With Canada’s last intact ice shelf recently collapsed, a June heatwave that roasted Siberia with temperatures over 37.8ºC, and Greenland’s ice sheet now losing a half-teratonne of ice yearly, it’s no wonder researchers now predict the Arctic could be ice-free in summer in less than 15 years.
And while the majority of the anthropogenic heating in the Arctic (which is occurring at a rate over twice the global average) can be attributed to plain old carbon dioxide, a host of secondary climate forcers, called short-lived climate pollutants, aid CO2 like sidekicks helping a villain. They don’t stay in the atmosphere nearly as long as carbon dioxide, but molecule for molecule are far more potent. Short-lived climate pollutants include methane, black carbon, tropospheric ozone and hydrofluorocarbons.
Of these, black carbon is unique, being a particle, not a gas, formed during the combustion of fossil fuels and other biogenic materials. In other words, black carbon is soot.
According to a major scientific assessment published in 2013, the pollutant is second only to carbon dioxide as a driver of global heating, although methane may have taken that dubious title since. Regardless, the warming effect of black carbon is so significant that its reduction offers the fastest, cheapest way to slow climate destabilization in the Arctic.
“Black carbon is a little bit esoteric, not a lot of people talk about it,” says Bryan Comer, a senior researcher at the International Council on Clean Transportation (ICCT). “We talk about carbon dioxide, we talk about methane – maybe not as much as we should – but we hardly talk at all about black carbon in the media.”
The main sources of black carbon worldwide are cooking and heating fires, wildfires, diesel engines, burning of agricultural wastes, and coal and heavy oil power plants.
As a component of fine particulate pollution, airborne black carbon is linked to cardiovascular diseases, strokes, cancer, and acute respiratory infections in children. The World Health Organization estimates air pollution causes seven million premature deaths each year.
The most-used ship fuel in the Arctic is Heavy Fuel Oil, a low-cost, tar-like residue from the leftovers of processing crude oil.
Whether emitted from a cooking fire in Africa, a diesel engine in Asia, or a wildfire in North America, black carbon drifts in the atmosphere for days to a couple weeks, travelling around the globe. The black particles absorb heat from the sun’s rays, warming the atmosphere.
But for the Arctic, the largest climate effect comes when the particles land on snow and ice and continue to absorb solar radiation.
“As this snow and ice melts, especially if it’s sea ice, it’s opening up darker-coloured patches of water, setting off a feedback loop where you have more melting, more warming, and so it’s accelerating the melt of snow and ice happening in the Arctic right now,” Comer says.
Black carbon sources in the Arctic, which include heating, transportation, and gas flaring, are tiny relative to sources from other parts of the globe, but due to their proximity have a surface warming effect nearly five times greater than black carbon emitted at more southernly latitudes.
Black carbon pollution from ships in the Arctic, though a lesser source, has shot up 85% since 2015, and is set to grow further. Ships are also “the only source that can plow through the ice and emit black carbon exactly where you don’t want it to be, which is right next to the arctic snow and ice and inside the sea ice,” says Comer.
Thankfully there’s a straightforward solution.
Heavy Fuel Oil
The most-used ship fuel in the Arctic is Heavy Fuel Oil (HFO), a low-cost, tar-like residue from the leftovers of processing crude oil. HFO emits high amounts of black carbon when burned. A switch from HFO to Marine Diesel Oil (MDO), a lighter distillate fuel, would cut black carbon emissions from ships in the Arctic by nearly a third. MDO-burning ships could then be outfitted with particulate filters, cutting black carbon emissions 90% or more.
It’s the type of measure the International Maritime Organization (IMO), the United Nations’ body that regulates shipping, has been pondering. For thirteen years.
“It’s been over a decade now that the International Maritime Organization has been discussing what to do about black carbon, or what it is, how you measure it, and ultimately how to reduce the emissions of it,” says Dr. Sian Prior, lead advisor to the Clean Arctic Alliance, a coalition of 18 environmental NGOs. “The solutions are actually relatively simple compared to some climate forcing gasses. We have alternatives available. They are cleaner, they’re not clean. They still produce black carbon, the most popular one anyway, diesel or distillate fuel. But if you combine moving to a cleaner fuel producing less black carbon, with the installation of a particulate filter, you can reduce your black carbon emissions dramatically…. There is a cost obviously associated with doing that, but in terms of the total impact that black carbon is having on the climate generally and the Arctic specifically, it’s almost a no brainer.”
But finally the IMO looks ready to move, albeit slowly, on black carbon. The organization has hammered out draft language for a ban on HFO in the Arctic that would take effect in July 2024 (HFO has already been banned in Antarctica since 2011 due to the risk of spills). Comer and Prior say that as the draft stands now, however, there are loopholes large enough to steam an oil tanker through.
“It used to be about trying to protect the Arctic before things got crazy up there. Now things are getting crazy up there.”
First, vessels with double-walled fuel tanks meeting certain specs would qualify for a five year extension, avoiding the ban until 2029. A study by the ICCT estimates this alone will exempt a third of HFO used in the Arctic.
Secondly, a proposal by Russia would see ships registered in Canada, Greenland, Norway, Russia, and the United States exempted until 2029. Under this arrangement, ships from non-arctic nations could be reflagged by Arctic nations, to burn HFO while in their flag-country’s sovereign waters.
Analysis by Comer and other ICCT researchers finds that less than one-third of HFO carried and less than one-fifth of HFO used would actually be banned in the Arctic under the current language, resulting in black carbon cuts of only five per cent.
“It’s not that the ban is pointless,” Prior says, “but if all you’re doing is banning less than a quarter of the fuel that’s being carried and used in the Arctic today, it’s ineffective regulation, it’s not what was intended when it was agreed that we would be banning heavy fuel oil in the Arctic.”
An IMO meeting in October will be the last chance to change the language of the ban before the resolution comes up for adoption.
A different fuel restriction from the IMO came into force at the beginning of 2020. HFO used in international waters must now have a sulphur content of not more than 0.5%, to reduce deadly sulphur emissions. The regulations were a landmark step to reduce air pollution from the shipping sector. But there’s a hitch. The formulations developed to replace high-sulphur HFO, called very low sulphur fuel oil, or VLSFO, may produce more black carbon than their predecessor, a study submitted to the IMO by Germany and Finland suggests. An increase in additives called aromatics is suspected, but Prior says until there’s concrete published data, if and how VLSFO raises black carbon emissions remains an open question.
Trading one pollutant for another?
For Russia, which dominates Arctic HFO use and black carbon emissions, the exemptions in the Arctic HFO ban would allow Russian-flagged ships burning or carrying HFO to transit the country’s entire Northern Sea Route from the Pacific to the Atlantic, or vice versa. This dovetails with Russia’s plans for economic expansion in the Arctic.
“It’s clear the Arctic is a huge economic possibility [for Russia],” Prior says. “They’re investing massively in infrastructure in the Arctic along the Northern Sea Route, a lot of that funded by or supported by China. They’ve set huge commitments, huge targets on increasing the volumes of goods being shipped that way.”
LNG ship engines are designed to run at low cylinder pressure and low ignition temperature…. This allows 3-4% of the methane fuelling the most common type of LNG engines to escape up the smokestack unburned.
Yet at the same time, Prior says Russia has sent signals it plans to move away from oil-based fuels in the Arctic altogether, transitioning instead to fossil gas, a resource Russia has vast Arctic reserves of.
“We are getting some very mixed messages from Russia at the moment,” says Prior.
Prior cautions, however, that while LNG ship engines emit no black carbon, they do emit carbon dioxide and leak methane, and so are not a solution for greenhouse gas emissions from shipping.
LNG ship engines are designed to run at low cylinder pressure and low ignition temperature, Comer says, to minimize nitrogen oxides that contribute to smog. This allows 3-4% of the methane fuelling the most common type of LNG engines to escape up the smokestack unburned.
“We don’t want to be in the business of trading one climate super pollutant for another,” Comer says.
HFO also carries significant spill risk, amply demonstrated by the Japanese bulk carrier MV Wakashio, which ran aground then broke up off the coast of Mauritius in August, bleeding over a thousand tonnes of HFO into the crystal waters of a protected marine park.
In the remote Arctic an HFO spill would be “horrendous,” says Prior. “They’re very persistent, nearly impossible to clean up… skimmers don’t work, absorbents don’t work, dispersants don’t really work. It’s just too thick and heavy.”
Distillate spills, while not exactly squeaky clean, can at least be expected to largely evaporate and disperse.
And HFO’s threat to the climate, Arctic ecosystem, and human health is growing, as oil, gas, and mining development drives rising Arctic ship activity.
Retreating summer sea ice is proving tempting for shipping companies, too. The prospect of a faster, cheaper route between Asia and Europe or North America has prompted shipping giants such as Maersk and Cosco to send ships through the Northern Sea Route on summer test runs.
Comer says that although it’s still early days for a well-trodden trans-Arctic shipping route, “companies and countries, including China for instance, are serious about taking the Arctic shortcut, especially the Northern Sea Route, which opens up a lot faster and has a lot more open ocean than the Northwest Passage.”
“[An HFO ban] used to be about trying to protect the Arctic before things got crazy up there,” Comer says. “Now things are getting crazy up there.”
The clock is ticking. As Finland’s President Sauli Niinistö said in 2019, “If we lose the Arctic, we lose the globe.”