Leaders from the Group of 20 major economies on Monday issued a joint statement highlighting the suffering caused by conflicts in Gaza and Ukraine, while calling for cooperation on climate change, poverty reduction and tax policy.

G20 leaders meeting at Rio de Janeiro's Modern Art Museum for a two-day summit tackled an agenda that reflected 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 at the summit were able to reach a narrow consensus on the escalating Ukraine war, focused succinctly on "human suffering" and the economic fallout of the conflict.

The leaders' statement also expressed "deep concern about the catastrophic humanitarian situation in the Gaza Strip," and called urgently for more aid and protection for civilians along with a comprehensive ceasefire in Gaza and Lebanon.

Russian President Vladimir Putin did not attend the summit, and Moscow was represented by Foreign Minister Sergey Lavrov.

It took marathon negotiations over the weekend for diplomats to finalise the joint statement, with debate over climate policy stretching into the dawn hours of Sunday, according to people involved in the talks.

In their statement, leaders agreed the world needs to reach a deal by the end of the United Nations Cop29 climate change summit in Azerbaijan on a new financial goal for how much money rich nations must provide to poorer developing nations.

Cop29 officials had called on the G20 leaders for a strong signal to help breach the impasse on climate finance.

While the joint statement said nations need to resolve the issue, they did not indicate what should be the solution at the UN summit set to end on Friday.

As host of this year's G20 meetings, Brazil expanded the group's focus on extreme poverty and hunger, while introducing debate on cooperation to fairly tax the world's wealthiest – topics also highlighted in the leaders' joint statement.

Brazilian 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.

President Xi Jinping also took the occasion to announce a raft of measures designed to support the developing economies of the "Global South," from scientific cooperation with Brazil and African nations to lowering trade barriers for least developed countries. (Reuters)