Arctic Ocean Oceans

They cover two thirds of our planet.

They hold clues to the mysteries of our past.

And they are vital for our future survival.

But the secrets of our oceans have remained largely undiscovered.

I am with a six gill shark.

Yes! Yes!

Explorer Paul Rose is leading a team of ocean experts

on a series of underwater science expeditions.

For a year, the team has voyaged

across the world to build up a global picture of our seas.

We are doing some pretty uncharted research here.

That is psychedelically purple.

We are here to try and understand the earth's oceans

and put them in a human scale.

Our oceans are changing faster than ever.

I've never seen ice like this before.

There's never been a better time to explore the last true wilderness on earth.

This expedition will explore

one of the most hostile bodies of water on the planet.

The icy wastes of the Arctic Ocean.

The water temperature hovers around zero.

About two million square miles of the ocean's surface is permanently frozen.

That's much colder ice, much firmer ice, actually breaking off.

This is serious. Massive chunks breaking off.

This is one of the least explored oceans on Earth.

It's barely a century since the first ships penetrated this ice-covered world.

The Arctic Ocean spans the North pole.

It's the smallest and shallowest of the five great oceans.

But, more than any other, it plays a vital role in regulating our climate.

Only now global warming is changing this region dramatically.

It's heating up twice as fast as anywhere else on Earth.

I think we're in a race with the Arctic Ocean.

It's changing fast so we need to learn and understand

what's going on while we can, because within our lifetime it's going to be unrecognisable.

The team has come to see what these changes will mean for life here, and how they could affect us all.

Marine Biologist and Oceanographer Tooni Mahto

dives beneath the polar ice cap

to reveal why it's vital to the health of our world.

We are completely dependent on this stuff to keep the planet cool.

Maritime Archaeologist Dr Lucy Blue

examines how man has exploited this ocean for hundreds of years.

It was diving and it had blood, it was bleeding, it was pulling boats.

It must have been absolutely horrendous.

And Environmentalist Philippe Cousteau,

grandson of ocean pioneer Jacques Cousteau, investigates how

the Arctic's uniquely adapted marine life is under threat.

These rely on the ice. I mean, without the ice, these can't exist.

Ice is the Arctic Ocean's dominant feature.

The way the ice forms and melts and changes and circulates around,

it governs the Arctic Ocean, it defines it.

This ice is vital to help stop the earth overheating.

Up to 80% of the sunlight that hits the bright, white surface

is reflected back into space.

But climate change means the Arctic ice cap is shrinking.

In the last 30 years,

almost 1.5 million square miles of ice has disappeared.

It's a major topic of concern,

what's happening here, the ice melting

and the implications that has for the rest of the world.

Understanding why, and how fast the ice is melting, is crucial.

But as getting here is so challenging,

the Oceans team will be one of relatively

few specialised expeditions,

not only to study the ice from the surface, but to dive beneath it.

Most people's experience of the Arctic sea ice would be remotely,

you know, scientists with remote sensing, satellite imagery,

computers models and all that. So even the best scientists

in the world who are studying Arctic sea ice

often wouldn't get the chance

to come to this remote location and go diving underneath it.

Working beneath the ice is hazardous.

For this extreme diving, the team needs careful preparation.

So the expedition begins by travelling to

the islands of Svalbard,

midway between the north pole and the tip of Norway.

Expedition Leader Paul has brought them to the relative safety

of a frozen fjord to find out if they can handle the harsh conditions under the ice.

You can't mess around with ice diving. It's essential we do this.

We couldn't even think about going north into the polar pack to dive

unless everything was 100% perfect.

It's not just the diving that's risky.

Beside the ship are the paw prints of the Arctic's top predator, the polar bear.

The crew is on armed watch.

We wouldn't dream of coming out on this ice without someone looking

after us, keeping an eye on polar bear.

So we have one person always, with his rifle.

There he is today. And his only job,

and not to be distracted, is to keep entirely a look out for polar bear.

Paul has diving experience in these extreme conditions.

For the rest of the team, it'll be their first time.

It's a really big deal. It's a real temperature shock.

And although I'm really well insulated, it's still going to be a shock.

Everyone needs to wear a lifeline.

If something goes wrong we can get pulled out of the water and at least find our way back to the entrance.

As you can see, if you don't come out the same way you went in, you're not coming out.

The team must spend ten minutes beneath the ice to test their

equipment and their own ability to withstand the physical stress.

The icy water puts a huge strain on the body.

Cold water robs it of heat 25 times faster than cold air.

The first ever Arctic dive for me.

It is cold.

If hypothermia sets in,

the divers can lose coordination and become confused.

Under the ice that could be fatal.

There's no margin for error.

We're slowly heading back.

The test dive is over.

Tired through.

Man, that's just ten minutes.

After 45 minutes of that, you'd just be dead, dead on your feet.

Up above you is this weird mass of solid ice that when you hit,

it's just...its like knocking on a door but nobody's going to let you out.

To understand the changes facing the Arctic Ocean, they'll need to

dive under the polar ice cap, a solid mass of free-floating pack ice.

The pack is so very different to this.

This is a bit like diving in the swimming pool when you learn to dive and that is like the real ocean.

It's a big step from this to what I know the pack ice really holds for us. It's a big challenge.

The team leaves Svalbard and heads north towards the ice cap.

It's a long way north.

78 north here.

80 north approximately there and the mainland Norway...

way down here to the south.

Our plan is to head directly north and when we hit the ice here,

we'll be working through the whole pack.

We want that very cold water, -1 or something, at least.

It will be some of the most extreme sites in the world to do

oceanography, do science, do diving, do our studies.

The ice has that incredible power so it can be calm where we are but

that pack is just moving and pushing and grinding with incredible forces.

It's one of the ultimate extreme environments.

This far north, the tilt of the earth's axis

means that for four months of the year the sun never sets.

They use the 24 hour daylight to force their way into the polar pack.

It's about 20 nautical miles left so it's quite a way,

and it's going to take quite a while going this slow

and it's gradually going to get tighter

and gradually going to get thicker.

After eight hours, expedition leader Paul

thinks they've penetrated far enough to start their exploration.

We're at 80 degrees, 14 minutes, so it's 600 and something miles

from the north pole. Nice feeling, isn't it?

This huge mass of ice is floating on the ocean's surface and can drift several miles a day.

The boat must be anchored to it so they move together.

As global warming raises the air temperature,

the surface of the ice melts.

But this alone may not account for the amount of ice we know is being lost.

So Paul and Tooni are going to dive beneath the polar-cap,

to see what else might be causing this ice cover to shrink.

First thing I want to do is get under there and find out if there's any evidence

of how it's formed. Are there features

we can look at, is there any evidence or any signs of melting?

Get underneath and see the ice for what it is from

a different perspective - looking up rather than looking down on it.

Let's head under the ice.

It's very, very dark here.

It's the darkest it's been since I've been here

in this land of 24-hour daylight.

Unlike icebergs, which come from fresh water glaciers,

this pack-ice forms when it gets so cold that the ocean freezes.

The ice only forms at -1.8 degrees centigrade

because of all the salt in the water.

The ice is formed from these tiny, tiny crystals

and forms into this huge mass of ice.

This sea ice can grow as much as three metres thick.

The shapes underneath reveal how different pieces drift together

to become a vast ice sheet.

As you can see, this has been formed

by these big sea ice floes just pushing together.

It's a bit like plate tectonics,

when great geological plates slide together and form mountains.

Well, these things slide together and form great ridges above,

and along with it, these fabulous keels down below.

Keels can extend down to 40 metres.

They help stabilise the ice floes

and stop strong winds from breaking them up.

But there are signs that the keels are also shrinking,

causing ice floes to break up more easily and melt even faster.

Hey, Tooni, you see these features here?

This is where it's melting.

As it does, the underside of the ice develops a series of depressions and ridges.

These are characteristic signs that the ice is melting underneath as well as on top.

As ice cover decreases in the summer,

the dark ocean absorbs more heat from the sun.

The water warms up and begins to melt the underside of the ice.

It's all our bubbles hitting the ceiling,

finding all the little pockets, isn't it?

You can literally stick your hand up, look, you lose your hand.

Some of this melting is seasonal.

What's changing now is how much ice is disappearing.

The whole of the Arctic ice cap is shrinking.

It's a difficult thought to have when you're in

-1 degree centigrade water and surrounded by ice.

This shrinking is so important,

it's being monitored by scientists around the world using satellites.

But there are relatively few direct measurements.

So Philippe and Lucy plan to head out onto the ice to measure its thickness.

Measuring sticks, some buckets.

The thickness will indicate whether this ice is likely to survive the summer.

The measurements they take will be sent to NASA.

For a few decades now, NASA has been using satellite technology

to track changes in the Arctic,

changes in the area covered by ice and the thickness of the ice.

But they need the truth, to verify that data with information on the ground.

So that's what we're doing - we'll be sending this straight to them.

Only ice over two metres thick is likely to make it through the summer.

To measure the thickness,

Philippe and Lucy need to drill right through the ice.

Pop that through.

We've essentially got to measure the depth of this hole that we've just drilled.

And this, if we lower this down...

hopefully the bar will catch on the underside of the ice.

The metal bar's horizontalled out so its sitting against the bottom.

-I think we've got it. So it's locked up.

-So that's the depth.

So its one metre and then

in the middle of this thing to that point, is 65.

So we've got 1 metre 65.

That's relatively thin and more likely to melt over the summer months.

But one measurement is not enough.

They need to drill several holes to take an average.

-1 metre...

-1 metre 76.

So that's 1.56. So basically, all four holes

have been less than two metres, so that's less than six foot.

The results are consistent with those of other scientists.

The majority of the ice in the Arctic

is now comparatively thin and more likely to disappear in the summer.

And this loss is accelerating.

In 2007 and 2008,

the extent of the summer sea ice was the smallest since records began.

The less ice coverage, the more the Arctic will absorb solar radiation -

it will get warmer, more ice will melt.

It's a vicious circle.

As the reflective sea ice disappears,

the water warms up, and more ice melts.

This leaves the ocean even more exposed

to the heating effects of the sun and the whole process speeds up.

And as the Arctic gets warmer, this accelerates global warming.

This isn't something that's going to happen down the road,

to our children, something in the future.

This is happening to us, now.

There's been permanent ice cover in the Arctic Ocean for thousands of years.

But as this NASA animation shows,

the ice cover in the summer has been changing fast.

In the 1980s it was receding by an average of about 3% per decade.

Now it's over 11%.

There will come a time when that will be a very, very different

animation because all of this ocean will be probably be blue come summer time. That's the projection.

It's all done on computer models, so computer modelling is an attempt

to predict the future which is incredibly difficult.

One estimate suggests the Arctic Ocean

could be ice free in the summer by 2013.

That would mean the loss of almost two million square miles of sea ice.

You see those images of polar bears floating on bits of ice and...

It doesn't really become tangible until

you're actually in it and witnessing it and seeing images like this.

And then you realise how in fact, the potential is, it's going to really impact on all of us.

The fundamental importance of this ocean to the rest of the world just really can't be overstated.

If the ice keeps melting, if the Arctic becomes this very, very much warmer ocean

in the way that scientists are predicting,

then that is going to change the entire planet.

A warmer Arctic Ocean would not just contribute to global warming.

It would affect the world in other ways.

Salty water cooled by the Arctic

helps to drive global ocean circulation,

a conveyor belt of currents that connects every ocean.

Cooling salty water from the Arctic region sinks to the ocean depths.

It moves towards the equator, mixes with warmer currents,

and eventually becomes lighter and flows back towards the pole.

This does two important things.

It helps to keep our oceans alive by moving oxygenated water

and nutrients around the planet.

And it regulates our weather by transferring heat around the globe.

If it's affected, it could radically change climate patterns

and have an impact on the health of our oceans worldwide.

And it all begins under the Arctic ice.

The team's preparing for their next mission, to search for what's living beneath the ice.

But then, something catches their attention.

We were part way ready for a dive

and bridge watch called out there's a polar bear coming.

He's come on quick so it's all stop for the moment.

This is the icon of the Arctic finally. I would have been disappointed

-if I'd come all the way up here and not seen a polar bear.

-You and me both.

The polar bear is the world's largest terrestrial carnivore.

Males can be up to 10 feet tall and weigh close to 800 kilograms.

They have that slow, ponderous lolloping kind of walk,

but they cover huge distance.

Polar bears are well adapted to Arctic conditions.

They have two layers of fur and black skin that absorbs heat from the sun.

Beneath this is ten centimetres of fat.

So they can have trouble keeping cool.

It's so cold out here that the reason they go so slowly

is they're so well insulated.

Here we are all freezing, and the polar bear has to go slowly so it doesn't overheat.

It's crazy!

But being so highly specialised makes them amongst

the most vulnerable creatures in the Arctic.

The polar bear is absolutely dependent on these ice floes to exist.

Today there are about 25,000 polar bears.

But as the ice cap recedes, the population could decline fast.

That's because the ice is a valuable source of food.

We look around and it kinda looks like a big white desert but it's actually a very diverse ecosystem

and it's critical to understand what is going on,

what lives here on the fringes of existence.

Life in the Arctic depends on the spring bloom.

It occurs after months of complete darkness.

When the sunlight begins to reappear, there's an intense growth of algae.

But this bloom is short-lived.

To survive, life here needs to store enough energy to make it through the long, dark winter.

Tooni and Paul plan to search for the creatures that provide the energy the Arctic relies upon

to see how they cope with the severe conditions.

To me, it seems like the most extreme environment living in minus degree centigrade waters

just underneath the ice and there is life that is perfectly adapted to those very specific conditions.

Life at the edge is just so fascinating.

The whole team gears up to work on the surface and beneath the ice.

Paul and Tooni will search underneath the ice cap for amphipods and copepods, the miniscule creatures

which help support this ecosystem.

They're hard to see.

So once these crustaceans have been collected, Philippe and Lucy will identify them on the surface.

The data they collect will be sent to The Census Of Marine Life,

a survey being conducted by hundreds of scientists around the world.

But first they've got to find the tiny creatures.

Yeah, it's pretty hard.

For a start, our bubbles are blowing them around.

Maybe that will dislodge them from the little crevices.

Oh, there you go, look. I can see some.

There you go, look.

Get it, go on. Catch it!

You got it?

To survive here, life must adapt to the icy conditions.

The creatures here have got proteins in their blood

that act as a kind of anti-freeze so they can actually keep on moving

and working in these sub-zero temperatures.

The water is clouded with algae as the expedition has arrived during the spring bloom.

It's the ideal time to track down the crustaceans.

Thank you. Fantastic.

Because there's still so much to learn about the fauna of the Arctic,

Philippe is keen to document what they find.

-Oh, yeah, well done.

-Couple more. Oh, yeah, definitely.

Well, we definitely got a few species of amphipods

and definitely some copepods in here.

We should get them out of there quickly cos the amphipods eat the copepods.

The last several years of work that I've been doing

in terms of conservation, I've heard so much about amphipods.

These are the classic base of the food chain in the Arctic.

I mean, grey whales travel 6,000 miles to feed on these all the way from Mexico.

And living along with the amphipods are these tiny copepods, just a few millimetres long.

These species hold the secret to survival in the Arctic.

They feed on algae and convert it into fat.

Fat acts like a biological battery, a long-term store of energy.

So everything living here relies on fat to get through the Arctic winter.

Copepods will live underneath the ice feeding on the algae,

sometimes only for a few months of the year.

They build up these fat layers and can go for eight to ten months without feeding.

The fact that these things are so high in fat

means they can pretty much fuel the rest of the food chain in the Arctic

and that fat gets passed on up the food chain

up to the fish, the fish gets eaten

by the seals, the whales the polar bears.

So fat is an incredibly important currency.

And these are the basis of the food chain.

I mean, this is such an important creature.

No-one knows how many different species of amphipods exist.

This world is so little explored,

that even a single sample can uncover a find.

That's a new one. It's very different to the others.

Definitely an amphipod.

DNA analysis will be needed to be certain,

but this may be a new species.

You know, people just think that we've explored it all,

and there's just so little we actually know.

And here's just a case in point, a perfect example.

-Now, then.

-Good work y'all, I gotta say.

-Let's have a look.

-We got a couple things laid out here for you.

You see these really big...

I mean, look what you found, these big amphipods.

These are the ones that walk upside down underneath the ice, we was watching them.

But as the ice shrinks,

these species could disappear faster than we can discover them.

These rely on the ice.

Without the ice these can't exist, and while that doesn't mean

necessarily that the whole ecosystem will collapse

but it definitely means it will be changing.

We'll see a shift in bio diversity, and we don't know what that means.

They're a hugely underrated resource in the Arctic ecosystem.

Nobody's ever interested in invertebrates.

Invertebrates hold the key to the giant charismatic mega fauna

that we're all so concerned about.

If the ice retreats, we could lose many of these tiny creatures.

Then all life here will be threatened.

The team is now heading south, back to the islands of Svalbard.

Maritime archaeologist Dr Lucy Blue

wants to explore the remains of a global industry

that almost wiped out entire species here.

Whaling.

It's estimated that in the last 400 years,

more than 2.5 million whales were killed worldwide.

This channel would have been absolutely teeming with whales.

-Kinda incomprehensible.

-I know. Completely is, completely is.

This is one of the places where the Arctic industry began.

In the early 1600s, the Dutch and English came here in droves

to satisfy the growing demand for whale oil.

It led to the wholesale slaughter of these ocean giants.

There was a lot of competition, particularly at the beginning the early 1600s.

They were actually fighting for the rights to catch the whales here.

Particularly somewhere like this fjord.

These waters in Northern Svalbard attracted huge numbers of whales.

The whales come in here because there were slightly shallower waters

to feed so, I mean, it was just a prime hunting area.

A Dutch settlement of up to 200 people grew here.

It was called Smeerenburg - Blubbertown.

You look at this and you look out into the fjord.

I mean, you can just imagine the 17th century ships moored up.

They would have been out there in the deeper waters and the smaller whalers chasing this living whale.

Contemporary paintings captured the scene.

The first person would harpoon it. They needed as many harpoons...

Every time it came up, you had to get another one in it.

And eventually, the thing would get exhausted from the fact

it was diving, it had blood, it was bleeding, it was pulling boats.

I mean, it must have been an absolutely horrendous exercise...

-A bloodbath.

-I know, completely and utterly.

It wasn't just the number of whales that made them choose this location.

One of the main reasons they settled here was because of this shallow sloping shoreline here.

It was like a natural ramp in a way, to winch the whales onto the beach.

Once on land, the blubber could be cut away,

boiled down into the precious oil and sent back to Europe.

This was the beginning of an industry that continued for hundreds of years,

becoming more and more intense.

Every species of whale in the Arctic was targeted.

One of the hardest hit was the Greenland Right Whale.

So called because it was the "right whale" to hunt.

Big and slow moving - it was easy to catch.

But the greatest advantage of all was that it floated when it was killed,

making it simpler to haul back to shore.

Over the course of the, sort of, 200-300 years

they were hunting the whales, about 120,000 were killed.

To almost the point of extinction.

It's quite remarkable.

But then, they were easy prey in a way.

The right whale.

The right whale population never really recovered here.

Today, there are almost none in the waters around Svalbard.

As larger whales became scarce, hunters turned to smaller species.

One was the beluga whale, which was hunted mercilessly.

Some of its oil was so fine, it was used to lubricate watches.

Having worked to conserve many species of whales,

Philippe is keen to see how the belugas here are doing.

You know, that stark white colour is so unique.

There are no other whales that look like that.

A bit like dolphins, actually, less like a whale.

They do have a little bit of a dolphin look, like a smile.

But that melon is so distinctive on its head.

This big melon, it's the typical beluga shape.

These belugas were filmed in captivity.

Getting close to them in the wild will be much more difficult.

I've heard that they're quite hard to actually see in the wild.

-Especially in this region.

-They are supposed to be quite shy.

That's why I wanted to see footage ahead of time.

The team will try to find some belugas to help assess the health of

the population in this part of the Arctic. But the fjords are immense.

So, to cover more ground, Paul and Tooni take a boat each.

It'll be a long cold trip, man.

Phillipe and Lucy stand by to go to whichever boat finds any belugas.

They centre their search along

the edge of the massive glaciers at the head of the fjord.

As the glacier's coming down, it stirs up all this silt, till,

and that helps to create a really nutrient rich area.

You have fresh water flowing in, so there's lots of fish, lots of stuff living in there.

These are ideal conditions for polar cod, fish the belugas feed on.

So it's perfect for the belugas, for them to hunt.

So this is prime...beluga zone.

We're just going to keep going looking this whole way along the glacier front.

Belugas are not easy to spot.

Their white colour is excellent camouflage.

I'm looking for things that look like breaking waves or lumps of ice

which is a bit confusing considering there are quite a few lumps of ice knocking around these parts.

We found a seal, I guess it doesn't count though...

This is a bearded seal, the largest species of Arctic seal.

They've got these red heads, and that's because

when they've been rooting around on the bottom for their food,

they're rubbing against all the iron ore that's up in the fjord.

So these are the only ones of these seals that have got red heads,

from rooting around on the bottom.

After several hours of searching, still no sign of belugas.

That's frustrating. It's a massive area, there's no question, but...

They're here somewhere, the little belugas.

We just got to find them.

Finally, Tooni has good news.

So, we've spotted the belugas.

I literally just looked round and it looked like this block of ice was coming up and going down again.

And we stopped the boat and I can see a few of them.

The whales are moving quickly towards the expedition ship.

It's the opportunity Philippe has been waiting for,

to assess the population of belugas at close quarters.

This is very rare, and, like, very lucky.

There's one over there.

Look, look!

We are surrounded by belugas.

Philippe and Lucy estimate

there are about 30 swimming around the boat.

They're very shy. I can't believe we're getting this close.

Wow.

Look, they're literally just off the bow.

Belugas are adapted to life in these ice-covered seas.

It's weird because there isn't a dorsal fin,

which you'd expect to see on most cetaceans or certainly dolphins.

We think they've evolved to not have them for one of two reasons.

When they're under the, ice it's much easier to swim along the ice without a dorsal fin sticking out.

The other reason is, it reduces the surface area that's out in the water that's not insulated so that

they stay warmer than having a whole area where there's blood flowing through that can cool.

This pod of belugas is all adults.

They don't turn completely white until they are at least seven years old.

Around 40% of their body weight is blubber.

One of the reasons they were attractive to the whalers.

I've never seen belugas in the wild before so that was brilliant.

-I say mission accomplished.

-The best thing was to see so many of them,

-to see that they were so healthy.

-Dozens of them.

While this pod might look healthy, the beluga whale could face a new threat.

A warming Arctic could speed up the retreat of the glaciers,

damaging their feeding grounds.

As soon as that glacier recedes far enough that it's on land,

it's not going to be the kind of habitat belugas need.

Increasingly, this is one of the most challenging places on earth to survive.

The Arctic Ocean is extremely cold,

not very nutrient rich and for four months of the year it's in darkness,

so there's a limit to the marine life that can exist here.

But are there corners of this ocean that can beat the odds?

Philippe wants to head south to the shallow waters of Isfjorden.

Here, icy Arctic water mixes with water from the Gulf Stream,

which began life thousands of miles south,

in the tropical Gulf of Mexico.

It's kind of a crossroads here.

It's just really the entrance the beginning of the Arctic habitat

and I'm very curious to see what the whole thing looks like, the whole environment looks like.

At first, it's not promising.

It still pretty barren and white, almost like the surface.

But the empty seascape does show how this fjord was created.

You can see the scarring where the glacier moved through the valley.

Deep gouges on the ocean floor reveal how millions of tonnes of ice

scraped across it, scoring the rock and shaping the fjord.

Then, the bleak seascape is transformed.

Look at all this life.

Yeah.

You know, this conception that the Arctic is this empty desolate place,

totally blown away by what we're seeing here.

There's an explosion of life. There's reds and greens.

That's a soft coral,

related to the kinds of corals that we've seen down in much warmer waters,

but this is a soft coral, it's purely a filter feeder.

Brilliant pinkish-red colour.

I did not expect to see a soft coral this vibrant here in the Arctic.

Almost no warm-water corals can survive through the winter darkness.

They rely on algae that live by photosynthesis and need the sun.

But these soft corals have no algae,

they just need a steady supply of nutrients.

It really is like a soup down here.

This is basically the confluence of the North Atlantic Drift

heading towards the Arctic waters and this is where the two meet.

So that's why it's incredibly nutrient rich.

It's a very unique environment in many ways.

The current doesn't just support the coral.

It also helps feed these anemones, by bringing prey within reach of their tentacles.

There's even a kelp garden here, something usually associated with warmer water.

If you look closely...

I can't see one right now but you'll also find Arctic kelp here.

It can photosynthesises,

take energy from the sun for just one week a year.

It stores up that energy and lasts for 51 weeks a year.

That's pretty incredible.

Other types of kelp have begun to thrive here in the last few years

as the ice has receded, allowing more sunlight to reach these shallows.

It demonstrates how life adapts to inhabit the most unlikely places.

It gives you that other dimension of just how rich the environment here -

how much richer than I thought it would have been when I first came here.

I just had no idea how much life there is

and that just confirms it. That was really amazing.

The warm current flowing from the Gulf Stream

also keeps much of the water around western Svalbard ice-free in summer.

It's home to another Arctic species almost hunted to extinction.

I'm just going to have a look and see what we can see.

Can you make any out?

They're quite a way off at the moment but I can see movement.

They've spotted Atlantic Walruses.

They were killed for their fat and tusks until there were only about 100 left here.

That was 60 years ago.

The team wants to see how the walrus population is doing now.

Walruses only live in the Arctic region, so for marine biologist Tooni

it's a rare opportunity to get close to them.

I've just been watching them all tumbling in the water and sometimes the play looks quite frantic.

They are literally rolling and falling over each other.

One of them lands on you and that's it, curtains.

They can weigh up to two tonnes, giving them immense power.

Look how far they can push themselves out of the water, though.

Now that summer has cleared the ice here, the walruses have come to feed.

They like to feed in about 15 metres of water and they're gatherers,

not hunters, and they're after these clams which are about that big.

The feeding season in the Arctic is short, so walruses are binge eaters.

They can consume more than 50 kilograms of clams in just one day.

Paul and Tooni move on to the land to get a closer look.

They want to observe the walruses and determine the size of the colony.

Walruses are suspicious by nature and easily alarmed.

So Tooni and Paul approach downwind

and crouch to avoid looking like predators.

Right, there's one.

Oh, yeah, he's coming up.

He's not facing us, let's keep going while he's busy.

I can smell 'em good now.

-They don't smell good.

-But this wind is perfect for us.

I don't believe they can smell us, Tooni.

Their Latin name is translates as tooth-walking sea horse,

which I just think is such a perfect literal translation.

That is perfect - look at 'em.

Judging by their large size, this colony is all male.

The one that's just stuck his head up has very short tusks which means it's quite young.

-He's younger, yeah.

-The one towards the back, see, he's much bigger

and has much longer canines, which means he's a much older male.

They grow to 40 years old so he might be 30 or 40 years old.

That big male there has lots of cuts all over his chest,

because they do use their tusks for fighting for establishing dominance.

Let's do a count, roughly.

The size of the colony will give an insight into the recovery of the species.

OK, I can see..

one, two, three, four...

They count 22 male walruses on the beach.

The rule of thumb is that about a quarter of the colony will be on land.

The rest will be in the water, feeding.

So this colony is 88.

That's about right.

-They say between 10 and 100.

-Perfect.

60 years ago, this colony would have represented

almost the entire walrus population of Svalbard.

They were made a protected species here in 1952

and their numbers are slowly recovering.

It's estimated that there are now around 2,000.

I love how on this great expanse of beach, they're all

collected in one group and they're just lying all over each other.

-They're very social.

-They're very communal creatures.

As the Arctic transforms, the Atlantic walrus could,

in the short term, be a climate change winner.

As their feeding grounds are usually near land,

they're not dependent on ice floes to help them reach their food.

And the retreating ice could expose more feeding grounds

and stimulate the growth of clams, their staple diet.

Which means there's plenty of opportunity for their population to keep on increasing.

At least initially, global warming could improve

the Atlantic Walrus's ability to survive.

It's a real interesting balance.

We talk a lot about the negativity of climate change

but it is always nice to have that little bit of a counterbalance,

to be able to say, you know what?

There are some creatures that might benefit in some way with the changing Arctic climate.

The changes in the Arctic Ocean are complex and not always predictable.

But what we do know is that they will affect us all.

A transformation in this remote, bitter ocean

will have a profound effect on life and climate around the globe.

As the team has journeyed across the world's oceans,

change has been the dominant theme, often triggered by human activity.

Habitats are being destroyed.

When something's so perfectly adapted to one particular ecosystem,

it's got nowhere else to go.

Species are being threatened.

We are totally decimating their numbers.

And the fragile balance of life is being disrupted.

They'll eat their way down the food chain

till there's nothing left down there.

But there are also signs of hope.

Some species are managing to adapt and are thriving.

And, with human ingenuity, we're attempting to restore the balance.

What we're looking at here

is almost the Indian Ocean equivalent of a garden centre.

The oceans are one of our planet's greatest assets.

And their future is in our hands.

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