Credit: Roberto Venturini, CC BY 2.0, via Wikimedia Commons.

ANCHORAGE — A new report released today lays out the case for why the International Maritime Organization (IMO) should immediately act on reducing black carbon pollution — a climate super-pollutant. On thin ice: Why black carbon demands urgent action, by Pacific Environment, explores how the expansion of Arctic shipping is causing an increase in the release of black carbon into the air, which then settles on snow and ice, accelerating dangerous melting.

“Despite more than a decade and a half of debate, U.N.’s maritime shipping body the IMO continues to ignore the simple solution: require ships to immediately switch to cleaner fuels when operating in the Arctic. Despite technical assessments and calls for voluntary measures at the IMO, black carbon emissions from Arctic shipping continue to grow unchecked. Without mandatory requirements, markets lack the certainty needed to shift fleet operations toward lower black carbon options. We call on the IMO to respond to this Arctic crisis and urgently address the growing health and human impacts of black carbon,” said Kay Brown, Arctic policy director, Pacific Environment.

Black carbon’s growing Arctic threat

Unchecked black carbon emissions from Arctic shipping represent a clear and present danger to the integrity of the Arctic cryosphere, global climate stability and the health and wellbeing of Arctic Indigenous and coastal communities. By mandating a swift transition to polar fuels – existing fuels with lower black carbon emissions which are suitable for use in the Arctic –  the IMO can enact a high-impact policy that achieves immediate benefits. Action ahead of PPR 13 – the IMO’s technical pollution prevention and response meeting – in early 2026 will allow Member States to agree on action that will help slow Arctic warming and uphold the IMO’s mandate to protect the marine environment and adjacent communities.

Arctic traffic surges 108%

According to the Protection of the Arctic Marine Environment’s (PAME) Arctic Shipping Status Report, the number of individual vessels entering the Arctic increased from 1,298 in 2013 to 1,781 in 2024 — a 37% rise — while the cumulative distance traveled within these polar waters rose by 108%, from 6.51 million to 12.7 million nautical miles. Commercial fishing vessels made up the largest share of vessel mileage at 34%. Bulk carriers, icebreakers and research ships made up significant shares. 

Melting ice, increasing risk

In addition, the retreat of Arctic sea ice is opening new shipping lanes and extending the months in which shipping is feasible. Increased shipping traffic is driving up emissions from vessels burning residual fuels, the most commonly used shipping fuels. When combusted, residual fuels including residual fuel blends,  produce high concentrations of black carbon and other hazardous pollutants, contributing to intensified regional warming in the Arctic with global climate repercussions, according to the Arctic Council. If spilled, the highly viscous oil can persist for weeks in cold waters or become trapped within and beneath sea ice, posing long-term threats to marine ecosystems and shorelines while complicating cleanup efforts. 

Read the report, On thin ice: Why black carbon demands urgent action

Additional key takeaways

• Opportunity: The IMO Pollution, Prevention and Response 13 subcommittee (PPR13) meets February 9-13, 2026. It can help protect the Arctic by recommending a mandatory switch from residual fuels to “polar fuels,” such as cleaner distillates, to its parent body, the Marine Environment Protection Committee (MEPC), for a decision later in 2026. Pacific Environment and its partner organizations in the Clean Arctic Alliance call on IMO Member States to jointly develop a robust Arctic BC proposal amending MARPOL Annex VI to be reviewed at PPR 13 in early 2026. 
• Black Carbon: After carbon dioxide, black carbon is considered the second largest cause of global warming from shipping and one of the causes of rapid sea ice decline. Between 2015 and 2021, Arctic shipping-related black carbon emissions approximately doubled. Globally, roughly 20% of shipping’s total climate forcing is from black carbon. Nearly half of global warming to date has been caused by ozone, methane and black carbon. 
• Climate impacts: Per unit of mass, black carbon has a warming impact up to 1,500 times greater than that of CO2. Black carbon has an outsized impact in the Arctic, where it heats the atmosphere and accelerates snow and ice melt. This exposes darker land and water surfaces that absorb more heat, amplifying warming and diminishing the region’s reflective albedo effect. Darkened surfaces absorb more solar radiation, accelerating melt and freshwater runoff from glaciers into the oceans. Glacier melt and sea ice decline can disrupt major ocean currents — such as the Atlantic Meridional Overturning Circulation (AMOC) — with cascading effects on weather patterns in the mid-latitudes. 
• Human health risks and community impacts: Beyond its climate impacts, black carbon is a component of fine particulate matter (PM₂.₅) and poses acute public-health risks. Inhalation of black carbon-laden air increases rates of cardiovascular disease, respiratory illness and premature mortality. In the Arctic, where communities rely on local subsistence hunting and fishing, increased black carbon and associated pollutants degrade air quality, impact traditional food sources through loss of sea ice and exacerbate existing health disparities among Indigenous and remote populations.

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About Pacific Environment

Pacific Environment works to stop climate change and ensure healthy ecosystems around the Pacific Rim for the benefit of people and our planet. We campaign to stop climate change by working to fast-track key industries toward zero carbon emissions. We focus on major global industries that have received less public attention but whose carbon emissions are significant and still growing: the maritime shipping and the petrochemical (plastics) industries.