Alaska Sea Grant ASJ Carrying Capacity

Arctic Science Journeys
Radio Script
1996

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Carrying Capacity
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STORY: To ecologists, the term "carrying capacity" is defined as the largest population of any species an ecosystem can adequately support. This can apply to any kind of organism, from elephants to insects. But social scientists have resisted using the term on humans. They argue that people, because of technology and global trade, are not constrained by limits that hold other species in check.

But William Rees says there are limits to the growth of human populations. Rees is a population ecologist at the University of British Columbia. He says the richest one-third of the people on Earth are already straining the planet's ability to produce food, fiber and energy.

"This means that the current patterns of economic welfare enjoyed by people in developed countries cannot possibly be extended with current technology to even the existing population of the planet."

Rees says the resources of two additional planet Earths are needed if the five-and-a-half-billion people alive in the world today are to have the standard of living now enjoyed by most Americans. But experts say the global human population will double in the next 50 years. Rees says the planet simply cannot sustain that many people.

"We figure we would need about five additional planet Earths with existing technology to do that sustainably."

Some people believe technology holds the key to boosting our supplies of food, clean water and energy. That may buy us some time, but Rees says the only realistic solution is to scale back our consumption of materials and energy. For Arctic Science Journeys, this is Debra Damron.

Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.

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