Projections of Changes in Dimethyl Sulfide Emissions from the Global Ocean

Oceanic dimethyl sulfide (DMS) is the largest natural source of atmospheric sulfur. DMS is biologically produced in seawater and emitted into the atmosphere, where its oxidation products contribute to aerosol formation with consequences for cloud albedo and the Earth’s radiative budget and climate. Climate model projections of how DMS emissions change with global warming are largely uncertain, even contradictory. This work reduces the current large differences and biases observed in the previous outcomes of the Coupled Model Intercomparison Project phase 6 (CMIP6) models in terms of the future changes in the seawater DMS concentrations and sea-air flux estimates. This not only increases our confidence in predicting future changes in DMS emissions but also addresses the current uncertainty in climate-DMS feedback impacts in the Intergovernmental Panel on Climate Change Sixth Assessment Report (IPCC AR6). The results show that seawater DMS will decrease in the future, but the sea-air emissions will increase. This suggests that DMS will play an increasingly important role as a sulfur source as further air quality measures reduce anthropogenic emissions of sulfur compounds.

Reference: Joge, S.D., Mansour, K., Simó, R, et al. (2025). Climate warming increases global oceanic dimethyl sulfide emissions. PNAS, 122(23), e2502077122. https://doi.org/10.1073/pnas.2502077122