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Per the IPCC’s AR5, the GWP20 (“Global Warming Potential, i.e. relative radiative forcing over 20 years) of methane is about 80X that of CO2, while the GWP100 i
by gumby 4y ago
Per the IPCC’s AR5, the GWP20 (“Global Warming Potential, i.e. relative radiative forcing over 20 years) of methane is about 80X that of CO2, while the GWP100 is 26-32, or about 28X.
I have a paper I’m (very slowly) working that argues that these figures may be too low. Our current model of CH4 emissions and natural destruction assume a lifetime of 9-10 years in the atmosphere. The problem is if you do some simple stoichiometry, net emissions are not enough to account for the roughly 4 Gt of excess CH4 in the atmosphere.
I’m hoping my math is wrong.
- hinkley 4y agoThe calculus on this is going to be hard because methane can’t absorb photons that have already been absorbed by the atmosphere around it. It’s a bit like calculating if I’ll die of cancer. If you could protect me from everything you might be able to know that I’d die of colon cancer at 75. But here I am breathing weird dust and walking a route that starts on city streets and driving X miles a year and you just don’t know what’s gonna get me.
- gumby 4y agoThe geophysicists and others who model this are aware of these issues. The question I am investigating is an input to such calculations; I am not qualified to estimate the impact.