Sulphur emissions have proven to be a complex problem for the environment. New studies show that while sulphur emissions, both into the air and into the oceans, threaten human health and biodiversity with smog, acid rain, cardiovascular and respiratory illnesses, there is one aspect in which sulphur emissions into the air were beneficial—keeping seawater temperatures low. Prior to the 2020 sulphur emission regulations on marine fuel taking effect, sulphur dioxide emissions from seagoing vessels were acting as a protective smog cloud barrier, reflecting excess sunlight away from our oceans and keeping global ocean temperatures cooler.

The study found that the 2020 shipping regulations, which reduced the maximum allowable sulphur content in marine fuel oils from 3.5% down to 0.5%, had an unintended consequence. The sharp reduction in sulphur atmospheric emissions greatly diminished the sulphur-smog barrier, allowing more of the sun’s heat to reach the earth’s surface. This has resulted in increased average temperatures year-to-year since the new fuel restrictions took effect, causing changes to animal migratory patterns, disruption of ocean currents like the Atlantic Meridional Overturning Circulation (AMOC), habitat destruction, diminished food and water supply, and higher glacial melt rates.

The alarming data reveals that scrubber washwater contains harmful substances, including polycyclic aromatic hydrocarbons (PAHs), lead, mercury, arsenic, iron, and copper. These substances are insoluble in water, react negatively with other compounds like sulphur, and are dangerous at high temperatures. They also contribute to further ocean heat trapping and the acidification of our oceans—one of the leading causes of coral reef extinctions across the globe.

Despite the damage, only recently have countries started to ban these dangerous scrubbers. Environmental organizations are calling for immediate action, advocating for alternatives such as low-sulphur fuels or advanced technologies that do not produce harmful byproducts. There is a growing push for stricter regulations and better enforcement to ensure that measures taken to reduce pollution do not inadvertently cause more harm.

As unsettling as this data is taken on its own – the most dire environmental effects can only begin to be understood when also taking into consideration the massive amounts of pollutants that scrubber-fitted marine vessels are intentionally pouring into our ocean waters on a daily basis, effectively bypassing any and all of the positive effects intended to come from the 2020 sulphur regulations in the first place, while also simultaneously accounting for 90% of all marine contaminants. This becomes a recipe for disaster.

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1. How Changing Ocean Temperatures Could Upend Life on Earth - The New York Times (nytimes.com)

2. Ships' scrubber discharge accounts for over 90 pct of marine contaminants, study reveals - Offshore Energy(offshore-energy.biz)

3. Venezuela becomes first country to lose all of its glaciers - UPI.com

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