Carbon dioxide (CO2) is a colorless, odorless gas that is present in Earth’s atmosphere. It is essential to life on Earth and is involved in many processes, including photosynthesis, respiration, the carbon cycle, and the greenhouse effect.
Carbon dioxide is produced by all aerobic organisms as a by-product of respiration. It is also produced by burning fossil fuels such as coal, oil, and natural gas. Carbon dioxide is removed from the atmosphere by plants during photosynthesis and by the ocean through a process called the biological pump.
The concentration of carbon dioxide in Earth’s atmosphere has increased significantly since the Industrial Revolution due to emissions from human activities such as the burning of fossil fuels and deforestation. This increase in atmospheric CO2 has led to global warming and climate change.
Carbon dioxide plays an important role in regulating Earth’s temperature through the greenhouse effect. When CO2 molecules absorb infrared radiation (heat), they re-emit it in all directions, both upwards towards space and downwards towards Earth’s surface. This downward heat transfer warms Earth’s surface and lower atmosphere causing what we experience as global warming. The more carbon dioxide there is in the atmosphere, the greater this warming effect will be.