Reforming the very nature of capitalism will be needed to combat the growing appeal of populist political movements around the world, the World Economic Forum said Wednesday.

Getting higher economic growth, it added, is necessary but insufficient to heal the fractures in society that were evident in the election of Donald Trump as U.S. president and Britain’s vote to leave the European Union.

In a wide-ranging report from the organizer of the annual gathering of political and business leaders in the Swiss resort of Davos, the WEF identified “rising income and wealth disparity” as potentially the biggest driver in global affairs over the next ten years...