Artificial light from Earth

© NAS

It’s World Population Day. Evidence of human habitation

Our photo today has been digitally altered by Nasa's Earth Observatory team to remove natural light, and doing so reveals just how much artificial light human settlements generate. We share this image to draw attention to the observance of World Population Day today. Each year, World Population Day encourages us to think about how our growing numbers might affect our future – and the future of the planet we live on. The event was inspired by The Day of Five Billion – 11 July 1987, when the United Nations estimated our global population reached that milestone. There are now 7.7 billion people in the world, and this figure is expected to reach 8.5 billion by 2030. Asia, which features on our homepage, is the most populous continent, with its 4.5 billion inhabitants accounting for about 60% of the world's population.