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.

Units and measures

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 teragram, 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 teragrams.

Insights from this chart

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.”

About the data

The data is from NOAA’s Global Monitoring Laboratory. The atmospheric methane increase is calculated by taking the difference between consecutive deseasonalized January 1st averages. For recent years where we have only parts of the months available, we compare the average of the available months to that same period of the previous year.

Data sources

Globally averaged marine surface annual mean growth rates data NOAA's Global Monitoring Laboratory
Credits: Ed Dlugokencky, NOAA/GML (gml.noaa.gov/ccgg/trends/trends_ch4/)Update cycle: annualDelay: ~ 3 months

Globally averaged marine surface monthly mean data NOAA's Global Monitoring Laboratory
Credits: Ed Dlugokencky, NOAA/GML (gml.noaa.gov/ccgg/trends/trends_ch4/)Update cycle: monthlyDelay: ~ 3 months