Cargo ships invested in technology to stop polluting the air. Now it’s polluting the seas instead.
Cruise and cargo ships around the world are cleaning up their dirty smokestacks, installing systems that prevent harmful pollutants in their exhaust from escaping into the air. Yet much of that pollution is winding up in the sea instead. And so a solution meant to reduce smog, experts say, is leaving a potentially toxic trail in its wake.
Thousands of ships use exhaust cleaning systems, or “scrubbers,” compared with hundreds of ships just a few years ago, as companies face rising pressure to tamp down on their pollution. International regulators now require vessels to burn low-sulfur fuels at sea, while local authorities are cracking down on emissions close to shore. Scrubbers offer a middle ground, allowing ship operators to keep burning sludgy, sulfur-laden “bunker fuel” and still comply with air quality rules.
The problem is that those ships are expected to dump at least 10 billion metric tons of what’s known as wash water — the contaminated byproduct — into seas around the world every year, according to a first-of-its-kind study from the International Council on Clean Transportation, a nonprofit research group.
Systems which reduce ships' air pollution end up increasing their ocean pollution.grist.org