Has Reducing Ship Emissions Brought Forward Global Warming?
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- Pacific Northwest National Laboratory Richland WA USA
- Florida State University Tallahassee FL USA
- Imperial College London UK
- University of Oxford Oxford UK
- University of California San Diego La Jolla CA USA
- Plymouth Marine Laboratory Plymouth UK
- University of Leeds Leeds UK
- University of Maryland Baltimore County College Park MD USA
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.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- European Commission; NERC; National Oceanic and Atmospheric Administration (NOAA); USDOE
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 2429058
- Report Number(s):
- PNNL-SA-196069; e2024GL109077
- Journal Information:
- Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 15 Vol. 51; ISSN 0094-8276
- Publisher:
- American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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