The European Union vowed Friday to "fight" for science at the UN climate summit after accusing some countries of seeking to undermine the world's leading authority on global warming.
A long-running disagreement over when to publish the next major reports by the Intergovernmental Panel on Climate Change (IPCC) is spilling into the COP31 talks in Turkey, threatening to complicate negotiations toward a final deal.
The EU and dozens of other nations want the next set of IPCC reports available before a crucial stocktake of global efforts to cut planet-heating emissions at the 2028 edition of the annual climate summit.
Saudi Arabia, China and India are among those pushing for the IPCC's "seventh assessment report" to be delayed until 2029.
The IPCC is deadlocked over the timetable, but some countries want the matter put on the table in Turkey, where negotiations are approaching the midway point.
"We will fight for this outcome to be there," senior EU climate official Diana Acconcia told reporters, cautioning it would "not be so easy" to bridge the gulf on the issue.
"There are some parties that are trying to undermine what science is telling us because they don't want to do what it takes to address climate change," Acconcia said.
"It is as simple as that," she added, lamenting the "polarised" nature of the debate.
The IPCC publishes a series of reports every seven years that provide the definitive scientific assessment of climate change and inform global policy responses to the crisis.
Pierre Friedlingstein, a climate scientist from the University of Exeter and author of previous IPCC assessments, said it was "always best for policy decisions to be based on the most up-to-date science".
"Updated figures are more appropriate than figures that are seven years old," he told AFP in Antalya.
"Presenting new evidence can help drive political decisions forward. That said, it is clear that this does not suit certain countries. They would prefer to stay where we were before."
Some countries fear updated findings could expose the gap between climate action and what is needed to limit warming at the 2028 global stocktake, several negotiators in Antalya told AFP.
The IPCC's last meeting in October failed to resolve the impasse, and the session was suspended until December 1.
"It's no secret that IPCC faces operational challenges and reputational risks from the current impasse on the timeline," IPCC chairman Jim Skea said in a speech on the first day of COP31.
Skea urged delegates to "use your influence here to prepare for a successful outcome" at the December meeting, reminding them that IPCC scientists volunteered their time to draft the reports.
Observers are not optimistic of resolving the dispute at COP31, where decisions must be taken by consensus among the nearly 200 nations that participate.
Those arguing for a delay say more time is needed for developing countries in particular to digest the thousands of pages of technical scientific findings.
But the Alliance of Small Island States and the Least Developed Countries group -- two blocs representing more than 70 developing nations -- have already expressed support for publishing the report in 2028.