Its key temperature goal has been missed but experts say the agreement is still proving a vital moral compass for progress

It was a curious way of conducting negotiations. Ahead of the 2025 climate summit, in the Amazonian port of Belém last year, the Brazilian hosts had taken off the table the issue that most had assumed would be at its heart: concrete plans from each country laying out exactly what they would be doing to cut their greenhouse gas emissions.

Brazil was insisting, instead, that these plans - the bedrock of the Paris agreement - were the business of national governments and not up for negotiation. “In that case, it will be a very short Cop,” one seasoned global south negotiator told the Guardian shortly before, reflecting a widespread unease. “There is nothing to negotiate.”