Antarctica (42 page)

While the rescuers toiled to fill in the crevasse and retrieve the $45 million plane, the researchers kicked their heels back at McMurdo and wondered if the season would be a bust or if they would still be able to salvage at least some of their plans. They learned to dance, and knit; they made snow sculptures, put on concerts and plays; they made a papier mâché piñata in the shape of a Hercules, with toilet paper rolls for engines, cardboard wings and lolly sticks for propellers, which they smashed open ceremonially to exorcise the evil spirits that were keeping them from their field site.

And then, in the second week of January when it was almost too late, the call finally came. The researchers raced to set up their drill rigs, and were now scrambling to do in two weeks what they had intended to do in twelve.

I had been in contact with the science team all along, and they had assured me that I was still welcome to join them. But then I hit a snag. Mactown's National Science Foundation representative, Dave Bresnahan, had decided that all visits were off. This camp had been enough trouble already. Anyone extraneous to the science was now officially banned. And that meant me.

I had wheedled and begged and argued, but the best I had managed was a reluctant offer to send me instead to Siple Dome. This was a temporary base on the tip of the western ice sheet, a few hours' flight from McMurdo. But still, it wasn't what I needed. At Siple Dome I would find a few researchers who had just finishing drilling an ice core, looking into the region's climate past. That was potentially important in its own way. But the camp I was trying to get to, which was called ‘Upstream D', was right on top of one of the ice streams draining the western ice into the sea. The researchers there were investigating just how vulnerable the West Antarctic Ice Sheet was. They were looking not at the dead and gone, but at the here and now and next.

And yet . . . Siple Dome was also just a short Twin Otter flight away from the Upstream D camp. Maybe, just maybe, I could still find a way.

When I arrived at Siple Dome I headed straight for the camp manager, Sarah Grundlock. I was bearing messages for her from several of my contractor friends at McMurdo, who had also assured me that if anyone could figure out how to get me to UpD, Sarah could. And, sure enough, when I delivered my messages and then explained my mission, she took me into the Jamesway tent that served as a galley and pointed out a man sitting at a table there. He was Henry Perk, chief pilot for the Twin Otters. He was doing regular hops to resupply UpD. In fact, he was going there tomorrow. And, what's more, he made colourful watch straps to sell. ‘Buy one of his watch straps,' Sarah advised. ‘That will be your boarding pass.'

A couple of hours later, with a new watch strap on my wrist, I was in the Siple Dome comms tent, putting a radio call through to Dave Bresnahan back in Mactown. He couldn't hear me, so everything had to be relayed through MacOps.

‘I have a ride to Upstream D,' I said. ‘Henry has offered to take me. Do I have your permission to go?'

I waited for the message to be passed on. The crackly reply came:

‘Will Henry pick you up on the same day or would you have to stay?'

‘I'd like to stay.'

Another pause.

‘He says you could be stuck there. He can't guarantee to fly you back out for maybe five days or more.'

‘Fine by me.'

This time the pause between messages was longer. I waited anxiously. And then through the static came the voice of MacOps. ‘He says tell her to enjoy her trip.'

 

The next morning Henry and I took off early. At first the ground was flat, white and featureless. But, suddenly, I saw crevasses on the surface of the ice, like score marks made by gigantic fingernails. Here and there, the snow bridge had broken open, and that familiar vivid blue ice shone through from beneath. Then the crevasses became less regular, criss-crossing, curving, a tangled mess of scattered dips and hollows. ‘We're right over the margin now,' Henry said from the cockpit.

That meant we were crossing over into the ice stream. On one side, the ice was moving perhaps several feet per year. On the other, it moved that same distance in a
day.
On the outside of the margin the ice was resting, on the inside it was racing, and the area between was being ripped apart with the strain, creating such extraordinary patterns of crevasses on the ice that the Twin Otter pilots had given the different margins fanciful sobriquets: ‘The Snake', ‘The Dragon', ‘Valhalla'.

Until now the biggest glacier I'd witnessed was the Beardmore, the staircase that Shackleton and later Scott had used to climb up on to the polar plateau. I'd seen it on the flight to the South Pole and it was streaked with flow lines, an impressive frozen river. This one was much, much bigger, too big to take in from the air. It was thirty miles wide, a half mile thick and ran inland for hundreds of miles. The great size and fantastic speed of these ice streams meant they were all colossal superhighways, transporting ice at an extraordinary rate from the interior to the sea. And because of this, many researchers were convinced that they were the key to the stability—or otherwise—of the West Antarctic Ice Sheet.

Moreover, these ice streams weren't just big and fast; they were also dynamic, stopping and starting, writhing from one place to another on timescales short enough to matter to humans.
⁴
The neighbouring ice stream to this one
⁵
was scarcely moving at all. And yet radar measurements of buried crevasses at its margin showed that it must have been moving as quickly as all the rest, as recently as 130 years ago.

There was something else odd about these ice streams. When we passed the jumbled, chaotic crevasses of the margin, the ice was completely smooth again. It was moving faster than any other glacier I had yet seen. That ought to mean that the ice was jumbled into crevasses as the racing glacier snagged on the ground beneath. But there were no flow lines, no signs of movement, nothing. Researchers had discovered that the ice streams had no flow lines because they slid incredibly smoothly on the base, so that there was nothing to rip, strain or distort the ice.

There were many theories for why the motion should be both so fast and so smooth, but now Barclay Kamb from Caltech was leading the effort to see for himself. One by one he was visiting as many as possible of the Siple Coast's six ice streams, drilling holes through them to find out what was happening at the business end, the meeting point where the ice slipped over the ground beneath.

Though I hadn't yet met Barclay, I'd read many of his papers. He habitually described himself as a ‘doubting Thomas', who needed to see and touch before he could believe. He called it ‘the truth of the drill'. ‘You can have remote-sensing data and interpretations and theories of what is down there, deep below the surface, but until you drill down and get hold of the actual materials, you never really know.'

We landed on a bright blue Antarctic morning. Steve Zebroski, the camp manager, had come to meet the plane and say a hasty hello. He was pale and red-eyed through lack of sleep; the team had been working round the clock to rescue their season. We went together into the galley tent, which held a fully working kitchen filled with the enticing smell of freshly baked bread. Lesley, the camp cook, had just pulled a tray of rolls out of the oven. She offered me one, with a cup of tea, but Steve warned me that the team at the drill site was within about fifteen minutes of breaking through to the base of the ice on its latest hole. I declined the tea, stuffed a roll into my parka pocket and followed him back out.

‘You can take this skidoo,' he said, pointing to one that had a name—
Clarence
—stencilled in duct tape on the side. It turned out that Barclay's team always chose a theme for naming their skidoos, and this year it was characters in the movie
It's a Wonderful Life.
Clarence was the angel who came to show James Stewart's failing businessman that his life wasn't so bad. I'd always found the movie too soppy for my taste, but I was still quite pleased to get the angel.

‘How do I find the drill site?'

Steve gave me a dry look. ‘There aren't many tracks around here,' he said. ‘Just don't go near any black flags.'

Ah yes. After the trouble with the Hercules, a team of mountaineers had scoured the area for any further crevasses, and had marked the few danger spots with flags. And in any case Steve was right. There was only one ‘road', where the snow had been churned up into a visible track. I turned on the engine, pulled down my goggles and headed off.

Barclay came to meet my skidoo. He was tall and clean-shaven—which was rare for men out in the field. I later discovered that among its other amenities this camp even had a shower. True, you had to shovel your own snow to make the water, but the result was as hot and comfortable as any hotel. (As instructed, I shovelled the snow after I'd finished, so the water could be ready melted for the next person to come along. It was hot work, so I didn't register how cold the air was—until I heard a tinkling sound, which turned out to be strands of my wet hair that had quickly frozen solid.)

The set-up at the drill site involved the same sort of derrick and cable winch that I'd seen for ice coring. But unlike the ice-corers who needed to bring back samples of the stuff they were drilling through, all Barclay wanted to do was get through the ice sheet to what lay beneath. So there was no need for a complicated drill with a rotating metal head and sharp teeth. Instead, the Caltech method was much quicker and cleaner—amounting more or less to a vertically mounted fire hose. The idea was to melt a large amount of snow—which is why there were three people frantically shovelling from a bulldozed snow pile into a large vat—heat the water to about 200°F and pump it under very high pressure through the tip of a jet that looked like the head of a spear. Then you just pointed the jet downwards, pressed the right buttons, and let the combination of hot water and gravity do the rest.

Still, the ice was so thick that it took twenty-four hours to get through it. The team had started this particular hole yesterday and were just about to hit the bottom. Various graduate students and field assistants were kneeling on sheets of plywood around the hole. The derrick was holding the hose in place and one woman was feeding it down through her hands, letting it slide, feeling for the tug it would give when it hit the floor. ‘Come on . . .' she said. ‘Break through.'

Barclay's colleague from Caltech, Hermann Engelhardt, emerged suddenly from the Jamesway tent, as short as Barclay was tall, as hirsute as Barclay was clean-shaven. He had been monitoring the instruments and seen the shift in tension on the hose. ‘That's it!' he shouted. ‘Pull it out!' Two people started heaving upwards on the hose, while another dangled his weight from the cable to lend additional pulling power. I ran over and joined in, heaving until someone said: ‘OK, she's safe.' Now, apparently, there was no chance of the drill sticking, though I didn't know how they knew. We let go and the winch took over, pulling the jet back up to the surface.

Barclay had ducked into the tent again with Hermann and I followed. Both were leaning over a laptop looking at a series of peaks in a graph. ‘That's beautiful,' Barclay said. Things were apparently going well.

He told me that this was the fourth hole they had drilled in very rapid succession and all were testing why the ice streams could move so quickly and so smoothly. The answer was a combination of two things that you wouldn't normally expect to find under a kilometre of ice: water and mud.

Previous holes that they had drilled through other ice streams had shown that these giant carpets of ice seemed to be sliding on their own bed of water. Though this might seem surprising, it's not that hard to make water at the bottom of the ice sheet. There is always a certain amount of warmth radiating outwards from the planet's hot interior, and this geothermal heat would certainly help. Then you have the weight of the ice, and the friction caused by its scraping along the bed. Put those together and you have enough energy to melt the ice at the base of the glacier and give it a reason to slip.

But it's hard to prove, really prove, that there's water down there if you're using a hot-water drill. How could you tell if you were just seeing your own water? So for the first hole that Barclay and his team had drilled here, they had deliberately used the lowest water pressure that they could get away with. If it was lifting up the entire weight of the ice sheet to let it slide, the water down below would have to be at a very high pressure. Go in there with a lower pressure, and the water from below should surge up the hole. And that's exactly what happened. When they broke through on that first hole, they saw a spike in the pressure caused by the ice sheet's own plumbing system. There was definitely water down there, and it was definitely at a high enough pressure to lift and lubricate the ice.

In subsequent holes they had been experimenting with how interconnected the plumbing was. This time, they had seen oscillations in the pressure as water swilled up and down first one of their boreholes then another, showing that the channels under the ice really were connected. That's what had caused the peaks in the graph that Barclay was so pleased about.

There was also another factor that affected why the ice streams moved so quickly and so smoothly. Their beds were made not of rock, but of mud. It was the same sort of stuff that you find on the sea floor, and was probably left over from the last time that West Antarctica was an ice-free ocean. On hole number two, the team had managed to drill out a plug of sediment from the bottom of the hole, quickly, before the water inside it froze and the hole closed over. Barclay took a small tub off the shelf and opened it to show me. Inside was dark slate-grey mud, gritty and very sticky, and embedded with small pieces of gravel. He smeared a little on my fingertips and I rubbed them together. Now it was strong, but Barclay assured me that when it was saturated with water—a half mile below our feet—it was soft and fluid. With the help of the water, this mud was strong enough to carry an ice sheet on its back, but weak enough to deform and slip and let the ice slide.