Countries attending a United Nations International Maritime Organization meeting in London signed an agreement calling for the shipping industry to reach net-zero emissions “by around 2050.”
UCG | Universal Image Group | Getty Images
Sweeping regulatory changes in 2020 to reduce air pollution from ships around the world could lead to an increase in average global temperatures, a controversial study has found.
The International Maritime Organization (IMO) implemented new standards on January 1, 2020, reducing the sulfur content of fuel oil from 3.5% to 0.5%. This was called “the biggest change in the history of the oil market” at the time.
A group of scientists said in a paper that the rule change led to an 80% reduction in sulfur dioxide emissions publish The research, published May 30 in the journal Communications Earth & Environment, may help explain why last year’s record high temperatures were so extreme.
Tianle Yuan, a research scientist at the University of Maryland and lead author of the study, explain Through social media, the impact of clean air regulations can be described as “an unintentional geoengineering event.”
This is because sulfur dioxide pollutants It is formed when sulfur-containing fuels such as coal or oil are burned, reacting with water vapor to create aerosols that reflect sunlight back into space.
Aerosols have a direct cooling effect, although climate scientists note that when aerosols decrease, their contribution to global cooling or warming remains an important factor. complex research areas.
Describing it as accidental geoengineering and providing data that may overestimate impacts could lead to incorrect assumptions about policies aimed at curbing future emissions.
Laura Wilcox
Associate Professor, National Center for Atmospheric Science, University of Reading
The study said a sharp decline in sulfur emissions since 2020 supports Ocean clouds brightenIt’s an area of growing scientific interest, and some researchers say it could be used to help cool the planet.
The question of whether reduced sulfur dioxide emissions are contributing to global warming is not new to climate scientists, but the debate has resurfaced recently after extreme heat waves in the North Atlantic and many parts of Europe.
Climate crisis is exacerbating extreme temperatures, with key drivers burning of fossil fuels.
Underestimating the impact
Jim Haywood, a professor of atmospheric science at the University of Exeter in the United Kingdom, told CNBC: “There are three interesting things that people try to explain why 2023 will be so warm, and the first one that everyone has heard of is El Niño. Phenomenon.
“The second thing is that people don’t realize that southernerthis is a very unusual volcanic eruption…The third is International Maritime Organization shipping regulations,” Heywood said.
El Niño is a naturally occurring weather pattern that causes global temperatures to soar, but has recently shown signs of ending, according to the weather service. United Nations Meteorological Service. The cooling effects of La Niña weather conditions are expected to return later this year.
Aerial top view of container ship moving at full speed with beautiful wave pattern, suitable for logistics, import-export, shipping or transportation.
Suryaporn Tromsavang | The Moment | Getty Images
“You have these brilliant climate scientists like (former NASA scientist) Jim Henson debate We don’t bounce back and the temperature traces don’t come back into the pack – I think I agree with him on that,” Haywood said.
“I think there are ways in climate models to underestimate aerosol cloud interactions and thus have accelerating effects,” he added.
“It’s hard to quantify how much. All climate models give slightly different answers because of how they emit sulfur dioxide,” Heywood said. “As a result, we are not sure how much impact the IMO regulations will have on average global temperatures.”
The International Maritime Organization stipulates that “there is only one influencing factor”
Scientists not involved in this paper Popular The study is timely, but some say it may overstate the impact of the IMO regulations.
Joel Hirschi, deputy director of ocean system modeling at the UK’s National Oceanography Centre, said research shows that the reduction in sulfur content in ship fuel since 2020 may accelerate planetary warming.
However, Hirschi said the authors may have overestimated the impact of the reduction in sulfur in ship fuels on last year and record-breaking global temperatures in 2024.
“The record high temperatures we are witnessing in 2023 and 2024 are striking and cannot be explained by a single factor. Research into why temperatures have been so high recently is ongoing, with reduced sulfur content in ship fuels being just one contributing factor.” Shirski said.
In addition, Laura Wilcox, an associate professor at the National Center for Atmospheric Science at the University of Reading in the United Kingdom, said that this study “makes very bold statements about temperature change and geoengineering, but it seems difficult to prove based on the evidence.” its rationality.
“For many people, switching to low-sulphur transportation fuels can reduce air pollution and reduce aerosol emissions, thereby moving away from human influence on the climate, while also reducing the health impacts of air pollution,” Wilcox said.
She added: “Describing it as accidental geoengineering and providing data that may overestimate impacts could lead to incorrect assumptions about policies aimed at curbing future emissions.”
About The Author
