From his perch in Hong Kong, Zhang Baohui worries how leaders in China, the United States and Russia will – or won’t – work with each other this year. If the three largest powers can find common ground on basic issues such as trade and fighting terrorism, global security will not be upset, says the director of the Centre for Asia-Pacific Studies at Lingnan University.

“But you never know,” he quickly adds. “If issues such as trade or the South China Sea develop, if these countries see each other as rivals, conflict could break out. That is my greatest fear.”

In Berlin, Henning Riecke of the German Council on Foreign Relations says his greatest concern focuses on whether Washington will remain a world leader in trying to slow the effects of climate change. The U.S. Environmental Protection Agency has been a “great player” internationally, he says, and the American leadership role cannot be easily replaced.