Climate Change, Irreversibility, and Urgency

 

Posted on 26 August 2012 by dana1981

http://www.skepticalscience.com/climate-change-irreversibility-and-urgency.html

 

Comment:

R. Gates at 17:19 PM on 26 August, 2012

 

“The rapidity of Arctic sea ice loss and the awakening of a the methane “time bomb” across the once frozen regions of the NH is something the 2007 IPCC report didn’t take into account at all. Limiting increase in global temps to 2C is out the window and 3C may be impossible to avoid now as well. Those fools who think that a melting Arctic is a great opportunity to plan for further fossil fuel extrapolation fail to understand the various stresses this will place on a civilization needing to feed 7+ Billion humans.”

 

Perhaps a reminder is warranted here about methane.  Yes, methane is a small percentage of the total greenhouse gas composition.  However, it carries a derringer strapped to its left leg in addition to the colt 45 in a shoulder holster.  Why?

 

“There is concern that, if rising global temperatures due to anthropogenic climate change cause the arctic permafrost to melt, massive quantities of methane would be released into the atmosphere, causing a catastrophic run-away greenhouse effect beyond even the upper 5.8ºC estimate postulated by the IPCC. Such a process is believed to have occurred in the Palaeocene-Eocene Thermal Maximum, 30

some 55 million years ago, when average global temperatures increased by 5ºC and which lasted for 150,000 years.”

 

“The atmospheric concentration of methane is thought to have increased by a factor of 2.5 since pre-industrial times, reaching 1745 ppb in 1998. This rate of increase far exceeds that of carbon dioxide, concentrations of which are only 30% higher than in pre-industrial times. In fact, information is sufficient for the IPCC to assert that the current methane concentration has not been exceeded in the last 420,000 years.”

 

http://www.eci.ox.ac.uk/research/energy/downloads/methaneuk/chapter02.pdf

 

 

“One of the most important ways in which methane differs from carbon dioxide is that it only persists in the atmosphere for roughly 10 years after it is released, whereas carbon dioxide persists in the atmosphere for about 100 years. This means that actions we take today to reduce methane will provide results in just a decade.”

 

http://oceanlink.island.net/ONews/ONews7/methane.html

 

 

 

It is important to note that although methane doesn’t persist very long in the air, when it does oxidise, it produces 1 Co2 and 2 H20 molecules.