Officials from around the world are still working to agree on the fine print of the Paris climate accord after two weeks of talks, even as workers dismantle sections of the conferenced venue around them.
Diplomats and ministers prepared for a closing meeting at noon Saturday, a day past the original deadline, but success was still uncertain.
The U.N. talks in Katowice, Poland, are meant to provide a rulebook for all signatories of the 2015 accord, ensure financial support for poor countries and send a signal that countries are prepared to increase their efforts in years to come.
The rules for carbon emissions trading remain a key sticking point.
Scientists say emissions of greenhouse gas like carbon dioxide need to drop sharply by 2030 to prevent potentially catastrophic global warming.