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00:30Icebergs, one of nature's most awe-inspiring creations, both beautiful and treacherous.
00:44Now it seems their numbers are on the increase.
00:49Locked within the ice are hundreds of thousands of years of climate history, and they could
00:54hold the key to a miserable prospect, that Northern Europe be plunged into an era of long,
01:01frozen winters.
01:18Few hazards of the sea are more treacherous than icebergs.
01:22For all our ingenuity, man has never been able to control or defeat them.
01:29Icebergs can reach over a hundred meters in height.
01:32A single berg can weigh in at more than 80 million tons.
01:38But their beauty masks a terrible force.
01:42Even the smallest of these icebergs can sink a ship, their terror lurking beneath the waves.
01:49For every meter showing above water, four meters are hidden below the surface.
02:03These icebergs are made from snow which fell almost half a million years ago.
02:12Several hundreds of thousands of years ago, it started to snow enough in central Greenland
02:21where the snow didn't melt in the summertime.
02:24And as it snowed more and more, the snow continued to pile up and you have a layer of snow on top
02:28of the previous many years of snow.
02:30And it just keeps growing higher and higher, except that the bottom layers are beginning to suffer
02:37from all this new snow on top of them.
02:39And the weight of the new snow compacts and presses down on the older snow,
02:44and eventually turning it into glacial ice.
02:47Greenland couldn't be more of a misnomer.
02:55This country, the size of Western Europe, is covered almost entirely by ice.
03:03From this hundred meter high glacier wall, a hundred million tons of ice are carved each day.
03:10This amount of ice would be enough to supply London with water for a year.
03:18The ice sheet of Greenland is constantly on the move, creeping outwards, and releasing thousands
03:25of icebergs each year into the North Atlantic.
03:50When the glacier meets the sea, tons of ice crash into the water.
03:57After half a million years' gestation, an iceberg is born.
04:14From its launch into the freezing seas around Greenland, an iceberg takes about three years
04:19to reach the open ocean.
04:22Protected from melting by the cold water of the Labrador current, some of the icebergs
04:27reach Newfoundland on the eastern coast of Canada, where they run aground, out of harm's
04:32way.
04:42Others are carried further out into the North Atlantic, a menace that wreaks havoc in the busiest
04:47shipping lanes in the world, where they have caused hundreds of deaths and millions of
04:53pounds worth of damage.
04:57In one occasion, I've actually seen what happens to a large vessel when it runs into an iceberg.
05:14The ship, when it made for it, looked like the bow was completely gone, it was completely
05:18flattened, it was square.
05:19And it looked like it had run into a brick wall, which is in fact what it did.
05:37One reason for all these iceberg collisions is that even with modern technology, icebergs
05:43are hard to detect by radar.
05:46There's only a two-mile window that a master on a ship has for detecting an iceberg, and
05:53if he's traveling at 15 knots, this gives him eight minutes.
05:56So if he's away from the radar for eight minutes, an iceberg, a small bird could stick up on him
06:01and cause damage.
06:03Hundreds of ships this century have fallen prey to icebergs.
06:06The last major disaster in 1959 involved the Hans Headtoft, the Danish government's ice-strengthened
06:13vessel built to carry Denmark's dignitaries.
06:18It was, they said, unsinkable.
06:21But on its maiden voyage, the ship struck an iceberg.
06:26All 95 crew and passengers perished.
06:29A single life belt was the only trace ever found of the ship.
06:44But it was another unsinkable ship that has become the most famous iceberg victim.
06:51The Titanic was a 60,000-tonne vessel built in 1910 to carry more than 2,000 passengers,
06:59a triumph of modern engineering.
07:02When the Titanic set sail on her maiden voyage in April 1912, it was an occasion of great celebration.
07:10At the same time, a few thousand miles away, an iceberg was drifting south on the Labrador
07:16current.
07:25The iceberg was carved from a West Greenland glacier in 1909, three years before its fateful
07:31rendezvous.
07:34Its long journey to the open ocean took it first into Baffin Bay, where it spent a year
07:40or more frozen in sea ice off the coast.
07:47As the Titanic approached completion, the iceberg began to pick up speed, drifting southwards
07:52more than 30 miles a day.
07:58As families waved off loved ones in Southampton, the iceberg sat, awaiting its quarry, protected
08:05by the cold Labrador current.
08:09Warm water was not far away.
08:11Another few days and it might have melted.
08:15On the evening of April the 15th, 1912, by a remarkable coincidence, the iceberg and the
08:21Titanic had both travelled 1,800 miles on their maiden voyages.
08:26The iceberg had taken three years.
08:30The Titanic was at sea for just three days.
08:37The Titanic happened about 400 kilometres off this coast.
08:42And I think you've got an appreciation now for how cold the water was.
08:46To jump in this water in your ballroom gown or your tuxedo.
08:50People are looking at a movie wondering why they didn't make it to the lifeboat.
08:53Your body can only live five minutes in this water before your muscles seize and your heart
08:58stops, ten minutes at the maximum before you're dead.
09:04The iceberg tore huge gashes in the Titanic's hull and more than 1,500 people lost their lives
09:10when she sank.
09:13It was a tragedy that shook the world.
09:16The maritime nations vowed it would never happen again.
09:19But the question was how to avoid it.
09:23After all, the Titanic was just the most grisly in a long succession of iceberg catastrophes.
09:32In 1913, an international conference was called.
09:37Delegates demanded a task force to protect mariners from icebergs.
09:43The result was the International Ice Patrol, funded by 17 countries including the UK and
09:50operated by the United States Coast Guard.
09:53The patrol keeps watch for icebergs and alerts shipping across half a million square miles
10:00of the most treacherous area of the North Atlantic.
10:04For almost half a century, the ice patrol nurtured an extraordinary ambition.
10:11It wanted to destroy the enemy.
10:17Captain Bob Dinsmore, commander of the patrol during the 1950s and 60s, led the battle against
10:23the Berg.
10:24Toward the elimination of icebergs, we tried everything we could think of, short of a nuclear
10:29bomb.
10:30The earliest tests were, as you would expect, gunfire, naval gunfire, but there was almost
10:37no effect at all.
10:40Their misguided belief was that machine guns might shatter the Berg.
10:44It was hopeless, but they weren't going to stop there.
10:48Then in the 1960s, we decided to get a little bit more serious on iceberg destruction and
10:55we tried bombs, leftover bombs from the war.
10:59The Navy, the US Navy gave us about 20 bombs and we went out and we started bombing icebergs.
11:07The idea was that bombs would break up an iceberg into several smaller pieces which would melt
11:12more quickly.
11:14What the ice patrol didn't realize is that icebergs are particularly good at absorbing
11:18shock.
11:23Although their attempts sometimes looked impressive, they were ultimately a failure.
11:30They went in search of other weaponry.
11:32Perhaps heat would be the answer.
11:35Another type of bomb that we thought, and we thought we may have had a winner there, was
11:40the use of thermite.
11:42Thermite is an intimate mixture of powdered aluminum and an iron and will burn with an extremely
11:51high temperature.
11:52But this required, however, burning the iceberg, which was no small feat.
11:59Early experiments by other scientists had suggested that thermite would have a thermal shock effect
12:04on icebergs which would cause them to fracture.
12:08When thermite explodes, it produces temperatures of several hundred degrees centigrade.
12:13However, Captain Dinsmore and his colleagues had to board the iceberg, drill holes to encapsulate
12:19the thermite within the berg and send leads out to a small boat to detonate the explosion.
12:26The technique would never have been feasible in the open sea.
12:31And even cornered in this secluded bay, the iceberg once again prevailed.
12:36It was absolutely spectacular, but really didn't do anything to the iceberg.
12:43I asked the project chief, Lieutenant Commander Bob Dinsmore, what went wrong?
12:47Well, as you can see, we didn't demolish the iceberg.
12:50However, the operation was without incident, and I think we established a rather good test
12:55of the thermite.
12:56We're going to tackle a big one over there now, a pinnacle berg, one that may have some
13:00internal stresses, which is the whole theory of this thing.
13:04And if you don't get some success then, what will your conclusion be?
13:08Well, we'll have to try something else.
13:09Certainly, thermite won't be the answer.
13:13Another idea we tried was coating the iceberg with a carbon black.
13:19The idea, the black surface coating would attract solar radiation and heat the iceberg.
13:27We once again, though, we had to board the iceberg.
13:30We had to spread by hand the carbon black and then wait for it to happen.
13:36The idea was simple.
13:38A white iceberg reflects the heat of the sun, but a black iceberg would absorb it and melt.
13:45It worked, but only after a fashion.
13:48While the surface of the berg did indeed melt, it took the paint with it.
13:55The ice patrol, now convinced that the subtle approach is the more likely answer, says it
13:59hasn't given up its battle with the berg.
14:06In future, the ice patrol would have to learn to live with the enemy, a challenge which would
14:10prove to be even more demanding than destroying the berg.
14:13After that, we will be keeping an eye on possible very large icebergs.
14:17This is a C-130, United States Coast Guard C-138 cargo plane, 1504, 25 years old.
14:24This plane is the workforce for the United States Coast Guard and the mainstay for the conduct
14:37of the International Ice Patrol.
14:40The International Ice Patrol has given up trying to destroy icebergs.
14:44Now they keep an eye on them from the sky, a strategy which has proved rather more successful
14:52than their earlier efforts.
14:53From their flight base in St. John's, Newfoundland, on the eastern coast of Canada, they fly reconnaissance
15:02trips searching for and tracking icebergs which might venture into the shipping lanes.
15:08They produce a facts chart which shows the extent of iceberg danger, or the limit of all
15:14known ice.
15:15Since the ice patrol was set up, no ships which have stayed outside this limit have struck icebergs.
15:26This is the flight deck.
15:27This is where the aircraft is flown from.
15:30This seats the aircraft commander, the pilots.
15:33This is the co-pilot seat.
15:35These are all the controls and instruments that they need to fly the aircraft.
15:40When we can see the surface of the ocean, it's often times the pilot and the co-pilot who
15:45are the first to sight icebergs.
15:49This area here is where one of the two ice observers would be positioned.
15:56And they would be viewing the area forward of the aircraft with their binoculars to scanning
16:02the ocean, trying to pick up icebergs.
16:06When they sighted icebergs, they would take the position off the global position of the
16:12device, plot the position on our flight track, and pass that information to the senior ice
16:17observer, who is backed by the radar console.
16:23This is where the senior ice observer will be found, in this seat.
16:28Between the two radar operators, who are in charge or responsible for each of the two radar
16:35systems that we use for iceberg detection.
16:40The ice patrol fly their reconnaissance trips about three times a week throughout the March
16:56to July iceberg season.
16:58Each flight lasts up to eight hours.
17:00During this time, they might see no icebergs, or as many as a hundred.
17:07My job description is called the ice observer.
17:13And I work in conjunction with the senior ice observer and the radar pallet people in the
17:18back.
17:19And I confirm all the targets that they pick up on the radar.
17:23And if it's an iceberg, I'll give a description and a size, confirm the location of it.
17:30And the ship, I'll confirm that it's a ship.
17:33It's got to be at the window most of the time in case it breaks up and we get a chance
17:38to see an iceberg.
17:40Our main product is the limit of all known ice, which is a line in the ocean on which
17:48one side it's safe for ships to operate, on the other side, to the best of our knowledge,
17:54is where the iceberg danger exists.
17:57The facts chart shows the precise location of icebergs, their positions and likely movements
18:02plotted on a daily basis.
18:04All bergs remain on the chart until the ice patrol have checked from the air that they have melted.
18:09The facts chart will show the island of Newfoundland for geographic reference.
18:16It shows the Grand Banks of Newfoundland, which is very important because along the edge of
18:23the Grand Banks is where you'll find the Labrador Current.
18:26And it will show an area of many bergs.
18:30And then outside the area of many bergs will be scattered estimated iceberg positions.
18:35And then that most important piece of information, which is the limit of all known ice.
18:39The information is used by thousands of mariners from more than a hundred different countries.
18:46Captain Saifala has just sailed to Newfoundland from Panama.
18:50We have the Paximila here, Paximila.
18:54So we exactly know the precision of the iceberg and then the limit of all known ice.
19:02And if we're entering the area, that limit of all known ice, we must report our precision,
19:10cost and speed.
19:13This is very important for the safety reason.
19:17As well as their eyes, the ice patrol used two kinds of radar to detect icebergs.
19:23The forward-looking airborne radar and the side-looking airborne radar, or the FLAR and the SLAR.
19:29I'm the senior ice observer and what my responsibility is to, I usually, I sit back by the radar pallet
19:37and I look at the radar information that we take in.
19:39We have the two radar operators that, one on the FLAR and one on the SLAR.
19:42And they'll look at the contacts and I'll look, I'll take that information and I'll ask the observers
19:47if we have visibility, if they can see what is out there as well.
19:50I'll correlate everything and we'll try and determine if it's an iceberg or if it's a vessel.
19:56And if we can't tell, sometimes what we'll do is we'll go down and take a look at it.
20:03The ice patrol also predicts where the Labrador current will go.
20:07This is the cold water which carries icebergs into the shipping lanes.
20:11From the air, they drop buoys or buoys, floating radio transmitters which can be tracked by satellite.
20:19These tell them the extent and speed of the current, indicating how far icebergs are likely to drift
20:25before meeting warmer water and melting.
20:30The buoy sends off an electronic signal about every 90 seconds and it'll do a little ping.
20:36And when it pings, he can hear it through that tube and that tells us that it's transmitting okay.
20:41So before we deploy every buoy, we want to check it with our office to make sure they've been receiving
20:46satellite transmissions signals and also we want to check it here physically to make sure that it is transmitting.
20:54The buoy simply mimics the behavior of an iceberg.
20:58Our buoy drop is up in this position and although that was in the northern area of the Labrador current,
21:04in an area we call Iceberg Alley.
21:06And we dropped in that position in hopes that it'll drift south with the Labrador current.
21:12With that, we're trying to get an idea of where the icebergs would be going if they were also in that area.
21:17Did you say a Mark 25 and a XBT and then a Mark 25 in the World Buoy?
21:22That's what the book says.
21:24Okay, so for the first one and now we're going to pause the track.
21:28Be advised, there is a target just left to track at 90 miles.
21:36Ain't nobody out there.
21:37You guys are BMC.
21:39Roger, got a copy on the wax.
21:41It's about 35 degrees low.
21:48You can locate 1500 in the red out.
21:50Drop, drop, drop.
22:00White deck SIO, we just want to make sure the buoy's out of the box.
22:03That's why we're going to make the left 270 back over.
22:06We got contacts out there?
22:07Yep, one in front and one right behind.
22:09And the one behind is right at our drop.
22:11Drop area.
22:12Imagine that.
22:13You guys are awesome.
22:17We're out here to help the Mariner transit through this area in a safe manner.
22:22If we can help them do that, that's our job.
22:25If nothing ever happens out here, we're doing our job.
22:28And that's what we're trying to look at.
22:35The Ice Patrol's record for keeping ships and icebergs apart has been an impressive one.
22:40But today, it's not just ships that need protection amid the treacherous waters around Newfoundland.
22:51Our new neighbors on the Grand Banks are the oil production platforms.
22:57And for the most part, we're extremely glad to have them out there because they're going to provide us, I believe, a tremendous amount of sighting information of icebergs as they come down past Iceberg Alley.
23:13For many years, there has been a reluctance to put oil rigs on the Grand Banks because of the danger for icebergs.
23:23The promise of oil brought millions of dollars of scientific research money to Newfoundland.
23:28Before they could contemplate the dangers of drilling on the Grand Banks in Berg-infested waters, the oil companies needed to assess their enemy.
23:37It soon became clear that very little was known about icebergs.
23:42How they moved, how hard they were, how much damage different types of icebergs could do.
23:48And even the one thing they thought they were sure of, that only the tip of the iceberg is above the water, was thrown into confusion.
23:55The proportion of an iceberg which is underwater is the subject of great controversy.
24:0185% of an iceberg is generally thought to be under the surface.
24:07When I went to shore, they used to tell us 90%.
24:10Between three and five times the above water height is below the water.
24:142% is over the water and 98%.
24:17Underwater.
24:18Iceberg is about 90% under the water, 82%.
24:23There's a kind of magic figure of 0.8.
24:2686% of their mass underwater.
24:28I'd make a guess, I'd say 9 tenths.
24:31Seven times its mass is under the water than it's actually sticking out above the water.
24:34Two thirds and it slowly melts and becomes one third and two thirds it is now reversed.
24:40It rotates and then you get a roller.
24:49There is no exact answer.
24:51It depends on two crucial factors, both of which can vary.
24:55The density of the ice and the salinity of the seawater it's floating in.
25:00So the proportion underwater can be anything between 70 and 90%.
25:06One thing is beyond question.
25:08The unseen part of the iceberg is not just the biggest part, it's also the most dangerous.
25:14The part above water is small.
25:17It's been eroded away by the waves so there's not much there.
25:21But below water you have a big mass of a material which weighs one tonne per cubic yard and is very, very strong.
25:29And that's what can sink a ship.
25:31Anxious oil companies wanted to know more.
25:35Millions of dollars were spent on research to discover exactly what force an iceberg can exert.
25:41The results were terrifying.
25:44Experiments in 1995 at Memorial University in Newfoundland involved towing icebergs into a fixed structure.
25:54Pressure pads fitted to it measured the force of the blow.
25:58The research showed that although the top part of the iceberg breaks up, the force in the underwater part could be up to 8 megapascals per square metre.
26:08Or the equivalent of the weight of 24,000 cars piled on top of one another.
26:17The ice from these pressure tests was subjected to further examination.
26:22Scientists discovered that iceberg ice made from compacted snow is much stronger than ice made from frozen water.
26:30When pressure is applied to this block of frozen water ice, it fractures quite readily.
26:38Iceberg ice endures more than twice the pressure before fracturing.
26:46There is no such thing as normal ice.
26:57Sea ice, formed when parts of the sea freeze over, differs from iceberg ice, which differs again from the ice you put in your drink.
27:06The unique crystalline structure of iceberg ice makes it particularly perilous.
27:11The crystal structure of ice is very interesting.
27:14It's a hexagonal crystal, and it looks a little bit like a beehive.
27:18You have layers, and if you look at ice from the side, from the crystals from the side, you have these separate layers.
27:26But looked at from on top, you have hexagons.
27:29Scientists decided to examine the crystal structure of ice more closely.
27:33Taking slices a few millimetres thick, they viewed them under polarising light.
27:38The light interacts with the crystals, and because they are sliced through different planes, they show up as different colours.
27:46This sample, taken from the top of an iceberg, is of relatively young ice, and is composed of many small crystals.
27:55But in older ice, they found that the crystals had coalesced into fewer, bigger crystals.
28:01This ice, from the underwater part of the iceberg, is much stronger.
28:07Strong enough to rip open the hull of a ship.
28:13The reason lies partly with the crystals, but also, they discovered, with air bubbles, which get trapped in the ice when it first falls as snow.
28:26The air between the crystals is compressed into small, high-pressure bubbles.
28:30The deeper down you go, the more compressed the bubbles are, and the smaller they get.
28:35So, older ice has fewer lines of weakness than younger ice.
28:41In simple terms, old ice is strong ice.
28:45When these air bubbles are released, when the iceberg is drifting along in Baffin Bay and melting,
28:51this can produce a fizzing noise, because the air bubbles are at high pressure.
28:55And this is called Berge Seltzer, and it was a noise that was first recognised by submarines,
29:01using sonar, wanting to avoid icebergs.
29:04They heard this fizzing noise, and knew this was an iceberg, and you should avoid it.
29:13The conclusions from all this research were becoming clear.
29:16The best strategy for an oil rig was to avoid contact with icebergs at all costs.
29:22But this was easier said than done.
29:24Icebergs are very hard to predict because of their irregular shape.
29:29The top part acts as a sail, and is driven by the wind,
29:33while the bottom part is driven mainly by current.
29:36This means they often don't move in the direction one might expect.
29:40So, predictions in the short term, crucial if a berg is approaching a drilling platform,
29:45are not very good at all.
29:46Which is why oil companies had to resort to towing icebergs out of the way.
29:53You can pretty much successfully tow up to about 2 million tonnes.
29:57And the icebergs, you're varying anything from, say, 10,000 tonnes,
30:01to getting upwards of 6 million tonnes or larger.
30:04Up off of Labrador, I have tried to tow 6 million tonne icebergs,
30:08but it wasn't very successful.
30:09It basically just drags the boat wherever it wants to go.
30:13Towing icebergs was seriously considered in the 1970s
30:18as a means of supplying fresh drinking water to Saudi Arabia.
30:22The oil companies were quick to exploit techniques
30:25developed for towing icebergs to protect their assets.
30:28The technique is not very sophisticated.
30:31It involves tying a lasso around the iceberg
30:34and pulling it with a high-powered tugboat.
30:36But towing is not foolproof.
30:39And the oil companies couldn't rely on it to keep all the bergs out of their way.
30:45So they deployed mobile rigs or semi-submersibles on the ground banks.
30:50Rigs which could, as a last resort, up anchor and move off the oil field
30:55if an iceberg was headed for them.
30:57There were four or five semi-submersibles drilling on the ground banks,
31:01fairly close to each other.
31:03We had an iceberg came in from the north-easterly direction.
31:07It turned out it was just another one of these ones
31:11that just didn't seem to want to get towed,
31:13couldn't seem to keep a line on it.
31:14And it basically just came in a nice straight line
31:18towards the most northerly of the six rigs that were there.
31:22And discretion is always the better part of valor.
31:25So they pulled up their anchor chains and disconnected from the well and moved off.
31:29And they'd no sooner done that and it changed direction
31:31and headed straight at the next one.
31:33And it systematically went through all six of the rigs.
31:36Drove, I mean, one single iceberg left on the ground banks.
31:39And that one berg, in the space of a week,
31:42drove all six rigs off location.
31:44But in the late 70s, the oil companies discovered huge reserves on the Grand Bank,
31:50which were simply too deep to be drilled by mobile rigs.
31:54A permanent platform was needed.
31:5920 years and $5 billion later,
32:02the Hibernia platform was launched this summer.
32:05It's the largest single insurance risk the world has ever seen.
32:11The reason?
32:12It is the first oil platform which has been designed to resist iceberg impact.
32:20Its huge concrete base, called the GBS,
32:24is over a hundred meters in height and weighs more than half a million tons.
32:28The 16 concrete teeth, which make up its ice wall, are designed to withstand the force of a berg.
32:38The GBS structure is going to be ballasted in the main traffic way,
32:44or as nicknamed iceberg alley, of the main flow and the greatest concentration of icebergs in the world.
32:52It would be about anywhere from 500 to 3,000 large, small, medium, all-sized icebergs flowing by,
32:59as well as first-year and multi-year Arctic ice.
33:05Despite the formidable vital statistics of Hibernia,
33:09no one is underestimating the power of the iceberg.
33:12And a massive defence operation is still planned to protect the platform from any approaching bergs.
33:18The GBS is designed to withstand the kinetic energy of a 6 million ton iceberg.
33:26And that's not to say a 6 million ton iceberg would be possible to get to Hibernia.
33:32Anything in excess of 24 miles from the platform, we just simply monitor.
33:38Anything that comes in within 24 miles, up to 6 miles from the platform,
33:42we monitor and do forecasting on, and given certain parameters, we tow.
33:47Anything coming within the 6-mile strategic zone, close to the platform, would be towed monetarily.
33:54Getting Hibernia to its final destination was itself an extraordinary feat.
34:07To move it took no less than nine of the world's most powerful tugboats.
34:12During the 500-kilometre journey, the platform had to negotiate its way around several icebergs,
34:19many of which had to be towed out of the way.
34:22But after 10 days, it made it.
34:25The platform is due to go into production later this year.
34:30But it's early days.
34:31The real test will come in the next iceberg season.
34:37And if scientists studying the ice in Greenland are right,
34:41Hibernia could be in for an unpleasant surprise.
34:44They believe there could soon be many more icebergs negotiating the journey down from Greenland to Iceberg Alley.
34:52Greenland is the birthplace of icebergs.
35:11The North Grid camp is on the centre of the Greenland Ice Sheet, ice which covers nearly 2 million square kilometres.
35:19Supplies arrive from the nearest town 600 kilometres away every three weeks.
35:25A group of 25 international scientists, led by a Danish team, have been studying the ice here for the last two years.
35:34Even in the summer months, the temperature averages minus 32 degrees centigrade.
35:43I'm standing here at ice, three kilometres of ice, where we are drilling a hole over here all the way through the ice sheet,
35:52which contains all information about the climate going 150,000 years back.
36:00By looking at what happened to climate in the past,
36:03the scientists here are hoping to shed light on the climate change we're experiencing now.
36:08This is the origin of the icebergs.
36:14We are standing on the middle of the Greenland Ice Sheet, 3000 metres above sea level.
36:20And at this particular spot, we are now performing an ice core drilling through the ice sheet.
36:27And it will take three summers, hopefully, if everything goes all right.
36:33And this ice that we are drilling out is going all the way down to the bedrock.
36:40And we have chosen this spot because this spot is exactly where the ice cannot decide whether to flow
36:47to the west coast of Greenland or to the east coast of Greenland,
36:50and we're standing up the so-called ice divide, the highest point across the Greenland ice sheet.
36:57The snow that makes up the Greenland ice sheet contains the history of the climate on Earth
37:02going back some quarter of a million years.
37:07The snowflake lands here, gets accumulated on top of another snowflake,
37:13and it will keep the memory of the weather and the climate.
37:18And that's why we are here to dig up some climate history of weather.
37:23As snow falls, it collects all the components in the atmosphere at the time,
37:28telling scientists where it came from and the temperature at the time it fell.
37:33From this, they can give in unprecedented detail a picture of past climate change.
37:39What we are trying to look at here is how climate actually influenced this ice sheet,
37:46but also how climate changes occurred and how fast they occurred.
37:50We build a about 15-centimeter hole where we take out a 10-centimeter ice core,
37:56and because the ice is flowing so gently right here on the ridge,
38:01we can drill through all the layers and we hope to reach back about 250,000 years or more in time.
38:08The ice core is made up of rings like the annual rings of a tree,
38:16each of which represents one year's snowfall.
38:19With careful analysis, scientists can count back in time year by year.
38:24When we then do the dating, we can then consult the history books.
38:30We can go, because we find acid layers in certain years,
38:34and then we can see, for instance, that in 1601, we have an acid layer,
38:39but it's also described in the history book in Europe as the year without summer,
38:42because a big volcanic eruptions have faced.
38:45And we can go back further back into history, and we count back to 79 AD,
38:50and we found another acid peak, Mount Vesuvius, that destroyed Pompeii in Italy.
38:55And we can go back even further, and we find an acid signal from volcanic fallout from 45 BC,
39:03the year that Caesar was stabbed to death in Rome.
39:08And the cores don't just tell scientists about this relatively recent history.
39:12By the time the work here is finished, they will have a yearly record of climate for the last 100,000 years.
39:19This ice will eventually wind up in an iceberg, either on the East Coast or the West Coast.
39:25And when we abandon this station and all this roofing, we will leave here,
39:31because it's just wood and there's no environmental hazard in that,
39:34it will wind up pretty squashed with an iceberg in what may be 100 or 200,000 years' time.
39:46Evidence from North Grip and other ice cores has made scientists concerned about the effect of global warming.
39:54They have found that in the past, when there were sudden temperature increases,
39:59glaciers melted very rapidly and released armadas of icebergs into the North Atlantic.
40:06This had a devastating effect on the climate in Northern Europe.
40:10Scientists are concerned that global warming could cause this to happen again.
40:15The clue as to whether it will rests on whether the Greenland ice sheet is growing or melting,
40:25or what scientists call imbalance.
40:29The idea of Greenland being imbalance concerns whether there's a difference between the total amount of water received by Greenland per year,
40:37by snow falling on the top of the ice sheet,
40:39and the amount of water lost from Greenland per year in the form of icebergs calving and meltwater.
40:46We know that the snow is accumulating over a large part of Greenland,
40:50and we know that there are places like here that are a much smaller fraction of the whole ice sheet that are melting or actively calving,
40:56and the tricky part of the equation is how do you measure both of those things.
41:01The glaciers of Greenland carve over a million million tons of icebergs each year,
41:10so measuring changes is no small feat.
41:13However, some of those on the front line are convinced that even over the course of just a few years,
41:20they have seen dramatic changes.
41:22When I was on ice patrols from 1950s into the 1960s, we would average about 400 icebergs a year.
41:36In some years there were none, other years we rarely had more than 600.
41:41This year, in 1997, I think that they're going to experience 700, and that's not considered a severe year.
41:49Last year, there was well over 900 icebergs.
41:53A severe season is one in which we have greater than 600 icebergs across 48.
42:00This year, we've already had in excess of 800 icebergs across that line.
42:07What International Ice Patrol classify as a medium count of icebergs, I think it's up around 600.
42:15Actually, I think 600 might even be the start to be a high season.
42:19And we've pretty much had consistent counts over the last five years of well up over 1,000 icebergs crossing 48 north.
42:29Icebergs, it seems, are providing one of the first tangible signs of global warming.
42:34The main way that the increase in temperature causes an increase in icebergs is, with a warming of the climate, you're getting more precipitation over Greenland, more snow, because you're having warmer, wetter winds moving in over Greenland, dumping more snow on it, which causes the ice sheet to get thicker and then start moving outwards more rapidly, producing more icebergs.
42:59There are several other reasons why global warming causes an increase in icebergs.
43:06Rising sea level means that the thicker part of the glacier meets the sea earlier, causing more icebergs to break off.
43:14Increased melting also means a bigger volume of water in the Labrador current, the cold water which carries and preserves icebergs.
43:24And wherever the Labrador current goes, the icebergs go.
43:31If you had a sudden melt with a big increase of icebergs and a big increase of meltwater at the surface, the influence of the Labrador current will extend further to the south, which is cold water.
43:44And so icebergs will probably be able to extend further to the south and be seen at lower latitudes in the North Atlantic.
43:51It's possible that one day icebergs could even be seen off the coast of Britain.
43:57Releasing fleets of icebergs into the North Atlantic could have a devastating effect.
44:13Evidence from the Greenland ice cores shows that the last time this happened, the Gulf Stream was diverted away from Europe.
44:22The Gulf Stream keeps the climate in northern Europe mild by bathing us in warm water from the mid-Atlantic.
44:31This is why Europe's climate is so pleasant compared to the climate at the same latitudes in Canada.
44:39If we talk about 50 or 55 degrees north in Canada, nobody lives there because it's very unpleasant, but most European countries are at these latitudes.
44:48So if the Gulf Stream stops flowing, then all of a sudden all of Europe becomes colder.
44:54And the Gulf Stream could stop flowing to northern Europe.
44:58A dramatic increase in the number of icebergs released into the North Atlantic could have a profound effect on key ocean currents in the northern hemisphere.
45:07The scenario we see that, okay, if we put these icebergs out in the North Atlantic, it changes the whole heat budget of the northern hemisphere because of stopping something called the thermohaline circulation.
45:19The thermohaline circulation system is the conveyor belt which brings warm water to northern Europe.
45:28The system is driven by cold, dense, salty water in the Greenland sea, sinking into the deep ocean and moving southwards.
45:37To replace it, warm surface water from the Gulf of Mexico is drawn northwards.
45:43A large part of this is the Gulf Stream.
45:47And scientists calculate it brings us a third as much heat as the sun.
45:53More icebergs and more meltwater could put a stop to this entire system.
45:59One of the consequences of turning off the thermohaline circulation according to computer models is that the Gulf Stream would change direction and it would meet the coast of Europe further south about the latitude of Spain instead of bathing Britain and Ireland and Norway in warm water.
46:17So although most of the world is warming up and this change is a consequence of global warming, the local effect on us would be a cooling.
46:32Global warming is still the subject of great controversy.
46:36But the consensus is that temperatures are set to increase by two degrees in the next century.
46:42The idea that this might mean pleasant summers and milder winters is, it seems, completely wrong.
46:49The great paradox is that this increase in global temperatures could mean that we in Europe get colder.
47:02The temperature changes involved are not very great.
47:05For instance, at the moment, the average global temperatures are only about four to five degrees warmer than during the depths of the last ice age.
47:15So four to five degrees makes the difference between an ice age and our present climate.
47:20And given that the warming produced by man is likely to be about two degrees during the next century, it means that global warming rates are actually very rapid compared to the changes that have happened over a much longer period due to natural factors.
47:39And the worrying thing is that this seems to be happening already.
47:43Many are convinced that the increase in icebergs is one of the earliest indicators of global warming.
47:50And scientists studying the thermohaline conveyor belt in the Greenland Sea say it hasn't been functioning properly for the last 20 years.
48:01The relatively small temperature changes in our lifetimes could precipitate drastic climate change.
48:13If past climate was capable of dramatic changes, rapid climate changes, then it means that we may be approaching unbeknownst one of these thresholds.
48:23And the consequences could be not just a slow change from what we're used to, but a rapid switch to something that we've never experienced in the last 11,000 years.
48:31If we could have a change of a mean annual temperature of five or six degrees in a decade, it's almost inconceivable that society could adapt to that without a huge disruption.
48:52Man has yet to prove a match for icebergs and their awesome power.
48:56We're only just beginning to unravel their ancient secrets. Secrets that could hold the key to our future.
49:26Next week, enter the world of numbers, meet the men who've dedicated their lives to them, and find out why certain numbers are crucial in understanding our world.
49:40Equinox, next Monday at 9, here on 4.
49:433
49:463
49:474
49:484
49:495
49:501
49:522
49:532
49:552
49:552
49:562
49:574
49:582
49:592
50:013
50:024
50:034
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