Methane (CH₄) is a simple hydrocarbon and the primary component of natural gas. It is composed of one carbon atom bonded to four hydrogen atoms, forming a tetrahedral molecule. Colorless, odorless, and highly flammable, methane is one of the most abundant and significant gases in both natural and industrial systems. It is produced through both natural processes and human activities, and plays a complex role in energy production and environmental change.

In nature, methane is generated by biological and geological processes. Biologically, it is produced by methanogenic archaea in anaerobic environments, such as wetlands, marshes, and the digestive tracts of ruminants like cows and sheep. This process, known as biogenic methane production, is a major contributor to atmospheric methane levels. Geologically, methane is found in fossil fuel deposits and can also be released from methane clathrates—ice-like structures containing methane trapped in ocean sediments and permafrost.

Human activities significantly contribute to methane emissions. The extraction and transport of fossil fuels—particularly oil and natural gas—account for a large share of anthropogenic methane. Agriculture is another major source, particularly enteric fermentation in livestock and emissions from rice paddies. Waste management practices, such as landfilling of organic waste, also release substantial amounts of methane into the atmosphere.

Methane is a potent greenhouse gas, with a global warming potential over 25 times greater than carbon dioxide over a 100-year period. Although it remains in the atmosphere for a shorter time than carbon dioxide, its impact on climate change is significant due to its efficiency in trapping heat. Efforts to reduce methane emissions have therefore become a priority in climate mitigation strategies. These include improving practices in agriculture, enhancing leak detection in natural gas infrastructure, and capturing methane from landfills and wastewater treatment plants for use as a renewable energy source.

In energy systems, methane is valued for its high energy content and relatively clean-burning nature compared to other fossil fuels. It produces less carbon dioxide per unit of energy released, making it a favored transitional fuel in the shift toward lower-carbon energy sources. However, controlling methane emissions throughout its lifecycle is essential to fully realize its environmental benefits.

Methane’s dual identity—as both a valuable energy resource and a powerful greenhouse gas—places it at the center of global discussions on energy sustainability and climate policy.