“You can’t build a peaceful world on an empty stomach,” Secretary of State John Kerry said yesterday at a high-level working session on resilience and food security, quoting Norman Borlaug, the father of last century’s “Green Revolution.”

As presidents, prime ministers, and other policymakers from across the continent gather in Washington, DC, this week for the first-ever U.S.-Africa Leaders Summit, what are the issues to watch?

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.

As the largest-ever generation of young people enters adulthood, armed conflict is having a profound effect on their future. People under the age of 24 comprise nearly half the world’s population but are the primary participants in conflict today. Conflict is more prevalent in younger societies, and half of all forcibly displaced people are children.

“You can look into the future a couple decades and get a very good idea about where countries are going,” said Richard Cincotta during a presentation at the National Defense University last summer – at least when it comes to demography.

Rapid population growth can be a contributing factor to climate change vulnerability and should be considered in climate adaptation and peacebuilding efforts, said the Wilson Center’s Roger-Mark De Souza at a workshop on climate change adaptation and peacebuilding hosted by the Institute for Security Studies (ISS) in Addis Ababa.