This year’s Convention to Combat Desertification focuses on rangelands and attempts to address an overlooked solution to climate change.By Georgina GustinIn Ulaanbaatar, Mongolia, policy makers, scientists and global negotiators are gathering to convey an urgent message: The world’s rangelands, which make up about half of Earth’s land surface, are in trouble. But these same lands offer an opportunity. If, collectively, farmers and land users restore rangelands and soils, they can combat drought and preserve a major global carbon sink.