As of Jan 1, a new International Maritime Organisation standard will seriously restrict the kind of air pollution that shipping vessels can emit; in response, the industry has invested more than $12b in "open-loop scrubbers," which capture the sulphur from heavy fuel oil exhaust and reroute it, along with CO2, into waste water that is dumped from the ships directly into the sea. Heavy fuel oil is the dirtiest form of fossil fuel.
Of the 3,756 ships — mostly oil tankers, container ships and bulk carriers — that have been equipped with open-loop scrubbers, only 23 store the sulphur for safe disposal in port; the rest dump it straight into the ocean.
The waste water is voluminous and fantastically toxic: every ton of fuel generates 45 tons of contaminated, carcinogenic water laced with polycyclic aromatic hydrocarbons and heavy metals. The scrubbers also increase fuel consumption by 2%, creating a vicious cycle.
The ICCT has estimated that cruise ships with scrubbers will consume around 4 million tons of heavy fuel oil in 2020 and will discharge 180 million tons of contaminated scrubber washwater overboard.
"About half of the world's roughly 500 cruise ships have or will soon have scrubbers installed," said Mr Comer. "Cruise ships operate in some of the most beautiful and pristine areas on the planet, making this all the more concerning."
Scrubbers generally cost between £1.6m and £8.1m depending on the vessel – and the adoption of this technology has cost billions of dollars over recent years, according to Mr Comer.
Thousands of ships fitted with 'cheat devices' to divert poisonous pollution into sea [Wil Crisp/The Independent]