Professor Paul Ehrlich who recently passed away<\/a>, analysed more than two hundred years of global population records and used ecological growth models to track how population size and growth rates have changed over time.<\/p>\nThey tested the direction of these trends and compared results across world regions. They also measured how population size has historically aligned with changes in climate, emissions, and the ecological footprint to understand how human numbers cause environmental stress.<\/p>\n
The study found that before the 1950s, global population growth actually sped up as human abundance increased. More people meant more innovation, more energy use, and more rapid technological development that supported further expansion.<\/p>\n
However, this pattern broke down in the early 1960s when the global growth rate began to fall even as the population continued to rise.<\/p>\n
\u201cThis shift marked the beginning of what we call \u2018a negative demographic phase,\u201d says Professor Bradshaw.<\/p>\n
\u201cIt 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.\u201d<\/p>\n
Professor Bradshaw says this upper limit is dangerous and has only been possible to date because human societies have relied on fossil fuels and drained natural resources faster than nature can replace them.<\/p>\n
\u201cThe truly sustainable population is much lower and closer to what the world supported in the mid-twentieth century. 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,\u201d he says.<\/p>\n
The researchers say the enormous gap between that sustainable number and today\u2019s population of now 8.3 billion highlights the scale of global overconsumption. They argue that this overshoot has been hidden for decades by heavy reliance on fossil fuels, which boosted food production, energy supply, and industry, but also accelerated climate change and pollution.<\/p>\n
The study shows a strong link between increasing population size and rising global temperatures, larger ecological footprints, and higher carbon emissions during the negative phase. Total population size explained more variation in these environmental indicators than per-capita consumption.<\/p>\n
Professor Bradshaw says this highlights how both human numbers and consumption patterns jointly intensify environmental stress. \u201cHumanity\u2019s current path will push societies into deeper crises unless we make major changes,\u201d he says.<\/p>\n
\u201cThe planet\u2019s life support systems are already under strain and without rapid shifts in how we use energy, land, and food, billions of people will face increasing instability. Our study shows these limits are not theoretical but unfolding right now.\u201d<\/p>\n
The researchers stress that the study does not predict sudden collapse, but instead offers a realistic assessment of the long-term pressures shaping humanity\u2019s future. The consequences of overshooting Earth\u2019s \u2018biocapacity\u2019 include stronger climate impacts, declining biodiversity, reduced food and water security, and widening inequality.<\/p>\n
Professor Bradshaw says society must rethink how it uses land, water, energy, and materials if future generations are to live safe and stable lives.<\/p>\n
\u201cSmaller populations with lower consumption create better outcomes for both people and the planet,\u201d he says. \u201cThe window to act is narrowing, but meaningful change is still achievable if nations work together.\u201d<\/p>\n
The team hopes the findings encourage governments, organisations, and communities to plan for the long term, recognise Earth\u2019s environmental limits, and focus on strategies that reduce consumption, stabilise population, and protect natural systems.<\/p>\n
\u201cThe choices we make over the coming decades will determine the wellbeing of future generations and the resilience of the natural world that supports all life,\u201d concludes Professor Bradshaw.<\/p>\n
Acknowledgements:<\/p>\n
The Kids Research Institute Australia and Population Matters supported various aspects of the project.<\/p>\n
The paper, \u2018\u2018Global human population has surpassed Earth\u2019s sustainable carrying capacity\u2019<\/a>\u00a0by Corey J.A. Bradshaw, Melinda A. Judge (University of Western Australia), Daniel T. Blumstein (University of California, USA), Paul R. Ehrlich (Stanford University, USA), Aisha N. Dasgupta (University of Cambridge, UK), Mathis Wackernagel (University of California, USA), Lewis J.Z. Weeda (University of Western Australia) and Peter N. Le Sou\u00ebf (University of Western Australia) was published in Environmental Research Letters. DOI: 10.1088\/1748-9326\/ae51aa<\/p>\n","protected":false},"excerpt":{"rendered":"Getty Images The Earth has already exceeded its ability to support the global population sustainably, with new research…\n","protected":false},"author":2,"featured_media":575580,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[64,63,7961,282276,75,282277,4359,25347,282278,128,282279,148823,282280],"class_list":{"0":"post-575579","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-au","9":"tag-australia","10":"tag-climate-crisis","11":"tag-college-of-science-and-engineering","12":"tag-environment","13":"tag-global-ecology-lab","14":"tag-global-warming","15":"tag-population-growth","16":"tag-professor-corey-bradshaw","17":"tag-science","18":"tag-sdg12","19":"tag-sdg13","20":"tag-sdg6"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/575579","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=575579"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/575579\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/575580"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=575579"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=575579"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=575579"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/03\/Corey-Bradshaw-300x200.png\")
Matthew Flinders Professor Corey Bradshaw<\/p>\n