The United States and Canada have signaled plans to curb the use of heavy fuel oil in the Arctic.

It’s a move welcomed by environmental groups and shipping experts, who say reducing use of the fuel, commonly known as HFO, ahead of a comprehensive ban in Arctic waters, has been on the horizon for some time now.

“I think the entire world sees the writing on the wall. The world is going to be moving toward non-HFO fuels, no doubt about it,” said Captain David Snider, the CEO of Martech Polar Consulting, a Canadian company providing ice navigation services and support for polar shipping.

In late December, U.S. president Barack Obama and Canadian prime minister Justin Trudeau announced several measures for the Arctic, including most notably a ban on offshore oil and gas licensing.

But a “phase-down” on the use of HFOs in the region was also part of the news.

Details have been sparse so far about how both countries will reduce HFOs in the Arctic, as neither has set an explicit reduction target or timeline for implementation. The two countries say they will raise the issue at the upcoming International Marine Organization (IMO) meeting next summer. In the meantime, the U.S. coast guard says it has started the process to reduce HFO use in U.S. waters, while Canada is reportedly looking into proposals on how it could do the same.

It also remains to be seen whether the U.S. will honor its commitment under the incoming Donald Trump administration, which appears to hold markedly different views on environmental issues from its predecessor.

The “change of government in the United States is huge on everybody’s mind,” Snider said. “The current administration wants to try and make some statements that will close off its legacy and hopefully protect some of that legacy from what is expected from a new presidential team.”

According to Snider, the announcement was nothing new: The U.S. and Canada have supported a ban on HFO for many years.

But he said that he expects the gradual “phase-down” to take place over several years, to give countries and companies enough time to update their fleets to run on alternatives to HFO.

“It costs billions of dollars to change a fleet of Arctic coastal ships that have been trading for decades from one fuel to another. It’s not overnight,” he said. “We have to balance the need to do this for the environment with the ability to do it in an economical way.”

For years, environmental groups and other supporters of a ban on HFO in the Arctic have pointed to HFO’s potential negative impact on the environment as a primary concern.

If a spill occurs, HFO is “pretty well impossible” to clean up in Arctic conditions, explained Paul Crowley, head of the Arctic program at the World Wildlife Fund-Canada.

That’s because HFO emulsifies in water, and “essentially turns to mayonnaise,” Crowley told Arctic Deeply. As its volume expands, HFO spreads throughout the water and then sticks to anything it touches, including birds and marine mammals.

There is also little documented proof that dispersants would be effective in cleaning up an HFO spill in the harsh Arctic environment, Crowley said. “Chances are that an oil spill in the Arctic will have much longer-lasting impacts than in other climates,” he said.

Running ships on HFO and transporting it aboard ships in Arctic waters also creates soot, or “black carbon,” which is deposited on snow and ice. By absorbing sunlight, black carbon is believed to quicken the rate of climate change and ice melting in the Arctic.

But HFO remains the preferred fuel of ships operating in the Arctic due to its low cost and widespread availability and the ability of large marine engines to burn it, explained Bryan Comer, a researcher at the International Council on Clean Transportation.

Larger ships – cargo ships, bulk carriers, oil tankers and large fishing boats – tend to operate on HFO in the Arctic, while smaller vessels are more likely to operate on higher-quality distillate fuel, Comer said.

These distillate fuels can range from marine diesel oil to sulfur diesel similar to the kind with which you might fuel a truck. “As you get higher in quality, you reduce air pollution emissions. You also reduce the density and the viscosity of the fuel,” Comer said.

But distillate fuels also come with a higher price tag than HFO.

“The lowest-quality marine diesel oil, which is a distillate fuel, is about twice as expensive as heavy fuel oil at the moment,” he said.

Comer said about half of the 2,000 vessels operating in the Arctic in 2015, as delineated by the IMO, were fueled by HFO. “The issue is that because the larger ships tend to operate on heavy fuel oil rather than the smaller ships, they carry a lot more fuel on board,” he said.

So while 44 percent of the ships were run on HFO, three-quarters of the oil being transported onboard vessels in the Arctic in 2015 was HFO.

“Any ship is capable of operating on distillate fuel that [currently] runs on heavy fuel oil. It’s not a technology problem or an engineering problem; it’s simply an economic problem,” Comer said.

A prohibition on the use and transport of HFO in Antarctic waters – Regulation 43 of the IMO’s MARPOL Convention (for the prevention of pollution from ships) – entered into force in 2011.

No similar, enforceable prohibition is currently in place for the Arctic. The Polar Code states, however, that “ships are encouraged” to apply Regulation 43 in Arctic waters.

Any amendments to include a permanent ban on HFO in the Arctic would need the agreement of the Marine Environment Protection Committee (MEPC), which is tasked by the IMO with preventing pollution from ships.

“It would be up to the member states meeting in the MEPC to decide the next steps,” an IMO spokesperson told Arctic Deeply in an emailed statement.

It has been more difficult to institute an HFO ban in the Arctic than in Antarctica because “there are less economic stakes in Antarctic,” said Frederic Lasserre, a geography professor at Laval University and an expert on the geopolitics of the Arctic.

“It’s different in the Arctic because the Arctic is a populated region, it’s an ocean bordered by inhabited countries … and there is economic exploitation of natural resources in the Arctic,” he said.

Lasserre told Arctic Deeply that the strongest opposition to an outright HFO ban has so far come from Russia, which has argued that switching away from HFO will be costly for residents of its isolated Arctic communities that rely on it to generate power.

Many Russian vessels in the region also still rely on HFO, and there are fears that switching over to more expensive fuel options would make the Northern Sea Route less profitable, he said.

“This is an unofficial reason that is important, as well, in Moscow’s mind,” Lasserre said.

Snider added that “Russia was not willing to back down” during discussions about including an immediate prohibition on HFO use in the Polar Code, because this would have effectively rendered their fleet “outlawed immediately.”

Going forward, Snider said the shipping industry has demonstrated the will to eliminate HFO use in the Arctic; it’s just a matter of giving the companies that would be affected the time they need to get it done.

Crowley at WWF-Canada, meanwhile, said the U.S. and Canada have taken a good first step in gradually moving away from HFOs, but more work needs to be done.

“The phasing-down is a good start, but it needs to be phased out,” he said. “And that goes back to the investment timelines: If you know it’s going to be phased out, then you will take it seriously and change your thinking as a consequence.”