the fjord. The edge of the glacier itself is more than five nautical miles east of us towards the ice cap, back the way we came.”
“It’s awesome.” Jeremy’s voice came cracking over the intercom, and for once he seemed at a loss for words. “So this is where the North Atlantic icebergs come from?”
“Ninety per cent of them,” Macleod replied. “Twenty billion tons every year, enough to affect global sea levels. That wall of ice may seem pretty static, but it’s sped up recently and is actually moving towards us at nearly fifteen feet an hour. Some of the large bergs will be pushed out more or less intact, but almost all of them calve, producing smaller bergs and vicious little slabs called growlers.
Almost ten thousand big bergs make it out of the fjord every year into Disko Bay. They process anti-clockwise with the current around Baffin Bay and then float as far south as the Grand Banks of Newfoundland and as far east as Iceland.”
“One of them’s calving now,” Jack said suddenly.
Without warning a vast slab of ice had cracked off the precipice immediately in front of them, the wrenching noise audible even above the din of the helicopter’s rotor. The slab of ice slipped straight down into the water and disappeared completely, then erupted upwards almost to its full height before settling down again, bobbing up and down until only a jagged pinnacle was visible above the slurry of ice fragments in front of the bergs.
“I see what they mean about icebergs being mostly underwater,” Jeremy said, his tone still awestruck. “The bigger ones must scrape along the bottom of the fjord.”
“That’s exactly what happens. Sometimes they drag along the sea floor, sometimes they tumble over.” Macleod flipped down a small video screen from the cockpit ceiling and tapped a keyboard, revealing an image of the fjord bathymetry.
Jack whistled. “Pretty deep.”
“Over three thousand feet.”
“That underwater ridge on the image, across the mouth of the fjord,” Jack said.
“I assume that’s where the ice tongue reached its maximum extent?”
“The Danes who settled here in the eighteenth century called it Isfjeldsbanken, the threshold,” Macleod replied. “A huge sill of sediment bulldozed by the glacier. The tip of the threshold’s only about six hundred feet deep, so the bigger bergs get stuck on it. Until recently it marked the edge of the ice tongue, the congestion of bergs that choked the fjord.”
“But now the breakup occurs several miles closer to the ice cap, where we are now?”
“Correct.” Macleod tapped the screen and another image appeared, a satellite photo of the fjord. “Courtesy of NASA, a composite image from the Landsat satellite. The sequence of red lines across the fjord shows the retreat of the calving front of the glacier between 2001 and 2005. At the same time the glacier has accelerated dramatically, almost doubling its velocity. And airborne laser altimetry measurements have shown a thinning of the glacier by up to fifty feet a year.”
“Global warming,” Jeremy said.
“Bad news for the environment, but good news for us.” Macleod snapped the screen closed and re-engaged the cyclic, pulling the helicopter round on a westward bearing and flying through the mist away from the ice face. “Bad news because it suggests global warming has a more dramatic effect on the ice cap than many have feared. Good news because it allows us to work in the fjord itself, to carry out research that’s never before been possible.”
“And now we’re into summer,” Jack said. “I’m assuming that increases the rate of calving and ice disintegration along the glacier front?”
“That’s why I wanted you here now,” Macleod replied. “A few more days and we’re closing shop. We’re working on the edge in more ways than one.”
Twenty minutes later he eased back on the cyclic and the Lynx began to descend over the jagged line of icebergs near the head of the
“It’s awesome.” Jeremy’s voice came cracking over the intercom, and for once he seemed at a loss for words. “So this is where the North Atlantic icebergs come from?”
“Ninety per cent of them,” Macleod replied. “Twenty billion tons every year, enough to affect global sea levels. That wall of ice may seem pretty static, but it’s sped up recently and is actually moving towards us at nearly fifteen feet an hour. Some of the large bergs will be pushed out more or less intact, but almost all of them calve, producing smaller bergs and vicious little slabs called growlers.
Almost ten thousand big bergs make it out of the fjord every year into Disko Bay. They process anti-clockwise with the current around Baffin Bay and then float as far south as the Grand Banks of Newfoundland and as far east as Iceland.”
“One of them’s calving now,” Jack said suddenly.
Without warning a vast slab of ice had cracked off the precipice immediately in front of them, the wrenching noise audible even above the din of the helicopter’s rotor. The slab of ice slipped straight down into the water and disappeared completely, then erupted upwards almost to its full height before settling down again, bobbing up and down until only a jagged pinnacle was visible above the slurry of ice fragments in front of the bergs.
“I see what they mean about icebergs being mostly underwater,” Jeremy said, his tone still awestruck. “The bigger ones must scrape along the bottom of the fjord.”
“That’s exactly what happens. Sometimes they drag along the sea floor, sometimes they tumble over.” Macleod flipped down a small video screen from the cockpit ceiling and tapped a keyboard, revealing an image of the fjord bathymetry.
Jack whistled. “Pretty deep.”
“Over three thousand feet.”
“That underwater ridge on the image, across the mouth of the fjord,” Jack said.
“I assume that’s where the ice tongue reached its maximum extent?”
“The Danes who settled here in the eighteenth century called it Isfjeldsbanken, the threshold,” Macleod replied. “A huge sill of sediment bulldozed by the glacier. The tip of the threshold’s only about six hundred feet deep, so the bigger bergs get stuck on it. Until recently it marked the edge of the ice tongue, the congestion of bergs that choked the fjord.”
“But now the breakup occurs several miles closer to the ice cap, where we are now?”
“Correct.” Macleod tapped the screen and another image appeared, a satellite photo of the fjord. “Courtesy of NASA, a composite image from the Landsat satellite. The sequence of red lines across the fjord shows the retreat of the calving front of the glacier between 2001 and 2005. At the same time the glacier has accelerated dramatically, almost doubling its velocity. And airborne laser altimetry measurements have shown a thinning of the glacier by up to fifty feet a year.”
“Global warming,” Jeremy said.
“Bad news for the environment, but good news for us.” Macleod snapped the screen closed and re-engaged the cyclic, pulling the helicopter round on a westward bearing and flying through the mist away from the ice face. “Bad news because it suggests global warming has a more dramatic effect on the ice cap than many have feared. Good news because it allows us to work in the fjord itself, to carry out research that’s never before been possible.”
“And now we’re into summer,” Jack said. “I’m assuming that increases the rate of calving and ice disintegration along the glacier front?”
“That’s why I wanted you here now,” Macleod replied. “A few more days and we’re closing shop. We’re working on the edge in more ways than one.”
Twenty minutes later he eased back on the cyclic and the Lynx began to descend over the jagged line of icebergs near the head of the
Similar Books
