In the last few days of 2018, as the Arctic archipelago of Svalbard, Norway, lay cloaked in the long darkness of polar night, a shrimp trawler called the Northguider ran aground off the coast of one of the islands.

A gale howled. The engine room flooded with seawater. A Norwegian coast guard helicopter managed to quickly rescue the crew. The ship, though, remained behind, along with the 300,000 liters of diesel oil stored in its fuel tanks. An oil spill in the surrounding Nordaust-Svalbard nature reserve—home to walruses, polar bears, and a wealth of seabirds—seemed all but certain.

Until relatively recently, the Northguider may not have even been in the area. But thanks to the climate crisis, temperatures in the Arctic are on the rise and the region’s sea ice is on the decline. New opportunities are opening up for fishing, research, pleasure, transport, mining, and oil and gas industry expansion. Traffic in the Arctic has ramped up accordingly, with the number of ships off Greenland’s coast, as well as the northern coasts of Alaska, Canada, Scandinavia, and Russia, increasing by 25 percent between 2013 and 2019, and the actual distance traveled jumping 75 percent over the same period.

Fishing vessels like the Northguider make up the largest share of this Arctic traffic, but cruise ships and other passenger vessels, cargo and container vessels, and tankers carrying oil, gas, and various chemicals are also creeping up in numbers. All of this traffic increases the risk of oil spills, not just because there are more ships, but because the Arctic’s environment is still harsh and dangerous. Unpredictable weather and free-floating ice remain, and the changing climate is expected to bring yet higher winds and waves over the coming decades. Moreover, ships that divert from existing routes stray far from well-established help, says Jens Peter Holst-Andersen, chair of a working group on emergencies for the Arctic Council, a forum for Arctic states, Indigenous communities, and other northern inhabitants.

Oil spills—both large disasters and chronic, smaller spills—are the “most significant threat to the marine environment” from this increase in shipping, the Arctic Council says. Unfortunately, scientists still know very little about the region’s marine ecology, and many local communities are ill-equipped to deal with maritime disasters. With ship traffic continuing to rise, nations are scrambling to improve remote responses to spills and accidents. And scientists are racing to collect as much information as they can about the Arctic as it is now—a picture against which to measure and hopefully mitigate inevitable catastrophe.

A year before the Northguider incident, researcher Ionan Marigómez from the University of the Basque Country in Spain, made a trip to Svalbard to collect mussels. A diver who accompanied him dipped repeatedly into the frigid water to grab bags full of specimens. Marigómez and his team dissected some of the mussels right away, removing their digestive glands and gills and immediately freezing them with liquid nitrogen to preserve key indicators of the mussels’ health that can be changed by the stress of transport. For less finicky measurements, like the ratio of flesh to shell, the mussels could be frozen whole. Some of these samples were destined not just for the lab bench, but for long-term storage in an environmental specimen bank—an archive of samples carefully curated to provide a snapshot of an ecosystem at a particular point in time.

The humble mussel may not be the first animal to spring to mind when thinking of oil spills, but mussels are important indicators of ecosystem health, says Marigómez. That’s because they’re highly sensitive, changing physiologically in response to shifts in water oxygen levels, temperature, contaminants, and pathogens. At the same time, they’re resistant enough to survive—storing this information in their bodies where scientists can access it later—and they’re easy to work with.

Marigómez did not foresee a career focused on mussels. “I’m a microscope man,” he says—a cell biologist. But his interest in how cells react to environmental changes led him to the digestive glands of mollusks like mussels and snails. He studies these multipurpose organs, which function a bit like a combined human liver, pancreas, and endocrine system, to take measurements such as how stable certain membranes are, or the proportions of different kinds of cells. Just as a doctor might test someone’s blood to ascertain their risk of heart disease, Marigómez tracks signs of toxicity and stress in these biomarkers, which paint a portrait of the health of the mussel—and therefore its environment.

It’s impossible to understand the potential consequences of an Arctic oil spill and cleanup without more fully understanding the ecosystem itself, says Kirsten Jørgensen, a marine pollution researcher with the Finnish Environment Institute who has been working on the problem of Arctic oil spills with Marigómez and a large team of other scientists. Much of the biological research on oil spills has focused on the visible impacts on animals like seabirds and seals. But studying less charismatic species like mussels can tell researchers whether exposure to toxic substances has sublethal impacts that weaken the tiny creatures that play a crucial role at the lower tiers of a food web, Jørgensen explains, potentially causing harm that cascades through the whole system.

Marigómez, Jørgensen, and their colleagues have a lot more work ahead of them. The trip to Svalbard was part of a two-year effort to gather blue mussels from polluted and less polluted areas across the Arctic and North Atlantic. Because the biomarkers they’re tracking can vary by season and possibly by latitude, it will take a long time to build a comprehensive data set. Ideally, it would have readings taken every few years for decades on end, says Marigómez—but getting funding for that ambitious a project “does not seem very likely.”

Other research efforts are also underway to build an Arctic baseline. Outside the realm of institutional science, for example, Inuit communities are banking ecological data. Rather than the university credentials often associated with science, Inuit knowledge “is based on generations upon generations of information that has been gathered and passed down,” says Neil Kigutaq, a senior Inuit stewardship manager at Qikiqtani Inuit Association in Iqaluit, Nunavut. When people are out hunting and fishing, they record the number and location of the animals they catch, like ringed seals and Arctic char. They also note movements, sightings, and signs of other animals. The growing data set not only contributes to scientific understanding for conservation, but could also help communities if they need to claim compensation for lost harvesting income as a result of activities like shipping.

There is no environmental specimen bank dedicated to the Arctic just yet, though other specimen banks have relevant samples. But Marigómez and other researchers want one just for the Arctic so that there are enough samples stored to record a thorough snapshot of the ecosystem before something goes badly wrong. Something like a ship running aground, spilling hundreds of thousands of liters of diesel oil into a still-healthy ecosystem.

The Northguider was taking a risk by trawling for shrimp far north of Svalbard in winter, according to Odd Jarl Borch, an emergency preparedness researcher at Nord University in Norway. When disaster struck, help was far away, communication options were limited, and conditions were horrendous. “I thought I was used to the polar night,” says Trond Hjort-Larsen, senior advisor on emergency preparedness for the Norwegian Coastal Administration, and part of a team that arrived in early 2019 to remove the Northguider’s diesel oil. “But I had never seen anything like it.”

In Svalbard’s main settlement, Longyearbyen, the city illuminates the mountains and surroundings so that there is plenty of light even during the weeks of winter when the sun doesn’t rise. But in the uninhabited region where the Northguider ran aground—the Hinlopen Strait, 200 kilometers north of Longyearbyen—there were no city lights, no moon, no northern lights, and clouds masked the stars. At noon, if the sky was clear, a small stripe of blue would appear on the southern horizon, Hjort-Larsen says. Aside from the crew’s artificial lights, that blue stripe “was the only light that I saw for three weeks.”

For those three weeks in early 2019, Hjort-Larsen and a large team worked to stave off the ecological ruin of an oil spill. There are floating bags with 25,000-liter capacity designed for cleaning up oil, but the team decided they were too puncture-prone for the dark, ice-covered water, and too cumbersome to use in the unpredictable weather. Instead, the team MacGyvered solutions with the equipment they had on hand. They removed the seats from tourist boats available in the nature reserve and stuffed the boats with general-purpose thousand-liter containers made from hard-shell plastic. They emptied the Northguider’s tanks into these, and then in turn into the coast guard vessel’s tanks, until all the diesel was safely removed. “We were lucky,” Hjort-Larsen says. Apart from a heavy storm on the first day, the weather was calm, the temperatures not too low, the ice manageable, “and the polar bears kept their distance.”

Without that luck, and a lot of ingenuity, the outcome could have been entirely different. A simulation suggests the fuel from the Northguider could have drifted as far as 40 kilometers down the coast. Although diesel is not as sticky as other oils—it evaporates and disperses more easily—it is one of the most toxic oils for fish and invertebrates.

Even under ideal circumstances, cleaning up oil spills is somewhat wishful thinking. Only tiny portions of the oil have been recovered from large spills like Deepwater Horizon, the catastrophic 2010 spill in the Gulf of Mexico. In the Arctic, complications multiply.

Because the region is only sparsely populated, oil spills stand a strong chance of being extremely remote, making rapid response difficult. In places where a community can respond quickly, local officials might not have the equipment they need, which means they lose precious time waiting for help from afar. When the Northguider ran aground, nearly a week had passed by the time a crew arrived to assess the wreck. Hjort-Larsen, based in mainland Norway’s Arctic city of Tromsø, had to fly to Longyearbyen and then join the coast guard vessel Svalbard for the 24-hour journey up to the Northguider—and other crew members came from even farther afield, including the Netherlands, where the company that the Northguider’s owner hired to advise on salvaging the wreck has its base.

Unlike in warmer climates, oil in the Arctic can get encapsulated within or trapped underneath ice, or absorbed into snow. Work is underway to develop oil spill cleanup methods that are suitable for the Arctic, but options are still limited: sea ice can make it impossible to use existing equipment meant to clean oil from the surface of the water, or to deploy floating containment booms, which act as barriers to stop spills from spreading.

In-situ burning, which is exactly what it sounds like—setting the oil on the surface alight—leaves sooty residue and produces carbon emissions. And chemical dispersants, which spread oil through the water column to prevent a slick that smothers seabirds, cause a new set of problems, says marine pollution researcher Jørgensen. These dispersants can combine with the oil to kill fish, plankton, and other life below the sea’s surface, taking the oil’s deadly effects into the depths.

The urgency to develop Arctic-specific tools for oil disaster response and an Arctic ecological baseline has only increased in recent months. In late May, news broke of a massive Arctic oil spill: not in the ocean, but inland in Norilsk, Russia, where a fuel storage tank at a power plant collapsed, dumping more than an estimated 15,000 tonnes of diesel oil into the Daldykan and Ambarnaya Rivers. Floating river ice broke the booms that officials used to try to hold the oil back from the large freshwater Lake Pyasino, with dire consequences for both the lake’s ecology and the animals—including humans—that depend on it for water. Shortly afterward, a scorching heatwave blasted through Siberia, with temperatures soaring past previous record highs, in one case hitting 25 °C at a time of year when daytime temperatures are usually 0 °C. And each summer, Arctic sea ice recedes a little more: September 2020 had the second-least coverage since record-keeping began, outstripped only by 2012.

As the Arctic opens up and the surrounding nations scramble for the region’s newly available mineral and oil resources, the Arctic Council has strengthened cooperation between its member states to cope with the climbing environmental risk. Member countries are building capacity to deal with oil spills by augmenting their stores of equipment, like dispersant equipment for helicopters and stronger booms that can handle ice; equipping people in remote Arctic communities to work as early responders until reinforcements arrive; and running training exercises to simulate actual oil spills.

When I speak to Hjort-Larsen over a video call, he’s about to leave for one of these exercises in Svalbard. The Norwegian coast guard has already made some adjustments based on lessons learned from the Northguider incident—most importantly to its remote-communication networks, with powerful new digital radios on board the Svalbard coast guard vessel, and a new, higher-coverage satellite communication system. But there are still challenges with coverage and power supply for these improvements. Later, Hjort-Larsen sends me photos of the training exercise: a small boat tugs a large oil bag before a stunning backdrop of snow-capped mountains and bright blue skies.

Meanwhile, farther north in Hinlopen, the hull of the Northguider sat for nearly two years, emptied of its dangerous fuel but still stranded by harsh conditions. Finally, this summer, a salvage crew managed to demolish what was left of the wreck, and divers scoured the seabed to remove any final traces. With luck, the next time something goes awry, the Arctic country unfortunate enough to play host to the disaster will be more ready.