Brazil pushed for concerted action to alleviate hunger Monday as it hosted a summit of the Group of 20 leading economies amid global uncertainty over two major wars and incoming U.S. President-elect Donald Trump.

Set against a backdrop of political turmoil, it's going to be a big ask for the leading rich and developing nations to sign up to any meaningful declarations.

Prime Minister Justin Trudeau spent his first day at the G20 leaders' summit Monday speaking in closed-door meetings about issues like continental trade, fighting world hunger and multilateralism, as Donald Trump's impending return to the White House poses risks to global support for all those things.