Leaders from the Group of 20 major economies have 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 US foreign policy.
G20 leaders meeting at Rio de Janeiro's Modern Art Museum for a two-day summit on Monday tackled an agenda that highlighted a shifting global order, trying to shore up multilateral consensus before US president-elect Donald Trump returns to power in January.
Their discussions of trade, climate change and international security will run up against the sharp US policy changes that Trump vows upon taking office, from tariffs to the promise of a negotiated solution to the war in Ukraine.
Still, leaders in Rio recognised that the G20 agenda, defined by this year's chair Brazil and reinforced by 2025 host South Africa, is already pushing conversations beyond the traditional comfort zone of Western powers.
"We are experiencing a major, major change in global structures," German Chancellor Olaf Scholz said on the sidelines of the summit, noting the growing weight of major developing economies.
"These are countries that want to have their say. And they will no longer accept that everything will continue to be the way it has been for decades."
Chinese President Xi Jinping took the occasion to announce a raft of measures designed to support the developing economies of the "Global South", from scientific co-operation with Brazil and African nations to lowering trade barriers for least developed countries.
While Xi played a central role at the summit, US President Joe Biden arrived as a lame duck with just two months left in the White House as he juggles escalating conflicts in Ukraine and the Middle East.
Diplomats drafting a joint statement for the summit's leaders have struggled to hold together a fragile agreement on how to address the escalating Ukraine war, even a vague call for peace without criticism of any participants, sources said.
A massive Russian air strike on Ukraine on Sunday shook what little consensus they had established, with European diplomats pushing to revisit previously agreed language on global conflicts. The United States has also lifted prior limits on Ukraine's use of US-made weapons to strike deep into Russia.
Russian President Vladimir Putin did not attend the summit, and Moscow was represented by Foreign Minister Sergey Lavrov.
Brazil's President Luiz Inacio Lula da Silva opened the summit on Monday with the launch of a global alliance to combat poverty and hunger, with backing from more than 80 countries, along with multilateral banks and major philanthropies.
"Hunger and poverty are not the result of scarcity or natural phenomena ... they are the product of political decisions," said Lula, who was born into poverty and entered politics organising a metalworkers union.
"In a world that produces almost six billion tons of food per year, this is unacceptable," he said.
Brazilian officials recognised the rest of their agenda for the G20 - focused on sustainable development, taxing the super-rich and reforming global governance - could lose steam when Trump starts dictating global priorities from the White House.
As the world awaits signals from Trump's incoming government, Xi has been touting China's economic ascendancy, including its vaunted Belt and Road initiative that inaugurated a massive deep-water port in Peru last week.
Trade talks around the G20 will be stoked by concerns of an escalation in the US-China trade war, as Trump plans to slap tariffs on imports from China and other nations.
Trump's tax-cutting verve will add to headwinds for a proposal for taxing the super-rich, an issue dear to Lula who put it on the G20 agenda and insisted in Monday remarks that global tax co-operation is key to reducing inequality.
