As global environmental change accelerates, understanding how population dynamics affect the environment is more important than ever. It seems obvious that human-caused climate change has at least something to do with the quadrupling of world population over the last 100 years.

The original version of this article, by Lisa Palmer, appeared on Future Food 2050.

As a boy growing up on the shores of Lake Victoria in Kenya, Harvard international development professor Calestous Juma noticed a thing or two about innovations designed to bring more food into his community. He noticed, for instance, that the fishermen were always tinkering with new ways to trap fish while his father, a carpenter, would build the traps. He also noticed that his grandmother, a peanut grower, and other farmers who grew traditional crops such as sweet potatoes, struggled with ways to increase production beyond simply planting the best quality seeds and tubers.

A roadside billboard in Malawi reads: “No woman should die while giving life.” But in many countries, death or grave injury during childbirth is an all too frequent occurrence. [Video Below]

In March, the Intergovernmental Panel on Climate Change released its latest comprehensive synthesis of climate change research. The report concludes that “impacts from recent climate-related extremes, such as heat waves, droughts, floods, cyclones, and wildfires, reveal significant vulnerability and exposure of some ecosystems and many human systems to current climate variability.”

World Population Day began in 1987 after public imagination was sparked by the idea that there could be 5 billion people on Earth. Today, we’re well past 7 billion and according to the latest UN projections, headed north of 9 billion by mid-century.