koldioxiden

Koldioxiden is the term used in several Nordic languages to denote carbon dioxide, the chemical compound with the formula CO2. It is a colorless, odorless gas at room temperature that occurs naturally in Earth's atmosphere at trace levels. It is produced by respiration in living organisms, decomposition of organic matter, volcanic activity, and the weathering of carbonate rocks. Human activities, including burning fossil fuels, cement production, and various industrial processes, have raised atmospheric CO2 concentrations, reinforcing the greenhouse effect and contributing to climate change. CO2 cycles between air, oceans, biosphere, and sediments.

Physically, CO2 is non-flammable and denser than air. It dissolves in water to form carbonic acid, along with bicarbonate and carbonate ions, a chemistry central to ocean and freshwater systems. A solid form, dry ice, sublimates at −78.5 °C at one atmosphere. Industrially, CO2 is used to carbonate beverages, for refrigeration and transport as dry ice, as a shielding gas in welding, and as a feedstock in chemical syntheses such as urea production.

Environmentally, rising atmospheric CO2 levels are linked to an enhanced greenhouse effect and ocean acidification, with widespread ecological and climatic implications. Global monitoring programs track CO2 concentrations, while policy measures seek to reduce emissions and promote mitigation strategies such as energy efficiency, renewable energy deployment, and carbon capture and storage. The name reflects its composition: one carbon atom bonded to two oxygen atoms.