Antarctica (27 page)

Even in a good winter, there can be times when you regret the choice you've made. There are stories of people getting ‘Dear John' or ‘Dear Joan' divorce letters by email while they are incarcerated down here and can't do a thing about it. In 2003, Robert Schwarz's brother was sick and all he could do was send emails and make calls. ‘It's a time when you want more than anything to be with your family.' In one of Larry's winters, he learned that his best friend had died. ‘One of my worst fears was realised,' he says. ‘It challenges your idea of surrendering and giving in and not worrying. That's the only time I've ever wished that I wasn't here. You work past it, and you realise how tight the community is. But that's when you also realise that nothing waits for you. You feel as if everything is on hold while you're here, but life outside is passing you by.'

 

The only remaining scientific block that I hadn't yet visited was the Clean Air Sector, where researchers studied the atmosphere.
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But now I had the perfect opportunity. During the South Pole summer, every Friday was ‘slushies' night. This consisted of a general invitation from the guys at the Atmospheric Research Observatory (ARO) to come over and drink cocktails that were cooled into slushies using a scoop of the cleanest snow on Earth. It was my chance both to find out about their science and to sample some of the legendary mixes.

ARO was only about half a kilometre from the main station but it was enough of a hike that I tried to beg a skidoo ride. No chance. Skidoos were strictly banned to protect the cleanliness of the air. The only way to get there was on foot.

The building was big, blue and blockish, set up on crisscrossing stilts over two floors, with snow-covered metal staircases running up the outside. The windows were large and oval, like elongated portholes looking over the frozen ocean. Most of them faced outwards, away from the station and the views were to die for: a glorious white emptiness of sculpted snow and shadows, delicately shaded in pastel colours by the softly slanting sunlight.

ARO looked oddly isolated against a backdrop of bare white plateau that stretched in an arc more than a third of the way around the Pole. To keep the air here as clean as possible, this entire arc upwind of here had been designated strictly no-construction. The prevailing winds blew true; for more than 90 per cent of the time they arrived directly from that empty stretch of ice. This meant that the air sucked into the sensors on the roof of this building was the purest on Earth. It was the background into which all of our human, industrial, polluting wastes were elsewhere being poured.

Squeezed in among all that astronomy, ARO was one of the few South Pole projects that had no interest in outer space. Instead, it was using the way the Pole stripped away outside influences to find out what we could learn about home. It was one of five global observatories run by America's National Oceanic and Atmospheric Administration to measure longterm changes in the air. This was the extreme end-member of the group, the base level against which all the others could be judged. It has also been responsible for some of the longest continuous records in the world; scientists had been measuring the air here since 1957. Long records aren't necessarily sexy. They don't tend to throw up exciting new surprises or eureka moments. But they are good at showing up the sorts of slow but inexorable changes that really matter to our climate, the ones that we wouldn't notice if we were only looking week to week or year to year.

And probably the most important record here was the one for carbon dioxide. This exists perfectly naturally in the atmosphere but we have also been adding to it ever since the Industrial Revolution, by burning first coal, then oil and natural gas. And the CO
₂
that comes out of your car's exhaust pipe or a power station chimney eventually finds its way here. CO
₂
is a survivor. It doesn't fall out of the air easily like soot or dust, but can stay up there for a hundred years or more, spreading to the farthest corners of the globe. The graph of ARO measurements placed prominently in the entrance hall showed that, over the past few decades, carbon dioxide had been rising upwards like a rearing cobra, waiting to strike.

ARO was built to replace the old Clean Air Facility, and had been around for only seven years. But already it had all the warm homely touches that the new station currently lacked. There were artificial flowers everywhere. One of the windows held a vase with plastic sunflowers; a fake poinsettia tied with a tartan ribbon was precariously balanced over one of the desks; and a plastic spider plant appeared to be growing out of the bathroom sink. A lopsided sign outside the bathroom read ‘Ladies' Powder Room'. (Apparently this came originally from Old Pole, the first South Pole station—not that ladies were allowed to visit there until the 1970s.) Another sign hanging from the ceiling of the tech shop suggested that this was the ‘Mental Ward'. Beside the small wooden table that functioned as a coffee station was a metal trolley crammed with bottles of whisky and gin, Grand Marnier and rum as well as more brightly coloured and dubious looking liqueurs. There was also a blender, though here the ice came ready slushed.

Beside the bar were bottles of soap solution and large improvised bubble wires. Blowing bubbles? In Antarctica? One of the slushies team quickly offered to show me how. Outside, the temperature was now around -40°F, which turned out to be perfect. You had to blow quickly or the liquid froze on the wire. But when you succeeded in making giant bubbles, you watched in wonder as they frosted over and shattered in the air, leaving frozen fragments to fly around your head. The pieces looked like plastic but if you tried to catch one, it broke up into fine wafers in your glove.

Back inside, my companion handed me some small sample bottles and bundled me on to the roof. Up aloft there was a stiff breeze, which made the cold almost unbearable—even for just a few minutes. But I drew my parka hood close, and followed my companion's instructions for collecting the perfect South Pole souvenirs. I held out my genii sample bottles to the wind and captured, and sealed in, magical whiffs of the cleanest air on Earth.

Downstairs, the party was now motoring. Someone had brought in a bucket full of snow and the room was full of Polies, with cocktails already in hand. I had decided not to be daring. Larry Rickard warned me days ago about the power, and pain, of high-altitude slushies hangovers. But after a couple of gin and tonics it began to seem churlish not to join in. My favourite was the concoction mixed for me by an ex-marine (and also ex-bartender), which contained Kahlua, Baileys and vodka—and of course perfectly pristine snow. It tasted delicious, like chocolate milk. The pain the next day was everything that Larry had warned me about. But it was still worth it.

Just as ARO was studying home rather than away, there was one other experiment at the Pole that was looking inwards, to the core of the Earth. I had heard about it, but hadn't much hope of getting out there. It was called SPRESSO, which stood for ‘South Pole Remote Earth Science and Seismological Observatory', and it was concerned with measuring earthquakes. Not nearby ones. There were no earthquakes at the South Pole. Instead, like ARO, this experiment was all about focusing on what was left when the messiness of the outside world had been left behind. And just as ARO had to be placed where the air was cleanest, SPRESSO needed to be in the quietest zone on Earth.

In principle, the South Pole was already a good spot for this. Elsewhere in the world, cars, trains, rattling cables or something as slight as the rustling of leaves could be enough to swamp the most delicate seismic instruments. But even here there were problems. The quiet sector was initially sandwiched between the dark and clean sectors, but half a kilometre from the station was too close. The researchers could hear the distant rumbling of the snow cats so clearly that they knew when the heavy equipment operators went to lunch. So they had to move their instruments out of town. After three years of construction and drilling, SPRESSO's delicate seismometers were now buried deep in the snow, some five miles away.

That far from the station, SPRESSO might as well have been on the Moon. There was no way anyone was going to let me go out there on my own, and little chance that anyone could spare the time and the vehicle to take me there. But then I hit lucky. It just so happened that two SPRESSO researchers, Kent Anderson and Steve Roberts, were coming through town. I grabbed them in the galley the day they arrived. Yes, they were planning an expedition out to SPRESSO. And, yes, I could come, too.

Kent was a stocky man, square of body and round of face with a tidy beard and jovial appearance. Steve was quieter and taller, sandy-haired and clean-shaven. Our expedition would be in the Sloth, a rumbling, grumbling yellow lump that ran on tank-like caterpillar tracks and had ‘US Navy, For Official Use Only' stencilled on the side. As its name implied it was known more for solidity than speed.

We were equipped, Steve told me, with full survival gear: orange bags packed with spare clothing, survival bags, emergency food and stove, two radios and an iridium satellite phone. In the outside world, packing all that for an eight-kilometre trip would seem absurd. Here, where the weather could turn on a sixpence, he assured me that it was essential.

As we jarred and jolted our way over the snow, Kent told me about SPRESSO. It was, he said, part of a global network, jointly funded by the United States Geological Survey and the NSF, through a university consortium called IRIS (Incorporated Research Institutions for Seismology).
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Appropriately for a station at the end of the world, and just like ARO, this was the extreme end-member of the network, by far the quietest seismic station on Earth.

The quietness mattered because, with no outside distractions, you could pick up the subtlest possible signals from the other side of the world. An earthquake doesn't just shake the nearby ground. It sends seismic waves down into the bowels of the Earth where they pass through the hot rocks of the planet's interior, squeezing and compressing them or nudging them from side to side. And when these waves, much diminished in strength and stature, make it out the other side, they bear traces of the rocks they have passed through. By measuring the relative speeds of waves that have come from different places and passed through different parts of the planet, SPRESSO could act as a sort of inward telescope, constructing an image of the Earth's mantle of rock, its liquid outer core made of almost pure iron, and the hot hard solid sphere of iron that lies at the centre of the Earth.

The South Pole was especially good for this not just because it was so quiet. Its unique positioning on the Earth's axis of rotation also meant it could hear events with a clarity that other stations couldn't reach. That's because in most places the Earth's own rotation can get in the way. ‘If you think of the Earth as a bell and you hit it with a big earthquake, it'll vibrate and the way it vibrates tells you something about the structure of the interior of the earth,' Kent said. ‘Anywhere where the Earth is spinning, the vibration of the ringing bell also changes. Here at the axis of rotation is the only place where you can hear the true ringing of the bell.'

SPRESSO was also uniquely placed to find out about the very centre of the Earth. Most stations pick up only the waves that have taken glancing paths through the Earth's interior. Here, you could detect ones that had passed through its heart. And SPRESSO was on hand to make sure nobody was cheating on the Nuclear Test Ban Treaty. Nuclear bombs also set off seismic waves. If they are far enough away, they will be faint. But sensitive SPRESSO would pick them up in a heartbeat. ‘If someone tried something in the middle of nowhere, in the southern seas, we would probably hear it.'

When we finally reached the SPRESSO site, the only surface sign of its presence was a set of brightly coloured flags, red, yellow, orange and green, fluttering on an apparently empty plateau. Some, Kent told me, marked the corners of the buried building, some the three boreholes where the seismic instruments lay and some, well, ‘just don't walk there,' he said.

As we came closer I realised there was a vent pipe, comically poking up out of the snow like a periscope from a submarine. There were also two hatches covered first with snow and then, when we had brushed that aside, with wood. One led to a few near-surface instruments, the other to a yellow stepladder that took us down to the surprisingly warm and cosy hut that serviced the seismic instruments.

Inside, as he stripped off his parka and gloves, Kent told me that they'd have preferred to put the site farther from the main station—twelve miles or more. But that was going to be too complicated, and expensive, to service. So the compromise was to put the instruments closer in but deeper down in the snow. It took three seasons to set up the hut and drill the holes and now the seismic instruments were irrevocably buried under a thousand feet of ice.

‘The chamber round the instruments is at about -51°F,' Kent said, ‘but the instruments themselves are wrapped in heat tape, so they're more like +25°. And if one tape fails, they're already wound with a back-up.'

‘What happens if both heat tapes fail?'

‘Then we've lost the instrument, so let's not think about that.' Eight thousand miles from here, on the other side of the world, a piece of the Earth's crust might be straining. The Earth's tectonic plates that hold our continents and oceans are constantly shifting, pushing and grinding against each other, striving for dominance. Sometimes, something has to give. Perhaps up in the Aleutian Islands off the coast of Alaska a section of crust might suddenly rise or fall. Tsunami warnings will chatter out from instruments around the Pacific. Sirens will sound, and sensible coast dwellers will head for high ground if they can. But the heaving crust won't just set off a mighty wave of water. It will also send other waves, seismic waves, downwards into the inner Earth.