I haven't followed methane much because I couldn't find a good data source, but now I have, from NASA. And even better source is the Global Carbon Project, which is updated every 7.6 days.
After that weird lull in the mid-aughts, methane is on the rise again and is the highest it's been in 800,000 years.
Methane's radiative forcing has increased by about 0.4 W/m2 since 1979, while CO2's has jumped about 1.6 W/m2 in the same interval.
Global radiative forcing has increased by about 50% (as of 2022) just since 1990. Here, "AGGI" is the ratio of radiative forcing to what it was in 1990.
It's incredible that the world, despite all the rhetoric and (token) efforts, keeps allowing this to happen. Clearly, I think, these trends will only be taken seriously once some catastrophic effects happen, and by then it will be too late. So human and we can't even help ourselves.
3 comments:
I found this paper on Interpreting contemporary trends in atmospheric methane.
It looks to be quite complicated to determine the cause of the pause:
Fig. 2, Left shows the observations of atmospheric methane and the proxies used to explain the stabilization and renewed growth. Studies using ethane have argued that decreases in fossil fuel sources led to the stabilization of atmospheric methane in the 2000s (e.g., refs. 11 and 15) and that increases in fossil fuel sources contributed to the growth since 2007 (e.g., refs. 18–20). Studies using isotope measurements tend to find that decreases in microbial sources led to the stabilization (e.g., ref. 12) and increases in microbial sources are responsible for the renewed growth (e.g., refs. 17, 24, and 25). Studies that include methyl chloroform measurements tend to find that changes in the methane sink played a role in both the stabilization and renewed growth (e.g., refs. 22, 27, 28, and 47). Finally, Worden et al. (31) included measurements of carbon monoxide and inferred a decrease in biomass burning emissions, an isotopically heavy methane source, that helps reconcile a potential increase in both fossil fuel and microbial emissions.
The problem of inferring processes responsible for the stabilization and renewed growth is often underconstrained when framed in a global or hemispherically integrated manner. From a globally integrated perspective, we have three observables (
,
C-
,
) and attempt to infer changes in methane emissions, the partitioning between methane source sectors,
emissions, and OH concentrations. Solving this requires additional constraints, which can also have large uncertainties. Adding ethane or carbon monoxide helps only if we can assume that their emission ratios (
/
or
/CO) and their variation in time are well known and well characterized. Many studies have assumed that OH is unchanging in the atmosphere (e.g., refs. 17, 24, and 25) because it is well buffered (38, 48), thus making the problem well posed, leading to stronger conclusions regarding the processes driving the stabilization and renewed growth. However, changes of a few percent in OH are sufficient to perturb the global budget (27, 28), with a 4% decrease in global mean OH being roughly equivalent to a 22 Tg/y increase in methane emissions.
It looks like the greek, superscript, and subscript were mangled. Follow the link and jump to "Atmospheric Clues and Inventory/Process Understanding of Atmospheric Methane" to see more clearly.
L, thanks for that interesting information.
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