In carbon cycle, sources release carbon dioxide into the atmosphere while sinks absorb or take in carbon dioxide from the atmosphere and store it. In this lesson, we will look at one of the largest sources of carbon dioxide -- fossil fuels. We will learn how fossil fuels were formed and how they're used to provide heat, energy, and transportation. And finally, we will learn about the impact of burning fossil fuels on the greenhouse effect.


Fossil fuels are natural materials, such as oil, coal, or gas, that are burned to create energy. You may know the word fossil; fossils are what remains of plants or animals that lived long, long ago. One example is the impression of a leaf or a small animal from millions of years ago that we see in a rock today. Fossil fuels are also what remains from living things from millions and millions of years ago.