Record-Breaking Heatwaves Linked to New Shipping Fuel Regulations

By Thea Felicity

Jun 19, 2024 09:44 AM EDT

US-WEATHER-HEAT — People sit in the grass at Domino Park in Brooklyn, New York, as a heat wave hits the northeast US on June 18, 2024. Extreme heat and high humidity smothered the central and northeastern United States on Tuesday, with temperature records expected to melt away in the coming days, authorities warned, as wildfires sizzled in the west.
(Photo : ADAM GRAY/AFP via Getty Images)

In 2020, the International Maritime Organization (IMO) implemented new regulations to reduce the sulfur content in ship fuel from 3.5% to 0.5%, which led to an 80% reduction in sulfur dioxide emissions.

However, a recent study shared by CNBC suggests that these new standards may have inadvertently contributed to last year's record-breaking global temperatures. Tianle Yuan, a research scientist at the University of Maryland and lead author of the study, described this impact as "an inadvertent geoengineering event."

Sulfur dioxide, produced by burning sulfur-containing fuels like coal and petroleum oil, forms aerosols that reflect sunlight back into space, cooling the planet. However, new low-sulfur fuel regulations have decreased these aerosols, potentially reducing this cooling effect and contributing to higher global temperatures.

Sulfur Fuel in Rising Heatwaves

The debate among climate scientists about the impact of these regulations has resurfaced, particularly in light of recent heatwaves across the North Atlantic and Europe.

Jim Haywood, a professor of atmospheric science at the University of Exeter, noted that while El Nino and volcanic eruptions also contributed to recent temperature spikes, the IMO regulations could be a massive factor. However, some scientists argue that the study may overestimate the impact of the IMO regulations by claiming that reducing sulfur in ship fuel decreases air pollution and health risks, a positive move despite its complex effects on climate.

Joel Hirschi from the UK's National Oceanography Centre pointed out that while the reduction in sulfur emissions likely accelerated warming, it is just one of many factors contributing to the recent record-high temperatures. The International Maritime Organization has yet to provide a statement regarding the new study, and for now, the effort to achieve net-zero shipping emissions by 2050 is still ongoing.

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