Air is important for the planet because it contains the gases necessary to support plants, animals and other organisms. Additionally, the presence of an atmosphere keeps the Earth at a habitable temperature.
The air on planet Earth is largely comprised of nitrogen and oxygen. Nitrogen is inert and does not affect most living organisms; however, all living animals require oxygen to survive. Plants require carbon dioxide to survive, which is also found in the earth’s atmosphere. Some bacteria require oxygen, but others are called anaerobic species, and they do not require oxygen. The balance of the various components of the atmosphere is very important to life on the planet.
If the world had no atmosphere, it would be very cold. Astronomers studying other planets know that planets without atmospheres have wildly fluctuating temperatures or they are cold all the time. The Earth’s air helps to moderate the temperature and make it a habitable place for living organisms.
The chemistry of the air surrounding the earth is very important. Currently, the world is warming as the ratio of carbon dioxide, methane and other gases increases. These chemicals are called greenhouse gases because they cause the planet to warm up, just as a greenhouse does.