The Los Angeles (LA) basin was responsible for approximately 20% of California's methane emissions in 2016. Hence, curtailment of these emissions is required to meet California's greenhouse gas emissions reduction targets. However, effective mitigation remains challenging in the presence of diverse methane sources like oil and gas production fields, refineries, landfills, wastewater treatment facilities, and natural gas infrastructure. In a recent peer-reviewed study, a team including AER Scientist Marikate Mountain studied temporal variability in the surface concentrations from February 2015 to April 2022 to detect a declining trend in methane emissions. They quantified the reduction due to this declining trend through inverse modeling and showed that methane emissions in the LA basin have declined by 15 Gg, or ∼7% over five years from January 2015 to May 2020.
Figure 1: Total emissions with 1 uncertainty bounds for the inversion domain for the spatio-temporal area of dominance region covered by GRA and ONT in-situ sites.
Citation: A declining trend of methane emissions in the Los Angeles basin from 2015 to 2020
V. Yadav, K. Verhulst, R. Duren, A. Thorpe, J. Kim, R. Keeling, R. Weiss, D. Cusworth, M. Mountain, C. Miller, J. Whetstone
Environ. Res. Lett., 18, 034004, 2023