Has Reducing Ship Emissions Brought Forward Global Warming?
Abstract Ships brighten low marine clouds from emissions of sulfur and aerosols, resulting in visible “ship tracks”. In 2020, new shipping regulations mandated an ∼80% reduction in the allowed fuel sulfur content. Recent observations indicate that visible ship tracks have decreased. Model simulations indicate that since 2020 shipping regulations have induced a net radiative forcing of +0.12 Wm −2 . Analysis of recent temperature anomalies indicates Northern Hemisphere surface temperature anomalies in 2022–2023 are correlated with observed cloud radiative forcing and the cloud radiative forcing is spatially correlated with the simulated radiative forcing from the 2020 shipping emission changes. Shipping emissions changes could be accelerating global warming. To better constrain these estimates, better access to ship position data and understanding of ship aerosol emissions are needed. Understanding the risks and benefits of emissions reductions and the difficultly in robust attribution highlights the large uncertainty in attributing proposed deliberate climate intervention.
Authors
- Mingxi Yang (ORCID: https://orcid.org/0000-0002-8321-5984)
- Andrew Gettelman (ORCID: https://orcid.org/0000-0002-8284-2599)
- Duncan Watson‐Parris (ORCID: https://orcid.org/0000-0002-5312-4950)
- Matthew W. Christensen (ORCID: https://orcid.org/0000-0002-4273-6644)
- Tianle Yuan (ORCID: https://orcid.org/0000-0002-2187-3017)
- Michael Diamond (ORCID: https://orcid.org/0000-0003-2147-5921)
- Peter Manshausen (ORCID: https://orcid.org/0000-0002-1603-7049)
- Edward Gryspeerdt (ORCID: https://orcid.org/0000-0002-3815-4756)
- Masaru Yoshioka (ORCID: https://orcid.org/0000-0003-2223-1734)
- Philip Stier (ORCID: https://orcid.org/0000-0002-1191-0128)
Institutions
- Florida State University (US)
- University of Leeds (GB)
- Pacific Northwest National Laboratory (US)
- Plymouth Marine Laboratory (GB)
- University of California San Diego (US)
- University of Oxford (GB)
- Imperial College London (GB)
- University of Maryland, Baltimore County (US)
Publication Details
- Journal
- Geophysical Research Letters
- Published
- 2024-08-12
- DOI
- https://doi.org/10.1029/2024gl109077
- Citations
- 63
- Primary Topic
- Maritime Transport Emissions and Efficiency
- Type
- article
- Field-Weighted Citation Impact
- 12.96
Funders
- U.S. Department of Energy
- Battelle
- Sight Research UK
- National Oceanic and Atmospheric Administration
- Office of Nuclear Energy
- Natural Environment Research Council
- Climate Program Office
- Pacific Northwest National Laboratory