Re: The Methane Thread pt. 2
Posted: Wed 19 Jun 2019, 14:54:15
Before anyone gets too wound up over current methane levels remember to look at this graph. Since high quality monitoring started we have gone from roughly 1.63 ppmv CH4 free in the atmosphere to 1.86 ppmv. Even if you take the worst case scenario with CH4 having 125*CO2 global warming potential that increase of 0.23 ppmv only adds up to 28.75 ppmv CO2 equivalent increase. During the same period actual CO2 levels increased from 338.1 ppmv in January 1980 to 410.83 ppmv CO2 in January 2019. That is a real world increase of 72.73 ppmv CO2 or more that three times the CH4 increase worst case scenario impact. While CH4 emissions continue to grow they are tiny in comparison to the main culprit in man influencing the climate. Also remember that about half of the actual change induced by CO2 is in the continuing increase in atmospheric humidity because warm air holds more water vapor and water vapor is the most powerful GHG. When the CH4 reaches the Ozone Layer it gets converted into CO2+2(H2O) if it doesn't get broken down by OH- radicals before it rises that high. So CH4 is a self limiting problem, as long as the sun keeps emitting so much UV radiation the Ozone layer gets constantly rebuilt. H2O on the other hand tends to saturate dust motes into micro droplets, then keep growing until the droplets are heavy enough to actually precipitate out of the atmosphere. Unlike those two however the CO2 in the upper atmosphere tends to remain in the upper atmosphere for geological timescales of thousands to hundreds of thousands of years.
https://www.esrl.noaa.gov/gmd/ccgg/trends_ch4/
https://www.esrl.noaa.gov/gmd/ccgg/trends_ch4/