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CENTER for BIOLOGICAL DIVERSITY Because life is good

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HUMAN POPULATION: A Key Factor in Species Extinction


The world’s human population doubled from 1 to 2 billion between 1800 and 1930, and then doubled again by 1975. At the end of October 2011, it surpassed 7 billion. This staggering increase and the massive consumption it drives are overwhelming the planet’s finite resources. We’ve already witnessed the devastating effects of human population growth on biodiversity: Species abundant in North America two centuries ago — from the woodland bison of West Virginia and Arizona’s Merriam’s elk to the Rocky Mountain grasshopper and Puerto Rico’s Culebra parrot — have been wiped out by growing human numbers.

As the world’s population grows unsustainably, so do its unyielding demands for water, land, trees and fossil fuels — all of which come at a steep price for already endangered plants and animals. Most biologists agree we’re in the midst of the Earth’s sixth mass extinction event; species are disappearing about 1,000 times faster than is typical of the planet’s history. This time, though, it isn’t because of geologic or cosmic forces but unsustainable human population growth.

Today’s global human population is over 7 billion. Every day, the planet sees a net gain of roughly 250,000 people. If the pace continues, we’ll be on course to reach 8 billion by 2020 and 9 billion by 2050.

Extinction and Population

By any ecological measure, Homo sapiens sapiens has exceeded its sustainable population size. Just a single human waste product — greenhouse gas — has drastically altered the chemistry of the planet’s atmosphere and oceans, causing global warming and ocean acidification.

In the United States, which has the world’s third largest population after China and India, the fertility rate peaked in 2007 at its highest level since 1971 before dropping off slightly due to the recent economic recession. At 2.1 children per woman, the U.S. fertility rate remains the highest among developed nations, which average around 1.6. The current U.S. population exceeds 300 million and is projected to grow 50 percent by 2050.

The mission of the Center for Biological Diversity is to stop the planetary extinction crisis wiping out rare plants and animals around the world. Explosive, unsustainable human population growth is an essential root cause of this crisis.

We can reduce our own population to an ecologically sustainable level in a number of ways, including the empowerment of women, education of all people, universal access to birth control and a societal commitment to ensuring that all species are given a chance to live and thrive. All of these steps will decrease human poverty and overcrowding, raise our standard of living and sustain the lives of plants, animals and ecosystems everywhere.