Cleaner ship emissions may warm the planet far faster than expected

2020 rule that slashed air pollution from ships may have boosted global temperatures sooner than thought, helping to explain why 2023 was so hot.

sharp drop in sulphur dioxide emissions from ships since 2020 may warm the planet more than expected this decade, although researchers disagree on the magnitude of this change in temperature.

“If our calculation is right, that would suggest this decade will be really warm,” says Tianle Yuan at the University of Maryland, Baltimore County. Combined with background warming due to rising greenhouse gas concentrations, the added heat could mean 2023’s record-breaking temperatures will be the “norm” in coming years, he says. Yuan and his colleagues compared the sudden rise in temperature to the “termination shock” that might occur if a solar geoengineering project to curb warming were to suddenly end without a corresponding decline in greenhouse gas emissions.

However, other climate researchers say there are issues with the new numbers. “This is a timely study, but it makes very bold statements about temperature changes and geoengineering which seem difficult to justify on the basis of the evidence,” says Laura Wilcox at the University of Reading in the UK.