Action Guide

Locate Sources of Methane and Other High-Impact Gases

Environmental Defense Fund

A greenhouse gas inventory typically includes carbon dioxide (CO2) as well as other greenhouse gases such as methane (CH4), hydrofluorocarbons (HFCs), and nitrous oxide (N2O). These other greenhouse gases can originate from various commercial and industrial sources, and their measurement and management are crucial alongside carbon dioxide.

Methane Emissions 

Reducing methane emissions is the fastest and most effective way to slow global warming. Methane is a short-lived climate pollutant that has a climate impact more than 80 times greater than carbon dioxide (CO2) over a 20-year time horizon. 

Agriculture and livestock represent significant sources of methane emissions. The agriculture sector accounts for 20% of the total global greenhouse gas (GHG) emissions when considering near-term impacts. Methane emissions in agriculture primarily result from enteric methane (gas produced by the digestive system of ruminant animals such as cows, sheep, and goats), the decomposition of livestock manure, and rice paddy cultivation. 

Methane emissions are also present throughout the oil and gas supply chain. According to EDF, the oil and gas industry emits 13 million metric tons of methane annually, which is enough wasted gas to fuel 10 million homes for a year. This is one of the reasons why natural gas is not considered a low-emission fuel. 


Refrigerants used in refrigeration and air conditioning systems can release emissions that contribute to global warming and ozone depletion. These emissions can be direct (from refrigerant gases) or indirect (from energy consumption). Common refrigerants, such as chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs), have high global warming potential, making them significant contributors to climate change. Hydrochlorofluorocarbons (HCFCs) have a lower global warming potential but are being phased out due to their ozone-depleting potential. 

Nitrous Oxide 

Over 70% of N2O emissions come from the agricultural sector, resulting from sources such as fertilized soil management and manure management. N2O is also a byproduct of fuel combustion from stationary sources, primarily the burning of coal at electric power plants, and mobile combustion, primarily from cars and other motor vehicles. N2O can also originate from industrial sources, such as the production of acids used as ingredients in fertilizers, nylon fibers, and plastics. Lastly, N2O is released in the treatment of residential and commercial wastewater.