The textbook outlines the fundamental principles governing the functioning of ecosystems and the biosphere as a whole, as well as the issues surrounding the biosphere's loss of stability and the unfolding global environmental crisis. It examines global environmental challenges—such as demographic issues, natural resource depletion, and energy-related problems—the resolution of which depends on humanity shifting toward a path of sustainable development. A general overview is provided regarding the principles and methods of protecting the biosphere from pollution and organizing environmental protection efforts, including within the framework of international cooperation.