The closing gavel was repeatedly pushed back as officials from big nations such as China, Brazil, Saudi Arabia, the United States and the European Union haggled through the weekend over the wording of key phrases in the text.
The report by the U.N. Intergovernmental Panel on Climate Change caps a series that digests vast amounts of research on global warming compiled since the Paris climate accord was agreed in 2015.
A summary of the report was approved early Sunday but agreement on the main text dragged on for several more hours, with some observers fearing it might need to be postponed.
The U.N. plans to publish the report at a news conference early Monday afternoon.
The unusual process of having countries sign off on a scientific report is intended to ensure that governments accept its findings as authoritative advice on which to base their actions.
At the start of the meeting, U.N. Secretary-General António Guterres called on delegates to provide “ cold, hard facts ” to drive home the message that there’s little time left for the world to limit global warming to 1.5 degrees Celsius (2.7 Fahrenheit) compared with preindustrial times.
While average global temperatures have already increased by 1.1 Celsius since the 19th century, Guterrres insisted that the 1.5-degree target limit remains possible “with rapid and deep emissions reductions across all sectors of the global economy.”
Observers said the IPCC meetings have increasingly become politicized as the stakes for curbing global warming increase, mirroring the annual U.N. climate talks that usually take place at the end of the year.
Among the thorniest issues at the current meeting were how to define which nations count as vulnerable developing countries, making them eligible for cash from a “loss and damage” fund agreed on at the last U.N. climate talks in Egypt. Delegates have also battled over figures stating how much greenhouse gas emissions need to be cut by over the coming years, and how to include artificial or natural carbon removal efforts in the equations.
As the country that has released the biggest amount of carbon dioxide into the atmosphere since industrialization, the United States has pushed back strongly against the notion of historic responsibility for climate change.
A previous version of this story corrected an erroneous reference to the United Nations, when it should have been the United States, in the third paragraph.