G20 leaders gather in Brazil on Monday for a G20 summit set to be dominated by differences over wars in the Middle East and Ukraine, and implications of Donald Trump's White House return. Security considerations -- always high at such meetings -- were elevated further after a failed bomb attack late Wednesday outside Brazil's Supreme Court in Brasilia. Police were probing the two blasts as a possible "terrorist act" committed by a Brazilian perpetrator, whose death was the sole casualty.

The summit venue is in Rio de Janeiro, in the city's stunning bayside museum of modern art, which is the epicenter of a massive police deployment designed to keep the public well away. Brazil's leftwing President Luiz Inacio Lula da Silva will be using the opportunity to highlight his position as a leader championing Global South issues while also being courted by the West. That role will be tested in the months and years ahead as Latin America and other regions navigate "America First" policies promised by Donald Trump when he becomes US president in January.

At this G20, it will be outgoing President Joe Biden who will represent the world's biggest economy, but as a lame duck the other leaders will be looking beyond. Just before the Rio summit, on Sunday, Biden will make a stop in Brazil's Amazon to underline the fight against climate change -- another issue that Trump is hostile towards. The G20 meet is happening at the same time as the UN's COP29 climate conference in Azerbaijan -- and as.