Arctic Sea Ice : Forum

AGW in general => Consequences => Topic started by: CraigsIsland on June 04, 2013, 08:23:59 PM

Title: "Methane leaks could negate climate benefits of US natural gas boom" The Gaurdia
Post by: CraigsIsland on June 04, 2013, 08:23:59 PM


http://www.guardian.co.uk/environment/2013/jun/04/methane-leaks-negate-climate-benefits-gas (http://www.guardian.co.uk/environment/2013/jun/04/methane-leaks-negate-climate-benefits-gas)
Title: Re: "Methane leaks could negate climate benefits of US natural gas boom" The Gaurdia
Post by: shmengie on December 14, 2016, 05:55:51 AM
This paper explains well, what had already come to believe is a looming problem with "human" / fossil fuel fracking.

http://www.eeb.cornell.edu/howarth/publications/f_EECT-61539-perspectives-on-air-emissions-of-methane-and-climatic-warmin_100815_27470.pdf (http://www.eeb.cornell.edu/howarth/publications/f_EECT-61539-perspectives-on-air-emissions-of-methane-and-climatic-warmin_100815_27470.pdf)

Can't help believing a significant portion sudden polar ice vanishing act is related to methane leaked from Aliso Canyon, California.

Not a definitive direct link...  El Nino, excessive persistent fracking, warmer oceans and unrelenting CO₂ play a role as well, I'm sure...  The timing seems chronologically significant, IMO.
Title: Re: "Methane leaks could negate climate benefits of US natural gas boom" The Gaurdia
Post by: AbruptSLR on December 17, 2016, 01:32:25 AM

The following linked reference on GTP and GWP for short-term forcers, indicates a GWP100 for methane of 35:

W. J. Collins, M. M. Fry, H. Yu, J. S. Fuglestvedt, D. T. Shindell, and J. J. West (2013), "Global and regional temperature-change potentials for near-term climate forcers", Atmos. Chem. Phys., 13, 2471–2485, doi:10.5194/acp-13-2471-2013


http://www.atmos-chem-phys.net/13/2471/2013/acp-13-2471-2013.pdf (http://www.atmos-chem-phys.net/13/2471/2013/acp-13-2471-2013.pdf)

Therefore,following NOAA's 2015 data the value of CO2-e of 485ppm for 2015 was calculated using GWP100 of 25; so when I use a GWP100 of 35, I get a CO2-e of 518ppm:


http://esrl.noaa.gov/gmd/aggi/aggi.html (http://esrl.noaa.gov/gmd/aggi/aggi.html)


         Global Radiative Forcing, CO2-equivalent mixing ratio, and the AGGI 1979-2013
                         Global Radiative Forcing (W m-2)           CO2-eq
                                                                                     (ppm)        AGGI
Year     CO2     CH4    N2O   CFC12 CFC11 15-minor  Total Total   1990 = 1   %change

2013   1.882  0.496   0.184   0.167   0.059   0.114  2.901   478      1.340        2.0
2014   1.908  0.499   0.187   0.166   0.058   0.116  2.935   481      1.356        1.6
2015   1.939  0.504   0.190   0.165   0.058   0.118  2.974   485      1.374        1.8

CH4   ΔF = β(M½ - Mo½) - [f(M,No) - f(Mo,No)]   β = 0.036

This gives a better idea of how much policy maker's are underestimating the current contributions of methane to global warming.
Title: Re: "Methane leaks could negate climate benefits of US natural gas boom" The Gaurdia
Post by: AbruptSLR on December 17, 2016, 01:46:16 AM
My last post used a GWP100 for methane of 35; however, estimates of combined natural and anthropogenic methane emission rates through 2100 justify the use of the findings from Isaksen et al's 7 x CH4 case for calculating a revised GWP for methane, as follows:
 
As the radiative forcing in a 50-year time horizon for 4 x CH4 additional emission of 0.80 GtCH4/yr is 2.2 Wm-2, and as the radiative forcing for the current methane emissions is 0.48 Wm-2, thus an updated GWP for methane, assuming the occurrence of Isaksen et al's 4 x CH4 case in 2040, would be: 33 (per Shindell et al 2009) times (2.2/[0.8 + 0.48]) divided by (0.54/0.48) = 50 by 2100.
 
If the GWP of methane increases to 50 by 2100 then the RCP 8.5 scenario will significantly under-estimate global warming by the end of this century.

Isaksen, I. S. A., Gauss M., Myhre, G., Walter Anthony, K. M.  and Ruppel, C.,  (2011), "Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions", Global Biogeochem. Cycles, 25, GB2002, doi:10.1029/2010GB003845