Carbon dioxide (CO2) is a colorless, odorless gas composed of one carbon atom bonded to two oxygen atoms. It is a crucial component of Earth's atmosphere, constituting about 0.04% of the air. CO2 plays a fundamental role in the carbon cycle, as plants absorb it during photosynthesis, converting it into oxygen. Human activities, such as burning fossil fuels and deforestation, have led to an increase in atmospheric CO2 levels, contributing to the greenhouse effect and climate change.
In industry, CO2 is used for various purposes, including carbonation in beverages and as a refrigerant.