• Biden will attend his last summit of world's leading economies.
• Lula da Silva promoting issues like fighting hunger, climate. 
• Antonio Guterres calls for G20 members to show "leadership". 

RIO DE JANEIRO: G20 leaders began arriving for a summit in Brazil on Monday to try reignite deadlocked climate talks and overcome their differences on the Middle East and Ukraine wars ahead of Donald Trump's return to the White House.

US President Joe Biden will attend his last summit of the world's leading economies, but as a lame duck leader eclipsed by Chinese President Xi Jinping, the most influential leader at this year's meeting.

Brazil's left-wing President Luiz Inacio Lula da Silva is using his hosting duties to promote issues close to his heart, including fighting hunger and climate change and taxing the super-rich.

But the wars which have bitterly divided G20 members are also set to feature prominently in the discussions.

A Brazilian foreign ministry source said Monday that some countries wanted to renegotiate a draft summit communique.

"For Brazil and other countries the text is already finalised, but some countries want to open up some points on wars and climate," he told AFP.

Biden's decision Sunday to allow Ukraine to use long-range US missiles to strike targets inside Russia — a major policy shift — could prompt European allies to also review their stance.

G20 leaders are also under pressure to try rescue UN climate talks in Azerbaijan, which have stalled on the issue of greater climate finance for developing countries.

UN Secretary-General Antonio Guterres has called for G20 members, who account for 80% of global emissions, to show "leadership" to facilitate a deal.

Security is tight for the gathering, which comes days after a failed bomb attack on Brazil's Supreme Court in Brasilia by a suspected far-right extremist, who killed himself in the process.

The get-together will cap a farewell diplomatic tour by Biden which took him to Lima for a meeting of Asia-Pacific trading partners, and then to the Amazon in the first such visit for a sitting US president.

Biden, who has looked to burnish his legacy as time runs down on his presidency, insisted in the Amazon that his climate record would survive another Trump mandate.

Spotlight on climate

All eyes at the stalled COP29 climate conference in Azerbaijan are on Rio to break an impasse over how to raise $1 trillion a year for developing countries to cope with global warming.

Rich countries want fast-developing economies like China and Gulf states to also put their hands in their pockets.

The meeting comes in a year marked by another grim litany of extreme weather events, including Brazil's worst wildfire season in over a decade, fuelled by a record drought blamed at least partly on climate change.

At the last G20 in India, leaders called for a tripling of renewable energy sources by the end of the decade, but without explicitly calling for an end to the use of fossil fuels.

Conspicuously absent from the summit is Russian President Vladimir Putin, whose arrest is sought by the International Criminal Court over the Ukraine war.

Lula, 79, told Brazil's GloboNews channel on Sunday that he did not want the wars in Ukraine and the Middle East to take the focus off global poverty.

"Because if not, we will not discuss other things which are more important for people that are not at war, who are poor people and invisible to the world," he said.

Taxing billionaires

The summit opens on Monday with Lula, a former steelworker who grew up in poverty, launching a "Global Alliance against Hunger and Poverty."

Brazil is also pushing for higher taxes on billionaires.

Lula had faced resistance to parts of his agenda from Argentinian President Javier Milei, a libertarian Trump uber-fan who met the Republican last week at his Mar-a-Lago resort.

The head of the Argentine delegation, Federico Pinedo, told AFP that Buenos Aires has raised some objections and would not "necessarily" sign the text, however. He did not elaborate.

But the Brazilian foreign ministry source on Monday downplayed the likelihood of Argentina blocking a consensus.