(Bernat Armangue | The Associated Press) COP25 President Carolina Schmidt, left, talks with party members during the closing plenary in Madrid, Sunday Dec. 15, 2019. Negotiators from almost 200 nations planned to gather for a final time at the U.N. climate meeting in Madrid early Sunday to pass declarations calling for greater ambition in cutting planet-heating greenhouse gases and in helping poor countries suffering the effects of climate change. But one of the key issues at the talks, an agreement on international carbon markets, has eluded officials even after the Chilean chair extended Friday's talks deadline to allow more time for negotiations.