Since the dawn of the Industrial Revolution, humans have so vastly altered Earth’s systems that we’re now in the midst of what many are calling the Anthropocene Epoch. Human activity has become the dominant influence on climate and the environment, inflicting changes that may persist for millennia.

We are razing the planet’s last intact wild lands, degrading, deforesting, carving up, and destroying huge swathes of habitat. We’re overfishing and poisoning our rivers and oceans. We continue to pump greenhouse gases into the atmosphere, raising CO2 levels and hastening climatic changes that are already affecting all life on Earth.

In the quarter century the Wilson Center’s Environmental Change and Security Program has been pondering the issues for which it’s named, the world’s demographic future has been wobbling. A key concern of analysts: How many people will farmers need to feed in 2050? Mainstream projections have teetered between 8.9 billion and 9.8 billion, amounting to an increase of between 13 and 21 percent over today’s 7.7 billion. This significant variation in projections is rarely acknowledged by prognosticators. Many simply round up today’s latest guess and state confidently that there will be 10 billion people in 2050—though just a few years ago, the number most confidently stated was 9 billion.

Early scholarship on environmental peacemaking recognized the important role that local civil-society can play in promoting regional cooperation while, at the same time, pressuring governments to protect the environment. For example, in the late 1980s/early 1990s, nongovernmental organizations (NGOs), such as the Union for Defense of the Aral Sea and Amu Darya in Uzbekistan and the Dashowuz Ecological Club in Turkmenistan, were at the forefront of the fight to restore the Aral Sea and protect the region’s biodiversity.

First published 30 years ago in the National Interest, Francis Fukuyama’s landmark essay, “The End of History?,” argued that, with the fall of fascism and communism, no serious blueprint for modern-state development lay open, save for those paths that would ultimately embrace both political and economic liberalism. Over the past two decades, movement toward this ideal end-state has trickled to a halt. Instead, the political elites of Eurasia’s regional powers—Russia, Turkey, Iran, and China—have crafted stable illiberal regimes that borrow whatever they need from free-market economics, electoral politics, nationalism, and religion. Their ascent has produced a form of “non-endpoint stability”—two mutually antagonistic camps: one composed of liberal democracies, the other a mix of illiberal hybrids. As long as these camps remain stable, the international system falls far short of Fukuyama’s theoretical end of history.

Exactly 25 years ago the international community met in Cairo for the 1994 International Conference on Population and Development. In the aftermath of the Cold War, ethnic conflict seemed to be exploding globally and research on the role of population growth and resource scarcity found an eager audience among policy makers struggling to understand this new international disorder. ECSP’s founding in that same year positioned the program as a leader in bringing together the scholarly and policy communities around non-traditional security issues over the last 25 years. The last two-and-a-half decades have brought tremendous change in population trends, environmental change, and the security landscape. Over the next 25 years three trends will shape the agenda of those working on the nexus of population-environment-security issues.

Climate change is widely recognised as one of the major forces shaping the future. Climate impacts illustrate in stark clarity how human actions fundamentally affect the basic physical processes of the planet with vast and, in the worst cases, disastrous consequences for communities around the world. Given these profound impacts, climate change is increasingly treated as a security risk. As a changing climate is causing and will continue to cause diverse impacts across the globe, the associated security challenges are multifaceted. They involve human, community, state, and international security risks, and will require responses across all levels of decision-making, from the local to international.