Some environmental groups do address population, though often in nuanced and muted ways. The subject can quickly become controversial, with environmentalists arguing it is not how many people are on the planet, but what resources they consume.
For example, Wendy Becktold wrote in 2019 in Sierra, the magazine of The Sierra Club, that the annual carbon footprint of the average U.S. resident—assuming they drive a car, heat their home with coal or natural gas and eat meat and hop an airplane for vacations is as much as 15 times greater than a Ugandan farmer.
But the underpinnings of the population vs. resources argument are changing, with billions of people rapidly moving into the global middle class, consuming more resources as they do. As a consequence, environmental groups and the public need to think in new ways about the issue, said Eileen Crist, a Virginia Tech associate professor emerita in the Department of Science, Technology and Society, and co-editor of the 2012 book, “Life on the Brink: Environmentalists Confront Overpopulation.”
All told, there were about 7.8 billion people as of mid-2021. World population has been growing at a rate of between 1 percent and 2 percent a year since 1950, but for the first time in modern history, global population is expected to all-but-stop at about 10.9 billion by 2100, because of declining fertility rates, according to a 2019 Pew Research Center analysis of United Nations data.
Still, that’s a lot of people—enough to concern nearly 14,000 scientists who have as of mid-2021 signed a call for urgent global action on climate change and included population among several challenges that must be met if the world is to successfully confront climate upheaval. Population should be stabilized and slowly reduced in ways that ensure social integrity and protect human rights, wrote Oregon State University forestry professors William Ripple, Christopher Wolf and two other scientists in the journal BioScience, under the headline “World Scientists’ Warning of a Climate Emergency.”
Crist is one of the signatories from 158 countries to the BioScience article. In a memo to Inside Climate News, Crist wrote that renewable energy systems of the scale needed to replace fossil fuels, in a world where the global middle class is burgeoning and consuming more energy, “will require vast metal and mineral resources, infrastructure build-out, and land and sea area for solar and wind farms. These requirements entail more ecological destruction, pollution, and natural habitat constriction. Moving intentionally toward decreasing our numbers will help downscale the material-technological demands of a renewable-energy economy, while preserving Earth’s remaining biological heritage.”
Crist also observed that the world is “on course to surpass the 1.5-degree Celsius warming that climate scientists hope is a safe boundary.” But even under best-case scenarios, Earth and its inhabitants will face worsening droughts, floods, heatwaves, storms, sea-level rise and mega wildfires.
“These catastrophes will pummel and displace tens, if not hundreds, of millions of people,” she wrote. “With this specter at our doorstep taking proactive steps to address the population factor … is the starkly rational course.”