The dock’s rubber bumpers groan as the Polarstern eases its weight off them. The ship lets off three long foghorn blasts, which are answered in kind by its companion vessel, the Akademik Fedorov, moored 50m (164ft) away. A brass band starts up as the Polarstern begins moving out of the harbour of Tromsø, on the northern fringes of the Norwegian coast. Before we’ve moved 10m (32ft) off shore, the Arctic breeze whips the sound away.
In the ship's gangway, one of the expedition leaders, Markus Rex of the Alfred Wegener Institute (AWI) in Germany, leans on the railing with some of the other scientists on board, looking out towards the dark fjords of the Norwegian coastline. He has just launched the largest Arctic expedition there has ever been.
"I don't know how I feel," he says. "I honestly don't know." He may not, but he looks ecstatic.
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Polarstern, whose name means North Star in German, is an icebreaker dedicated to scientific research. It has just begun a year-long mission to the ice cap of the central Arctic Ocean. The ship will sail to the eastern edge of the ice at around 85 degrees north and 135 degrees east – about 500km (310 miles) from the pole, although the exact location will depend on the state of the ice we find.
Once there, the scientists will search for the perfect ice floe to anchor the vessel to. They will then build a frozen metropolis – an extensive research camp with outposts up to 50km (31 miles) away from the ship.
Polarstern itself will remain frozen in place to drift with the camp wherever the winds and currents will carry the ice. During its ponderous, 10km-a-day drift across the Arctic, the ship and its crew will experience sub-zero temperatures with just curious polar bears for company. And for the first few weeks of this adventure, so will I.
The German icebreaker Polarstern passes through rough Arctic seas on the way to the sea ice (Credit: Martha Henriques)
As one of the few journalists taking part in the journey, I have come to observe the work they are doing and find out for myself the impact that humans are having on this frozen, little understood environment. While I’m only due to be onboard for five or six weeks, my return may depend on the changing weather and ice conditions.
There is a good reason for this extraordinary expedition.
Despite the countless satellites blinking overhead, and numerous short sampling excursions made to the central Arctic Ocean over the years, the picture that scientists have built of the environment in the far north is still a vague sketch.
Summertime data is easier to retrieve, when the ice extent is lowest and temperatures are most bearable. But accessing the pole in winter with vast quantities of highly delicate scientific instruments requires money, time and an extent of international collaboration difficult to achieve.
The Arctic remains something of a blank patch in the map of the world's climate
It has meant that the Arctic remains something of a blank patch in the map of the world's climate. Many predictions about its future have relied upon approximations, extrapolations and assumptions. On a broad scale we know the Arctic sea ice is declining. At the end of this year’s summer it hit its second lowest level since records began in the 1970s. The sea ice spanned just 4.15 million sq km (1.6 million sq miles), a level also seen in 2016 and in 2007. The sea ice extent has only been recorded lower once, in 2012, when it fell to just 3.41 million sq km (1.32 million sq miles).
But exactly what this means for the ocean, the wildlife and the wider climate is still largely unclear. These missing data are one of the last great mysteries of the global climate. What we do know is that the Arctic is among the most sensitive parts of the world to climate change, warming at around twice the rate of any other region. But the impact will not be confined to the top of the world – small perturbations in the Arctic are expected to ripple outwards to lower latitudes, driving more widespread climate changes.
The Mosaic expedition is taking a large team of scientists to the Arctic sea ice, where they will take year-round measurements of the Arctic climate (Credit: AWI/Stefan Hendricks)
There are some tangible examples already. One of the best-studied is what happens when the bright white northern ice cap melts. As it shrinks, the Sun's light and warmth that was previously reflected back into space by snow and ice is instead absorbed by the dark oceans. Those warmed oceans then lap at the ice, causing it to melt more, potentially leading to a runaway cycle of melting until it vanishes entirely in the summer months. There are already fears we are approaching this tipping point.
This dramatic change is expected to have knock-on effects across the northern hemisphere, including altering ocean currents, rising sea levels, shifts in major fisheries and impacts on wildlife both on and off the land.
To find out with any precision how severe these changes will be, it takes an expedition on the scale of the one I have joined.
The Multidisciplinary Drifting Observatory of the Study of Arctic Climate, or Mosaic as it is known, dwarfs previous expeditions of its kind. Its price tag comes in at well in excess of 140m euros (£124m/$153m), without even considering the value of the instrumentation on board.
Earlier, while the ship was still being loaded, one scientist showed me an instrument that he had built over the course of 37 years – more or less his entire career. On the outside, it looked unremarkable, like a domestic freezer turned on its side.
"It cost more than a million dollars,” he told me, resting his hand on the white metal casing. “Well, how much for a life's work?"
We are advised not to stand close to it for too long, otherwise it will be my face appearing in the data instead of information about the cloud cover
After nearly a decade of planning, Polarstern is packed almost to bursting point with devices of this nature. One instrument overlooking the stern looks like an old-fashioned overhead projector, with a domed mirror in place of the usual flat surface for sheets of acetate. This Total Sky Imager that will take pictures of the Arctic sky as Polarstern drifts with the ice. We are advised not to stand close to it for too long, otherwise it will be my face appearing in the data instead of the cloud cover.
Taking stock of all the experiments like this on board, it is easier to understand expedition leader Rex's numbness as we depart.
The facts and figures of the expedition give some idea of its scale. More than 600 scientists from 19 different nations will take part over the course of the year. Some are staying for a total of nine months. Living on a boat and floating ice camp more than 1,000km (621 miles) from the nearest solid land, they will work in vicious polar storms, temperatures as low as -45C and the long months of polar night over the winter.
The 118m (386ft) long ship is, for the most part, a winding network of narrow corridors over six decks, from the engine room and laundry down below to the bridge high over the bow. A series of small "shops", or hatches from which the ship's crew offer beer, sweets, tobacco and toiletries, open at set times throughout the week, usually for just 15 minutes at a time. Mealtimes are equally regimented, with breakfast from 07:30 to 08:30, briskly followed by lunch at 11:30, coffee and cake at 15:00, and dinner at 17:30.
Daily measurements will be taken on, above and below the ice to build up a better picture of how the Arctic is responding to climate change (Credit: AWI/Esther Horvath)
Deciphering the rhythm of life on the ship is made easier for me by my cabinmate, Nicole Hildebrandt. This is her eighth year and tenth expedition on board Polarstern. A researcher at AWI, she is part of Mosaic’s ecology team, sampling zooplankton. Zooplankton, small marine organisms that carried by currents, are a crucial part of the Arctic food web – supporting life from whales to fish, and the seals and polar bears that eat the fish.
Hildebrant’s speciality is using a series of large nets, which she casts from the side of the ship into a hole in the sea ice where they can drift for up to 2,000m (6,500ft) in the water beneath. She knows the ship backwards and forwards, describing the circuitous paths through the warren of steep stairs and cramped corridors to reach more or less anywhere I want to go. She tells me when it is a good time to get your laundry done, and when to beat the dinner queues. Among her baggage she has brought a few things to make our cabin more homely – her own pillow and bedlinen, fairy lights and a selection of snacks not available on board
This is the first time Hildebrandt will be working on Polarstern through the Arctic winter. Among her supplies this time is a stash of vitamin D to compensate for the lack of sunlight. This first leg of the expedition is expected to end in mid-December, followed by a two-week journey back on another icebreaker, which will plough through the ice to get as close as possible to Polarstern so people, fuel and food can be transferred.
None of the first leg participants expect to be back for Christmas. "I think it will be beginning of January. We won't make new year," says Hildebrandt.
In the first few days on board, sense of time on the ship dissolves. As we move east, through the Norwegian Sea to the Barents Sea, a muffled voice declares on the public announcement system, first in German then in English, that the clocks will go forward one hour that night. This happens every afternoon for the first week. Like many things on the ship, it happens in a strictly regulated way. Time will be lost in three 20-minute intervals spread throughout the night, so that the shortening of the shifts is spread fairly between the three night watches. Each night the minutes between 20:00 and 20:21, between midnight and 00:21, and then 04:00 and 04:21 go missing.
Compounding this sense of slipping time is the lack of windows in the communal spaces in the ship. On C-deck is the Red Saloon, where most people spend their idle moments, lit by a soporific glow from yellow-shaded wall lamps. The ship rolls heavily in the swells, causing a pen hanging on a string on the saloon wall to swing like a pendulum. In the bar down on D-deck, a stool spins slowly by itself. It’s as if the Polarstern is rocking us to sleep, regardless of whether it is 21:00 or right after breakfast.
The waves outside are 3-4m high on average, their tips whipped into white horses by a north-easterly wind
But everyone's experience of the motion is different. For Hildebrandt, it is unbearable. She spends most of day three in the top bunk of our cabin with her eyes tight shut. The waves outside are 3-4m high on average, their tips whipped into white horses by a north-easterly wind. Seven-metre waves roll through every now and again. We hear a faint crash as the ship hits a trough, sending a wall of spray flying up to the windows of the bridge.
As the short days pass, it becomes clear that I am one of the irritating few who doesn't suffer at all from seasickness. Instead I thoroughly enjoy the sensation of being magnetised to the floor one moment and floating near-weightlessly the next. As I climb the steps from deck to deck, I imagine that I am walking on the surfaces of different worlds – first struggling on a vast planet with an overbearing gravitational field, a second later skimming lightly across the surface of the moon.
The scientists and crew on board Polarstern catch sight of the aurora on their journey to the ice, but soon they will be too far north to see it (Credit: AWI/Stefan Hendricks)
By day four of the voyage, as we pass the tip of Novaya Zemlya, a pair of islands extending from northern Siberia, those who have been suffering from seasickness begin to emerge from their cabins as their bodies adjust to the unstable floor.
They check the maps on touchscreen monitors in the Red Saloon, zooming in to see our progress and adjusting the settings to see the ice thickness data further ahead, superimposed on the map in bright purple. We are soon set to pass a handful of Siberian islands, including Severnaya Zemlya to the west and Bolshevik Island to the north. Just beyond them, a nasty tongue of ice curls out from the ice cap. "It is a question of whether we go through that ice field, which could be slower and with more icebergs, or if we take the long way around it," says Rex.
People murmur about passing between the islands. The route is rumoured to be extraordinarily beautiful, and it would be our first up-close sight of land since leaving Norway. But it is also a tricky stretch to navigate.
"We are now past the area where we can rely on the maps," says Rex. Another large ship passed through that stretch a few days ago, so we know it is possible. But Polarstern has a deep hull, and accurate data on the depth of the sea floor is scarce. There is also the problem that the more time we spend travelling through ice, the trickier the ride. "Polarstern can't go through icebergs," says Rex. "Ice sheets, fine, that is just a couple of metres or so. But icebergs are much, much larger. They can go way down for a hundred metres."
Scientists on Polarstern are protective about the welfare of their scientific instruments, which are crucial for the success of the expedition (Credit: AWI/Esther Horvath)
An unwelcome image floats into my mind. Felix Lauber, a senior crew member, assures me that even if Polarstern crashed headlong into an iceberg at speed, we would not be in serious trouble. "You won't break this ship in the ice – we've tried hard already," he says.
Lauber has worked on the bridge for 10 years (he's still "the new guy" by the crew's standards, he tells me) and appears to have a strong attachment to Polarstern, both for its scientific capacity and its physical sturdiness. "If we hit a massive iceberg straight on, the ship will shake a bit,” he says. “You will have some damage on the nose but not under the waterline. Everyone would take a step forward but we would be fine. She is an amazing build, really."
I interpret this as professional understatement.
Lauber's view from the bridge looks out onto the bow, where the iron grey waves turn into a white sheet that showers down on the containers stored on the deck. The rough seas have already posed challenges for some of the scientific instruments they contain. Water has been sloshing in through the inlets at the bottom of the containers, which are there to ensure that they don't trap water inside, but also allow a good quantity of sea foam to bubble in from below.
Instruments like Katarina Abrahamsson's "Miss Sophie" require constant attention to keep them working (Credit: Martha Henriques)
The instruments are, of course, the scientists' only way of getting their jobs done once we find ice. Without fully functional tools, they would have come to the North Pole for nothing. Some of the scientists care for them almost as if they were living creatures.
Most of those not kept in exposed sea containers on the bow live down in labs on E-deck. The confined corridors are painted a faded shade of institutional green. I follow a blast of hot air, along with the sound of hissing and burping machines, to the lab of Katarina Abrahamsson, of Göteborgs Universitet, Sweden. I find her working at a screen showing a black-and-white trace with clusters of sharp peaks. She is measuring the levels of naturally occurring ozone-degrading compounds in the Arctic.
The release of these compounds, produced by microorganisms and geochemical processes, can have the same degrading effect on the atmosphere as CFCs, the now-banned class of chemicals used as refrigerants and propellants since the 1930s. Abrahamsson is travelling north to find out whether the young, thin sea ice that now dominates the Arctic is a potent emitter of these compounds, as studies in the Antarctic have suggested it might be. (Read more about the detectives hunting down ozone-killing chemicals.)
Looking around her lab I see a white unit with a glowing green hexagonal design cut into its front and in one corner a discreet label that reads "Good Boy". On the other side of the lab I see an identical instrument, only its label says "Bad Boy". One of the instruments worked perfectly well out of the box in the lab back home, Abrahamsson tells me. The other, not so much. Between the two green-glowing instruments sits a complicated steel box with a tangle of wires among dozens of gauges and dials. Its name: "Miss Sophie".
"Oh, they all have different personalities," says Abrahamsson. "Sometimes you have the thing working fine, and then you go away for a night and you come back and it has shut down for no reason," she says, frowning fondly at Miss Sophie. "You try and try to get it working again next day and it won't do a thing. It's as if it's saying, 'Why did you leave me?'"
Abrahamsson now has a routine to check on her instruments every night before bed, to make sure they won't be “sulking” come morning. When I visit, only half of Abrahamsson's whizzing, hissing instruments have been turned on. The others, she says, are too temperamental. The motion of the ship – particularly when we meet the sea ice – could break a delicate arm that transfers samples from one part of the machine to another. That instrument, which doesn't yet have a name, is tied down securely under a blue strap.
After a week at sea, Polarstern reaches the edge of the Arctic sea ice, and the waves die away to nothing (Credit: Martha Henriques)
It is still four or five days before we are due to arrive at our first ice floe. The search to find the perfect floe is uppermost in people's minds after the health of their instruments. Five days are budgeted for the hunt, but it could take longer. "We want to take some time to find our home for the next year," says Rex.
All we know so far is that we are heading for 85 degrees north and 135 degrees east. There, Rex is hoping to find a sweet spot that will set the vessel on a drifting path – carried by the wind and currents – as close to the North Pole (perhaps even over it), and then westward across the ice sheet. A year later the ship is expected to emerge, with luck, from the ice in the Fram Strait.
A lot hinges on finding the right piece of ice. If it is too thin, it might not support the runway needed for supply planes. If we spend too long looking for it, it will cut into valuable time for setting up the camp. And if the expedition is unlucky, the floe we attach Polarstern to could break up in one of the many vicious winter storms passing through. If this happens, all the instruments out on the ice could slip irretrievably into the sea.
The team have help from satellite images beamed down daily, detailed sea ice forecasts and on board experts with years of knowledge of the vicissitudes of the ice.
But in the end, much of the fate of the expedition will be left to the whims of the unpredictable Arctic climate that they have come here to capture.
As I finish writing on the morning of our fifth day at sea, there is a low rumble that seems to come from deep inside the ship. My desk begins to judder. Out of my cabin window, I see that we have just met our first ice.
* Martha Henriques is a senior journalist at BBC Future. She is spending six weeks on board Polarstern and Akademik Fedorov as they embark on their mission. You can follow her progress on Twitter @Martha_Rosamund
This article is part of our Frozen North series. Climate change is already transforming the Arctic. In many areas, what was ice is now open water. But in the most inaccessible reaches of the far north, how much has changed? And what will the knock-on effects be for the global climate?
The world’s largest polar expedition has just set off to answer those questions – and BBC Future’s Martha Henriques is one of the lucky handful of journalists onboard. In our series Frozen North, she reports from the Arctic’s floating sea ice as scientists seek to find out how this shifting environment will affect all of us.
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