Methane is the number two greenhouse gas in the atmosphere in terms of effect (quantity x potency)
Average Methane Levels by Year
Information obtained from the NOAA Earth System Research Laboratory
Measurements taken at Mauna Loa Hawaii. Annual numbers derived by averaging daily measurements for each year.
Starting 2015 I am excluding 1987 data from this chart as that year's records began in April
I thank Ed at NOAA for kindly keeping me informed about the latest dataset activity
December 10, 2016 update: I've come across a website which publishes methane levels more frequently, with apparently a different method of measurement.
The 2015 daily figures have been posted and the chart updated accordingly
Note: 5 days were missing from the 2015 dataset, these days were filled by propagating previous readings to obtain the average figure.
Previous years with missing data were treated in the same way, the overall data image should be very close to reality.
This chart is updated once a year, after the data is posted
Zoom out 420,000 years and you get this:
This chart showing Methane, Carbon Dioxide and Temperature Variation was created by Reg Morrison and published at http://regmorrison.edublogs.org/files/2012/03/Climate-Debate4-1if6jnl.pdf
© Reg Morrison
The increase in Methane has been generally ongoing since records have been kept starting in 1987 except for a lull in the early 2000's and a sharp drop in 2016 although 2016's absolute level was still the 2nd highest. Current levels are unprecedented going back over 400 thousand years.
Annual Methane average level changes (parts per billion)
Derived from in situ air measurements at Mauna Loa, Observatory, Hawaii
See data credits for the first chart for source data
While the annual CO2 equivalency of Methane emissions is currently about a quarter of CO2, the fear is as oceans continue to warm and tundras melt a feedback loop will be triggered which will cause run-away massive levels of trapped Methane to escape into the atmosphere causing huge ecological changes which could bring about mass extinctions, including our own. So far, the worrisome uptrend in Methane levels which resumed in 2007 has been linear. Rather than wait for tipping point acceleration in the trend line, increased world wide action is required at an extraordinary level to turn these graphs of CO2 and Methane levels to the down side.
According to the EPA (http://epa.gov/climatechange/ghgemissions/gases/ch4.html), the sources of Methane emissions in the United States are:
29% - Natural Gas and Petroleum Systems (e.g. leaks in pipelines, gases escaping during fracking)
25% - Enteric Fermentation (e.g. gases from digestion released by cow belching and farting)
18% - Landfills
10% - Coal Mining
9% - Manure Management
9% - Other
Sam Carana at http://arctic-news.blogspot.com looks at the global method emissions and suggest large quantities are also being emitted via nature sources, some accelerated by global warming
28.1% - Wetlands
25.9% - Ruminants, Rice growing, Landfills and Waste
17% - Fossil Fuels and Biomass Burning (includes Biofuels)
16% - Other natural sources (Geological, lakes, wildfires, termites, etc.)
13% - Hydrates and Permafrost