Elephants in the savannah

Population and Biodiversity Loss

Biodiversity, the diversity of all life on Earth, is essential for ecosystem health and provides humanity with immeasurable services, from clean water and air, to food, building materials and medicines, as well as psychological, cultural and spiritual benefits. Unfortunately, species of animals and plants are now going extinct so fast that scientists have declared a sixth mass extinction, also called the Anthropocene or Holocene extinction.

The previous (fifth) mass extinction, the Cretaceous-Tertiary or ‘K-T’ extinction, occurred 66 million years ago, likely because a massive comet or asteroid collided with Earth. This event devastated the global environment and wiped out 80% of animal species, including the dinosaurs.


Today, human activity is causing species to disappear at 1,000 times the normal rate.


According to the landmark 2019 global assessment report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), one million species are now threatened with extinction.

The International Union for Conservation of Nature (IUCN) Red List classifies 26% of mammals at risk of extinction, as well as 41% of amphibians, 21% of reptiles, 13% of birds, 37% of sharks and rays, 33% of reef corals and 34% of conifers.

Poison dart frog


The World Wildlife Fund’s (WWF) latest Living Planet Report found that wild vertebrate populations have crashed by more than two-thirds since 1970.


During that same time, our human population more than doubled.

Habitat loss and overexploitation

By far the biggest driver of biodiversity loss is habitat destruction, followed by overexploitation of wild species — both are fueled by rapid global population growth and by unsustainable consumption patterns, especially in high-income countries.

It took us until 1800 to reach one billion people — now, we add a new billion every 11-12 years. Our population today stands at close to eight billion, leaving little space and resources for the other millions of species who share our planet. According to IPBES, only one-quarter of land and one-third of marine areas remain undisturbed by human activity.

Agriculture is the main cause of habitat loss — it currently takes up 50% of all habitable land on Earth, and most of this (77%) is used for rearing livestock. In fact, livestock now make up a staggering 60% of all mammalian biomass on Earth — another 36% is humans, and only 4% is wild mammals. Farmed poultry make up 70% of the biomass of all birds, with wild birds making up only 30%.

Crop harvest

Overexploitation of nature through deforestation, overfishing, bush meat hunting, and the trade in wild species, including poaching, is also endangering countless wild plant and animal species.

Climate change and pollution

Climate change is an additional threat to biodiversity that is rapidly worsening due to our failure to curb greenhouse gas emissions. Increasing temperatures and changing weather patterns are causing more ‘natural’ disasters such as wildfires, droughts and floods, and are creating conditions that make it harder for species to survive.

Animals with very specialized needs that are living in the fastest changing habitats, such as polar bears, are particularly hard-hit. Ocean warming is hurting marine species too, including through coral bleaching. Climate change is also affecting the timing of seasonal events such as egg laying, insect emergence and flowering, meaning co-dependent species are at risk of falling out of synch.

Polar bears

Many invertebrates, including crucial pollinators, are in sharp decline due to our widespread pesticide use, and aquatic species like fish and killer whales are suffering from persistent chemical pollution. Noise and light pollution also detrimentally affect species’ survival rates by increasing stress levels and changing behaviors.


Invasive species and disease

The introduction of alien invasive species and diseases into new areas through our extensive movement around the world is also endangering numerous native species. For example, scientists believe a rapidly spreading fungal disease is a significant contributor to the alarming global decline in amphibian populations.

Turning the extinction tide

While the world would be a lot worse off without conservation efforts, the conservation movement is failing to stem the tide of biodiversity loss. In fact, the sixth mass extinction is still accelerating due to our failure to tackle its root causes: overpopulation and overconsumption.

Only by transforming our relationship with nature, from one of unchecked exploitation to one of nurture and respect, can we stop this erosion of life on Earth. We are a part of nature, not separate from it, and protecting biodiversity is essential for our own health and well-being too — the COVID-19 pandemic made this crystal-clear. It is high time we became worthy of the scientific name we gave our own species: Homo sapiens, the wise ape. We can and must leverage humanity’s extraordinary abilities to create a better world for all living beings.

Person holding baby sea turtle

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Deforestation and Agriculture

The growing human population has dramatically altered Earth’s ecosystems, transforming forests, grasslands, and other wilderness into farms, pasture, timberland, mines, and settlements.

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Zoonotic Diseases

Zoonotic disease emergence is closely linked to global population growth. Animal-to-human viral spillovers are increasing because the growing human population is encroaching on wildlife habitats and disrupting ecosystems.

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Natural Resources

Humanity has an extensive history of using Earth’s life-sustaining natural resources unsustainably. The aggregate human demands on resources have exceeded the planet’s regenerative capacity since the 1970s.

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