The UN Population Fund established World Population Day as a day of awareness about global population in 1987. As we approach seven billion just 24 years later, the UN is kicking off their 7 Billion Actions campaign, designed to raise awareness about the resource, health, and environmental challenges raised by our numbers. Population and its more detailed cousin-indicator, demography, impact the world in a great many ways – from contributing to resource scarcity and environmental destruction to creating social imbalances that can lead to civil instability.