People affect the environment as they interact with it, using it for food, shelter, and recreation and making changes to better suit their needs, purposes, and inclinations. Through our ability to adapt natural resources to our use, we have altered the environment in ways that can now be objectively measured. This publication presents images from space that portrays the nature and extent of our impact on the planet. Chapter 3 examines common issues regarding the Earth’s land cover and provides examples that illustrate environmental status, trends, causes and consequences of change in the atmosphere, oceans and coastal zones, freshwater ecosystems, forests, cropland, grasslands, urban areas, and tundra including polar regions.