Tag Archives: greenhouse emissions ships

How Air Pollution Infiltrates the Seas

A global effort to curb pollution from the heavy fuel oil burned by most big ships appears to be encouraging water pollution instead. A 2020 regulation aimed at cutting sulfur emissions from ship exhaust is prompting many owners to install scrubbing systems that capture pollutants in water and then dump some or all of the waste into the sea.

Some 4 300 scrubber-equipped ships are already releasing at least 10 gigatons of such wastewater each year, often in ports and sometimes near sensitive coral reefs…. The shipping industry says pollutants in the waste don’t exceed national and international limits, and that there’s no evidence of harm. But some researchers fear scrubber water, which includes toxic metals such as copper and carcinogenic compounds called polycyclic aromatic hydrocarbons, poses a rapidly growing threat, and they want to see such systems outlawed.

The emerging debate is the result of a 2020 regulation put into place by the International Maritime Organization (IMO), an arm of the United Nations that works with 174 member states to develop common rules for international shipping. By banning the use of sulfur-heavy fuel oil, the rule intended to reduce pollutants that contribute to acid rain and smog. IMO estimated the rule would slash sulfur emissions by 77% and prevent tens of thousands of premature deaths from air pollution in ports and coastal communities.

But cleaner fuel can cost up to 50% more than the sulfur-rich kind, and the rule allows ship owners to continue to burn the cheaper fuel if they install scrubbers. In 2015, fewer than 250 ships had scrubbers (often to comply with local regulations); last year, that number grew to more than 4300, according to industry figures.

A scrubber system sends exhaust through a meters-tall metal cylinder, where it is sprayed with seawater or freshwater, depending on the type, at rates comparable to gushing fire hydrants, to capture pollutants. In the most popular systems, called open loop scrubbers, seawater is discharged to the ocean after little or no treatment. Other systems retain sludge for disposal on land and release much smaller (but more concentrated) amounts while at sea….Researchers are particularly worried about discharges in areas that IMO has designated as ecologically sensitive. The Great Barrier Reef, for example, receives about 32 million tons of scrubber effluent per year because it’s near a major shipping route for coal. Ships also release scrubber water around the Galápagos Islands….

Ports see substantial discharges, too. Cruise ships dominate those releases, contributing some 96% of discharges in seven of the 10 most discharge-rich ports. Cruise ships typically need to burn fuel in port to continue to operate their casinos, heated pools, air conditioning, and other amenities. Most ports have shallow water, so pollutants are less diluted and can accumulate more rapidly….

Researchers, who are participating in a €7.5 million European effort to study shipping pollution called EMERGE, would like to study how scrubber water affects fish larvae.

But shippers have become hesitant to share samples and data with scientists. “We’re reluctant to give it to organizations which we know have already an established agenda,” says Mike Kaczmarek, chairman of the Clean Shipping Alliance 2020

The ultimate solution is to require ships to use the cleanest fuel, called marine gas oil. In the meantime, 16 countries as well as some localities have banned the most common scrubbers.

Excerpts from Erik StokstadShipping rule cleans the air but dirties the water, Science, May 13, 2021

The International Council on Clean Transportation (ICCT) study, released on April 9, 2021

Sailing the Seas Pollution Free

The shipping industry made a historic step toward cleaner air on April 13, 2018 with a deal to cut greenhouse gas emissions by half by 2050 compared to 2008…  Shipping and aviation were excluded from the Paris climate agreement adopted under a United Nations framework in 2015, with governments entrusting the International Maritime Organization (IMO) to come up with a consensus on carbon reduction measures from ocean going vessels.

The aviation sector reached a deal on carbon emissions in 2016, but it took shipping much longer as ocean carriers and regulators considered measures such as the adoption of clean-burning fuels or electric propulsion, slower sailing speeds and hull design improvements at a cost of hundreds of billions of dollars.  The deal puts the agreement into force world-wide, with no other action needed by the regulatory body. The final pact was a compromise between groups and countries including the European Union, China, and other Asia and Pacific nations that pushed for reductions in emissions by as much as 70% and the U.S., Argentina, Brazil and Saudi Arabia, among others, that pushed for lower targets.

Of the 173 IMO-member states, only the U.S. and Saudi Arabia, objected to the draft IMO agreement…Shipping contributes about 3% of total annual carbon dioxide (similar to an economy the size of Germany), or CO2, world-wide emissions, about the same as an economy the size of Germany, according to an IMO study. But vessel emissions are projected to increase by between 50% and 250% by 2050 as global trade grows and carriers add capacity without any action to intervene.  The IMO reductions would aim to cut carbon emissions to half the 2008 carbon dioxide levels.

The emission cuts will also affect thousands of exporters world-wide. Brazil, for example, exports large amounts of iron ore to China and fears strong caps will push up freight rates, helping rival Australia, whose iron exports sail half the distance to China.  Slow steaming, in which ships purposely throttle back to slower speeds, is also an anathema for countries exporting perishable goods like cherries from Chile and meat from Argentina.  Some countries with big shipping registries like the low-lying Marshall Islands, that want to stop the effects of climate change, led the call for strong cuts…

Excerpt from Shipping Regulators Reach Deal to Cut Carbon Emissions, Wall Street Journal,  Apr. 13, 2018

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