introduced you. This is Dr. Inuva Nannansuit, with the Geological Survey. She’s a native of Ilulissat, the town on the headland, so she grew up with the glacier in her backyard. She’s been a fantastic addition to the team.”
“So what have we got?” Jack said.
“It’s behind the stern, but the captain’s swinging the ship round to give us a broadside view to starboard. It’ll be a few minutes yet. We’re using the dynamic positioning system, as we don’t want water movement from the main screws to disturb what you’re about to see.”
“That berg out by the island, dead ahead of us now,” Maria said, pointing towards the ship’s bow. “It’s got a streak of black on the top. Is that ancient sediment from the glacier?”
“Well spotted, but no,” Macleod said. “If you look at the berg, it’s smooth and rounded, like a sculpture, quite different from the jagged and fissured bergs we saw when we flew over the fjord.”
“It must have rolled,” Costas said.
“Correct. We watched it happen last night. One of the most awesome sights you can imagine, a quarter of a million tons of ice doing a somersault in the water. You don’t want to be anywhere near one of those babies when that happens.”
“Of course,” Maria exclaimed. “That smear is from the sea floor!”
“Exactly. When we arrived two weeks ago that berg was butted up against the threshold on the north side of the fjord, but we already knew from side-scan sonar that the submerged part had become eroded and lost much of its mass. It was only a matter of days before it would roll, and we kept well clear. Some of the bergs make it out that way, others get pushed upright over the sill. You can always tell from whether they look like Henry Moore sculptures or Disneyland ice castles.”
“You mean like that one,” Jack said.
They followed his gaze to starboard as a vast wall of ice came into view, about a quarter of a mile distant and clearly taller than the superstructure of the ship. It had the same contorted and jagged face as the front of the glacier, riven with veins of deep blue where meltwater had frozen inside crevasses, except for a wide flat area in the middle where it sloped down smoothly from the summit. The berg was immense, at least a quarter of a mile across, and blocked a large stretch of the entrance to the fjord along the line of the underwater threshold.
They stared in awe until Macleod broke the silence. “Remember, three-quarters of that thing’s underwater. You’re looking at a cubic kilometre and a half of frozen water, at least a million and a half tons.”
Costas let out a low whistle. “That’d keep all the bars in the world in ice well into the next century.”
“A single day’s outlet from this glacier would be enough to supply New York with water for a year. Twenty million tons a day. We’re talking global impact here.”
“Tabular bergs of this size are pretty rare in the Arctic,” Inuva said. “We think it’s atmospheric warming again, resulting in the glacier receding to a point where larger fractures occur. It’s the biggest berg I’ve seen here in my lifetime.”
“Why hasn’t it broken up?” Costas said.
“It’s had one major calving event, where you can see that smooth face,” Macleod said. “But the core’s unusually compact, solid glacial ice you’d crack only with explosives. It’s ideal for us. That face calved back to the core ice, so it’s relatively safe to work under. If you look closely you’ll see the drilling team in a couple of Zodiac inflatable boats out there now.”
“I don’t understand it.” Jeremy had been quietly absorbing everything since arriving on the ship, but had now recovered his normal inquisitiveness. “What’s to stop that thing tumbling over and crushing them?”
“That’s where the conditions really work in our favour,” Macleod said enthusiastically. “Without the pressure of the ice tongue behind them, bergs trapped on the sill are a lot safer to work on. The glacier itself is way too dangerous for coring, especially now that it’s flowing at such a rate. Bergs floating down the fjord are out of the question because they’re moving, and once they’re beyond the fjord they’re not only moving but are more liable to tumble. So a relatively fresh berg trapped on the sill is ideal for us. It’s a unique opportunity, but the window is closing fast.”
“How long has it been there?” Jack said.
“About three months. Lanowski’s run a simulation that shows it processing down the fjord and jamming against the threshold. Any chance of seeing it?”
“You’ll be lucky.” Lanowski muttered irritably to himself as he tapped a sequence of keys, and then visibly relaxed. “Finally.”
The screen displayed a 3-D isometric simulation of the fjord, with the glacier at one end and the arc of the threshold at the other. The berg was shown perched perilously on the sill, its vast bulk underwater now visible but with the seabed dropping off to even greater depths on either side.
“You can see the scour channel,” Inuva said. “That groove in the seabed leading up the threshold. As they grind along the bottom, the bergs pulverize the seabed, crushing everything to powder. It creates a sterile biotope, devoid of life. But the sampling we’ve been able to do here shows something else, that it actually benefits the diversification of species, allowing life to regenerate like a forest after a fire. And there are other pluses. James said you saw a berg calving as you flew in. Each time that happens, the upwelling brings up a host of nutrients. These were incredibly rich fishing grounds for my ancestors.”
“A biologist,” Lanowski muttered. “Just what we need.”
Inuva glared at Lanowski, and Jack quickly moved on. “How stable is that thing?”
“I created a simulation of ice conditions in the fjord over the planned period of the project, from two weeks ago ending tomorrow.” Lanowski said. “Everything’s happened exactly as I predicted. This should give you an idea of what we’re looking at.” He pressed a key and they watched as the screen sped through several dozen images on the same backdrop, showing the glacier receding alarmingly and a procession of bergs tipping over the threshold.
“A few years ago that would have been a whole season. Now it’s two weeks.” Lanowski pushed up his glasses and peered rheumily at Jack. “At the moment, the berg’s fine. There’s diurnal fluctuation in the grounding line, of course, about three metres as the tide goes up and down, and eventually the abrasion will knock off enough ice at the bottom to unbalance the berg. Right now the worst-case scenario is a major calving event, losing a lot more ice underwater than above, making the berg top-heavy. Then, say at high tide, we get an earthquake, or a storm, or ice from the glacier coming down the fjord and pressing from behind. That could push the berg against the sill and topple it.”
“What are the odds?”
“We’re not predicting any big ice coming down the fjord for at least a few days. An earthquake’s pretty well out of the question. A storm’s a possibility. There’s a local freak storm that could affect water movement against the threshold.”
“A piteraq,” Inuva said quietly.
“A what?” Costas asked.
“A piteraq. Caused as cold air tumbles down the ice cap and meets the warmer air of the sea.”
“Of course. James mentioned it as we flew in.”
Lanowski ignored them and carried on. “But there haven’t been any storms of the magnitude needed for almost seventy years. The last one recorded was in 1938.”
“What about calving?” Jack said.
“That’s where the simulation runs dry,” Lanowski said. “I just can’t predict it.” He looked at the floor in consternation, as if the limitations of science were his own personal failing, then relaxed his shoulders and gave Jack a defeated look. “All I can say is that the chances increase with the summer heat, especially now with the twenty-four-hour Arctic summer daylight. Forty-eight hours down the road I’ll be recommending that all work at the berg cease and advising the captain to reposition Seaquest II at least two miles farther offshore.”
Macleod turned to Jack with a sense of urgency in his expression. “All the more reason for us to get on.” He nodded thanks to Inuva, handing her a two-way radio from the command chair, which she took out of earshot through the side door on to the deck wing. “While Inuva sets up the final part of your tour, I think we’re ready to show you what this is really all about.” He tried and failed to catch Lanowski’s attention, then led them to a workstation on the other side of the room where a large man in a checked shirt and jeans was positioning a long metal tube like an oversize map case.
“Don Cheney, senior glaciologist from NASA,” Macleod said. “Don, show us what you’ve got.”
They quickly shook hands and stood behind the table and computer monitor. Cheney carefully pulled out an
