The COP30 climate conference in the city of Belem from November 10 to 21 will be preceded by a summit of heads of state and government on November 6-7 -- held separately this year to ease accommodation pressures.

Some 50,000 people are expected in Belem, which is home to 1.4 million residents, more than half of whom live in shantytowns.

With a shortage of traditional hotel rooms, conference organizers scrambled to find alternative accommodation in private homes, universities and schools, and even two cruise ships docked in the harbor some 20 kilometers (12 miles) from the conference center.

Prices skyrocketed, and environmental groups warned COP30 could be "the most exclusionary in history."

Insisting the conference be held in the Amazon -- a potent symbol of the importance of Earth's carbon-absorbing forests -- President Luiz Inacio Lula da Silva batted away concerns and said in February delegates can "sleep under the stars."

By Friday, 57 heads of state and government had confirmed their summit attendance, Brazil's chief negotiator Mauricio Lyrio told reporters.

Last year, 75 leaders attended COP29 in Azerbaijan, about half the number in Dubai in 2023.

The leaders of Germany, the United Kingdom, the Netherlands, Norway, Colombia, Chile, Cape Verde and Liberia will attend, their governments have confirmed to AFP.

China has said Vice Premier Ding Xuexiang will represent President Xi Jinping.

The United States and Argentina, led by climate skeptics, have not said who they will send, if anyone.

In all, 170 delegations are accredited for the main COP30 conference, taking place at a time of global political turmoil many fear will overshadow the climate emergency.