As a backdrop to optimism, Belém has plenty to offer.

The waterside city in northern Brazil is the gateway to Amazonia and the rivers and rainforests that represent all that is rich, vibrant and vital in the natural world.

Host to the Cop30 climate summit, which begins next week, Belém is supposed to be a reminder to thousands of international delegates of what is at stake in their talks.

The global climate negotiation process was initiated in Brazil with the Rio Earth Summit in the hopeful 1990s. This is to be its homecoming.

It will be the 30th Cop convened since then and it takes place on the 10th anniversary of the Paris Agreement, formulated to strengthen resolve and ambition for the process.

You could pluck symbolism in handfuls from the mango trees.

But just days from the start of the gathering, the mood is subdued and Belém’s capacity to act as a beacon of hope for action on the climate crisis is uncertain.

“There isn’t a huge amount of optimism heading to this Cop from a political or scientific standpoint,” says Ross Fitzpatrick, who will be attending Cop30 for Christian Aid Ireland.

[ ‘They’re behaving like gangsters’: Will the rest of the world stand up to the US at Cop30?Opens in new window ]

The science is alarming, with recent reports from the World Meteorological Organisation and leading research institutes reiterating how perilous Earth’s position is.

Map of Brazil

Despite three decades of climate agreements, the concentration in the atmosphere of carbon dioxide, the main warming gas, is now the highest humans have ever encountered and still rising.

This year, 2024 and 2023 are set to become the three hottest years on record. The litany of worsening heatwaves, droughts, wildfires, floods, storms and loss of life and livelihoods keeps growing.

Politically, the temperature is also febrile.

“Climate denialism is back at a point we thought we’d moved on from,” Fitzpatrick says.

He refers to US president Donald Trump’s address to the United Nations General Assembly last month in which he claimed climate change “the greatest con job ever perpetrated on the world”.

The US isn’t the only problem.