Overpopulation: The Elephant in the Living Room
"Pressure resulting from unrestrained population growth puts demands on the natural world that can overwhelm any efforts to achieve a sustainable future."
-- "World Scientists' Warning to Humanity," 1993
Overpopulation is the most critical problem facing humanity. Overpopulation is a product of the number of people on Earth multiplied by their per capita consumption and waste production. Population growth is unsustainable. A short-term supply of cheap, abundant fossil fuels has temporarily enabled human population to greatly exceed the carrying capacity of the planet. World population has grown rapidly from 1 billion in 1804 to 2 billion in 1927, 3 billion in 1960 and 6.8 billion today. World population is projected to reach 9 billion by 2040.
The World Wildlife Foundation's "Living Planet Report, 2008" estimated that human ecological impact now exceeds the Earth's ecological carrying capacity by 25%. In the Western Hemisphere, the United States and Mexico have the most severe overpopulation problem. The US and Mexico each have an ecological footprint (impact) about twice the carrying capacity of their land, but the average person in the United States has three times the ecological impact of the average person in Mexico.
The United States has the second highest per capita ecological footprint of any nation (9.4 hectares per person). The United States has the world's worst overpopulation problem because we consume and waste the most. About 5% of the world's population lives in the United States, but the US accounts for 25% of global consumption and carbon dioxide emissions. The "American way of life" that George H.W. Bush said is "not negotiable," is made possible by extracting the wealth of other nations through imperialism.
If the average human had the same ecological impact as the average American, the Earth could now support a maximum of 1.45 billion people, with no room left for nature. Human demand on the biosphere more than doubled from 1961 to 2005. About one billion people now suffer from chronic malnutrition. Global carrying capacity will shrink with the effects of fossil fuel depletion, destructive agricultural practices, deforestation, and climate change.
Human population has grown by 4 billion since the "Green Revolution" started in 1950, using petrochemical fertilizers, pesticides, and hydrocarbon fueled irrigation to increase grain production by 250%. With the peak of global oil and natural gas production, these agricultural techniques cannot be sustained. A 2009 report from the Department of Energy projected that global production of all liquid fuels, including oil, will drop by 2030 to about half of what it is today, while energy demand continues to rise.
At the 1996 Earth Summit, the Presidential Council on Sustainable Development concluded that the world's human population should not exceed 500 million people. The UN Biodiversity Assessment of 1994 concluded: "A reasonable estimate for an industrialized world society at the present North American material standard of living would be one billion people."
Achieving a sustainable human population requires both a reduction in global birth rates substantially below replacement level and a radical restructuring of our way of life to reduce our ecological impact. We must move away from our energy intensive, mass consumption, automobile centered economy and destructive meat-based diet. We need to shift away from globalization toward decentralization, voluntary simplicity, a low-energy economy using appropriate technology and renewable resources, alternative transportation, and a plant-based diet.