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The world has exceeded its capacity to sustainably support the world’s population, with new research warning of increasing pressure on food security, climate stability and human health. However, slowing population growth and increasing global awareness can still give people hope.
Published in Environmental Research LettersThe study shows that humans have pushed well beyond the long-term capacity of the planet and that continued growth under current consumption patterns will exacerbate environmental and social problems worldwide.
The research analyzed more than two centuries of world population data and discovered a major shift in human behavior that began in the mid-twentieth century.
The lead author, Matthew Flinders Professor of Global Ecology Corey Bradshaw, of Flinders University says this method reveals a clear biological signal that people are living far from what the Earth can support.
Professor Bradshaw of the College of Science and Engineering’s Global Ecology Laboratory says: “The world will not keep up with the way we use resources.” It will not be able to support even today’s demand without major changes, as our research shows that we are pushing this planet harder than it can handle.
Researchers, including the late Professor Paul Ehrlich, analyzed more than two centuries of world population records and used ecological growth models to track how population and growth rates have changed over time.
They evaluated the direction of these methods and compared the results in regions of the world. They also measured how population size has historically adapted to changes in climate, emissions, and the environment to understand how human numbers cause environmental stress.
The study found that before the 1950s, global population growth increased as the number of people increased. Many people pointed to new methods, increased energy consumption, and rapid technological advances that support further expansion.
However, this trend collapsed in the early 1960s when the world’s growth rate began to decline and population growth continued.
Professor Bradshaw says: “This change marked the beginning of what we call the ‘bad demographic phase’.
“It means that adding more people no longer leads to faster growth.” Analyzing this trend, we found that the world’s population is likely to increase by somewhere between 11.7 and 12.4 billion people by the late 2060s or 2070s if current trends continue.
Professor Bradshaw says this upper limit is dangerous and has been until now because human societies are dependent on fossil fuels and depleting natural resources faster than nature can replace them.
“Truly stable populations are very low and close to what the world supported in the mid-20th century,” he says.
Researchers say the large gap between that fixed number and today’s population of 8.3 billion highlights the extent of global overexploitation. They argue that this excess has been hidden for decades by a heavy reliance on fossil fuels, which has fueled food production, energy supply and industry, but has also accelerated climate change and pollution.
The study shows a strong correlation between population growth and rising global temperatures, larger environmental footprints, and higher carbon emissions during the worst-case scenario. Total population size explained more variation in these environmental indicators than individual consumption.
Professor Bradshaw says this highlights how population and consumption patterns increase environmental pressure. He says: “The current way of people will push the society into serious problems unless we make big changes.
The world’s life support systems are already under pressure and without urgent changes in the way we use energy, land and food, billions of people will face increasing uncertainty.
The researchers emphasize that education does not mean a sudden collapse, but instead provides a realistic assessment of the long-term pressures that shape the future of people. The consequences of exceeding the Earth’s ‘biocapacity’ include severe climate impacts, reduced biodiversity, reduced food and water security, and increased inequality.
Professor Bradshaw says society must rethink how it uses land, water, energy and resources if future generations are to live safe and sustainable lives.
“Lesser populations with lower consumption produce positive outcomes for people and the planet,” he says. “The window for action is still narrow, but meaningful change can still be achieved if countries work together.”
The group hopes that the findings encourage governments, organizations and communities to plan for the long term, recognize the limits of the Earth’s environment, and focus on strategies to reduce spending, stabilize populations and protect natural systems.
Professor Bradshaw concludes: “The decisions we make in the coming decades will determine how the future generations will live and whether they will be able to withstand the natural conditions that will last them a lifetime.
Acknowledgments:
The Kids Research Institute Australia and Population Matters supported various aspects of the project.
Paper, ‘‘Global population has exceeded Earth’s carrying capacity’ by Corey JA Bradshaw, Melinda A. Judge (University of Western Australia), Daniel T. Blumstein (University of California, USA), Paul R. Ehrlich (University of Stanford, USA), Aisha N. Dasgupta (University of Cambridge, UK), Mathis Wackernagel (University of California, USA), Lewis JZ Weeda (University of Western Australia) and Peter N. Le Sou Australia (University of Western Australia) Environmental Research Letters. DOI: 10.1088/1748-9326/ae51aa
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