Black carbon puts shipping on a collision course with the climate

Global shipping is the world’s sixth-largest source of greenhouse gas emissions. Black carbon, mainly from heavy fuel oil (HFO) used by some ships, contributes a fifth of these climate-warming emissions. ANDREW DUMBRILLE explains why HFO has to go—and why the International Maritime Organization and Arctic states need to ban it.

Black carbon is generated from the incomplete combustion of HFO in ship engines. Emitted from ships’ exhaust stacks, it is the world’s most polluting and hazardous fuel. When released in the Arctic, some of it lands on surfaces like snow and ice, absorbing sunlight and increasing temperatures—and accelerating local warming through ice and snow melt.

Normally, snow and ice reflect heat back to the atmosphere. Reduced amounts of snow and ice (thanks in good part to the impacts of black carbon) diminish this effect, hindering the Arctic’s ability to help regulate the climate. As the saying goes, what happens in the Arctic doesn’t stay in the Arctic.

Impacts on people

There are immediate human health consequences from exposure to black carbon emissions, including coughing or breathing difficulties, heart problems, aggravated asthma, and premature death in people with heart or lung disease.

Health problems like these compound the hardships that Arctic communities and Indigenous People are already experiencing from the impacts of the climate crisis. For example, snow and ice are at the centre of Inuit culture, and as they diminish—compromising infrastructure and altering ecosystems—it becomes harder for these communities to maintain their ways of life.

Yet Arctic shipping is on the rise. The Arctic Council’s Protection of the Arctic Marine Environment Working Group recently found that from 2013 to 2019, there was a 25 per cent increase in the number of ships in the area and a 75 per cent increase in the distances travelled. Perhaps unsurprisingly, data from 2015 to 2019 indicate an 85 per cent increase in black carbon emissions.

There is hope, though: a recent study from the International Council on Clean Transportation modelled five transit routes through the Arctic and found that if ships switched from HFO to cleaner-burning distillate fuels (similar to diesel), black carbon emissions would fall by 50 to 80 per cent. Cleaner fuels are available worldwide, are already being used in some marine fleets, and can be used without the need to retrofit ships.

Time to act

So why aren’t ships switching from HFO to cleaner alternatives? We can trace the answer back to the International Maritime Organization (IMO).

Given the nature of international trade and vessel traffic, rules to reduce emissions and pollution from ships need to be set globally—and the IMO is the body in charge of doing this. However, the most recent round of negotiations at the IMO did not result in an effective HFO ban. As of July 1, 2024, only 30 and 16 per cent of the HFO carried and used in Arctic waters, respectively, will be prohibited.

To strengthen the HFO ban and more effectively reduce black carbon emissions, the responsibility now rests with Arctic states. Progressive states could ban all HFO carriage and use and mandate a switch to cleaner-burning distillate fuel in their waters. Norway has taken a similar approach in its state waters near Svalbard, so we know it can be done.

We are all familiar with the concept of a catastrophic tipping point in the climate crisis. The Intergovernmental Panel on Climate Change Sixth Assessment Report found that the maritime industry, global supply chains and the infrastructure on which they depend are particularly exposed to climate shocks, extreme weather, sea-level rise, and environmental disruption caused by the climate crisis. Forcing the elimination of HFO use is a necessary step forward for northern communities, the world’s climate systems and the maritime industry itself—a rare win–win–win climate solution.