Arctic methane emissions help increase methane levels in the atmosphere. While the Arctic is one of many natural sources of methane, human activities now also play a role because of climate change. In the Arctic, the main human-influenced sources of methane include thawing permafrost, melting Arctic sea ice, breakdown of ice-like structures called clathrates, and melting of the Greenland ice sheet. This methane release creates a feedback loop that worsens global warming, as methane is a strong greenhouse gas. When permafrost thaws due to rising temperatures, large amounts of organic material become available for processes that produce methane, which can then be released into the atmosphere.
Since about 2018, global methane levels in the atmosphere have been increasing steadily. The increase in 2020 was 15.06 parts per billion, breaking the previous record set in 1991, and the increase in 2021 was even larger at 18.34 parts per billion. However, there is no current evidence linking the Arctic to this recent rise. In fact, a 2021 study found that methane contributions from the Arctic were likely overestimated, while contributions from tropical regions were likely underestimated.
Despite this, scientists believe the Arctic’s role in global methane trends will likely grow in the future. Evidence shows that methane emissions from a Siberian permafrost site have increased since 2004, linked to rising temperatures.
Reducing carbon dioxide emissions by 2050 (reaching net zero) may not be enough to stop the loss of summer Arctic Ocean ice. Reducing methane emissions is also needed, and this must happen even faster. These efforts should focus on three main areas: oil and gas, waste, and agriculture. Using available methods, these actions could reduce global methane emissions by about 180 million tons per year, or roughly 45% of current (2021) emissions, by 2030.
Observed values and processes
NOAA has updated its yearly records of methane levels in the atmosphere since 1984. These records show a large increase in the 1980s, slower growth in the 1990s, little change (including some years with lower levels) in the early 2000s, and a steady rise again starting in 2007. Since about 2018, methane levels have increased every year. The biggest yearly increase happened in 2020, when levels rose by 15.06 parts per billion (ppb), breaking the previous record from 1991. In 2021, the increase was even larger, at 18.34 ppb.
Methane stays in the atmosphere for 7–12 years, much shorter than carbon dioxide, which remains for hundreds of years. This means methane’s changes in the atmosphere are harder to track than those of carbon dioxide.
Scientists are worried about these trends. Some think they may be linked to natural methane emissions increasing beyond their levels before the industrial era. However, there is no clear evidence that the Arctic is connected to this recent rise. A 2021 study found that the Arctic’s role in methane emissions was often overestimated, while tropical areas were underestimated. This study suggested that methane from wetlands in tropical regions caused the recent increase. A 2022 study supported this, showing that tropical land areas were responsible for 80% of global methane changes between 2010 and 2019.
Still, scientists believe the Arctic may play a bigger role in methane trends in the future. Evidence shows that methane emissions from a Siberian permafrost area have increased since 2004, likely because of rising temperatures.
Research using radiocarbon dating of methane in lake bubbles and soil found that 0.2 to 2.5 petagrams of carbon from permafrost has been released as methane and carbon dioxide over the past 60 years. The 2020 heat wave in Siberia may have released large amounts of methane from permafrost.
Methane released from permafrost could add about 205 gigatons of carbon to the atmosphere by the end of the 21st century, possibly causing an extra 0.5°C (0.9°F) of warming. However, a study based on carbon types in Antarctic ice suggests that methane from permafrost and methane hydrates was not a major source during past climate changes, which may mean future emissions from these sources could be smaller than expected.
Methane levels in the Arctic are 8–10% higher than in the Antarctic. During cold periods, this difference becomes very small. Scientists think land areas are the main reason for this difference, though one 2007 study suggested the Arctic Ocean’s role may have been overlooked. In tundra areas, soil temperature and moisture levels greatly affect how much methane is released from the soil.
Sources of methane in the Arctic
Large amounts of methane are stored in the Arctic in natural gas deposits, permafrost, and as undersea clathrates. Permafrost and clathrates break down when temperatures rise, which can lead to large methane releases from these sources due to global warming. Other methane sources include submarine taliks, river transport, ice complex retreat, submarine permafrost, and decaying gas hydrate deposits. A 2024 study estimated that Arctic–Boreal landforms release about 48.7 (13.3–86.9) Tg CH₄ per year, with marine sources contributing around 4.9 (0.4–19.4) Tg CH₄ per year. Permafrost holds nearly twice as much carbon as the atmosphere, with about 20 gigatons of methane trapped in clathrates. When permafrost thaws, it can create thermokarst lakes in ice-rich yedoma deposits. Methane frozen in permafrost is slowly released as the ground thaws.
Global warming in the Arctic increases methane release from existing stores and from the breakdown of organic material. Methanogenesis, the process of methane production, requires completely oxygen-free environments, which slow the release of old carbon. A 2015 review in Nature found that methane emissions from thawed anaerobic permafrost sites were 75–85% lower than from aerobic sites, and methane emissions made up only 3 to 7% of CO₂ emissions by weight of carbon. These emissions still contributed 25–45% of CO₂’s climate impact over 100 years, but aerobic thaw had a greater warming effect overall. However, a 2018 study in Nature Climate Change found that methane production in anaerobic sites became equal to CO₂ production once methanogenic microbes were established. This increased the warming impact of anaerobic thaw sites.
Since methanogenesis requires oxygen-free conditions, it is often linked to Arctic lakes, where methane bubbles can be seen. Lakes formed by thawing ice-rich permafrost are called thermokarst lakes. Not all methane produced in lake sediments reaches the atmosphere, as some is destroyed in the water or sediment. Observations from 2022 show that at least half of the methane in thermokarst lakes escapes into the air. Another major source of methane emissions is the collapse of permafrost-stabilized hillsides, known as retrogressive thaw slumps (RTS). These processes, along with thermokarst lake formation, are called abrupt thaw because they rapidly expose large amounts of soil to microbes in days, unlike the slow, gradual thaw of most permafrost. In 2019, three permafrost sites that would have remained frozen under the "intermediate" climate scenario for 70 years experienced abrupt thaw. A 2020 Siberian heatwave caused RTS numbers to increase 17-fold in the Taymyr Peninsula, and soil carbon release rose 28-fold, averaging 11 grams of carbon per square meter per year.
Until recently, models of permafrost carbon feedback (PCF) focused on gradual thaw because abrupt thaw was hard to model and assumptions about methane production rates were incorrect. A 2018 study using field data, radiocarbon dating, and remote sensing found that abrupt thaw could more than double permafrost carbon emissions by 2100. A 2020 study showed that under high-emission scenarios (RCP 8.5), abrupt thaw emissions across 2.5 million km² would match the feedback of gradual thaw across all 18 million km² of near-surface permafrost. This would add 60–100 gigatonnes of carbon by 2300, increasing emissions by ~125–190% compared to gradual thaw alone.
Scientific debate remains about methane production rates in thawed permafrost. A 2017 study found that less than 10% of methane emissions in thawing peatlands with thermokarst lakes came from old, thawed carbon, with most from modern organic matter. A 2018 study suggested that rapid peat formation in thermokarst wetlands might offset increased methane release. Another 2018 study noted that permafrost emissions are limited after thermokarst thaw but increase after wildfires. A 2022 study found that methane emissions from permafrost thaw initially peak at 82 milligrams per square meter per day but decline by nearly three times as the permafrost bog matures, suggesting emissions may decrease over decades to a century.
A 2015 study found that Arctic sea ice loss increases methane emissions from tundra, with emissions from 2005–2010 being about 1.7 million tonnes higher than they would have been with 1981–1990 sea ice levels. Researchers noted that further sea ice loss could raise Arctic temperatures and methane emissions from wetlands.
Cracks in Arctic sea ice expose seawater to air, allowing mercury in the air to dissolve into water. This mercury enters the food chain, harming fish and the animals and people who eat them. Mercury is naturally present in the atmosphere and also comes from human activities.
The clathrate gun hypothesis suggests that changes in ocean currents during the Quaternary caused methane clathrates on continental slopes to be released, rapidly warming the planet. Methane is a powerful greenhouse gas, with a global warming potential 72 times greater than CO₂ over 20 years and 25 times over 100 years. These warming events may have caused Bond cycles and interstadial events like the Dansgaard–Oeschger events.
A 2018 study suggested methane hydrates would contribute "negligible" warming by the end of the century but could raise global temperatures by 0.4–0.5°C over millennia. The 2021 IPCC Sixth Assessment Report no longer listed methane hydrates as potential tipping points, stating it is "very unlikely" that clathrate emissions will
Reducing methane emissions
Over half of the methane released into the air comes from human activities in three main areas: fossil fuels (35%), waste (20%), and agriculture (40%). In the fossil fuel area, oil and gas activities like extraction, processing, and distribution add 23% of emissions, and coal mining adds 12% of these emissions. In the waste area, landfills and wastewater make up about 20% of human-caused emissions. In agriculture, emissions from livestock manure and the digestion process in animals account for about 32%, and rice farming contributes 8% of human-caused emissions. Using available methods, these emissions could be reduced by about 180 million tons each year, or 45%, by 2030.
Reducing CO2 emissions by 2050 may not be enough to stop the loss of summer Arctic Ocean ice. Reducing methane emissions is also needed, and this must happen even faster.
From 2021 to 2023, ARPA-E supported a research project to create a "smart micro-flare fleet" that burns methane at remote locations.
A 2012 review found that most current technologies work best with small methane gas streams (0.1%) and are suitable for areas where methane is released in small amounts.
Using Best Available Technology (BAT) and Best Environmental Practices (BEP) in petroleum gas flaring at Arctic oil and gas sites can greatly reduce methane emissions, according to the Arctic Council.