40% of Earth’s land is degrading. A UN summit wants to stop it.

Desertification is not the spread of deserts. It is the slow destruction of fertile soil, and it now affects 40 percent of the planet’s land surface. Every year, roughly 100 million hectares of once-healthy land become unproductive. This week, governments meet in Mongolia for the United Nations’ Cop17 desertification summit. Scientists warn that restoring soil health is no longer optional. It is critical for food security, for the livelihoods of billions, and for building resilience against climate change. The land that feeds us is quietly dying. The summit’s goal is to reverse that trend before it is too late.