Populations of organisms do not remain constant; the number of individuals within a population changes, sometimes dramatically, from one time period to the next. Ecologists have documented examples of ...

Population ecology is the study of how populations — of plants, animals, and other organisms — change over time and space and interact with their environment. Populations are groups of organisms of ...

Discover the significance of the working-age population, typically aged 15-64, in shaping economic outcomes and employment ...

More than a third of 50 recently surveyed Nobel laureates cited “population rise / environmental degradation” as the biggest threat to humankind. Second on the list was “nuclear war”, cited by 23 ...

The past 10 years have seen a steady increase in the number of international migrants across the globe, now totaling 214 million people. Ahead of the upcoming Commission on Population and Development, ...

Research shows that our rapidly growing human population increases pressure on society and the environment, making it harder to address problems ranging from public health concerns to climate ...

The senior population in the U.S. has grown as the baby-boom generation has progressed into the 65 years and older age group. In 2023, there were 59,307,056 Americans over the age of 65. This is a ...

Note (June 2025): Religious composition estimates in this report are based on 2010 baseline numbers that have since been updated. Please refer to our 2025 report “How the Global Religious Landscape ...