Blended satellite data reveal what drove methane's 2019–2024 rise worldwide

cross-posted from: https://news.abolish.capital/post/42582

Because methane has around 80 times the warming potential of CO2 over a 20-year period, it has been a major focus for climate action groups. The Global Methane Pledge, launched at COP26 in November 2021, aims to cut human-caused methane emissions by 30% by 2030.

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Fig. 1. Trends in global annual mean methane concentrations from 2019 to 2024.

The NOAA trend is from globally averaged marine surface annual mean data (87). The TROPOMI trend is from blended TROPOMI+GOSAT observations (35). The GEOS-Chem posterior trend is from a simulation using our posterior estimates of methane emissions and OH concentrations for individual years, sampled at the locations of the TROPOMI observations and with the TROPOMI observation operator applied (65). The gray dashed lines show the evolution of atmospheric methane concentrations if sources and sinks had remained constant at either 2019 or 2021 values.

Fig. 2. Contributions of global sources and sinks to the 2019–2024 methane trend as inferred from inversion of TROPOMI data.

(A) Posterior annual estimates of global methane emissions and methane lifetime against oxidation by tropospheric OH. Solid lines indicate results from our base inversion, and shaded areas represent the range from a 27-member inversion ensemble with varying inversion parameters (see Materials and Methods). (B) Attribution of the 2019–2024 year-to-year rise in atmospheric methane to relaxation to steady state from 2019 conditions ( term in Eq. 1), changes in methane emissions relative to 2019 (), and changes in tropospheric OH concentrations relative to 2019 (). The orange dashed line shows the annual atmospheric methane growth rates as reported by NOAA (87) from the deseasonalized trends at marine surface sites and using a conversion factor of 2.77 Tg methane per ppb (88). (C) Posterior annual estimates of global anthropogenic emissions and wetland emissions, with ranges from the inversion ensemble. (D) Posterior annual estimates of global emissions from major anthropogenic sectors including livestock, waste (landfills and wastewater treatment), oil and gas, rice agriculture, and coal mining, with ranges from the inversion ensemble. Note the different y-axis scales between panels.

Fig. 3. Regional distribution of methane emissions and 2019–2024 trends from inversion of TROPOMI data.

(A) 2024 mean posterior methane emissions from the base inversion. Pie chart shows the sectoral attribution of global emissions (Tg year−1) in 2024. Ocean fluxes are assumed to be zero. (B) 2019–2024 methane emission trends fitted by ordinary linear regressions to the annual posterior emissions in each 2° by 2.5° grid cell. Only significant trends (P < 0.05) are shown. Total growth rates for individual geographical regions are shown in the inset.