Home > Encyclopedia of Science > Carbon Dioxide

• History
• Properties and uses

Carbon dioxide is a chemical compound consisting of one part carbon and two parts oxygen and represented by the chemical formula CO₂. For a number of reasons, carbon dioxide is one of the most important gases on Earth. Plants use carbon dioxide to produce carbohydrates (sugars and starches) in the process known as photosynthesis. (In photosynthesis, plants make use of light to break down chemical compounds and produce energy.) Since humans and all other animals depend on plants for their food, photosynthesis is necessary for the survival of all life on Earth.

Carbon dioxide in the atmosphere is also important because it captures heat radiated from Earth's surface. That heat keeps the planet warm enough for plant and animal (including human) life to survive. Increasing levels of carbon dioxide in the atmosphere may...