Colcom Foundation Draws on a Classic Environmental Equation
Half a century ago, two scientists proposed a simple formula for thinking about humanity’s toll on the planet. Colcom Foundation still treats it as a cornerstone of its approach to environmental protection.
The formula, known as I = P × A × T, was developed in 1971 by biologist Paul Ehrlich and scientist John Holdren. It holds that total environmental impact (I) equals population size (P) multiplied by per capita affluence (A) and a technology or efficiency factor (T).
Reading the Formula
The value of the equation lies in how its parts interact. Improve technology, and impact per person may fall. Grow the population, and total impact can climb anyway. Colcom Foundation’s resource page uses this relationship to explain why progress on one variable can be undone by movement in another.
U.S. data from 1970 to 2021 serve as the Foundation’s evidence. Per capita CO2 emissions dropped 35% during that period, while population increased 62%. Total emissions still rose by a net 15%. Colcom Foundation draws these figures from its Our Story documentation, which tracks U.S. population growth and ecological footprint from 1970 to the present.
From Theory to Grantmaking
The formula helps explain why Colcom Foundation addresses both consumption and population. Its stated mission is to foster a sustainable environment for all Americans “by addressing the major causes and consequences of overpopulation and its adverse effects on natural resources.”
Grants cover a wide spread of activity. Some target the technology side of the equation through clean energy, recycling and reuse programs, and alternative transportation. Others protect land and habitat directly through acquisitions, conservation easements, reforestation, and endangered species preservation. Still others fund public education on how population growth affects the environment.
The page frames these efforts as complementary. Efficiency gains, it argues, translate into real environmental improvement only when population growth is limited and large natural areas are permanently protected. Without both conditions, the Foundation contends, the additional demands of more people tend to absorb whatever progress technology delivers. Read this article for additional information.
More about Colcom Foundation on https://gwpa.org/redhen/org/347