In 2020, new international shipping regulations drastically cut sulfur emissions from ships, leading to a sharp reduction in the formation of bright, reflective clouds known as “ship tracks.” These clouds had been playing a subtle but significant role in cooling the planet by reflecting sunlight back into space. In a new study published in Geophysical Research Letters, researchers show that there has been a slight warming effect since these regulations were implemented, particularly in the Northern Hemisphere, raising concerns that the changes in shipping practices might be inadvertently accelerating global warming.
While reducing sulfur emissions is crucial for improving air quality and public health, it also eliminates the cooling effect that had been offsetting some of the warming caused by greenhouse gases. This research emphasizes the need for more detailed data and better modeling to understand the full impact of such environmental regulations. The findings are significant for policymakers and scientists as they navigate the balance between reducing pollution and managing the pace of global warming, especially as the world seeks to decarbonize and reduce all forms of harmful emissions.
The Climate Program Office supports contributing authors Michael Diamond of Florida State University and Tianle Yuan of the University of Maryland, Baltimore County. The Earth’s Radiation Budget (ERB), Atmospheric Chemistry, Carbon Cycle and Climate (AC4), and Climate Variability & Predictability (CVP) programs awarded these authors a grant to analyze satellite observations of cloud and radiation properties within a shipping corridor in the southeast Atlantic.
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