Reducing black carbon in the Arctic
By Bill Hemmings, Advisor, Clean Arctic Alliance
Two major pollutants present in crude oil — sulphur and aromatic compounds — have been heavily restricted for years in fuels used for road transportation, mobile machinery, rail locomotives and inland shipping. These measures have cut air pollution significantly.
Yet the international shipping industry still operates mainly with cheap, dirty residual marine fuels. These fuels contain comparatively high levels of sulphur as well as aromatic compounds that generate black carbon (soot), causing ultra-fine particle pollution.
But there are ways to “clean up” these residual fuels. More intense refinery processes can reduce or remove pollutants to produce distillate fuels, which are cleaner-burning and already used in a variety of large marine vessels, including cargo ships, tankers and passenger ships operating in certain regulated areas, such as the Baltic and North seas.
The use of distillate fuels allows for the fitting of diesel particulate filters that further cut air pollution. These filters already dramatically reduce pollution from road vehicles, and they could do the same on ships—but they cannot be used with residual fuels because these would clog the filters immediately.
Little progress since 2011
In 2011, the International Maritime Organization (IMO)—the United Nations body responsible for ensuring that international shipping is safe and has minimal environmental impact—was tasked with limiting the impact of black carbon from ships on the Arctic. Black carbon had been recognized not only as a human health hazard, but a powerful, short-lived, climate-forcing pollutant whose impact is magnified when it is released in the Arctic, especially if it settles onto snow, ice and frozen seas.
Arctic ship traffic was already growing, and minimizing this source of black carbon was seen as urgent, given the evident signs of impending Arctic climate breakdown. Yet more than a decade later, sadly, little has been achieved.
In 2012, a study conducted for the IMO identified that switching from residual fuels to cleaner marine distillate fuels would be an effective, immediately feasible approach that would cut black carbon emissions from Arctic ships significantly. (The only downside is its 20+ per cent price premium versus residuals.) Civil society began pressing the IMO to mandate this fuel switch.
But under IMO rules, only Member States can initiate such regulatory action. So instead, working groups convened over successive years to develop a definition of black carbon that everyone could agree on. The groups also set out to identify ways to measure black carbon emissions from shipping, and drew up a long list of potential technical and engine abatement measures, recognizing that ship engine condition, type and load have major influences on emissions. But work to investigate and prioritize the most effective and feasible measures was not pursued.
Polar fuels and loopholes
In 2021, an IMO resolution called for ships to voluntarily switch from residual fuels to distillate or other cleaner fuels in the Arctic. To reinforce the focus on engine-based solutions, voluntary guidelines for ships to measure and report their Arctic black carbon emissions and set reduction targets for black carbon were also developed and agreed upon by the IMO’s Marine Environment Protection Committee in October 2024.
Pressure for the distillate switch was stepped up after the IMO agreed to a ban on the use and carriage of heavy fuel oil in the Arctic. The ban took effect in July, but it is full of loopholes and will not be fully effective until 2029. Moreover, it covers only IMO Arctic polar waters (those specified by the Polar Code), leaving out major areas of the Arctic north of the 60th parallel.
Distillate grade marine fuels were proposed as ideal polar fuels in February 2024 to replace residuals and significantly reduce ship black carbon emissions. The term “polar fuels” was first coined by IMO delegates from Norway and Iceland to disallow the use of high pour-point marine fuels in the Arctic. (High pour-point fuels need high water temperatures in order to remain fluid during an oil spill. In an Arctic oil spill, these fuels would congeal instead of dispersing, and would be virtually impossible to clean up.) Distillate grade marine fuels have low pour points. Last October, IMO delegates stressed that any definition of polar fuels should also include other clean fuels in use today as well as future low-carbon fuels.
Imposing an immediate and mandatory switch to distillate grade marine fuels or other cleaner fuels remains the quickest and most effective way for the IMO to finally act to reduce the impact of pollution from shipping in the Arctic.
BILL HEMMINGS is a Brussels-based expert on environmental issues related to international shipping and aviation. He also an advisor to the Clean Arctic Alliance.
