carbon dioxide (CO2)

Colorless, odorless, non-combustible greenhouse-gas that contributes to global warming. Formed by complete combustion of fossil fuels (coal, charcoal, natural gas, petroleum) and carbon containing products (such as wood), it is released also through respiration by living organisms and by the gradual oxidation of organic matter in soil. Although relatively non-hazardous, it can create lethal oxygen-deficient environments in high concentrations (specially in confined spaces). It is one of the greenhouse gases and, since over the last 200 years its concentration in upper atmosphere has increased from 270 parts per million (PPM) to 350 ppm, it is said to be the cause of changes in global climatic patterns. Discovered in 1754 by the Scottish scientist Joseph Black (1727-1799). See also carbon monoxide.