Ice Worlds Planet Earth

Both poles of our planet are covered with ice.

They're the largest and most demanding wildernesses of all.

Nowhere else on Earth is seasonal change so extreme.

It causes the ice to advance and retreat every year.

And all life here is governed by that.

When the first polar explorers headed south,

giant cathedrals of ice marked their entry into uncharted territory.

Passing the towering spires,

they must have wondered what unearthly sights lay in store.

As they battled on, the ice became increasingly dominant,

but nothing could have prepared them for the ice world

that finally loomed into view.

Terra Incognita.

The unknown land.

At the southernmost extreme of our planet, the continent of Antarctica

is as large as the United States of America.

90% of all the world's ice is found here.

This frozen world is largely deserted until the start of spring.

Adelie penguins.

In a hurry.

The clock is ticking.

Instead of waiting for the summer melt, the new arrivals hasten south

over the frozen sea.

They have come here to breed, but polar summers are so short,

they must be in position before the thaw starts.

As the sea ice retreats, life can journey farther south.

Antarctic waters are so rich

that visitors come from far and wide to harvest them.

Vast numbers of chinstrap penguins come ashore to breed.

No bird will lay their eggs directly onto ice,

so bare rock is a vital commodity.

The best patches are worth the climb.

The cliff tops are soon stained pink

with the droppings of tens of thousands of nesting penguins.

Only in a land almost entirely covered in ice

could bare rock be reckoned an oasis.

Some will travel into the heart of the continent to find it.

These are nunatacks, the exposed peaks of vast mountain ranges

buried in ice over a mile deep.

The eerie silence here is only broken in spring.

SQUAWKING

The snow petrels have arrived and are courting.

SQUAWKING

Antarctic petrels now join the most southerly bird colony on Earth.

The birds have flown inland for over 300 miles

to reach this breeding site.

Once their eggs have hatched, they will be forced repeatedly

to make the 600-mile round trip to gather food in the ocean.

First though, valuable nesting places must be defended

from property thieves.

After laying their eggs, the petrels take time out to clean their plumage.

The south polar skua is a formidable opportunist.

But the skuas have not chanced upon the petrels.

They've been waiting for them.

These birds do not need to go to the ocean for their food.

The skuas can survive further south than any other predator

by exploiting the petrels' desperate need for bare rock.

SQUAWKS

Even at the height of summer, less than 3% of Antarctica is free of ice

and nearly all of that exposed rock

is found in one place - the Antarctic Peninsula.

Its long arm extends further north than the rest of the continent,

so spring arrives here first.

The thaw unlocks sheltered bays that provide refuge

from the relentless battering of the Southern Ocean.

In the depths, something stirs.

Humpback whales.

They have travelled over 5,000 miles to reach these waters.

The whales are harvesting krill,

shrimp-like creatures that begin to swarm here

as soon as the ice retreats.

Diving into the heart of the swarm,

teams of whales spiral round each other in close co-ordination.

WHALE TRUMPETS

Now they turn, blasting air from their blowholes,

and ascend towards their prey.

WHALE TRUMPETS

The krill becomes concentrated

as the spiralling net of bubbles draws inwards.

WHALE CRIES

WHALE CRIES

WHALE RUMBLES

The team of whales work round the clock, for the boom is short-lived.

Summer is already fading

and the whales will soon be forced north as winter returns.

The sun's influence diminishes and the ocean starts to freeze.

The greatest seasonal change on our planet is under way.

The ice grows at an extraordinary rate,

advancing two and a half miles a day.

In a matter of weeks, the continent effectively doubles in size.

Life flees from Antarctica.

But one creature is just arriving.

Every winter, emperor penguins leave the comfort of their ocean home

and begin a remarkable journey.

They head towards their breeding grounds

almost a hundred miles inland.

Eventually, the emperor penguins

reach the place where they were hatched,

an area sheltered by icebergs trapped in the frozen ocean.

Here they will raise the next generation.

But first, each must find a mate.

The males begin to serenade.

And if a female replies, they pair up, posing like statues.

New couples quickly form a strong bond.

They seem oblivious to the noisy crowd around them.

To cement their relationship, the male steps out with his female.

The brief courtship complete, there isn't a moment to lose.

With so much pressure to perform,

any male would struggle to stay on top.

Several weeks later, and it seems that most couplings were successful.

But producing the egg has taken its toll.

The females no longer have the energy to incubate.

The male takes over.

It's still minus 20 degrees centigrade

so the transfer must be done quickly or else the egg will freeze.

With no bare rock to nest on,

the male tucks the egg into a special pouch

where he can keep it warm.

It requires an extraordinary piece of teamwork.

Driven by hunger,

the exhausted females now return to the ocean on their own,

repeating the epic journey they made with the males only a month before.

Now the sun barely appears above the horizon.

As the days shorten, its warmth is withdrawn from the continent.

WIND HOWLS

With the females gone, the colony undergoes a strange transformation.

The males shuffle into groups,

their eggs still tucked away above their feet.

They lock together in tightly packed huddles

as they struggle to keep warm.

Speeding up the action reveals

how these huddles constantly shift and change

as each penguin works its way towards the warmer interior.

Crammed into this scrum, the birds are remarkably good-natured,

but they have to be.

If the huddle breaks, even for a moment, precious heat escapes.

It's imperative they reform as quickly as possible,

for only by acting as one, can the males withstand the elements

and protect their eggs.

But their greatest test lies ahead.

As winter advances, frequent blizzards drive the temperature down.

It's now 60 degrees below zero.

The birds at the edge of the huddle bear the brunt of the 100mph winds,

and so provide shelter to those taking their turn in the middle.

Abandoned by the sun, the males are left alone with their eggs

to face the coldest, darkest winter on Earth.

At the northern extreme of our planet,

the sun rises for the first time in months,

illuminating a very different ice world.

Unlike Antarctica, the Arctic is a vast frozen sea surrounded by land.

Here, winter is coming to an end,

but this bleak wilderness remains locked in ice.

Eider ducks break the silence.

They have stayed here, braving the northern winter,

instead of flying south to warmer climes.

Flocks, 40,000 strong, sweep across the frozen wastes.

They all have the same goal - a polynya,

a permanent hole in the sea ice kept open throughout the winter

by strong ocean currents.

This unusual duck pond provides an overnight sanctuary

and, when day breaks, a rare chance to feed.

Just ten metres beneath the ice,

the seafloor is carpeted with dense mussel beds.

These can only be reached during a brief lull in the currents.

The ducks must quickly prise the mussels free

before the tide starts to turn.

The window of opportunity is short.

As the current begins to build, it's up, up and away.

These permanent holes in the ice

provide seafood throughout the winter.

The diners attract others.

In the Arctic, any breach in the icy barrier can be a lifeline.

Musk oxen create their own.

These giants have the strength to smash through the frozen crust

to graze on the vegetation below.

These icebreakers create an opening for other over-winterers.

Flocks of ptarmigan make unusual grazing companions to the musk oxen,

whose entourage grows throughout the day.

This odd assembly of vegetarians doesn't go unnoticed.

An Arctic fox.

The musk oxen have recently given birth.

For the fox, it's a chance to scavenge.

But half a ton of mad, hairy cow...

..is not to be trifled with.

The calves are born well before the spring melt,

giving them a head start when summer finally arrives.

It must get to grips with its new ice world - benign one minute,

life-threatening the next.

WIND HOWLS

Even in spring, winds chill to the bone.

The calf must stay close to its mother

to avoid getting lost in the sudden blizzard.

Arctic wolves.

In the whiteout, the threat is almost impossible to detect,

but the musk oxen instinctively retreat to higher ground.

Forming a defensive ring around their calves,

the adults present a barricade that few hunters could breach.

But the wolves need not risk injury today.

A calf has been left behind in the panic.

WOLF HOWLS

With each passing day, the sun climbs higher in the sky

and its rays strike the Arctic more directly.

It's spring and new life stirs.

The polar bear cubs emerge from the den in which they were born.

Their mother stretches her legs after five months under the snow.

They're just two months old and instinctively follow her lead.

A steep slope makes the best site for a den

but it's a tricky place to take your first steps.

It may look like fun, but this is serious training for the task ahead.

There's no food on the slopes

and the family will need to head out across the frozen sea

before the mother's milk runs dry.

Two weeks later, they're ready.

Out on the sea ice, the female can hunt for seals,

but it will take all her mothering skills to keep her cubs safe

in this dangerous world of ice.

The annual melt has begun.

This is a challenging time for the bear family.

One out of every two cubs do not survive their first year

out on the ice.

As the sun's influence increases,

the sea ice seems to take on a life of its own.

Glacial meltwaters pour from the land,

mingling with the sea and speeding up the thaw.

The seascape is in constant flux

as broken ice is moved on by winds and currents.

The ice is becoming too weak to support a male polar bear.

He attempts to spread his weight,

but the ice that has supported him all winter

is rapidly disintegrating.

Each year, as the climate warms, the Arctic holds less ice.

This is a disaster for polar bears.

Without its solid platform,

they can't hunt the seals they need in order to survive.

This may be a glimpse of the unstable future

faced by this magnificent creature.

As the ice disappears, seabirds return to the high Arctic.

SQUAWKING

Little auks arrive in their millions.

In some ways, these birds are the penguins of the north.

They seek bare rock on which to lay their eggs

and they look rather like penguins too.

Unlike Antarctica, the Arctic can be reached by land-based predators,

which is why little auks have kept the ability to fly.

SQUAWKING

They use scree slopes to protect their eggs,

burrowing up to a metre beneath the rocks.

At the height of summer, the sun never sets

but just skims the horizon before rising again.

Migrants return to the Arctic from far and wide.

They've come to make the most of the brief flush of food

and to produce their young.

Sandhill cranes have travelled all the way from New Mexico.

Their chicks join the growing band of youngsters exploring the tundra.

For a few months each year,

the Arctic becomes the land of the midnight sun,

and 24 hours of daylight allow animals to feed around the clock.

The Arctic fox finally has enough food to raise her large family.

If you choose to nest in the open, you must be prepared for a fight.

FOX SCREECHES

BIRD SQUAWKS

Arctic skuas will see off any trespassers, even large vegetarians.

GRUNTING AND SQUAWKING

The male polar bear's ice world has finally vanished beneath him.

While the female is still kept on land by her dependant cubs,

the male can take to the sea in search of food.

Ducking and diving,

he hopes to ambush seals resting on the remaining fragments of ice.

In these new surroundings, he is a surprisingly adept swimmer.

Once an extremely rare sight,

polar bears have recently been seen over 60 miles from the shore.

There is now no turning back for this bear.

He's forced to head out into deeper water.

His giant front paws help him to fight the ocean currents.

He seems at home in the sea, but he can not swim indefinitely.

He will drown if he doesn't find land somewhere in this vast ocean.

Walruses are now gathering on low lying islands.

They gave birth on sea ice but with this platform now gone

they need a new place to haul out and nurse their young.

After several days at sea, the male bear finally makes landfall,

drawn by pungent smells emanating from the island.

By the end of summer, the bear has lost half his weight.

With the ice long gone, he is forced onto land in search of food.

There will be no easy meals on this island.

Walruses are the largest seals in the world.

They weigh over a tonne and are armed with tusks a metre long.

Exhausted from his swim, the bear must regain his strength.

The next day, a sea fog shrouds the island.

The walruses sense that they're in danger.

Using the fog as cover, the bear approaches the herd.

The adults close ranks around their young,

presenting a wall of blubber and hide.

He tests the barrier,

but it stands firm.

It appears that the world's largest land carnivore has met his match.

There must be a chink in the armour somewhere.

Not here!

This female walrus is shielding her pup.

If he can just prise her off...

The bear's paws and teeth can't penetrate her thick hide.

With the herd retreating to water, the bear must move quickly.

Having failed with one, he heads straight for another.

The chance of his first meal in months is slipping away.

He seems increasingly desperate.

It's now or never!

He must avoid the stabbing tusks if he's to win.

The flailing walrus is immensely powerful

and drags the bear away from the shallows

towards the safety of the herd.

It slips from his grasp.

Only at the height of summer,

when bears are on the verge of starvation,

will they risk attacking such dangerous prey.

It was a gamble that this bear took and lost.

The stab wounds he received from the walrus

are so severe that he can barely walk.

The walruses are calm again,

seemingly aware that the injured bear

no longer poses a threat to them or their young.

BEAR GROWLS

Unable to feed, this bear will not survive.

If the global climate continues to warm

and the Arctic ice melts sooner each year,

it's certain that more bears will share this fate.

At the southern end of our planet,

fiery ribbons are illuminating the winter skies -

the Aurora Australis.

This light brings no warmth to the male penguins

who are still huddling,

defying the coldest conditions on the planet.

Their ordeal is drawing to a close.

30 days after it last set, the sun rises once more on Antarctica.

Their appalling trials have all been for this.

CHICK SQUEAKS

Each father has just one meal left inside him.

He's been saving it all winter.

This single feed will sustain the chicks for a few more days.

But the males have not eaten for nearly four months.

If they do not eat soon, they and their chicks will die.

But there is hope on the horizon.

The females are returning and their bellies are full with fish.

As they approach, waves of excitement ripple through the huddle.

Each female calls to her mate

and he, recognising her song, trumpets back.

Reunited at last.

The mother sees her chick

for the first time.

She's keen to start parenting,

but the father needs persuading

to surrender the chick he's been caring for all winter.

He must now put his chick at risk.

In these temperatures, it could freeze in seconds.

The male will have to let go.

Eventually, the transfer to the mother is safely made.

The chicks grow quickly on a diet of fish and squid.

Soon they're keen to explore,

but always with mother in tow.

This chick is less fortunate. Its mother has not returned to claim it.

Another orphan is searching for a new family

but this female already has a chick of her own.

Some orphans receive too much mothering from penguins

whose own chicks have not survived.

The urge to parent is so strong that they will compete with one another

to adopt any chick they find.

Many of these squabbles end in tragedy

as the poor chick is trampled to death.

Those chicks that DO have parents quickly learn survival skills.

Even in spring, they must huddle together for warmth

just as their fathers did in the depths of winter.

A group of chicks has got lost in the blizzard.

Cold and disorientated, they search for the colony.

It will not be long before the storm claims its first victims.

By early summer, the chicks are surprisingly well developed

and now look ready to take on the world.

Those that survive their first year

have the best possible start in life,

thanks to the extraordinary hardships endured by their parents -

parents who battled with the Antarctic winter and won.

In the Arctic,

the two polar bear cubs are now independent of their mother

and they briefly reunite where their home ranges overlap.

Their time together will be fleeting.

Most of their lives are now spent alone,

wandering the vast tracts of frozen ocean.

Following their mother has prepared them for life at the pole,

an ever-changing land ruled by ice.

Whether they are ready for the bigger changes

that have begun to shape the ice worlds of our planet

remains to be seen.

Filming at the poles calls for extraordinary dedication.

To capture the private life of penguins,

cameraman Wade and his partner Frederique

would spend a year in Antarctica,

with only 20,000 emperors as neighbours.

As you can probably see, we've got a bit of weather.

Somewhere behind me is the birds.

Every now and then, when the snow clears,

you can just catch a glimpse of them.

Poor buggers, they'll all be huddled in tight.

That's where I'd rather be. So we'll go over and have a look.

It's cold out here. Cold and windy.

In fact, it was minus 50 degrees centigrade

and the winds were close to hurricane force.

Wade had waited six months for this chance to film the penguin huddle,

but the extreme cold soon took its toll.

Oh, it's really frustrating.

It takes so much effort to film in these sort of blizzard conditions.

I mean, just to get here and...

Had a pretty good run there but the camera's just jammed.

The film's jammed.

There's nothing I can do about it out here, there's just no way.

Wade was forced to retreat to the relative comfort of the hut,

leaving the penguins out in the cold.

I was just lying in bed thinking about those penguins

and all the huddles - all the males will be huddled together -

and how they can possibly survive in this sort of weather

is just absolutely extraordinary,

and I really feel quite sorry for them at this moment.

With the camera fixed,

Wade set off again the next day, but the storm was even worse.

The 100mph winds

forced Wade onto his knees,

as he struggled to haul the weight of the camera.

The two-mile walk to the colony now became an epic struggle.

It's hard to imagine a more brutal challenge

for a natural history cameraman.

Wade's extraordinary endurance finally delivered remarkable images

of penguins braving the worst winter on the planet.

These are scenes that few humans have ever witnessed.

In sharing the ordeal with the emperors,

Wade and Fred developed a deep bond with their penguin neighbours.

Two months on and the colony is bustling with new life.

But there was trouble for one young chick.

We saw a chick's head sticking out of the snow

and we just realised he's been trapped in a hole

as the snowdrift surrounded him.

So, during the last blizzard, he must have been there for a few days.

So we're going to try and get him out.

Don't be scared, chicken. I'm gonna cut the snow.

Without help, this youngster would soon have starved.

Natural history film crews do not normally interfere

with the course of nature,

but having shared the penguins' six-month struggle for survival,

it was impossible for Fred to just sit back.

The chick's mother looked on helplessly.

Come here. Yes, grab my hand.

That's it, come, chicken.

There you go.

CHICK WHISTLES

Luckily, the chick was none the worse for its experience.

CHICK WHISTLES

As soon as the chick got out, it bound with its parent again

and it straight away got a feed, so that's really good.

Thanks to the remarkable efforts of its parents

and with just a little help from its human neighbours,

this chick has a bright future.

HELICOPTER WHIRRS

For one of our Arctic filming crews,

visits from the neighbours were to prove less welcome.

Hungry polar bears are extremely dangerous and, given the chance,

will kill and eat humans.

Drawn by the smell of Doug's home cooking,

this male bear seems particularly fearless.

Jason fires blanks to scare it away.

GUNSHOTS

-Was that him?

-That was him.

Keep it locked. I'll check the window.

We think he's gone.

But we're not sure.

-Day one.

-Day one.

Bear outside the cabin.

Chewing on a generator cable will hardly satisfy the appetite

of the world's largest land carnivore.

He was after something more substantial.

This is just a bit of a problem when we get bears

as close as this to the cabin.

He's a big boy.

As the day went on,

it became clear that this was one very determined bear.

Oh, he might wander off.

Explosive charges known as "bear scarers"

are the polite way to persuade him to leave.

Come on, let's go!

Give him another one. He wasn't too bothered about that. Got the pistol?

They had to resort to a bigger bang...

a "thunder flash" fired from a pistol.

But this bear is his own boss and will leave when ready.

Quite exciting, really.

The crew were not here to film hungry male bears.

They were after females and cubs emerging from their winter dens,

but to find them they had to leave the safety of the hut

and enter the bears' domain.

Planet Earth had been given special permission to film

on this remote Norwegian island,

the first human visitors for 25 years.

Motorised vehicles are prohibited in this fragile environment,

so the crew had to do things the old-fashioned way.

When the polar explorers

used to haul their gear like this,

they used to have names for their sledges,

things like Intrepid and Braveheart.

I'm gonna call mine

-"You

-BLEEP BLEEP

-Awkward Heavy Object".

Argh!

Doug's sledge seemed determined to live up to its name.

Oh, no! LAUGHTER

Oh, no!

Isolated and on foot, the crew were vulnerable at all times

and, with so many male bears out on the sea ice,

Doug had to keep his wits about him.

Where's the batteries?

Females den on steep slopes,

but predicting where they would emerge was proving a real challenge.

After weeks of searching, the crew finally got lucky.

This is fantastic. She's out on the slopes.

Four...four weeks we've been waiting to get this one little opportunity,

but now that it's happening, it's just fantastic.

Close behind the mother bear, her tiny eight-week-old cubs.

With the sequence in the can, the crew were able to relax,

-but not for long.

-I dunno.

I thought...

I thought I heard something.

This bear is much too close for comfort.

Now, this guy...

A reminder that we are only visitors in the polar bear's world.

Yeah, give it time. You get...

Hang on. Hang on, Doug, he's going back that way.

Get the gun ready. Get the gun ready, Doug!

Subtitles by Red Bee Media Ltd, 2006.

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