Turning on the television, driving a car, drying hair, and using the air conditioner all use energy. This energy usually comes from burning fossil fuels like natural gas, petroleum and coal. Burning these fuels releases carbon which combines with oxygen and increases the amount of carbon dioxide in our the atmosphere. Also, many third-world countries are cutting down forests to make room for people, farming, and raising cattle. This mass removal of trees is called deforestation.
Trees release oxygen in to the atmosphere and take carbon dioxide from the atmosphere.
The fewer trees there are, the more carbon dioxide stays in the air. When the trees are cut down, they are usually burned which releases even more carbon into the air. We can conserve energy by simply being more conscious of the way we use energy. Turning off electrical appliances when they are not in use, carpooling and reducing the overall amount of fossil fuels we burn will be a big help. The Troposphere is the area we are most familiar with.