Carbon dioxide (CO2) is an inorganic chemical compound with a wide range of commercial uses, from the production of lasers to the carbonation of soft drinks. This compound exists naturally in the Earth's environment, and it is produced in a variety of ways; commercial CO2 is usually derived from the byproducts of industrial processes. The simple gas has become a topic of interest for humans because it is classified among the greenhouse gases, which impact the Earth's environment when they reach high concentrations in the atmosphere.
This compound takes the form of two oxygen molecules covalently bonded to a single carbon molecule. It is produced through decomposition of organic materials as well as through respiration and combustion. The amount of carbon dioxide in the environment prior to the beginning of the 20th century were kept stable by plants, which are capable of absorbing this gas as it was produced for use in photosynthesis.
As early as the 1600s, people were beginning to think about carbon dioxide, although they didn't know what to call it. Flemish chemist Jan Baptist van Helmont made observations which hinted at its existence, setting the stage for breakthrough work in the 18th century by Joseph Black, a Scottish chemist who identified the compound and explored many of its properties. By the 1800s, people had succeeded in creating and studying many of its forms.
At room temperature, carbon dioxide takes the form of an odorless, colorless gas that is incombustible in normal conditions. It can be forced into a solid form, in which case it is known as dry ice, and the gas is toxic to animals in high concentrations. People who inhale too much essentially suffocate, ultimately falling into unconsciousness as their oxygen saturation level drops.
This gas is used for things like creating an inert environment for welding, fire suppression, and the carbonation of beverages. It is an important part of the carbon cycle, a complex cycle that underlies many of the mechanics of life on Earth. While this gas is entirely natural, some people began to be concerned about rising levels towards the end of the 20th century. Scientists became concerned that humans were producing too much of the compound for plants to process, a practice that could potentially lead to serious environmental problems.