Leaders from the Group of 20 major economies on Monday discussed proposals to reduce poverty, support developing nations and reform global institutions to give more voice to the "Global South" as they braced for whiplash from U.S. foreign policy.

G20 leaders meeting at Rio de Janeiro's Modern Art Museum for a two-day summit tackled an agenda that highlighted a shifting global order, trying to shore up multilateral consensus before U.S. President-elect Donald Trump returns to power in January.

Their discussions of trade, climate change and international security will run up against the sharp U.S. policy changes that Trump vows upon taking office, from tariffs to the promise of a negotiated solution to the war in Ukraine.