments. Climate change currently affects at least 10,967 species on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, increasing the likelihood of their extinction.^[4]

Rising global temperatures have already led to ecological and behavioural changes within animal species. Examples include changes in the migration and spawning seasons of Chinook salmon to Arctic rivers,^[5] and the earlier breeding times of North American tree swallows.

Climate change is also causing significant physiological changes. For example, warmer temperatures during egg incubation is causing imbalanced female to male sex ratios among endangered green sea turtles, with females now accounting for 99 per cent of all newly hatched turtles on some nesting beaches.

Climate change is damaging ecosystems and affecting species throughout the entire the food chain. Increased sea-ice melt and ocean acidification in the Arctic Ocean is reducing krill populations, threatening the survival of whales, penguins and seals that depend on krill as a primary food source. And because species lowest in the food chain are often among the first impacted by climate change, the full impacts of species loss may not be seen for decades to come.

The infographic below illustrates the decline of populations of vertebrate species by global region.

Invasive alien species are among the main causes of biodiversity loss and species extinctions, and the rapid rise of invasive species is often exacerbated by climate change.

Non-native organisms (animals or plants) introduced to a new environment, can cause severe and permanent ecological damage, and compete with native species for resources.

Climate change and habitat loss can frequently force species to begin migrating to new regions and ecosystems. But most invasive species are introduced to new areas through human activity; in the ballast water of oceangoing ships, the intentional or accidental release of aquaculture species or bait, or by many other means.^[6]

Invasive alien species can affect native species directly by eating them, competing with them, or introducing pathogens and parasites that sicken or kill them. They can also put native species at risk indirectly, by destroying or degrading their habitat.

Coral reefs support around a quarter of all marine life but are, proportionally, more endangered than all main animal groups inland.^[7] Almost half of the world’s reef-building corals are at risk of being wiped out in the coming decades due to climate change caused by human activity.

Europe’s largest wildlife crime is the illegal trade of the critically endangered European eel, an illegal operation worth up to €4 billion a year. Gangs are believed to be smuggling up to 350 million live eels each year out of Europe and shipping them to Asia.

Chimpanzees are at risk of being eaten into extinction, killed by hunters for food almost everywhere they live, despite being critically endangered. Current estimates suggest that within three decades chimpanzees could be extinct in the wild.^[8]

[1] World Wildlife Fund

[2] World Wildlife Fund Living Planet Report 2024

[3] World Wildlife Fund

[4] IUCN Red List of Threatened Species

[5] Adult spawners: A critical period for subarctic Chinook salmon in a changing climate – research article by Kathrine G. Howard & Vanessa von Biela

[6] National Geographic

[7] IUCN Red List Summary Statistics

[8] Jane Goodall Institute

University of Oxford

The Message is the ground-breaking debut novel by Yan Vana, a thought-provoking and critically acclaimed book that will change the way you think about human overpopulation, its effects and consequences.