An international food crisis is currently unfolding on a scale not seen since World War II. More than 20 million people in Somalia, Nigeria, South Sudan, and Yemen are in danger of famine. UN Under-Secretary-General and Emergency Relief Coordinator Stephen O’Brien said in March, “We are facing the largest humanitarian crisis since the creation of the United Nations.”

It’s often assumed that in the modern era, food security is an achievable goal. But between 2007 and 2008, a confluence of conditions shook the international food system to its core, fueling unrest and riots in more than 40 nations around the world. What’s more, this “perfect storm” may have been only a harbinger of challenges to come, according to a new report by Emmy Simmons of the Center for Strategic and International Studies (CSIS).

The effects of climate change combined with breakdowns in governance are leading to food insecurity “on a scale that we’ve rarely seen,” said Alex de Sherbinin, associate director of Columbia University’s Center for International Earth Science Information Network, at the Wilson Center on January 26.