The Misguided Crusade to Reduce Anthropogenic Methane Emissions
19 hours ago Guest Blogger 66 Comments
Clyde Spencer
2023
ABSTRACT
The role of anthropogenic methane (CH4) in global warming is exaggerated. The atmospheric concentration of carbon dioxide (CO2), as measured at Mauna Loa Observatory (MLO), is above 420 ±0.7 ppmv (parts per million-volume) and is increasing about 2.8 ppmv annually. CH4 has a concentration of about 1.9 ppmv and is increasing about 0.014 ppmv annually. The anthropogenic contribution to the annual CH4 increase is a fraction of the total, probably about one-third, albeit the official estimate was increased in recent years. CH4 has more potential for warming than CO2, but it is effectively gone in about a decade, having a commonly cited long-term impact that is only about 32X that of an equal weight of CO2. Accounting for the CO2 warming equivalence on a mole-fraction basis reduces the equivalence factor to less than 12X. It is the long-term impact we need to be concerned about because of an arbitrary temperature threshold claimed to be threatening our survival after 2050. With CO2 being more than 200X as abundant, even with the greater potential impact of CH4, the Global Methane Pledge will, at most, achieve a 0.58% annual decrease in CO2-equivalent CH4.
INTRODUCTION
More than 100 member nations, represented at the 26th Conference of the Parties (COP26) to the UN’s Framework Convention on Climate Change, committed to the Global Methane Pledge (GMP). The GMP was created using information provided by Krane (2022) and others; it is a commitment to reduce the estimated 33% of total annual methane (CH4) emissions derived from fossil fuels, by at least 30%, compared to 2020. The intent is to reduce methane emissions because of the claimed greater warming potential of CH4 than CO2.
From the International Energy Agency (IEA):
“…, the most common [metric] is the global warming potential (GWP). This can be used to express a tonne of a greenhouse-gas emitted in CO2 equivalent terms, in order to provide a single measure of total greenhouse-gas emissions (in CO2-eq).
The Intergovernmental Panel on Climate Change (IPCC) has indicated a GWP for methane between 84-87 when considering its impact over a 20-year timeframe (GWP20) and between 28-36 when considering its impact over a 100-year timeframe (GWP100). This means that one tonne of methane can considered to be equivalent to 28 to 36 tonnes of CO2 if looking at its impact over 100 years.”
https://wattsupwiththat.com/2023/03/06/the-misguided-crusade-to-reduce-anthropogenic-methane-emissions/
