Nitrous Oxide (N2O) is the third most important individual greenhouse gas. Nitrous oxide (N2O) is approximately 310 times more effective in trapping heat than carbon dioxide on a molecule for molecule basis. Nitrous oxide (N2O) has an atmospheric lifetime of about 114 years.
- The Natural Nitrous Oxide Cycle
- The Impact of Human Activities
The natural nitrous oxide cycle
Nitrogen is removed from the atmosphere by plants and converted into forms such as ammonia, which can then be used by the plants. This is called nitrogen fixation. At the same time, micro-organisms remove nitrogen from the soil and put it back into the atmosphere - denitrification - and this process produces nitrous oxide. Nitrous oxide (N2O) also enters the atmosphere from the ocean.
The impact of human activities
Globally, anthropogenic nitrous oxide emissions are primarily from fertiliser use in agriculture. Land use change also contributes to nitrous oxide (N2O) emissions. Sewage treatment plants may also be a source of this gas.
Since pre-industrial times (1750), the atmospheric nitrous oxide (N2O) concentration has increased from 270 ppb to 319 ppb in 2005 with an increase of approximately 18% since pre-industrial values.
Due to the long time it spends in the atmosphere, the nitrous oxide (N2O) that we release today will still be trapping heat well into the next century.