It seems that all of a sudden, everybody is talking about methane. Many question why there is a sudden focus on methane, which is a short-lived gas in the earth’s atmosphere, and wonder if it is this detracting the focus from carbon dioxide, which is a long-life gas.

Methane has been identified as one of the fastest growing greenhouse gases, two-thirds of which emanate from human activity.

According to the UN Climate and Clean Air Coalition (UN CCAC), methane is responsible for 40% of global warming since the industrial revolution. It is 86 times more powerful than carbon dioxide over a 20-year period and is much more efficient at trapping radiation.

As it only has a lifetime of 12 years in the atmosphere, it is thought that reducing methane production will bring immediate benefits for the climate and human health. Methane is also the main precursor to tropospheric ozone, which is a powerful greenhouse gas and air pollutant.

Sources of methane

Scientists have found that atmospheric methane concentrations have grown as a result of human activity related to agriculture, including rice cultivation and ruminant livestock, coal mining, oil and gas production and distribution, biomass burning and municipal waste landfilling.

Emissions are projected to increase unless immediate action is taken. Agriculture has been identified as the source of 42% of methane emissions - 36% emanate from fossil fuel operations, 18% from waste and 3% from other sources.

Methods of reducing methane

The UN CCAC has identified a range of control measures that, if globally implemented by 2030, could reduce global emissions by as much as 40% and many with net savings.

Emissions from coal mining and the oil and gas sector could be reduced by 65% by preventing gas leakage during transmission and distribution, recovering and using gas at the production stage and by carrying out pre-mine degasification and recovery of methane during coal mining.

In agriculture, improved livestock feeding strategies could reduce 20% of global emissions by 2030, while 30% could be reduced from rice cultivation by operating what is known as alternate wetting and drying cultivation.

Agriculture

  • Improve manure management and animal feed quality.
  • Apply intermittent aeration of continuously flooded rice paddies.
  • Improve animal health and husbandry by combining herd and health management, nutrition and feeding management strategies.
  • Introduce selective breeding to reduce emission intensity and increase production.
  • Promote farm-scale anaerobic digestion to control methane emissions from livestock.
  • Adopt guidelines on healthy dietary choices.
  • Fossil fuels

  • Carry out pre-mining degasification and recovery and oxidation of methane from ventilation air from coal mines.
  • Reduce leakage from long-distance gas transmission and distribution pipelines.
  • Extend recovery and utilisation from gas and oil production.
  • Recover and use gas and fugitive emissions during oil and natural gas production.
  • Waste management

  • Separate and treat biodegradable municipal waste and turn it into compost or bioenergy.
  • Upgrade wastewater treatment with gas recovery and overflow control.
  • Improve anaerobic digestion of solid and liquid waste by food industry.
  • Upgrade primary waste water treatment.
  • Divert organic waste.
  • Collect, capture and use landfill gas.
  • Global methane pledge

    As reported previously by the Irish Farmers Journal, the EU and US announced a joint agreement to cut global methane emissions by 30% by 2030 from 2020 levels.

    The pledge commits countries to collectively reduce methane emissions from all sectors and to take comprehensive domestic action to achieve this 2030 target. It is not a commitment by individual countries to a 30% reduction, rather participants agree to take voluntary actions that will collectively reduce methane by 30%.

    Over 100 countries, including Ireland, accounting for 50% of anthropogenic methane, have signed up to the pledge.

    The sixth assessment report of the Intergovernmental Panel on Climate Change concluded that methane mitigation is a standout option for achieving near- and long-climate and air quality benefits. Essentially, this is a catalyst for global action which, if successful, could result in 0.2% warming by 2050.