Carbon Dioxide

Definition

From the point of view of the scientific discipline of chemistry, the concept of carbon dioxide refers to a molecule in which two oxygen atoms are bonded to a central carbon atom. Technically speaking, at standard pressure and temperature (near mean sea level pressure and at 0 degrees Celsius) CO2 exists as a gas. Only at lower temperatures, below minus 78 degrees Celsius, the gas deposits directly in its solid form: dry ice. Carbon dioxide exhibits a variety of traits, making it useful for contemporary societies. To illustrate, the beverage industry uses the acidic characteristic of CO2 to produce carbonated drinks, like soda water. Another characteristic of the gas is its nonflammability. This is used, for example, in fire extinguishers.

Effects on Climate

In the second half of the 20th century, scientists increasingly alarmed the public about the relationship between the proportion of CO2 in Earth's atmosphere and global warming. Svante Arrhenius provided an argument mentioning the possibility of such warming in 1896. This relates to another quality of the chemical compound: CO2 in the atmosphere lets solar radiation pass onto Earth, but traps some of the radiation when reflected back toward space. In effect, the atmosphere is heating up—just like a greenhouse experiencing increasing temperatures under solar radiation. Thus, the more carbon dioxide is in the atmosphere, the more intense is the greenhouse effect. Based on this understanding, which is routinely elaborated on and updated by the Intergovernmental Panel on Climate Change (IPCC), many governments set up mechanisms to reduce the concentration of CO2 in the atmosphere.

Reduction Initiatives

For setting up such mechanisms, the sources of the increase of atmospheric carbon dioxide had to be identified. The Environmental Protection Agency (EPA), for example, names as the five largest human-related sources of carbon dioxide emissions as the combustion of fossil fuels, nonenergy use of fuels, iron and steel production, cement manufacturing, and natural gas systems. All these processes are not primarily targeted to produce carbon dioxide. Rather, CO2 is a by-product. Thus, carbon-as-waste is socially created by defining processes as designed to produce a specific output (for example, energy), while the by-product CO2 emission is implied as something not wanted.

At Kyoto, Japan, in 1997, the international community devised a central mechanism through which [Page 105]the concentration of atmospheric carbon dioxide was to be reduced: carbon markets. At these markets, permits to emit CO2 would be traded. Furthermore, the international community intended to reduce the amount of several other significant greenhouse gases in the atmosphere, rather than merely focusing on carbon dioxide. Other greenhouse gases have also been conceptualized in magnitudes of the global warming potential of CO2. This allowed using the market mechanism to target CO2 as well as equivalent greenhouse gases.

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