But fewer top leaders are making the trip to the Azerbaijani capital than went to COP28 in Dubai and the one before in Glasgow in 2021.

- G20 -

Only four G20 leaders from the world's major economies have so far confirmed their presence, according to AFP bureaus and a provisional list drawn up by the United Nations -- Britain's Keir Starmer, Italy's Giorgia Meloni, Recep Tayyip Erdogan of Turkey and Saudi Crown Prince Mohammed bin Salman.

Russian President Vladimir Putin is not likely to attend but his prime minister Mikhail Mishustin is expected.

Yet G20 countries are responsible for 77 percent of greenhouse gases, according to the UN.

- European Union -

Of the larger EU countries, only Spain (Pedro Sanchez) and Poland (Andrzej Duda) are sending leaders.

But the heads of government of Belgium, Bulgaria, Cyprus, Croatia, Denmark, Finland, Greece, Malta and the Czech Republic will attend, according to a provisional UN list that could yet change.

European Council chief Charles Michel is also due to give a speech Tuesday, though Commission President Ursula von der Leyen is not coming.

- Developing countries -

Dozens of leaders of poor countries threatened by climate change -- particularly African and Pacific nations -- are making the trip, led by Kenya's William Ruto and Bangladesh's interim leader Muhammad Yunus.

Mia Mottley, the Barbados premier who has for years pushed for reform of the system for climate funding, will also speak.

- Latin America -

Latin America will be hardly represented at all by its leaders, with Brazil's President Luiz Inacio Lula da Silva, Colombia's Gustavo Petro and the new Mexican leader Claudia Sheinbaum all absent.

Vice President Geraldo Alckmin will instead represent Brazil, which is holding COP30 in Belem in a year's time.