The word environment often makes people think of protecting the Earth, but in truth the word environment is a scientific term. It means all the living and non-living things on Earth. Living things (biotic) include animals, plants, bacteria, algae, fungi, etc. Nonliving things (abiotic) include rocks, mountains, streams, lakes, rain, snow and even clouds, oxygen and carbon dioxide.
The Earth has many interconnecting cycles that keep it in balance. The water cycle keeps rain and snow falling and evaporating back up to the clouds over and over. The oxygen cycle depends on plants releasing oxygen that animals use and recycling carbon dioxide that they release. The nutrient cycle works as plants make energy from the sun and provide food for animals, which then release their nitrogen when they die back into the environment. The nitrogen is then used to nourish new growing plants all over again. These cycles are how our environment is balanced.
The environment does change over time. Glaciers advance and retreat. Temperatures change. Animals go extinct and populations evolve. The continents slowly drift over millions of years. Volcanoes erupt and spew carbon dioxide into the air. Hurricanes flatten forests and change the shape of shorelines.
Though our planet may seem like a vast and powerful place, we are affecting the Earth's biosphere. There are more than 6 billion people on Earth and our activities do affect the environment. In the topics below, read about how we have affected the planet and what we can do to protect it for generations to come.