How can 8 billion people sustainably share a planet?

As of November 15, the world's population has exceeded 8 billion people — a growth of another billion in just over a decade. "The growth of the world population is a remarkable success story," said Sara Hertog, a population expert with the United Nations in New York, highlighting the 25-year increase in average global life expectancy since 1950 and declining birth rates that come with better access to reproductive services, family planning and more education opportunities for girls and women. "Biodiversity loss, climate change, pollution, deforestation, water and food shortage — these are all exacerbated by our huge and ever-increasing numbers," said UK-based NGO Population Matters. "It's rising incomes that have been much more important than population growth in driving increased consumption and associated pollution," she said, pointing out that the world's richest countries, where population growth has slowed or reversed, are using the most resources per capita. To meet the needs of the current world population, environmental NGO Global Footprint Network has estimated that we need an unsustainable 175% of the world's ecological resources every year.