Methane is a powerful greenhouses gas with a 100-year global warming potential 28-34 times that of CO2. Measured over a 20-year period, that ratio grows to 84-86 times.
About 60% of global methane emissions are due to human activities. The main sources of anthropogenic methane emissions are the oil and gas industries, agriculture (including fermentation, manure management, and rice cultivation), landfills, wastewater treatment, and emissions from coal mines. Fossil fuel production, distribution and use are estimated to emit 110 million tonnes of methane annually.
Methane is the primary component of natural gas, with some emitted to the atmosphere during its production, processing, storage, transmission, distribution, and use. It is estimated that around 3% of total worldwide natural gas production is lost annually to venting, leakage, and flaring, resulting in substantial economic and environmental costs.
Coal is another important source of methane emissions. Coal mining related activities (extraction, crushing, distribution, etc.) release some of the methane trapped around and within the rock. Methane is emitted from active underground and surface mines as well as from abandoned mines and undeveloped coal seams.
The geological formation of oil can also create large methane deposits that get released during drilling and extraction. The production, refinement, transportation and storage of oil are all sources of methane emissions, as is incomplete combustion of fossil fuels. No combustion process is perfectly efficient, so when fossil fuels are used to generate electricity, heat, or power vehicles these all contribute as sources of methane emissions.
On a global scale, methane emissions from oil and natural gas systems account for 1,680 MtCO2e. The estimates are considered to be uncertain and are thought to be low.
Based on the best currently available data, around 3.6 trillion cubic feet (Tcf) (or 102 billion cubic meters (bcm)) of natural gas escaped into the atmosphere in 2012 from global oil and gas operations. This wasted gas translates into roughly U.S. $30 billion of lost revenue at average 2012 delivered prices, and representes about 3% of global natural gas production.
Emissions are expected to grow under a central growth scenario by 23% between 2012 and 2030.
Regarding the global reduction potential by 2030, it is estimated that emissions could be reduced by 26% using existing technology (equal to 1,219 MtCO2e).
Despite methane’s short residence time, the fact that it has a much higher warming potential than CO2 and that its atmospheric volumes are continuously replenished make effective methane management a potentially important element in countries’ climate change mitigation strategies. As of today, however, there is neither a common technological approach to monitoring and recording methane emissions, nor a standard method for reporting them.