In the discussion thread: Climate Change: Carbon Dioxide Levels In World's Air Reach 'Troubling Milestone' [View all]
Response to ErikJ (Reply #2)
Thu May 31, 2012, 02:43 PM
solarman350 (136 posts)
9. Methane is at least 21 times more effective at trapping heat in the atmosphere when compared to CO2
This post is just intended to add some support and depth to your claim:
Global Warming Potentials
The concept of a global warming potential (GWP) was developed to compare the ability of each greenhouse gas to trap heat in the atmosphere relative to another gas. The definition of a GWP for a particular greenhouse gas is the ratio of heat trapped by one unit mass of the greenhouse gas to that of one unit mass of CO2 over a specified time period.
As part of its scientific assessments of climate change, the Intergovernmental Panel of Climate Change (IPCC) has published reference values for GWPs of several greenhouse gases. While the most current estimates for GWPs are listed in the IPCC's Third Assessment Report (TAR), EPA analyses use the 100-year GWPs listed in the IPCC's Second Assessment Report (SAR) to be consistent with the international standards under the United Nations Framework Convention on Climate Change (UNFCCC) (IPCC, 1996). According to the SAR, methane is 21 times more effective at trapping heat in the atmosphere when compared to CO2 over a 100-year time period.
Now, let's see what Wikipedia Claims About This:
2011 methane concentration in the upper troposphere
Methane is created near the Earth's surface, primarily by microorganisms by the process of methanogenesis. It is carried into the stratosphere by rising air in the tropics. Uncontrolled build-up of methane in the atmosphere is naturally checked — although human influence can upset this natural regulation — by methane's reaction with hydroxyl radicals formed from singlet oxygen atoms and with water vapor. It has a net lifetime of about 10 years, and is primarily removed by conversion to carbon dioxide and water
Methane also affects the degradation of the ozone layer.
In addition, there is a large (but unknown) amount of methane in methane clathrates in the ocean floors as well as the Earth's crust. Most methane is the result of biological process called methanogenesis.
In 2010, methane levels in the Arctic were measured at 1850 nmol/mol, a level over twice as high as at any time in the previous 400,000 years. Historically, methane concentrations in the world's atmosphere have ranged between 300 and 400 nmol/mol during glacial periods commonly known as ice ages, and between 600 to 700 nmol/mol during the warm interglacial periods. It has a high global warming potential: 72 times that of carbon dioxide over 20 years, and 25 times over 100 years, and the levels are rising.
Methane in the Earth's atmosphere is an important greenhouse gas with a global warming potential of 25 compared to CO2 over a 100-year period (although accepted figures probably represents an underestimate). This means that a methane emission will have 25 times the effect on temperature of a carbon dioxide emission of the same mass over the following 100 years. Methane has a large effect for a brief period (a net lifetime of 8.4 years in the atmosphere), whereas carbon dioxide has a small effect for a long period (over 100 years). Because of this difference in effect and time period, the global warming potential of methane over a 20 year time period is 72. The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases (these gases don't include water vapour which is by far the largest component of the greenhouse effect). Usually, excess methane from landfills and other natural producers of methane is burned so CO2 is released into the atmosphere instead of methane, because methane is a more effective greenhouse gas. Recently, methane emitted from coal mines has been successfully utilized to generate electricity.
Set the World on fire already--in a "positive" feedback way!
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Replies to this discussion thread
|magical thyme||May 2012||#14|
Methane is at least 21 times more effective at trapping heat in the atmosphere when compared to CO2
|Uncle Joe||May 2012||#10|
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