6th January 2022
Global methane concentration hits 1,900 ppb
The National Oceanic and Atmospheric Administration (NOAA) has published its latest data for atmospheric methane. This shows that globally, methane is now at its highest level in recorded history and has just passed the 1,900 parts per billion (ppb) milestone.
Although carbon dioxide’s contribution to climate change is greater overall, methane is far more potent on a per molecule basis. The global warming potential of methane has been estimated at 70 to 100 over a 20-year period. That is, over a 20-year period, it traps 70 to 100 times more heat per mass unit than CO2.
NOAA’s newly published data – based on air samples taken at dozens of sites around the world – confirms that global atmospheric methane in September 2021 (the latest available month) reached 1,900.5 ppb, the highest level in human history and probably the highest in at least the last 800,000 years. For comparison, methane in pre-industrial times tended to stay below 700 ppb. The jump between 2020 and 2021, a difference of nearly 16 ppb, is also the highest annual increase on record.
Methane accounts for about 20% of the greenhouse gases produced by human activities. Its concentration appeared to flatline in 1999, before resuming an upward trend in 2007. Analysis of carbon isotopes has revealed important clues as to what might be driving the more recent growth. Rather than fossil fuels and fugitive methane from oil and gas drilling, the main culprits are agriculture and the natural decay of wetlands (in part driven by human influences). The huge and growing amount of methane from landfills and other waste sites is also playing a significant role.
If the current trend continues, the global atmospheric concentration of methane could exceed 2,000 ppb within a decade, and may exceed 3,000 ppb by the middle of the century.
The good news is that methane has a rather short lifetime compared with most other greenhouse gases: just 12.5 years, according to studies by the Intergovernmental Panel on Climate Change (IPCC). It therefore represents “low hanging fruit” in terms of efforts to reduce global warming. Indeed, at the recent COP26 summit, more than 100 nations pledged a 30% cut in methane emissions by 2030.
The International Energy Agency has also published a report showing that major cuts in methane can be achieved in a realistic and cost-effective way. If its recommendations are followed, worldwide oil and gas sector methane emissions could be shrunk from 72 megatons to just 21 megatons by 2030.
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