IB Environmental systems and societies 8.1 Human Populations Key Definitions

An age-sex pyramid visually represents the composition of a population by age groups and gender.

Biocapacity is the capacity of a biologically productive area to continuously provide renewable resources and assimilate the waste generated by human activities.

A carbon sink is any natural or artificial system that absorbs more carbon than it releases, thus removing CO₂ from the atmosphere.

The dependency ratio is a measure of the proportion of dependents (people under 15 and over 64) to the working-age population (15–64 years). It is calculated as:

The Doughnut Economics model, proposed by economist Kate Raworth, offers a framework to address these challenges by balancing human needs with planetary boundaries.

Environmental migration refers to the movement of people caused by changes in the environment, which can be either sudden or gradual.

Food security is defined as the physical and economic availability of food, ensuring all individuals can access the balanced diet necessary for a healthy and active life.

Malnutrition is the condition of having an inadequate or unbalanced diet, including both insufficient intake (undernourishment) and excessive intake (overnourishment).

Population momentum refers to continued population growth even if the fertility rate declines.