The United Nations Convention to Combat Desertification is an agreement between countries to help stop deserts from growing larger. Deserts are dry areas of land with little rainfall, few plants, and animals. Deserts can grow larger and take over other areas of land if people don't take steps to protect the environment. The convention is an agreement to use technologies, policies, and other methods to keep the desert from growing bigger. This includes things like planting trees, using less water, protecting the soil, and so on.