Recent Publications

The Overpopulation Project studies the causes of human overpopulation and the role ending population growth can play in dealing successfully with global environmental and social problems. Believing that much of this century’s projected population increase can and should be avoided, we also explore humane policies to end population growth sooner rather than later. Our interdisciplinary work, straddling the disciplines of ecology, demography, policy analysis and environmental ethics, is made possible by generous funding from the Global Challenges Foundation and our home institutions: Colorado State University and the University of Gothenburg. Our recent scholarly reports include the following:

Population Growth and Climate Change: Addressing the Overlooked Threat Multiplier. Jenna Dodson, Patrícia Dérer, Philip Cafaro, and Frank Götmark. Science of the Total Environment 748, 141346 (2020) pdf may be obtained free up to late October at

Discussing Population Concepts: Overpopulation is a Necessary Word and an Inconvenient Truth. Frank Götmark, Jane O’Sullivan, and Philip Cafaro. International Journal of Population and Development. In press.

Human Fertility in Relation to Education, Economy, Religion, Contraception, and Family Planning Programs. Frank Götmark and Malte Andersson. BMC Public Health 20, 265 (2020):

The Social and Environmental Influences of Population Growth Rate and Demographic Pressure Deserve Greater Attention in Ecological Economics. Jane O’Sullivan. Ecological Economics 172 (2020): 106648.

From Population to Production: 50 Years of Scientific Literature on How to Feed the World. Lucia Tamborino et al. Global Food Security 24 (2020): 10036.

The Elephant in the Room: The Role of Interest Groups in Creating and Sustaining the Population Taboo. Karin Kuhlemann. In Almiron, N and Xifra, J (eds) “Climate Change Denial and Public Relations: Strategic Communications and Interest Groups in Climate Inaction” 1st edition (2019): 74-100.

The Potential Environmental Impacts of EU Immigration Policy: Future Population Numbers, Greenhouse Gas Emissions and Biodiversity Preservation. Philip Cafaro and Frank Götmark. Journal of Population and Sustainability 4 (2019): 71-101.

How Should Ecological Citizens Think About Immigration? Philip Cafaro and Jane O’Sullivan. Ecological Citizen 3 (2019): 85-92.

Policy-based Population Projections for the European Union: A Complementary Approach. Philip Cafaro and Patricia Dérer. Comparative Population Studies 44 (2019): 171-200. Animated populated projections.

Complexity, Creeping Normalcy and Conceit: Sexy and Unsexy Catastrophic Risks. Karin Kuhlemann. Foresight 21 (2019): 35-53.

Aging Human Populations: Good for Us, Good for the Earth. Frank Götmark, Philip Cafaro and Jane O’Sullivan. Trends in Ecology and Evolution 33 (2018): 851-862.

Immigration Ethics: Creating Flourishing, Just, and Sustainable Societies in a World of Limits. Addison Phillips. Masters thesis, Department of Philosophy, Colorado State University, 2018 (directed by Philip Cafaro).

Discussing Population Growth in the Magazine Sveriges Natur 1950-1995 and 2014-2017. Ann-Marie Ljungberg. Masters thesis Department of Biological and Environmental Sciences, Gothenburg University, 2018 (directed by Frank Götmark).

‘Any Size Population Will Do?’: The Fallacy of Aiming for Stabilization of Human Numbers. Karin Kuhlemann. Ecological Citizen 1 (2018): 181-189.