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Reduce Methane Emissions

What is Methane (CH4)?

Methane is a colourless, odourless gas occurring abundantly in nature and as a product of certain human activities. Its chemical formula is CH4. Globally, it is the second most important greenhouse gas (GHG). Its contribution to global warming is estimated at 27 times that of carbon dioxide, over a 100 year period. Once produced, methane persists in the atmosphere for around 9-12 years after which it is eventually broken down into carbon dioxide and water. 

Methane and Agriculture

Biogenic methane (methane produced by animals and plants) is one of the predominant GHG emissions emitted from global agricultural, the majority of which is originates from ruminant livestock as enteric or manure methane. Ruminant livestock have a unique ability to convert grass into high quality sources of dairy and meat protein for human consumption. In the rumen or forestomach of ruminant livestock there is a microbial ecosystem with bacteria, archaea, protozoa and fungi, collectively known as the rumen microbiome. This microbial ecosystem allows ruminant livestock to obtain nutrition from plant matter. Enteric methane is a natural by-product of this process, and is estimated to account for some 90-95% of the methane associated with ruminant livestock.

Biogenic methane cycle, explained in text

Biogenic methane cycle: Methane (CH4) is emitted to the atmosphere by ruminant livestock as a by-product of feed degradation in the rumen (enteric) or from manure. Over the course of 9-12 years, methane is converted to carbon dioxide (CO2) and water (H2O). The carbon dioxide is eventually taken up and used by plants to grow, as part of photosynthesis, which are subsequently consumed by livestock, restarting the ruminant biogenic methane cycle.

How much methane does Irish agriculture produce?

A 500kg beef animal on a high concentrate diet produces 230 g methane per day and a 550kg dairy cow grazing on pasture emits about 320-330 grams of methane per day.

The reporting of Irish GHG emissions in 2022, as part of the national GHG inventory produced by the EPA, attributes 65% of Irish agri emissions to methane produced by the rumen of cattle and sheep. A further 9% of national agricultural emissions originated from methane associated with the storage of manure and slurry from ruminants, as well as pigs. This is produced by microbes that have passed through the animal in the faeces. Methane associated with ruminant livestock production accounts for three-quarters (74%) of Irish agricultural GHG emissions. As a result, reducing the volume of methane produced by ruminant livestock, will be critical to achieving the agricultural sectors 2030 GHG emissions reduction target.

What are the Solutions?

Enteric methane emissions

  1. Animal breeding - breed animals which emit less methane; this is a long term strategy
  2. Dietary supplementation/management - feeding of methane reducing supplements
  3. Improved animal health – a healthy animal will be more productive during its lifetime 
  4. Improving lifetime performance/reducing the age at finishing – finishing prime beef animals at a younger age can reduce the volume of methane produced over the animal’s lifetime.

Please note: All farms are unique and please contact your local Teagasc advisor for your individual enquiries before carrying out any solutions listed above.

On this episode of The Signpost Series which took place on Friday, 7 June 2024, host Mark Gibson, Teagasc Head of Outreach and Innovation was joined by Dr. Hazel Costigan & Dr. Laurence Shalloo, Teagasc to give an update on feed additives to reduce methane emissions. A questions and answers session took place at the end of the presentation, which was facilitated by Dr. Siobhán Kavanagh, Teagasc Signpost Programme.

Current Research Projects

Current Climate Centre research projects focusing on Reducing Methane Emissions

Methane Green Feeds

Across the entire organisation, Teagasc has some of the most up to-date and advanced research technology for measuring both enteric and manure methane emissions. Centres at Grange, Moorepark and Athenry, all have the capacity to measure individual feed intake, which is a critical factor influencing the quantity of enteric methane emitted by ruminant livestock. Read more about Methane Green Feeds here