Pope Francis called on leaders at the COP28 climate summit in Dubai Saturday to step up and achieve a "breakthrough" on saving the planet.
"May this COP prove to be a turning point, demonstrating a clear and tangible political will that can lead to a decisive acceleration of ecological transition," he said.
The 86-year-old pontiff also said the world should move to end using fossil fuels.
The speech by Francis, who cancelled his trip to the United Nation climate talks due to the flu, was read by the Vatican's second highest officer, Cardinal Secretary of State Pietro Parolin.
The transition must be "efficient, obligatory and readily monitored" and apply to "four sectors: energy efficiency; renewable sources; the elimination of fossil fuels; and education in lifestyles that are less dependent on the latter," he said.
"Please, let us move forward and not turn back," said the pope, who has made ecology one of the major themes of his papacy and whose 2015 encyclical "Laudato si" ("Praise be") laid out the Vatican's case for defending the environment.
"May the year 2024 mark this breakthrough," he told COP28.
Last month Francis published another text on climate challenges, "Laudate Deum" ("Praise the Lord"), which called on developed economies to stop using fossil fuels.