Is the Earth really overpopulated? Yes, for two main reasons.

First, people are rapidly displacing wildlife species across the globe, initiating a mass extinction event. Second, we are degrading ecosystems that provide essential, irreplaceable environmental services that future generations will need to live decent lives. Both these trends are driven, in large part, by immense and unprecedented numbers of human beings. Because there are too many of us to share the Earth fairly with other species and with future human generations, Earth is overpopulated.

Overpopulation already exists for billions of poor people living under insecure conditions around the world: on unsuitable land, in unsafe houses, lacking fresh water, or living in severely polluted environments. Natural catastrophes such as drought, flooding, or earthquakes may kill people, but overpopulation does too, by severely increasing people’s vulnerability. But the news media rarely reports this fact.

Overpopulation exists today in crowded mega-cities where many residents have never seen a wild landscape. Even small green spots are disappearing in densely populated urban areas, which will become increasingly crowded as population growth and urbanization continue. The negative effects of crowding and lack of connection to nature are well documented.

We are currently 7.6 billion people and the United Nations predicts an increase of almost 4 billion by 2100 if current trends continue. Our overpopulation is obvious if we compare the population in 1960 (3 billion) to today’s and ask questions such as: “How serious a problem would climate change be if we had kept our population at 3 billion?” “How many fewer people would have died due to famine, conflict and war?” “How much less pollution and plastic garbage would there have been?” and “How much less food would have been needed and how many millions of acres of forests, grasslands, wetlands and other ecosystems would have been spared?”

Studies suggest that a future population of 11 or 12 billion could require a doubling of global food production. Tens of millions of people around the world already go to bed hungry every night. Continued population growth, combined with the uncertainties of climate change, could lead to much greater food insecurity in the years ahead. Meanwhile, the attempt to feed ever more people will inevitably come at the expense Earth’s remaining biodiversity, shrinking wild lands and extinguishing many thousands of species. Human beings have no right to act so selfishly and destructively. Earth is their home, too.

The word ‘overpopulation’ is rarely used by political leaders, the news media, or even many environmentalists. But a recent international survey showed that people in many countries consider overpopulation to be a serious problem. In this case, common people seem to be out in front of their leaders. They are also more willing to consider futures that do not rely on endless growth—an ecological impossibility on a finite planet.

The good news is that it is possible to end global population growth, fairly and without coercion. The right policies have already helped dozens of nations stabilize their populations, and many others have made substantial progress toward doing so. Ending population growth and then reducing current excessive populations are necessary steps toward creating ecologically sustainable societies. They will help enable future populations, human and nonhuman, to flourish far into the future.