When measured by land transformation, the environmental footprint of U.S. population growth over the past half century is striking. By 2020, the United States had paved or developed an area of land equivalent to the combined size of Montana, West Virginia, and South Carolina. Agricultural operations consumed 52 percent of the country’s total land base. Conservation protections covered just 13 percent.

Colcom Foundation draws a direct line from these land use figures to the ongoing extinction crisis affecting American wildlife. The Endangered Species Act had 1,300 species listed as threatened or endangered by 2020. In 2021, federal officials proposed removing 23 species from the list not because they had recovered, but because they were gone. North American wildlife populations overall have declined by 20 percent since 1970.

Birds as a Measure of Ecosystem Health

Bird populations offer one of the most documented windows into ecological change. The North American bird population stood at approximately ten billion in 1970. By 2020, that number had fallen to seven billion a loss of 2.9 billion birds in fifty years. The decline tracks closely with habitat conversion from natural areas to developed and agricultural land.

The broader picture is similarly sobering. Wild vertebrate animal populations have fallen by roughly half since 1970, even as the human population doubled. The total weight of wild land animals now accounts for just one percent of all terrestrial vertebrate biomass, compared to 32 percent for humans and 67 percent for livestock. Ten thousand years ago, wild animals made up 99 percent of that total.

The 30×30 and Half Earth Benchmarks

Colcom Foundation notes that when biocapacity calculations are adjusted to reserve land for other species as the 30×30 initiative proposes with 30 percent of U.S. territory, or Half Earth with 50 percent American consumption rises to 341 percent or 478 percent of sustainable levels, respectively.

Colcom Foundation’s core argument is clear: addressing the extinction crisis and broader ecological overshoot requires confronting population growth, not only consumption patterns or industrial emissions. Read this article for related information.

More about Colcom Foundation on https://www.colcomfdn.org/