04/09/2024
Methane (CH4) is a very simple substance that consists of one carbon atom and four hydrogen atoms. It is also called ‘natural gas’. Methane is created when organic matter decomposes and there is very little or no oxygen present.
Organic matter comes from plant and animal material or from micro-organisms, and 90–100% of it consists of C (carbon), H (hydrogen) and O (oxygen) atoms. The other 0–10% is made of minerals, which are important for our nutrition and health. Some important minerals are nitrogen, phosphorus, calcium and iron.
In agriculture, organic matter can decompose without oxygen. This happens in:
a) The digestive processes of ruminants (cattle, sheep and goats)
b) Manure storage of all farm animals
c) Wet rice cultivation
Natural sources of CH4 include thawing permafrost in the north of Russia and Canada. Due to climate change, the thawing of the permafrost is accelerating, which is releasing a lot of methane. Marshes and wet peat soils are the second largest natural source.
Slightly over half of all emissions, 51%, are made up of CH4 created by humans. The extraction of fossil fuels and livestock farming are the main sources of this (see figure), but our waste contributes to the formation of CH4 too.
The total global emissions of CH4 are estimated at an annual 750 megatons, of which 115 megatons are created by livestock farming. Dutch livestock farming emits around 0.6 megatons of methane annually. This is less than 1% of the total worldwide methane emissions from livestock farming.
