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Global shipping pollution still rising despite green pledges

Global shipping pollution still rising despite green pledges
Global shipping pollution still rising despite green pledges | Photo: CHUTTERSNAP

The global shipping industry, responsible for moving more than 90% of the world’s traded goods, underpins modern commerce yet remains one of the least visible contributors to marine pollution and climate change. From the fuel burned in its engines to the waste discharged into the sea, every aspect of shipping carries a heavy environmental toll. Despite international efforts to regulate emissions and waste, the scale of the problem continues to challenge sustainable ocean management and global climate goals.


Invisible emissions, vast consequences

Ships primarily use heavy fuel oil, one of the dirtiest fossil fuels available. Burning this fuel releases large quantities of carbon dioxide (CO₂), methane, nitrogen oxides (NOₓ), and sulphur oxides (SOₓ). Collectively, these pollutants account for around 3% of global greenhouse gas emissions ,  roughly equal to those of Germany. Such emissions accelerate climate change, contribute to acid rain, and intensify ocean acidification, damaging marine ecosystems and coastal communities.


The establishment of Emission Control Areas (ECAs) has reduced air pollutants in specific zones such as the North Sea and North America’s coastline. However, with global trade expected to double by 2050, these efforts risk being outpaced by economic demand unless the sector embraces cleaner propulsion technologies and energy-efficient designs.


Oil, waste, and invasive species

While dramatic oil spills capture headlines, routine discharges from ships cause greater long-term harm. The washing of bilges, ballast water drainage, and accidental leaks steadily release oil residues and chemicals into the sea. This chronic pollution suffocates marine life and accumulates in the marine food chain, posing risks to human health through seafood consumption.


Equally concerning is the transfer of invasive species through ballast water. Each year, ships move billions of tonnes of seawater across regions, unintentionally transporting microscopic organisms and larvae. Once released into new environments, some thrive uncontrollably, outcompeting native species and reshaping entire ecosystems. The Ballast Water Management Convention, implemented in 2017, seeks to mitigate this problem, but compliance and enforcement remain inconsistent.


The plastic and noise burden

Shipping also contributes significantly to marine litter. Solid waste, including plastics, cleaning chemicals, and sewage, continues to find its way into the ocean despite bans on deliberate dumping. Lost containers, estimated at more than 1,500 annually, further pollute waters, especially when they carry hazardous materials or plastic pellets.


Less visible but equally damaging is underwater noise pollution. The constant rumble of engines and propellers disrupts the communication and migration patterns of whales, dolphins, and other marine mammals. Physical impacts from dredging, port expansion, and anchoring also destroy fragile seabed habitats, including coral and seagrass ecosystems essential for carbon storage.


The slow path to cleaner seas

The International Convention for the Prevention of Pollution from Ships (MARPOL) remains the cornerstone of global maritime environmental governance. Its six annexes regulate oil, chemicals, sewage, garbage, and air emissions, yet enforcement varies widely. Many vessels operate under flags of convenience, registering in nations with weaker oversight to avoid stricter environmental rules.


Efforts to modernise the sector are growing. The adoption of liquefied natural gas (LNG), hydrogen, ammonia, and even wind-assisted propulsion offers promise, though each presents logistical and cost challenges. The International Maritime Organization (IMO) has set an ambitious target of achieving net-zero emissions by around 2050, aligning with the broader objectives of the Sustainable Development Goals related to ocean health and climate action.


Still, real progress will depend on global cooperation, stronger port infrastructure for waste management, and financial incentives for cleaner fleets. The shipping industry’s transformation is not merely a technical challenge but a moral one: safeguarding the oceans that sustain life and commerce alike.


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