Human-induced CH4 emissions are the primary driver of the increase in atmospheric CH4. Its high global warming potential makes CH4 a very significant contributor to climate change.

Atmospheric CH4 and human-induced emissions

Latest data and insights on CH4 (Methane) levels in Earth's atmosphere, including human-induced (anthropogenic) CH4 emissions, increases, breakdowns, absorption, and carbon sinks.

CH4 Methane Levels and Emissions

What is the Yearly Atmospheric CH4 Methane Increase?

This is the difference in the atmospheric methane of a given year compared to the previous year. We call it an ‘increase’ because in recent history, most years have had more methane in the atmosphere than the previous year; however, several years have had a negative value, which means there was a decrease.

Methane has a large warming effect, considering its much higher Global Warming Potential (GWP) than CO2, but it only acts for a relatively brief period compared to CO2. Methane breaks down quickly in the atmosphere, and a reduction in emissions can cause a rapid decline in its levels and impact.

The yearly methane increase depends on the processes that emit methane into the atmosphere and on methane sinks, like atmospheric breakdown and soil reactions.

The primary unit here is parts per billion (ppb), which describes the increase in the concentration of atmospheric methane per year. The secondary unit here is a megatonne, which describes the weight of the increase of atmospheric methane per year. We show this to be able to relate to emissions, which are commonly expressed in megatonnes.

In the long term, there is an average yearly increase in atmospheric methane largely due to human emissions. There are still many uncertainties about the causes of the fluctuations. Since the 1980s there has been a reduction in the increase in atmospheric methane, and between 2000 and 2006 there was even a period of almost no increase. These reductions were partly due to the Mount Pinatubo volcanic eruption and the reduction of emissions in the oil and gas sectors. The high increase from 2014 to 2019 is thought to be partly due to prolonged El Niño conditions.

NOAA has reported a record increase in atmospheric methane during 2021: “For the second year in a row, NOAA scientists observed a record annual increase in atmospheric levels of methane, a powerful, heat-trapping greenhouse gas that’s the second biggest contributor to human-caused global warming after carbon dioxide.”

NOAA News: Increase in atmospheric methane set another record during 2021

The data is from several sources linked to the National Oceanic and Atmospheric Administration (NOAA). National Centers for Environmental Information has data from ice core studies where we average the extrapolated yearly increases of the individual studies. That is used for the time period prior to 1984 and highlights the long term trend, but does not show actual yearly fluctuations. Since 1983 NOAA has measured methane at a globally distributed network of air sampling sites.

Global Monitoring Laboratory provides annual methane mole fraction increase (ppb) from Jan 1 through Dec 31. For the current year we compare the available months to those a year earlier.

NOAA GML: Trends in Atmospheric Nitrous Oxide

Globally averaged marine surface annual mean growth rates data

Globally averaged marine surface monthly mean data

Law Dome Ice Core 2000-Year CO2, CH4, and N2O Data

Yearly Atmospheric CH4 Methane Increase

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What is the Yearly Average Atmospheric Methane?

This is the average amount of methane (CH4) that is in the atmosphere in a given year. The yearly average highlights the long-term trends and hides the seasonal variation.

Methane has a large warming effect, considering its much higher Global Warming Potential (GWP) than CO2, but it acts for a relatively brief period compared to CO2. Methane breaks down quickly in the atmosphere, and a reduction in emissions can cause a rapid decline in its levels and impact.

The primary unit here is parts per billion (ppb), which describes the average concentration of atmospheric methane per year. The secondary unit here is megatonnes, which describes the average weight of atmospheric methane per year. We show this to be able to relate to emissions, which are commonly expressed in megatonnes.

In 1983 humans started collecting atmospheric methane concentration measurements, and since then the concentration has risen from around 1645 ppb to more than 1900 ppb. To realize how high these concentrations are compared to pre-industrial values, we compare them to long-term historical concentrations revealed by ice core studies.

When we look at the last 1,000 years, we can clearly see that the methane concentration started rising at the end of the 18th century, coinciding with the industrial revolution.

Throughout the last glacial period, roughly 100,000 to 12,000 years ago, we can see a drastic variation in methane levels. It was also a drastic period! Ice sheets reached the northern parts of the US, the UK, Germany and Northeast Siberia. There were sea-level changes up to 120 meters. The changes in methane levels were smaller and much slower compared to what we have been experiencing over the last 200 years.

The last 800,000 years give perspective on the methane levels during recurring glacial periods and the unusually high methane level of our time. Current day level of over 1900 ppb was unheard of in the very long period with values between 350 ppb and 700 ppb.

Wikipedia: Methane in Earth&apos;s Atmosphere

The data is from two subgroups of NOAA, the Global Monitoring Laboratory for recent data and the National Centers for Environmental Information for paleoclimatology data.

The Global Monitoring Laboratory has an annual mean dataset starting in 1984.

National Centers for Environmental Information holds datasets that contain reconstructions of historic methane levels based on Antarctic ice cores.

Globally averaged marine surface annual mean data

Yearly Average Atmospheric CH4 Methane

What is the Monthly Average Atmospheric Methane?

This is the average amount of methane (CH4) that is in the atmosphere in a given month. The monthly average highlights the seasonal variation. The graph shows the last 3 years to highlight the seasonal variation.

We see a seasonal cycle with peaks around April and November and lows around February and July. A combination of the following causes drives these seasonal differences:

link.springer.com: Investigation of monthly and seasonal changes of methane gas with respect to climate change using satellite data

The data is from NOAA’s Global Monitoring Laboratory. We are specifically using the monthly average instead of the deseasonalized trend.

Monthly Average Atmospheric CH4 Methane

What are Human-Induced Yearly Methane Emissions?

These are the total yearly methane (CH4) emissions from human activities expressed as weight in megatonnes (Mt). In the scientific literature, these are referred to as anthropogenic emissions. Examples of human-induced emissions include rearing livestock, fugitive and combustion emissions from fossil fuels, and other sources, as you can see in the next breakdown chart.

Breakdown of Human-Induced Yearly Methane Emissions

Human-induced methane emissions increase atmospheric methane, which is warming the Earth. It has a large warming effect, especially since it has a much higher Global Warming Potential (GWP) than CO2. However, the effect lasts only for a relatively brief period (9 years on average), compared to hundreds of years for CO2. A reduction in emissions can cause a rapid decline in its atmospheric levels and climate impact.

The unit megatonne (Mt) describes the weight of emitted methane per year.

There has been steady growth in human-induced methane emissions since 1850. There was a period of fast growth between 1950 and 1970, which was largely due to the growth of the oil industry and the increased rearing of livestock; The oil industry releases large amounts of fugitive methane.

Current human-induced methane emissions are around 300 Mt per year, and all of these emissions end up in the atmosphere. The yearly increase in atmospheric methane is almost 50 Mt per year. The difference (around 250 Mt) is due to natural sinks of methane that remove methane from the atmosphere, such as atmospheric breakdown.

The scientific community has a high confidence in the accuracy of the atmospheric increase values, and is reasonably confident about the human emissions; however, there is less confidence about the natural emissions and natural sinks of methane.

The PRIMAP-hist dataset is a rich dataset that combines several published sources to create a historic emissions time series for methane and many other greenhouse gases.

Human-Induced Yearly CH4 Methane Emissions

What is the Breakdown of Human-Induced Yearly Methane Emissions?

This is a breakdown by source of the yearly methane (CH4) emissions from human activities and processes. It is expressed as weight in megatonnes (Mt). Human-induced methane emissions increase atmospheric methane, which is warming the Earth. The sources of human methane emissions are

Livestock emits methane that is produced in the animals&apos; digestive system. Most methane is emitted from the mouth during rumination. A much smaller amount of methane is emitted from the manure. Depending on how the manure is managed, i.e., wet or dry, more methane is emitted. Wet management leads to higher methane emissions than dry management. However, dry management also emits nitrous oxide (N2O), which is another potent greenhouse gas.

Fugitive emissions from fossil fuel industry

Fugitive methane emissions are from the intentional and accidental release of methane, which happens during the extraction, storage, and transportation processes in the fossil fuel industry. Examples are methane leaks during oil and gas handling, storage, transport, incomplete combustion, and many more. Also, methane is deliberately ventilated from mines during the extraction of coal.

Methane is a primary part of “gas”, also called “natural gas” or “fossil gas”. Natural gas is used, for example, for heating and electricity generation, whereby it emits CO2 during the combustion process. However, when natural gas leaks (unburned) it contains a lot of fugitive methane emissions.

Waste from landfills and wastewater produces a lot of methane when biodegradable material breaks down without oxygen.

Crop production emissions are largely from rice cultivation, which generates large amounts of methane during plant growth. These emissions are from flooded paddies, which create the swamp-like environment of rice fields. There are agricultural techniques to reduce emissions significantly, like periodic drainage and aeration. Rice is the main staple for about half the world’s population, and its emissions are a significant part of total human methane emissions.

Fuel combustion emissions are mostly from the incomplete combustion of fossil fuels. As mentioned before, natural gas consists largely of methane, and when the combustion does not happen completely, methane enters the atmosphere.

Other human-induced methane emissions include industrial processes and product uses.

Emissions from livestock and fugitive emissions from fossil fuels are the two largest contributors, each accounting for about a third of total emissions. Livestock emissions are still growing on a yearly basis with minimal fluctuation. Fugitive emissions from fossil fuels rose rapidly after the second world war until the 1970s and continued increasing until around 2005; since then, the emissions have been relatively stable till this day. Emissions related to waste are also very significant and also continue to increase steadily every year. Crop production and fuel combustion have had relatively stable emissions for a long time. Other sources of human-induced methane emissions are negligible.

Wikipedia: Atmospheric methane; Role in climate change

IPCC: AR6, 5.2.2.2 Anthropogenic CH4 emissions

The PRIMAP-hist dataset is a rich dataset that combines several published sources to create a historical emissions time series for methane and many other greenhouse gases.

Atmospheric CH₄ and human-induced emissions

Yearly Atmospheric CH₄ Methane Increase

Yearly Average Atmospheric CH₄ Methane

Monthly Average Atmospheric CH₄ Methane

Human-Induced Yearly CH₄ Methane Emissions

Breakdown of Human-Induced Yearly CH₄ Methane Emissions