NOAA's Global Monitoring Laboratory releases CarbonTracker-Methane 2023

October 12, 2023

On October 10, scientists in the Global Monitoring Laboratory released NOAA’s latest global atmospheric methane assimilation/flux inversion system, CarbonTracker-CH4 2023. In CarbonTracker-CH4, GML and CIRES researchers used measurements of atmospheric methane and its stable carbon isotope ratio to constrain estimates of methane emissions at the atmospheric model grid-scale, incorporating spatially- and temporally- resolved isotopic source signatures, state-of-the-art prior emission and atmospheric chemical loss estimates, and estimating fluxes from microbial, fossil, and pyrogenic fluxes from 1997 to 2021.

CarbonTracker-CH4 provides quantitative estimates of methane emissions at a global scale that are consistent with observed patterns of methane (CH4) and its stable isotopic ratios (δ13C-CH4) in the atmosphere. Using observations of both CH4 and δ13C-CH4 allowed the researchers to better discriminate between fossil fuel and microbial emissions. Microbial sources of methane include emissions from wetlands and anthropogenic emissions associated with agriculture and waste management.

The new CarbonTracker-CH4 emissions estimates provide insight into what caused long-term methane growth and record-high global methane growth in 2020 and 2021. The researchers found that the growth in atmospheric methane in 2020-2021 was primarily caused by a large increase in microbial sources, likely due to a combination of natural and anthropogenic sources in low and populated latitudes. In a long-term analysis (2006-2021), the researchers also observed a significant increase in microbial emissions.

CarbonTracker provides policy makers, industry, scientists, and the public with information that allows informed decisions about limiting greenhouse gas levels in the atmosphere.

ch4 concentrations

In this three-dimensional CarbonTracker-CH4 visualization of simulated CH4 concentrations for July-August 2021, “warm” colors show high atmospheric CH4 concentrations and “cool” colors show low concentrations. This sequence shows emissions from both natural and anthropogenic regions. Weather systems then move the resulting high CH4 air masses to form the patterns shown in this animation. Credit: NOAA Global Monitoring Laboratory