New Paper: Methane Concentration Increase Not Related to Fossil Fuels
10 hours ago Charles Rotter
A new paper just published in the PNAS identifies different culprits.
https://www.pnas.org/doi/10.1073/pnas.2411212121Abstract
The growth rate of the atmospheric abundance of methane (CH4) reached a record high of 15.4 ppb yr−1 between 2020 and 2022, but the mechanisms driving the accelerated CH4 growth have so far been unclear. In this work, we use measurements of the 13C:12C ratio of CH4 (expressed as δ13CCH4) from NOAA’s Global Greenhouse Gas Reference Network and a box model to investigate potential drivers for the rapid CH4 growth. These measurements show that the record-high CH4 growth in 2020–2022 was accompanied by a sharp decline in δ13CCH4, indicating that the increase in CH4 abundance was mainly driven by increased emissions from microbial sources such as wetlands, waste, and agriculture. We use our box model to reject increasing fossil fuel emissions or decreasing hydroxyl radical sink as the dominant driver for increasing global methane abundance.
https://www.pnas.org/doi/10.1073/pnas.2411212121Methane (CH4) is the second-most abundant anthropogenic greenhouse gas and has global warming potential (GWP) of 28 over 100 y (1); as a result, CH4 has consequential near-term radiative effects and is a prominent target for mitigation (2). Following a short pause in growth from 1999 to 2006, both the abundance and growth rate of atmospheric methane have been increasing (3). During 2020–2022, the observed CH4 growth rate reached a record high since NOAA measurements began in 1983, averaging 15.4 ± 0.6 ppb yr−1 (4). Understanding the mechanisms driving this accelerated growth is essential for predicting its future climate impact and providing scientific support for climate mitigation strategies (2).
https://wattsupwiththat.com/2024/10/22/new-paper-methane-concentration-increase-not-related-to-fossil-fuels/
