Role of Non-CO2 gases and air pollutants
Apart from carbon dioxide (CO2), the climate system is affected by other substances in the atmosphere with human sources, including non-CO2 greenhouse gases and air pollutants. Some of these have a shorter residence time in the atmosphere than CO2. The residence time and the strength of the effects on climate are determined by processes in the atmosphere, including chemical processes between emitted species and physical processes including these species as well, influencing direct lights scattering and cloud cover and properties. In particular the effects of air pollutants, such as sulphate aerosols and soot, are very uncertain and the topic of continuing research.