Human activities threaten the Earth's natural balance. Cutting down trees, pollute air and water or let the desert stretches are the ways in which humans alter the environment. If damage to the environment in which we live continue, Earth will soon be in danger. Could cease to be a living planet. Life is possible on Earth because the air holds that living beings need to breathe, the nutrients they need to feed and grow, and the right climate for a living, a climate that is neither too cold nor too hot. The area of the Earth on which life develops on plants, animals and microscopic organisms called biosphere. The biosphere consists of three areas: air, water and land. Between them there is a delicate natural balance that makes life comfortable for the beings that inhabit our planet. However, human activities over the past hundred years is altering this balance in a very fast pace. The consequences of our way of life are visible today in the forests, especially tropical forests, also in coastal and other aquatic environments. Pollution is one of the greatest dangers threatening the environment. All parts of the biosphere (land, water and air) pollution suffer. Pollute the air with smoke from industries and from our cars. Pollute rivers and lakes through sewage from the cities or toxic chemical dumping. The seas are polluted by oil, and fields with fertilizers and pesticides. The air, water and soil are essential for life, so we must take care of them. They give us the oxygen we breathe, the water we drink and the food we need to grow and reproduce. Among the most visible consequences of human activities on the environment are the extinction of animal and plant species, climate change and desertification. Each of us, our lifestyle, we can help improve the health of the planet on which we live. It is not easy to prevent pollution, but we must be aware of the problems we cause in order to make solutions.