\u201cIt means that every year, quite high concentrations will accumulate in these areas and will be growing and growing,\u201d said Liudmila Osipova, the study\u2019s lead author and an ICCT researcher in Berlin. <\/p>\n\n\n\n
Separate scientific research has shown that scrubber wash water can be acidic and poisonous to some marine life, though the overall effect on coastal environments and communities isn\u2019t fully understood. \u201cWe don\u2019t know what kind of consequences that will have,\u201d Osipova said. <\/p>\n\n\n\n
Only a fraction of the global shipping fleet \u2014 roughly 8 percent \u2014 uses scrubbers. Other vessels have switched to cleaner-burning but more expensive petroleum products like \u201cmarine gas oil.\u201d But scrubber adoption continues to grow<\/a>, particularly among giant cargo vessels and cruise ships with huge appetites for fuel. The bigger the vessel, the bigger its scrubber, and the more wash water the system will ultimately discharge.<\/p>\n\n\n\n Most scrubber systems are \u201copen-loop,\u201d meaning they mix seawater with exhaust gas, filter it, then discharge the resulting effluent. \u201cClosed-loop\u201d systems treat and recirculate their wash water and dispel a smaller amount, but fewer shipping companies use them because they cost more to install and operate. Until ICCT researchers studied some 3,600 scrubber-equipped ships, there wasn\u2019t a solid sense of how much polluted water these systems produce around the world or where it winds up. Some 700 more ships now use scrubbers since the research data was collected, so the volume of wash water is likely much higher than estimated, Osipova said.<\/p>\n\n\n\n For environmental groups, the study compounds their broader frustration with the industry\u2019s seemingly tepid efforts to address climate change. Cargo shipping is responsible for nearly 3 percent<\/a> of the world\u2019s annual greenhouse gas emissions. Yet rather than pursue technologies to replace bunker fuel, some shipowners are spending millions of dollars to install equipment that addresses one problem \u2014 air pollution \u2014 but does nothing to advance the industry\u2019s decarbonization efforts, said Dan Hubbell, manager of the Ocean Conservancy\u2019s shipping emissions campaign in Washington, D.C. <\/p>\n\n\n\n \u201cWe\u2019re facing a truly global crisis, and it\u2019s the kind of thing that requires bold solutions,\u201d Hubbell said. \u201cA piece we\u2019ve struggled with is the industry\u2019s preference for short-term fixes.\u201d<\/p>\n\n\n\n Proponents of scrubber systems pushed back<\/a> against the ICCT study and other criticisms. The Clean Shipping Alliance, an industry group that includes the cruise giant Carnival, said the report\u2019s estimates of 10 billion tons of wash water are \u201cgreatly exaggerated.\u201d The alliance pointed to industry-funded research<\/a> that suggests that wash water has the \u201csame overall water quality\u201d as the seawater it returns to. In a statement, Capt. Mike Kaczmarek, the alliance\u2019s chairman, said that scrubbers have become \u201ca successful bridging solution to carbon neutrality.\u201d<\/p>\n\n\n\n Independent research had already raised flags about the effects of scrubber wash water on the marine environment. Last year, a study<\/a> on ships in Belgium found their scrubber discharges to be acidic, with elevated concentrations of metals like nickel, copper, and chromium \u2014 all of which can hurt fish and other marine life. In April, the Swedish Environmental Research Institute found<\/a> that wash water from North Sea ships has \u201csevere toxic effects\u201d on the zooplankton that serve as food for cod, herring, and other important fish species. Researchers suggested that ships\u2019 scrubber systems might serve as a \u201cwitch\u2019s cauldron,\u201d meaning that chemical compounds brew in a hot, acidic environment and become more toxic together than they would if taken individually.<\/p>\n\n\n\n Kerstin Magnusson, an ecotoxicologist and co-author of the Swedish study, noted that scrubber wash water doesn\u2019t affect all species the same, and it may be less toxic in certain environments than others. But research on the topic is still relatively limited, in large part because scientists have trouble getting their hands on wash water samples. \u201cShip owners don\u2019t want us to collect it,\u201d she said. \u201cThey think we are seeking to find adverse effects, but this is not the case.\u201d<\/p>\n\n\n\n Given such uncertainty, governments worldwide are taking steps to protect the waters they control. Thirty countries and ports have banned or put limits<\/a> on scrubber wash water in their jurisdictions, including major shipping countries like China, Singapore, and Norway, as well as authorities in charge of the Panama and Suez canals. In the United States, California and Connecticut have scrubber-related restrictions. And in Washington state, officials are considering a proposal to prohibit wash water in the Puget Sound, a busy cruise hub that\u2019s home to threatened orca whales and Chinook salmon. <\/p>\n\n\n\n The Port of Seattle last year banned cruise ships from dumping<\/a> wash water \u201cout of an abundance of caution\u201d to protect fish and wildlife habitats near the Seattle waterfront, said Alex Adams, the port\u2019s senior manager of environmental programs. \u201cUntil we can learn more about the impacts of wash water discharges, we\u2019re going to continue this prohibition,\u201d Adams said. In response to the policy, most cruise ships now plug into the port\u2019s shoreside electricity to avoid running their scrubbers. <\/p>\n\n\n\n Groups like Ocean Conservancy and Stand.earth are calling for a blanket ban on scrubber use within U.S. and Canadian waters. The ICCT recommends that the International Maritime Organization \u2014 the United Nations body that regulates the shipping industry \u2014 prohibit ships from using scrubbers to meet environmental protocols and phase out scrubbers on existing ships. That might encourage companies to get more of their vessels to run on low-sulfur fuels like marine gas oil until fossil fuel alternatives such as green methanol<\/a>, hydrogen, and ammonia become viable.<\/p>\n\n\n\n Without tighter restrictions on wash water pollution, or stronger requirements to reduce ships\u2019 greenhouse gas emissions, cruise and cargo ships are expected to continue installing scrubbers. That could lead to even more wash water getting dumped overboard. The way things are going, Osipova said, \u201cWe\u2019ll just see more and more emissions of water pollution in the future.\u201d<\/p>\n This story was originally published by Grist<\/a> with the headline Cargo ships are cleaning up smog \u2014 by dumping pollution into the seas<\/a> on May 17, 2021.<\/p>\n![\"An](\"https:\/\/grist.org\/wp-content\/uploads\/2021\/05\/scrubber-diagram.jpg\")