A Year on Ice

Sounds of cheers, toasts, and a brass band serenaded the scientists aboard the Polarstern as the icebreaker left dock in late September 2019. A crowd had gathered onshore in Tromsø, Norway, to celebrate the beginning of the yearlong MOSAiC expedition and wish the researchers luck against the many challenges — both known and unknown — that lie ahead.

“Arctic fieldwork takes an unbelievable amount of preparation, and it was both exciting and a huge relief when we finally set off,” said Senior Research Scientist Steve Archer, who lead a study as part of the recently completed expedition. “We faced a lot of obstacles over the year, but dealing with unexpected problems is a big part of research expeditions — especially in the Arctic. Even in this modern age, it’s a humbling place to work.”

The scope of the MOSAiC expedition was mammoth: a comprehensive, yearlong study of sea ice dynamics and climate. With more than 300 experts from 20 countries, it was the largest Arctic research expedition in history, and its launch was the product of years of logistical fervor, meticulous personnel arrangements, and the careful plotting of plans and back-up plans.

Short for “Multidisciplinary drifting Observatory for the Study of Arctic Climate,” MOSAiC’s aim was to moor the Polarstern to slowly moving Arctic sea ice, where it would drift for a year and serve as the research base for a wide array of measurements and experiments.

As the team neared the North Pole in early October 2019, they selected a site, secured the ship to the ice, and began to assemble their carefully planned field camp in the waning summer sunlight. Before long, a web of power and data cables stretched across the sea ice connecting research sites that spanned a square mile around the ship.

“By the time we got set up, the long months of winter darkness had arrived,” Archer said. “It was cold and dark and fantastic to experience. It felt like we were working on the moon.”

Over the next three months, Archer lived and worked in the strange lunar landscape. He and his team were there to discover how gases flow between the ice, ocean, and atmosphere. This critical exchange shapes the global climate by controlling the movement of ozone, methane, carbon dioxide, dimethyl sulfide, and other influential gases.

Most of the researchers’ time was spent on the ship, where they had set up numerous instruments and could remotely monitor their equipment on the ice. They would make regular trips out into the field camp, but each trip required advance planning — and an armed guard to protect against polar bears.

In January 2020, Archer completed the first stint of his MOSAiC research, and headed home for a few months before he was scheduled to return to the field site in March.

Soon after arriving in Maine, reports of a strange new virus began to emerge and concern began to mount among the expedition leaders. As the next few weeks passed, the research continued, and the world unraveled. The uncertainty caused by the COVID-19 pandemic engulfed MOSAiC operations and threatened to upend a decade’s worth of careful plans and preparations.

The Best Laid Plans

As countries locked down their borders, the personnel exchange that would have brought Archer back to the expedition in March was put on indefinite hold. While the researchers who were about to be relieved from their duties settled in for an extended stay, MOSAiC leaders began to formulate new plans that would protect the research and the safety of all involved. The field camp had effectively already been in quarantine for months, but any exchange of supplies or personnel could put the entire mission at risk.

A resupply date was eventually rescheduled for May; however, the delay had caused a new problem: there were no longer any icebreakers available to bring Archer and the others north to the field site. It soon became clear that the Polarstern would have to leave the ice — and break down much of the carefully constructed field camp to do so.

“It was a tough decision, as we knew we’d miss out on several weeks of data,” Archer said. “I think it was all pretty confusing for the team in the field as well, as the communication capabilities were pretty limited. They knew there was a pandemic, but they didn’t understand the extent to which it had changed things.”

In late April, Archer flew to Bremerhaven, Germany, where he and all the incoming team members quarantined in their hotel rooms for two weeks. With a clean bill of health, they sailed to Svalbard, Norway. There they rendezvoused with the Polarstern, resupplied the ship, exchanged personnel, and began the return journey to the field site they were forced to leave for several weeks.

“Returning to the ice floe was a bit like meeting up with an old friend, although I'm not sure I would have recognized it without the instruments and flags that were still scattered over it,” Archer said. “When we left after the first leg it had been cold and dark for several months, and now it was light around the clock and the seasonal ice melt was well underway."

The Arctic landscape had changed, and so had the world, but the clock was still ticking on MOSAiC’s yearlong mission to build new understanding of the changing Arctic. The role of Archer and his team was to collect continuous measurements that would reveal how the exchange of gases between the ocean and atmosphere varied throughout the annual sea ice cycle. They also investigated how different types of snow and ice cover affected this important process.

“The Arctic influences the entire planet, and it’s changing rapidly,” Archer said. “As warming temperatures continue to reduce sea ice coverage in the region, we’re going to see increasing consequences around the globe. These changes are coming, and the research we’re doing can help us prepare.”

New Perspectives

As the pandemic progressed, Senior Research Associate Kevin Posman prepared for his own epic journey to reach the expedition and relieve Archer for the last few months of research. His departure was delayed from May, to June, before finally taking place in the middle of July. By the time he arrived on the resupply vessel, the expedition had been transformed once again.

An especially warm summer had ravaged the sea ice, forcing the expedition team to pack up the field camp and prepare to push north into colder waters. There, they would reestablish the camp on stronger ice and spend their final weeks studying the sea ice refreeze that heralds the return of winter.

After a brief reunion with Archer, Posman and the crew of the final MOSAiC leg headed toward the pole through relatively ice-free seas.

“The conditions were great for getting to the North Pole, but a sad commentary on the state of the Arctic,” Posman said. “This is a historic year for sea ice melting, but historic melting is the new normal.”

After crossing the pole, the expedition team essentially found themselves starting over. The final few weeks played out like an accelerated replay of the year up to that point. They had to again find a suitable ice floe, set up camp, conduct their research, and break everything down.

“We really benefitted from the experience of the team members who had worked on previous legs of the expedition,” Posman said. “The month we had on the ice was one of the most intense and successful periods of the expedition. We collected a lot of good data in the short time we had.”

As the days began to take on a golden hue, the Arctic summer — and MOSAiC’s year on the ice — came to an end. Nearly 13 months after its cheerful sendoff, the Polarstern pulled back into port in October 2020. The MOSAiC expedition was completed, but the hard work of scientific discovery was just beginning.

The massive scope of the project was in large part due to its multidisciplinary nature. The hundreds of researchers who participated during the year worked to gain a holistic view of the changing Arctic. They studied the biology, physics, and chemistry of the sea ice. They studied the ocean below it, and the atmosphere above it. By collecting all these measurements at the same location and time, they have gathered the pieces of an enormous puzzle that they now need to assemble. “MOSAiC scientists collected data from 3,000 feet below the sea surface to 30,000 feet above it,” Archer said. “There's a huge opportunity to connect everything, and that’s as big of an undertaking as the expedition itself.”

This new understanding could revolutionize climate models. Despite the importance of the Arctic, most computer models are currently forced to take a simplistic approach to the complex region. Scientific understanding of the sea ice is largely based on research carried out near the easier-to-access ice edges, and Archer said his team’s observations have already made it clear that the central Arctic works very differently.

“We have a good sense for some of the big themes that are going to come out of the research,” Posman said. “But there was so much multidisciplinary data collected that I think there are going to be some unanticipated and really exciting discoveries in the coming years.”

Photos by Esther Horvath (top) and Daiki Nomura (center).