Bookmark and Share

Methane vs. CO2 Global Warming Potential



 

Methane and Carbon Dioxide - CH4 and CO2

72 times.  Methane has a global warming potential 72 times greater than carbon dioxide over a 20 year period.  Compared with carbon dioxide, methane has a high global warming potential of 72 (calculated over a period of 20 years) or 25 (for a time period of 100 years).  (Intergovernmental Panel on Climate Change - IPCC - "Climate Change 2007:  The Physical Science Basis - Summary for Policymakers," Fourth Assessment Report -FAR, Working Group 1, Chapter 2, IPCC Secretariat, Geneva, Switzerland, February 2007, p. 212)

72 times.  Over 20 years, emission of 1 ton of methane has the same climatic impact as the emission of 72 tons of carbon dioxide.  "After Carbon Dioxide, Methane is the next most important GHG [greenhouse gas], because it has high capacity to absorb infrared radiation and is relatively abundant.  [T]he observed lifetime of methane, in today’s atmosphere, is on average 12 years.  Methane has a GWP [global warming potential] of 72 over a 20 year period, meaning that over this time period, the emission of 1 ton of methane will have the same climate impact as the emission of 72 tons of carbon dioxide, or in other words methane is 72 times stronger than carbon dioxide. When looking at a 100 year period of time, however, the emission of 1 ton of methane has the same climate impact as the emission of 25 tons of carbon dioxide."  Energy + Environment Foundation, info@eeocw.org, Global Warming Potentials, Energy + Environment OpenCourseWare, Washington, DC, 2008, p. 3)

Coal mines have traditionally vented methane into the atmosphere.

Coal mine ventilation systems are the biggest source of methane emissions, accounting for 81 billion cubic feet, or 51% of coal mine methane emissions in 2006. (2)

Kris Maher
The Wall Street Journal

 

64 times.  Number of times more potent that methane is compared to carbon dioxide as a heat-trapping gas.  “For the same volume, methane is 64 times more potent as a heat-trapping gas than carbon dioxide, and there is a lot of it.”  Methane compared to carbon dioxide. (Ian Hoffman, Staff Writer, “Global warming could trigger methane release,” The Oakland Tribune, Oakland, California, August 29, 2006 reporting findings in T. M. Hill, J. P. Kennett, D. L. Valentine, Z. Yang, C. M. Reddy, R. K. Nelson, R. J. Behl, C. Robert, and L. Beaufort, “Climatically driven emissions of hydrocarbons from marine sediments during deglaciation,” published online before print August 30, 2006, doi: 10.1073/pnas.0601304103 and published in print Proceedings of the National Academy of Sciences PNAS September 12, 2006 vol. 103 no. 37 13570-13574 pp. 13570–13574)

40 times.  Methane releases are 40 times more potent in terms of warming than CO2.  “As catastrophic as all this is, [Kevin Schaefer [kevin.schaefer@nsidc.org], a scientist at the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado] acknowledges his study underestimates what is likely to happen. The model does not measure methane releases, which are 40 times as potent in terms of warming as carbon.  Methane could have a big impact on temperatures in the short term, he says.  ‘There would be a lot of methane emissions. We're working on estimating those right now,’ he said.  The model also does not include emissions from the large region of underwater permafrost.  IPS previously reported that an estimated eight million tonnes of methane emissions are bubbling to the surface from the shallow East Siberian Arctic shelf every year.  If just one percent of the Arctic undersea methane (also called methane hydrates) reaches the atmosphere, it could quadruple the amount of methane currently in the atmosphere, Vladimir Romanovsky of the University of Alaska in Fairbanks previously told IPS.”  (Stephen Leahy, “Permafrost Melt Soon Irreversible Without Major Fossil Fuel Cuts,” IPS, Uxbridge, Canada, February 17, 2011 reporting findings in Kevin Schaefer, Tingjun Zhang, Lori Bruhwiler, Andrew P. Barrett, Amount and timing of permafrost carbon release in response to climate warming, Tellus B, 2011; DOI: 10.1111/j.1600-0889.2011.00527.x, article first published online on February 15, 2011)

30 times.  Number of times more potent methane is than CO2 in terms of heat-trapping potential. “Methane is a greenhouse gas more than 30 times more potent than carbon dioxide.”  How does methane compare to carbon dioxide?  (“Methane Releases From Arctic Shelf May Be Much Larger and Faster Than Anticipated,” Press Release 10-036, National Science Foundation, March 4, 2010)

25 times.  Methane GWP potency compared to carbon dioxide over a 100 year period.  “Methane is a relatively potent greenhouse gas. Compared with carbon dioxide, it has a high global warming potential of 72 (calculated over a period of 20 years) or 25 (for a time period of 100 years).  (Intergovernmental Panel on Climate Change - IPCC - "Climate Change 2007:  The Physical Science Basis - Summary for Policymakers," Fourth Assessment Report, Working Group 1, Chapter 2, IPCC Secretariat, Geneva, Switzerland, February 2007, p. 212)

23 times.  Methane has about 23 times the global warming potential of carbon dioxide when it is released into the atmosphere.  “Methane (CH4) . . . is the simplest hydrocarbon, and is the primary component of the natural gas that we burn for energy. Methane is also an important greenhouse gas, it has about 23 times the global warming potential of carbon dioxide when it is released into the atmosphere. There are many sources of methane. Some methane comes from human activities, for example, landfills, rice cultivation, and ruminant farm animals (like cows) are all large methane sources. Other large methane sources, like the ocean and wetlands, are natural.” (Monica Heintz, University of California, Santa Barbara, “Methane in the Ocean,” Ocean Explorer, ,” National Oceanic and Atmospheric Administration, Washington, DC, revised August 25, 2010)

21 times. Methane is about 21 times more powerful at warming the atmosphere than carbon dioxide.  “Methane (CH4) is a principal component of natural gas. It is also formed and released to the atmosphere by biological processes occurring in anaerobic environments. Once in the atmosphere, methane absorbs terrestrial infrared radiation that would otherwise escape to space. This property can contribute to the warming of the atmosphere, which is why methane is a greenhouse gas.  Methane is about 21 times more powerful at warming the atmosphere than carbon dioxide (CO2) by weight. . . Methane's chemical lifetime in the atmosphere is approximately 12 years. Methane’s relatively short atmospheric lifetime, coupled with its potency as a greenhouse gas, makes it a candidate for mitigating global warming over the near-term (i.e., next 25 years or so).” (U.S. EPA, Science - Greenhouse Gas Properties, Climate Change Division – 202-343-9990, Office of Atmospheric Programs, U.S. Environmental Protection Agency, Washington, DC, June 22, 2010)

20 Times.  Global warming potential of methane compared to carbon dioxide.    “In the ongoing debate over global warming, climatologists usually peg carbon dioxide as the most dangerous of the atmosphere's heat- trapping gases. But methane, a greenhouse gas 20 times more potent than carbon dioxide, might be even more problematic. According to Tessa Hill, a geologist at the University of California, Davis, more methane is released into the atmosphere from ocean deposits during periods of warming than previously thought.  This expelled methane increases temperatures and releases more methane, creating a positive feedback loop.” (Elizabeth Svoboda, “Global Warming Feedback Loop Caused by Methane, Scientists Say,” National Geographic News, August 29, 2006 reporting findings in Tessa M. Hill - tmhill@ucdavis.edu, J. P. Kennett, D. L. Valentine, Z. Yang, C. M. Reddy, R. K. Nelson, R. J. Behl, C. Robert, and L. Beaufort, “Climatically driven emissions of hydrocarbons from marine sediments during deglaciation,” published online before print August 30, 2006, doi: 10.1073/pnas.0601304103 and published in print Proceedings of the National Academy of Sciences, PNAS vol. 103 no. 37 13570-13574, September 12, 2006, pp. 13570–13574)  

Methane Heat-Trapping Potential Compared to CO2

methane carbon dioxide

Source: Adapted from IPCC, FAR, WG1, Chapter 2, February 2007, p. 212. 

 

CH4 - CO2 • Methane and Global Warming

methane carbon dioxide
 
Video of Kirk R. Smith making the above PowerPoint presentation, Carbon on Steroids: The Untold Story of Methane, Climate, and Health, California Air Resources Board, Sacramento, California, November 10, 2008.  How does methane compare to carbon dioxide?

 ___________________________________________________ 

Are policymakers failing to pay sufficient attention to the climate disruption risks of methane?

Focusing disproportionately on controlling those greenhouse gases like carbon dioxide that produce warming impacts in the distant future at the expense of not controlling those gases like methane that inflict climate disruption impacts in the immediate future, could yield a harvest of regrets.

In the words of Nobel Laureate Dr. Kirk R. Smith, doing so engenders the undesirable result of "spending more money to protect people thousands of years into the future and ignoring the needs of ourselves and our children." (1)

 ___________________________________________________ 

 

Increases in Natural Gas Production
Produce Increases in Methane Emissions

See accompanying PowerPoint presentation by Robert W. Howarth, Renee Santoro and Anthony Ingraffea, Developing Natural Gas in the Marcellus and other Shale Formations is likely to Aggravate Global Warming, Department of Ecology & Evolutionary Biology and School of Civil and Environmental Engineering, Cornell University, Ithaca, New York, March 15, 2011 

(1) Kirk R. Smith, PhD, Nobel Laureate, "Carbon on Steroids, The Untold Story of Methane, Climate, and Health," PowerPoint presentation to the California Air Resources Board (CARB), Sacramento, California, November 10, 2008, Slide 18.  See video of presentation.
(2) Kris Maher, “Mining Project Aims to Capture Methane,” The Wall Street Journal, New York, June 2, 2010

 
 
 
Bookmark and Share

Don't forget to bookmark this page
Methane Carbon Dioxide Global Warming Potential