Humanity is using Earth’s resources faster than the planet can sustainably replenish them, a new study published in Environmental Research Letters warns, with today’s population and consumption levels placing increasing pressure on ecosystems, the climate, and food security.
While the global population currently stands at about 8.3 billion, the planet could better sustainably support closer to 2.5 billion people if everyone enjoyed ‘comfortable living standards’ while staying within ecological limits.
Lead author Corey Bradshaw, professor of global ecology at Flinders University, said the findings show humanity is placing demands on Earth that cannot be maintained indefinitely.
“Earth cannot keep up with the way in which we are using resources. It cannot support even today’s demand without major changes, with our findings showing that we are pushing the planet harder than it can possibly cope,” Bradshaw said.
The international research team analysed more than 200 years of global population data alongside trends in carbon emissions, ecological footprints, and global temperatures.
They found that while the world’s population has continued to grow, the rate of growth began to slow in the early 1960s.
“This shift marked the beginning of what we call ‘a negative demographic phase’,” Bradshaw said.
“It means that adding more people no longer translates into faster growth. When we examined this phase, we found the global population is likely to peak somewhere between 11.7 and 12.4 billion people by the late 2060s or 2070s if current trends hold.”
The researchers argue that modern population growth has been made possible largely by heavy reliance on fossil fuels and by consuming natural resources faster than the planet can replace them.
“The truly sustainable population is much lower and closer to what the world supported in the mid-twentieth century,” Bradshaw said.
“Our calculations show a sustainable global population closer to about 2.5 billion people if everyone were to live within ecological limits and comfortable, economically secure living standards.”
The researchers stress that the study is not predicting an imminent collapse of civilization. Instead, they say it highlights the growing risks associated with exceeding Earth’s ecological limits, including climate change, biodiversity loss, food and water insecurity, and widening inequality.
Bradshaw said meaningful action is still possible if countries work together to reduce resource use, stabilise population growth, and better protect natural ecosystems.
“The choices we make over the coming decades will determine the well-being of future generations and the resilience of the natural world that supports all life,” he concluded.
