Abrupt reduction in shipping emission as an inadvertent geoengineering termination shock produces substantial radiative warming

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Jun 2, 2024, 8:30:39 AMJun 2
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Tianle Yuan, Hua Song, Lazaros Oreopoulos, Robert Wood, Huisheng Bian, Katherine Breen, Mian Chin, Hongbin Yu, Donifan Barahona, Kerry Meyer & Steven Platnick

30 May 2024

Citations: Yuan, T., Song, H., Oreopoulos, L. et al. Abrupt reduction in shipping emission as an inadvertent geoengineering termination shock produces substantial radiative warming. Commun Earth Environ 5, 281 (2024). https://doi.org/10.1038/s43247-024-01442-3

Human activities affect the Earth’s climate through modifying the composition of the atmosphere, which then creates radiative forcing that drives climate change. The warming effect of anthropogenic greenhouse gases has been partially balanced by the cooling effect of anthropogenic aerosols. In 2020, fuel regulations abruptly reduced the emission of sulfur dioxide from international shipping by about 80% and created an inadvertent geoengineering termination shock with global impact. Here we estimate the regulation leads to a radiative forcing of 
Wm−2 averaged over the global ocean. The amount of radiative forcing could lead to a doubling (or more) of the warming rate in the 2020 s compared with the rate since 1980 with strong spatiotemporal heterogeneity. The warming effect is consistent with the recent observed strong warming in 2023 and expected to make the 2020 s anomalously warm. The forcing is equivalent in magnitude to 80% of the measured increase in planetary heat uptake since 2020. The radiative forcing also has strong hemispheric contrast, which has important implications for precipitation pattern changes. Our result suggests marine cloud brightening may be a viable geoengineering method in temporarily cooling the climate that has its unique challenges due to inherent spatiotemporal heterogeneity.

Simulated impact of IMO2020 on AOD and Nd.
figure 1

A simulated annual mean aerosol optical depth change induced by IMO2020 using NASA GOES-GOCART. B the ratio of aerosol optical depth changes between that induced by IMO2020 and that between 1750 and 20052C map of simulated annual mean Nd change due to IMO2020. D) same as B, but for Nd change.

Calculated IMO2020 forcing maps from different components.
figure 2

Source: Nature 

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