Jun 22, 2024 16:00:00

Ironically, the reduction in ocean air pollution may have 'accelerated global warming'

A combination of intensifying climate change and rising sea temperatures due to

the El Niño phenomenon has made 2023 the hottest year on record. Furthermore, a study has reported that a significant reduction in air pollutants emitted by the shipping industry has accelerated the rise in sea temperatures, leading to further climate change.

Cutting pollution from the shipping industry accidentally increased global warming, study suggests | Live Science
https://www.livescience.com/planet-earth/climate-change/cutting-pollution-from-the-shipping-industry-accidentally-increased-global-warming-study-suggests

In 2020, the International Maritime Organization (IMO) reduced the regulatory limit for sulfur content in fuel oil by nearly 80% from 3.5% to 0.5% in order to prevent air pollution from ship exhaust gases.

On the other hand, aerosols made of air pollutants such as sulfur dioxide have the effect of blocking sunlight and increasing the reflectivity of clouds, so the reduction in emissions may have caused ocean temperatures to rise.

To examine the impact of the new regulations on ocean temperatures, Tianle Yuan and his team at the University of Maryland, Baltimore County, ran simulations that combined aerosol data from NASA weather satellites with weather models.

The results showed that the amount of solar energy that heats ocean waters increased by 0.1 to 0.3 watts per square meter due to the reduction in aerosols. This is twice the previous estimate and is equivalent to 80% of the global warming that has occurred since 2020. The research team estimates that this effect will cause global temperatures to rise by 0.16 degrees in the seven years from the start of the regulations.

'Around 0.2 watts per square meter is a big number, and it happened in a year, so it's a big shock to the environment,' Yuan said.

The study comes amid a

contentious debate at the United Nations over solar radiation management (SRM) , a technique that aims to stop climate change by deliberately releasing aerosols into the atmosphere, with governments sharply divided over the issue.

Michael Diamond of Florida State University, who was not directly involved in Yuan's study, said the new estimate is on the high side, but is broadly consistent with other studies, including one that looked directly at cloud changes since 2020 and found similar results to the simulations.

Meanwhile, Zeke Hausfather, a climatologist at the climate think tank Berkeley Earth, said Yuan's study confuses ocean warming with global warming and that the simplified climate model led to extreme simulation results.

Hausfather said current climate models have a very hard time accounting for warming of more than 0.1 degrees Celsius in the short term.

Gavin Schmidt, director of NASA's Goddard Institute for Space Studies, said that while the estimates of solar energy hitting Earth were accurate, 'the estimates of temperature response in this study are less accurate.'