Arctic methane emissions

Arctic methane emissions are releases of methane into the atmosphere from high-latitude natural and human sources, including wetlands, thawing permafrost, and fossil-fuel operations.

Methanogenesis: The microbial production of methane under oxygen-poor conditions. Anaerobic microbes produce much of the methane released from Arctic wetlands and thawing soils.
Methane: A colorless, odorless hydrocarbon gas with the chemical formula CH₄. This molecule is the emitted gas whose sources and atmospheric effects define the topic.
Greenhouse gas inventory: A quantified account of greenhouse gas emissions and removals within a defined area and period. Inventories estimate Arctic methane contributions from natural sources and industrial activity.
Atmospheric methane: Methane present in Earth’s atmosphere, where it absorbs infrared radiation and is removed through chemical reactions. Arctic emissions add to the atmospheric methane burden, alongside emissions from other regions.
Arctic methane budget: An accounting of methane sources and sinks across the Arctic region. The budget remains uncertain because emissions vary across space, seasons, and measurement methods.
Permafrost thaw: The warming and loss of ground that remains frozen for at least two consecutive years. Thaw exposes previously frozen organic matter to decomposition that can generate methane.
Permafrost: Ground that remains at or below 0°C for at least two consecutive years. It stores frozen organic carbon that can become available to methane-producing microbes as it thaws.
Earth system model: A computer model that represents interactions among the atmosphere, oceans, land, ice, and living systems. Models test how Arctic methane emissions may change as climate and landscapes shift.
Arctic amplification: The phenomenon in which the Arctic warms faster than the global average. Rapid Arctic warming can intensify thaw and ecosystem changes that affect methane release.
Permafrost carbon feedback uncertainty: Uncertainty in forecasts of how thawing permafrost will alter carbon emissions and climate. The balance between methane and carbon dioxide release shapes projected warming.

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