We Are Exceeding Earth's Carrying Capacity

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Originally posted on undark.org

Written by Richard Heinberg

In his article, “The Earth’s Carrying Capacity for Human Life is Not Fixed,” Ted Nordhaus, co-founder of the Breakthrough Institute, a California-based energy and environment think tank, seeks to enlist readers in his optimistic vision of the future. It’s a future in which there are many more people on the planet and each enjoys a high standard of living, while environmental impacts are reduced. It’s a cheery vision.

If only it were plausible.

Nordhaus’s argument hinges on dismissing the longstanding biological concept of “carrying capacity” — the number of organisms an environment can support without becoming degraded. “Applied to ecology, the concept [of carrying capacity] is problematic,” Nordhaus writes, arguing in a nutshell that the planet’s ability to support human civilization can be, one presumes, infinitely tweaked through a combination of social and physical engineering.

Few actual ecologists, however, would agree. Indeed, the concept of carrying capacity is useful in instance after instance — including modeling the population dynamics of nonhuman species, and in gauging the health of virtually any ecosystem, be it ocean, river, prairie, desert, or forest. While exact population numbers are sometimes difficult to predict on the basis of the carrying capacity concept, it is nevertheless clear that, wherever habitat is degraded, creatures suffer and their numbers decline.

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