More Than Just DMS: Why Methanethiol Deserves a Starring Role in Climate Models

The gases dimethyl sulfide (DMS) and methanethiol (MeSH) are produced by oceanic phytoplankton. In the atmosphere, they act as key precursors to climate-cooling aerosols. In a recent Geophysical Research Letters article, a team of Australian researchers reported Southern Ocean atmospheric measurements from an Antarctic research voyage (Multidisciplinary Investigations of the Southern Ocean, MISO) and multiseasonal observations at Kennaook/Cape Grim (KCG), Tasmania, Australia. Findings constrain the relative importance of MeSH to the marine atmospheric reactive sulfur across space and time, quantifying the coupling between DMS and MeSH over the open ocean which breaks down in winter and along the Antarctic coast. While DMS is the dominant driver of biogenic marine aerosol formation, MeSH is increasingly recognised as a potentially important contributor to consistent radiative model biases over the Southern Ocean.

Reference: Mynard, C., Franklin, E.B., Alroe, J., et al. (2025). Constraining Atmospheric Methanethiol Estimates Over the Southern Ocean. Geophys. Res. Lett., 52(18), e2025GL116470. https://doi.org/10.1029/2025GL116470