Carbon dioxide

How it is used

Written CO2 and read 'C O two'. In climate work it is the reference gas: other gases are converted into CO2 equivalent (CO2e). Concentrations are given in parts per million (ppm) and emissions in tonnes. People also just say 'carbon': carbon emissions, cut carbon.

Example sentences

1. The concentration of carbon dioxide in the atmosphere is now above 420 ppm, compared with about 280 ppm before industrialization.

2. A cement kiln releases carbon dioxide both from burning fuel and from the limestone itself.

Common collocations

• carbon dioxide emissions
• release carbon dioxide
• absorb carbon dioxide
• atmospheric carbon dioxide
• tonnes of carbon dioxide

Related terms

• greenhouse gasA gas in the atmosphere, such as carbon dioxide, methane or nitrous oxide, that traps heat from the sun and warms the Earth's surface.
• CO2eShort for carbon dioxide equivalent: a unit that expresses the warming effect of different greenhouse gases as the amount of CO2 that would cause the same warming.
• carbon footprintThe total amount of greenhouse gases caused by a person, product, company or event, usually given in tonnes of CO2 equivalent.
• carbon sinkA natural or artificial system, such as a forest, ocean, soil or wetland, that absorbs more carbon from the atmosphere than it releases.
• fossil fuelA fuel such as coal, oil or natural gas, formed underground over millions of years from the remains of plants and animals. Burning it releases carbon dioxide.

More terms: Emissions and Carbon

• emissions
• net zero
• carbon neutral
• decarbonization
• carbon offset
• methane
• emission factor
• carbon credit