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Just 50 years ago,
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we finally ventured to the moon.
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For the very first time,
we looked back at our own planet.
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Since then, the human population
has more than doubled.
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This series will celebrate
the natural wonders that remain,
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and reveal what we must preserve
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to ensure people and nature thrive.
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The polar regions of our planet
may seem beyond the reach of most of us,
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but they are not beyond our influence.
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We, unintentionally,
are changing these frozen worlds,
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and these changes
will not just affect the poles
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but the whole planet.
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Antarctica.
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The southern end of our planet,
and the coldest place on Earth.
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It has been frozen for 30 million years.
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In its center, the covering of ice
is over four kilometers thick.
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Entire mountain ranges
are buried beneath it.
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Here, it is so cold that each winter
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19 million square kilometers of ocean
freezes,
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more than doubling
the size of the ice cap.
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But when, in spring, the sea ice melts,
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life returns once again
to the continent's shores.
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The peninsula that stretches north
towards South America
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is the first part of it
to be released from winter's grip.
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As the sea ice breaks up,
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life returns.
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There is a greater variety
of living creatures here
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than anywhere else in Antarctica.
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Gentoo penguins
spend most of their lives at sea,
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but now, in spring,
they have to come ashore to breed.
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They're the fastest of all penguins
in water,
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but on land,
life takes on a slower pace.
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It's an uphill struggle
to reach their nesting grounds...
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...but penguins never give up.
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The paths they follow,
carved by thousands of tiny footsteps,
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lead to Antarctica's rarest commodity.
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Bare rock.
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Less than one percent of Antarctica
is ice-free,
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and these rocky patches
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are the only places
where gentoos can lay their eggs.
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It's been a 30-minute struggle,
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but he's almost at the top,
where his mate is waiting for him.
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He presents her with a stone,
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a gift to improve the nest
and so win her favor.
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He's back just in time.
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There's another mouth to feed.
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Gentoo penguins used to be rare
in this part of Antarctica,
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but now, as temperatures rise,
their numbers here are increasing.
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Sea ice may appear to be flat
and lifeless,
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but beneath it there is another world.
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As the ice melts,
the light filters through,
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and algae, that have been trapped
within the ice all winter, flourish.
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This upside-down world
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is the polar equivalent
of the great grasslands.
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The ice is the soil
upon which plant life grows,
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and the herds of grazers soon arrive.
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Antarctic krill.
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Trillions of them swarm
in the waters around Antarctica.
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Protected by the ice above,
they graze on algae whilst the sun shines.
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But the good times don't last long.
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Once all the ice has melted,
the krill lose their protection,
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and predators appear.
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Penguins may have lost
their ability to fly,
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but they still form flocks,
as so many birds do.
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The longer they dive,
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the longer it takes them
to catch their breath.
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Ruffling their feathers traps air,
which makes their bodies more streamlined.
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One last breath...
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and the whole group dives down together.
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The gentoos follow the krill
down to depths of over 200 meters.
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What a flock can catch in one dive,
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a giant traps in a single mouthful.
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Humpback whales from the tropics
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have traveled
over 8,000 kilometers to get here.
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This one chooses to feed alone.
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This technique, part lunge, part pounce,
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only works when the krill
are close to the surface.
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As more humpbacks arrive,
they begin to work in teams.
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By lunging together,
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the overspill from one huge mouth
is not lost but collected by another.
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Some humpbacks regularly work
in an even more coordinated way.
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They do so
when krill has descended to some depth.
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Once in position,
they blast air from their blowholes.
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Working together,
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they create a curtain of bubbles
around their prey.
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As the spiraling net tightens,
the krill are driven closer together,
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and then the whales lunge upwards
and collect them.
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Almost all humpback whales
in the southern hemisphere
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come to the Antarctic to feed on krill.
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Since the ban on commercial whaling,
their numbers have recovered dramatically,
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but their food supply is now under threat.
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In the last 50 years,
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with warming temperatures
and disappearing sea ice,
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krill stocks
in this part of the Southern Ocean
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have more than halved.
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Other sea hunters come here
seeking bigger prey than krill.
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Antarctica's top predators.
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Orca, killer whales.
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Over half of the world's orca
patrol these polar seas.
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This particular pod
specializes in hunting penguins.
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They shift into stealth mode.
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Hunting without making a sound,
so that their prey won't hear them coming.
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A penguin can outmaneuver
a single killer whale,
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but it can seldom escape a pod.
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This hunt may seem cruel,
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but important life skills
are being passed down the generations.
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From killer whales to krill,
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all life here ultimately depends
upon Antarctica's sea ice.
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The seas that surround Antarctica
are the roughest on our planet.
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These churning waters
draw up nutrients from the deep
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and create vast, rich fishing grounds
for nomads like the wandering albatross.
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Beneath the waves,
currents are flowing away from Antarctica,
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transporting nutrients across the planet,
fertilizing the oceans
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and helping to regulate
global temperatures.
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The island of South Georgia.
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It's far enough north
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to be beyond the reach of the sea ice
even in midwinter,
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and many animals live here
the year round.
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This wandering albatross chick
has been sitting on its nest all winter,
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and is entirely dependent
on its parents returning with food.
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It may have to wait a few days
between meals, or even a couple of weeks,
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but at least
it's not the only one who's waiting.
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Albatross chicks need to spend
a whole year growing
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before they're ready
to take their first flight.
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And then they spend several years at sea
before they return to land.
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Coming in to land
on three-meter wings takes some practice.
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Albatross don't have reverse thrusters.
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The chick
is this female's first.
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She's been raising it for six months,
and has another six to go.
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Her chick is smaller than it should be,
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a sign that her mate
has not been returning with food.
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He may well have been
one of the many that die,
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entangled on longline fishing lines.
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South Georgia is an ideal place
for wanderers to raise their young,
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but now fewer adults
are returning here to nest,
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and in recent years,
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the breeding population
has declined by 40 percent.
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For now, waiting on its nest,
the chick is safe.
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There are no land predators here.
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But the same cannot be said
for South Georgia's seas.
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Giant kelp flourishes
in these ice-free waters.
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The perfect place for an ambush.
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Leopard seals overwinter here
to escape Antarctica's frozen ocean.
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They should have returned south by now,
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but this year they've stayed longer.
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And they've delayed their departure
for good reason.
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There are king penguins here.
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Each is a substantial meal,
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if you can catch it.
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Returning to feed their chicks,
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the kings have no choice
but to run the gauntlet.
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Kings rarely porpoise like this.
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It uses more energy,
but it's faster than traveling underwater.
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It's hard to select a moving target
in a panicking crowd,
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but if there are stragglers,
the odds change.
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Razor-sharp teeth versus a stabbing beak.
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It's stalemate.
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Both are exhausted after the chase.
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The hunter decides that the meal
is not worth the fight.
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For the penguin,
it was too close for comfort,
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but that was just the first hurdle
in getting back to feed its chick.
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It isn't going to be
a walk in the park.
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Luckily, penguin is not on their menu.
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Still, it's best
to let sleeping giants lie.
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Elephant seal females
don't take kindly
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to being disturbed from their slumber,
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but it's the four-tonne males
you need to look out for.
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They are fighting
for access to the females.
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Getting bulldozed under angry blubber
is to be avoided at all costs.
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An escape route.
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Time to run for it.
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At last, he's reached the nursery.
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Now comes his final challenge.
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Finding his chick
in the crowd of half a million.
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He calls...
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...and listens
for a recognizable reply.
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His chick could be
another mile or two away,
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at the back of the colony.
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But that's the trouble with chicks.
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They're never where you left them.
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Astonishingly, in all this racket,
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a parent and its chick
can recognize each other's calls.
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The things parents go through
to deliver a meal.
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If only they knew.
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For such a small island,
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South Georgia supports
an extraordinary quantity of life.
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All these creatures
ultimately depend on the krill
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that develops under the sea ice
around the Antarctic peninsula.
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With sea ice disappearing,
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so South Georgia's future
is far from certain.
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At the other end of the planet,
in the north,
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the effects of climate change
are being felt even more intensely.
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The Arctic is not a continent
surrounded by sea
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but a frozen ocean ringed by land.
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Here, in spring, the sea ice
is still at its maximum extent.
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It's a vast, firm hunting ground
for the planet's largest land carnivore.
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A male polar bear
in search of his next meal
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on the frozen fjords of Svalbard
in the high Arctic.
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He's looking for seals,
which make up the bulk of his diet.
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He must eat two-thirds
of the food he needs for the whole year
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before the ice melts
and his hunting platform disappears.
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The ringed seal mother had no choice
but to leave her pup alone on the surface.
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In the past, she would have built a den
inside a ridge on the ice,
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but now the sea freezes so late
that the ice is flat,
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and she had to leave her pup
out in the open.
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These changes in the ice
may benefit the bears for now,
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but in the long term,
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a crash in their most important prey
will follow.
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This new, flatter ice
makes life difficult for the bears, too.
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There's nowhere for them to hide
in order to creep up on a seal.
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And for a mother with a young cub in tow,
being stealthy isn't easy.
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The cub doesn't yet appreciate
the need for care
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when sneaking up on a seal.
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With fewer seals hiding in dens,
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learning this pounding technique,
once so useful,
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is now almost pointless.
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Still, at least he's discovered
what a seal hole looks like..
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His mother knows that overcast conditions
are good for hunting,
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and he knows when she's serious.
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Adult seals make a much better meal.
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Her cub carefully treads in her footsteps,
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and takes care not to break her outline.
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Neither must put a foot wrong.
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They must move as one.
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Most seal hunts end in failure.
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The bears must keep searching.
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Her cub wanders off,
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and gets another chance.
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A seal pup alone on the ice.
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Now it's not stealth
that is needed, but confidence.
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There's nothing the mother can do,
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except hope that the pup makes it
back to her hole in time.
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The inexperienced young hunter
hesitates.
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Its mother knows better.
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Safe under the ice.
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Polar bears are adaptable predators,
but they rely on sea ice.
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If that disappears, so will the bears.
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Summer at the ice edge
in the Canadian Arctic,
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and the annual retreat of sea ice
is well underway.
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As it melts, nomads arrive.
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Narwhal, the origin of the unicorn legend.
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Their three-meter tusk is, in fact,
no more than an overgrown canine tooth,
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but its exact function,
like so much about narwhals,
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is still, in part, a mystery.
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Each summer, narwhals travel
to the same part of the Arctic,
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and patiently wait at the ice edge
for a crack to open up.
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A lead in the ice,
wide enough for them to swim along.
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Eventually, a crack appears.
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Their passage to sheltered, shallow bays.
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Narwhals are extremely timid
and rarely filmed underwater.
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These ice whales eagerly travel
down the leads as soon as they open
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because they're safer from predators
protected by the ice.
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00:42:01,560 --> 00:42:05,439
The leads may also give them access
to new feeding grounds.
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Sea ice is not just crucial
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00:42:20,663 --> 00:42:23,707
to the lives of those creatures
that live around the poles.
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00:42:25,709 --> 00:42:30,381
It plays a vital role in determining
the climate of the whole planet.
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A white surface keeps the earth cool
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by reflecting most of the sun's energy
back into space.
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00:42:50,693 --> 00:42:52,903
A dark surface does the opposite,
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absorbing over 90 percent
of the sun's energy
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00:42:57,199 --> 00:42:58,826
and so warming the earth.
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00:43:03,372 --> 00:43:04,707
As the sea ice shrinks,
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we're starting to lose one of our planet's
protective white shields.
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For thousands of years,
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there's been a balance
in the advance and retreat of the sea ice,
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but that is no longer the case.
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Today, during the summer months,
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00:43:24,935 --> 00:43:30,065
there is 40 percent less sea ice cover
than there was in 1980.
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00:43:39,533 --> 00:43:44,288
The Arctic is warming twice as fast
as anywhere else on our planet.
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By 2040, the ocean here
will be largely free of ice
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during the summer months.
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This loss of ice will inevitably
have devastating consequences
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for all those that still depend on it.
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The far northeastern coast
of Russia.
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This is the largest gathering
of walrus on the planet.
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00:45:06,912 --> 00:45:12,251
Over a hundred thousand have hauled out
on one single beach.
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They do so out of desperation,
not out of choice.
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00:45:27,766 --> 00:45:31,186
Their natural home is out on the sea ice.
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00:45:38,152 --> 00:45:41,071
But the ice has retreated
away to the north,
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00:45:42,740 --> 00:45:46,368
and this is the closest place
to their feeding grounds,
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00:45:46,618 --> 00:45:48,036
where they can find rest.
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00:46:02,885 --> 00:46:05,929
This calf must stay close to its mother.
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00:46:14,521 --> 00:46:17,524
But every square inch is occupied.
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00:46:37,085 --> 00:46:39,880
Climbing over
the tightly packed bodies
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00:46:39,963 --> 00:46:42,382
is the only way across the crowd.
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00:46:44,968 --> 00:46:47,429
Those beneath can get crushed to death.
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00:46:55,896 --> 00:46:58,398
A stampede can occur out of nowhere.
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00:47:20,420 --> 00:47:25,717
Under these conditions,
walruses are a danger to themselves.
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00:47:31,557 --> 00:47:35,435
Some manage to find space
away from the crowds.
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00:47:40,941 --> 00:47:43,652
They struggle up the 80-meter cliffs,
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00:47:49,533 --> 00:47:54,788
an extraordinary challenge
for a one-tonne animal used to sea ice.
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00:48:08,135 --> 00:48:10,929
At least up here there's space to rest.
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00:48:18,729 --> 00:48:21,523
A walrus's eyesight out of water is poor,
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00:48:23,609 --> 00:48:26,153
but they can sense the others down below.
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00:48:31,742 --> 00:48:35,454
As they get hungry,
they need to return to the sea.
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00:49:22,084 --> 00:49:24,252
In their desperation to do so,
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00:49:24,836 --> 00:49:28,840
hundreds fall from heights
they should never have scaled.
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00:50:30,902 --> 00:50:36,616
These mass gatherings of walrus
are now happening almost every year.
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00:50:43,790 --> 00:50:49,421
So the lives of walruses,
like those of polar bears and seals,
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00:50:49,796 --> 00:50:50,796
are changing.
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00:50:53,216 --> 00:50:56,636
All are living at the frontier
of climate change,
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00:50:58,722 --> 00:51:01,391
and all are suffering as a consequence.
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For now, the Arctic winter returns
and the sea ice reforms.
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00:51:28,543 --> 00:51:30,670
Order is restored.
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00:51:34,800 --> 00:51:39,262
Relief for the many creatures
that depend on the ice.
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00:51:52,567 --> 00:51:54,277
But for how much longer
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00:51:54,653 --> 00:52:00,200
will their frozen worlds
be a part of life on our planet?
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00:52:18,385 --> 00:52:20,470
Please visit ourplanet.com
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00:52:20,762 --> 00:52:25,183
to discover what we need to do now
to keep the polar wilderness.
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00:52:27,727 --> 00:52:33,567
♪ I can hear the whole world
Singing together ♪
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♪ I can hear the whole world
Say it's now or never ♪
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00:52:44,953 --> 00:52:49,332
♪ 'Cause it's not too late
If we change our ways ♪
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00:52:49,416 --> 00:52:52,919
♪ And connect the dots to our problems ♪
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00:52:53,253 --> 00:52:59,009
♪ I can hear the whole world
Say we're in this together ♪
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00:52:59,426 --> 00:53:01,094
♪ We're in this together ♪