we finally ventured to the moon.

人類がようやく 月に到達したのは

For the very first time, we looked back at our own planet.

わずか50年前のこと

Since then, the human population has more than doubled.

その時に我々の住む惑星を 初めて一望できた

This series will celebrate the natural wonders that remain,

それ以来 地球の人口は 二倍以上になった

and reveal what we must preserve

このシリーズでは 残存する美しい自然を尊び―

to ensure people and nature thrive.

人類と自然が共に 繁栄して行くために

The polar regions of our planet may seem beyond the reach of most of us,

守らなければならないものを 明かしていく

but they are not beyond our influence.

北極と南極は はるか彼方―

We, unintentionally, are changing these frozen worlds,

そう思うかも知れない

and these changes will not just affect the poles

しかし両極は 我々の影響範囲外ではない

but the whole planet.

我々は 意図せずして これら極寒の地を変化させ―

Antarctica.

そこでの変化は 両極のみならず―

The southern end of our planet, and the coldest place on Earth.

地球全体に波及する

It has been frozen for 30 million years.

凍てつく世界

In its center, the covering of ice is over four kilometers thick.

南極大陸

Entire mountain ranges are buried beneath it.

地球の最南端にあり 地球で最も寒い場所

Here, it is so cold that each winter

3000万年凍ったままの大地

19 million square kilometers of ocean freezes,

大陸内部では 氷の厚さが ４キロメートルを超える

more than doubling the size of the ice cap.

広大な山脈が氷の下に埋まる

But when, in spring, the sea ice melts,

冬にはあまりの寒さに―

life returns once again to the continent's shores.

1900万平方キロメートル にわたり 海が凍り―

The peninsula that stretches north towards South America

海氷面積が２倍以上になる

is the first part of it to be released from winter's grip.

しかし春になり 氷が溶けると―

As the sea ice breaks up,

この大陸に再び命が吹き返す

life returns.

南アメリカ大陸に近い 半島から―

[gulls cawing]

先に春が訪れる

There is a greater variety of living creatures here

海氷は割れ

than anywhere else in Antarctica.

生命の躍動が再び始まる

Gentoo penguins spend most of their lives at sea,

ここは 南極大陸で―

but now, in spring, they have to come ashore to breed.

最も多様な生き物が 生息する場所

They're the fastest of all penguins in water,

ジェンツーペンギンは 生涯のほとんどを海で過ごす

but on land, life takes on a slower pace.

春だけは 子育てのために岸に上がる

It's an uphill struggle to reach their nesting grounds...

水泳速度が ペンギン随一の彼らも―

[penguins honking]

陸ではヨチヨチ歩きだ

...but penguins never give up.

巣作りする場所まで 上り斜面を懸命に進む

The paths they follow, carved by thousands of tiny footsteps,

ペンギンは諦めない

lead to Antarctica's rarest commodity.

何千個の小さな足跡がつけた 幾重いくえもの道は

Bare rock.

南極で最も貴重な 場所へと続く

Less than one percent of Antarctica is ice-free,

岩場だ

and these rocky patches

ここで岩が見えるのは 大陸の１パーセント未満

are the only places where gentoos can lay their eggs.

この岩場でしか―

It's been a 30-minute struggle,

ジェンツーペンギンは 産卵できない

but he's almost at the top, where his mate is waiting for him.

30分かけ 彼はようやく―

[honking]

妻の待つ頂きに着いた

He presents her with a stone,

石のプレゼントを忘れない

a gift to improve the nest and so win her favor.

巣を頑丈にする石に 妻も大喜びだ

[both honking]

間に合った

He's back just in time.

子育てが始まる

There's another mouth to feed.

ジェンツーペンギンは この地域では珍しかったが―

[chirrups]

気温が上昇した現在 生息数が増えている

Gentoo penguins used to be rare in this part of Antarctica,

海氷は静かで生命が 感じられないかも知れない

but now, as temperatures rise, their numbers here are increasing.

水面下は別世界だ

Sea ice may appear to be flat and lifeless,

氷が溶け 光が差し込むと

but beneath it there is another world.

冬の間に氷に挟まれていた 藻が一気に広がる

As the ice melts, the light filters through,

この天と地が 逆さになった世界は

and algae, that have been trapped within the ice all winter, flourish.

南極の草原だ

This upside-down world

ここで生息する植物にとって 氷は土壌

is the polar equivalent of the great grasslands.

そして それを食べる生物が 集まる

The ice is the soil upon which plant life grows,

南極オキアミ

and the herds of grazers soon arrive.

南極海には何兆匹の オキアミがいる

Antarctic krill.

氷に守られ 太陽が差し込む この場所で食事を楽しむ

Trillions of them swarm in the waters around Antarctica.

それもつかの間

Protected by the ice above, they graze on algae whilst the sun shines.

氷がすべて溶ければ 守る盾はなくなり―

But the good times don't last long.

敵が現れる

Once all the ice has melted, the krill lose their protection,

ペンギンは飛ぶ能力を 失っても―

and predators appear.

鳥と同様に 群れで暮らしている

Penguins may have lost their ability to fly,

長く潜った後は

but they still form flocks, as so many birds do.

長く水面で過ごし 態勢を整える

The longer they dive,

毛を逆立て 空気を閉じ込め 泳ぎやすくするのだ

the longer it takes them to catch their breath.

息を深く吸い―

Ruffling their feathers traps air, which makes their bodies more streamlined.

全員で潜る

One last breath...

オキアミを追って 水深200メートル以上 潜る

and the whole group dives down together.

群れ全員が１回の潜りで 捕る量を―

The gentoos follow the krill down to depths of over 200 meters.

“彼”は口を１回 開けるだけで捕る

What a flock can catch in one dive,

ザトウクジラは

a giant traps in a single mouthful.

熱帯域から8000キロメートル 泳いでここまで来る

Humpback whales from the tropics

このクジラは一人で 漁をしている

have traveled over 8,000 kilometers to get here.

突進と急襲を合わせた この方法は―

This one chooses to feed alone.

オキアミが水面近くに いることが必須条件だ

This technique, part lunge, part pounce,

他のクジラが到着すると チームワークを開始する

only works when the krill are close to the surface.

並んで漁をし

As more humpbacks arrive, they begin to work in teams.

１頭の口を逃れたオキアミを

By lunging together,

もう１頭が効率良く捕まえる

the overspill from one huge mouth is not lost but collected by another.

彼らがより際立った チームワークをする時がある

Some humpbacks regularly work in an even more coordinated way.

それは オキアミが 深く潜った時だ

They do so when krill has descended to some depth.

位置につくと 噴水孔から空気を吹き出す

Once in position, they blast air from their blowholes.

協力し合いながら

Working together,

オキアミ周辺に 泡のカーテンを作る

they create a curtain of bubbles around their prey.

らせん状の網に挟まれ オキアミは一箇所に集まる

As the spiraling net tightens, the krill are driven closer together,

そこで一気に上昇し 飲み込むのだ

and then the whales lunge upwards and collect them.

南半球のザトウクジラ の 殆ほとんどが―

Almost all humpback whales in the southern hemisphere

南極海に来るのは オキアミが目当てだ

come to the Antarctic to feed on krill.

商業捕鯨が禁止され 生息数は劇的に回復した

Since the ban on commercial whaling, their numbers have recovered dramatically,

しかし現在 その食料が 危機的状況にある

but their food supply is now under threat.

過去50年

In the last 50 years,

地球温暖化が進み 海氷が消失し

with warming temperatures and disappearing sea ice,

南極海のオキアミの数は 半減した

krill stocks in this part of the Southern Ocean

オキアミより大きな 生物を狙う補強者も来る

have more than halved.

南極海で食物連鎖の 頂点に立つ―

Other sea hunters come here seeking bigger prey than krill.

海の暴れん坊 シャチだ

Antarctica's top predators.

世界のシャチの 半数以上が―

Orca, killer whales.

北極海と南極海にいる

Over half of the world's orca patrol these polar seas.

この群れは ペンギンだけを狙っている

This particular pod specializes in hunting penguins.

海に潜伏して

They shift into stealth mode.

標的に気づかれないよう 静かに泳ぐ

Hunting without making a sound, so that their prey won't hear them coming.

１頭のシャチなら 逃げおおせても―

A penguin can outmaneuver a single killer whale,

群れとなれば 話は別だ

but it can seldom escape a pod.

残酷に見えるだろうが

This hunt may seem cruel,

これは親から子へ 受け継がれる―

but important life skills are being passed down the generations.

重要な生き抜く術だ

From killer whales to krill,

シャチも オキアミも

all life here ultimately depends upon Antarctica's sea ice.

ここの生物はすべて 南極の海氷に依存している

The seas that surround Antarctica are the roughest on our planet.

南極海は地球で 最も過酷な環境だ

These churning waters draw up nutrients from the deep

この渦を巻く海は海底から 栄養分を浮上させ

and create vast, rich fishing grounds for nomads like the wandering albatross.

アホウドリなどの放浪者に―

Beneath the waves, currents are flowing away from Antarctica,

またとない豊かな漁場を 提供する

transporting nutrients across the planet, fertilizing the oceans

海面下では 南極大陸からの海流が

and helping to regulate global temperatures.

栄養分を地球の全ての 海へと運び―

The island of South Georgia.

地球温暖化も防いでいる

It's far enough north

サウスジョージア島

to be beyond the reach of the sea ice even in midwinter,

南極からずっと北の この場所には―

and many animals live here the year round.

真冬でも海氷はない

This wandering albatross chick has been sitting on its nest all winter,

一年中 多くの生物が生息する

and is entirely dependent on its parents returning with food.

このアホウドリのヒナは 冬の間 巣で暮らし―

It may have to wait a few days between meals, or even a couple of weeks,

両親が運んでくる食べ物に 完全に依存している

but at least it's not the only one who's waiting.

次の餌にありつけるのは 数日後か 数週間後か

Albatross chicks need to spend a whole year growing

少なくとも 友達と一緒だ

before they're ready to take their first flight.

アホウドリのヒナは 飛ぶまでに１年かかる

And then they spend several years at sea before they return to land.

その後 数年海で過ごし ふたたび陸へ戻る

[honking]

３メートルの大きな羽で 着陸するには練習が要る

Coming in to land  on three-meter wings takes some practice.

スローダウンする術がない

Albatross don't have reverse thrusters.

このメス鳥の 初めてのヒナだ

[chirping]

生後半年 あと半年で巣立ちだ

The chick  is this female's first.

このヒナは小ぶりだ

She's been raising it for six months, and has another six to go.

父親が餌を 運んでこなかった証だ

Her chick is smaller than it should be,

父親が死んでしまった 可能性もある

a sign that her mate has not been returning with food.

釣り糸に絡まり死んだ 仲間のように

He may well have been one of the many that die,

サウスジョージア島は 子育てに最適だが―

entangled on longline fishing lines.

巣に戻ってくる 成鳥の数は減っている

South Georgia is an ideal place for wanderers to raise their young,

近年―

but now fewer adults are returning here to nest,

子育てをする個体数は ４割減少した

and in recent years,

現時点では 巣で待つヒナは安全だ

the breeding population has declined by 40 percent.

餌にしようと狙う敵もいない

For now, waiting on its nest, the chick is safe.

しかしサウスジョージアの 海は違う

There are no land predators here.

海氷のないこの海では 真昆布が繁殖する

But the same cannot be said for South Georgia's seas.

待ち伏せにうってつけだ

Giant kelp flourishes in these ice-free waters.

ヒョウアザラシは―

The perfect place for an ambush.

極寒の南極海を逃れ ここで冬を越す

Leopard seals overwinter here to escape Antarctica's frozen ocean.

いつもなら―

They should have returned south by now,

すでに南極に戻っている頃だ

but this year they've stayed longer.

彼らが長居する理由がある

And they've delayed their departure for good reason.

キングペンギンだ

There are king penguins here.

捕まえることができれば―

Each is a substantial meal,

ごちそうだ

if you can catch it.

ヒナに餌を持って帰るため

Returning to feed their chicks,

ペンギンは危険をおかす

the kings have no choice but to run the gauntlet.

彼らが水面を泳ぐのは 稀まれだ

Kings rarely porpoise like this.

疲れるが この泳法が一番早い

It uses more energy, but it's faster than traveling underwater.

カオスの中で獲物を １匹選ぶのは難しい

It's hard to select a moving target in a panicking crowd,

１匹だけはぐれれば 風向きが変わる

but if there are stragglers, the odds change.

鋭い歯とくちばし攻撃の戦い

Razor-sharp teeth versus a stabbing beak.

休戦

It's stalemate.

戦いの後で両者ぐったりだ

Both are exhausted after the chase.

戦う価値はないと アザラシが諦めた

The hunter decides that the meal is not worth the fight.

間一髪だった

[cawing]

あれは食料を持ち帰るための 第一関門に過ぎない

For the penguin, it was too close for comfort,

陸上にも敵はいる

but that was just the first hurdle in getting back to feed its chick.

今日のメニューには ペンギンがないらしい

[cawing]

眠っているなら それに越したことはない

It isn't going to be  a walk in the park.

メスのゾウアザラシは 昼寝の邪魔をされてイライラ

[elephant seals snoring]

でも 気をつけるべきは ４トンのオスだ

Luckily, penguin is not on their menu.

メスに近づくと激怒する

Still, it's best to let sleeping giants lie.

怒った巨体の下敷きに なるのはゴメンだ

[penguin honks]

逃げ道は？

Elephant seal females  don't take kindly

走れ！

to being disturbed from their slumber,

ようやくヒナのもとに…

but it's the four-tonne males you need to look out for.

ここで最後の関門だ

[rasping grunting]

50万羽の中から我が子を 見つけなければ…

They are fighting for access to the females.

我が子を呼ぶ…

Getting bulldozed under angry blubber is to be avoided at all costs.

そして 聞き覚えのある 声を待つ

An escape route.

群れの外れに―

Time to run for it.

行ってしまったかも…

At last, he's reached the nursery.

ヒナの問題はこれ

Now comes his final challenge.

一箇所にとどまらない

Finding his chick in the crowd of half a million.

この喧騒の中で 親子は相手の声が分かる

He calls...

この食事のために 親がくぐった試練を―

[cawing]

子は知らない

...and listens  for a recognizable reply.

こんな小さな島なのに―

[chirping]

脅威的な数の生物を 養っている

His chick could be another mile or two away,

南極周辺で繁殖する オキアミに―

at the back of the colony.

ここのすべての生物が 究極的に頼っている

But that's the trouble with chicks.

海氷の消失はこの島の未来に 影を落としている

They're never where you left them.

その裏側にある北極では

Astonishingly, in all this racket,

気候変動の影響が さらに大きい

a parent and its chick can recognize each other's calls.

北極は海に囲まれた 大陸ではない

[chirping]

陸に囲まれた 凍った海だ

The things parents go through to deliver a meal.

ここでは春でも 海氷が永遠に広がる

If only they knew.

氷の大地は広大で頑丈なため 地上最大の肉食動物も安心だ

For such a small island,

オスの北極グマが 獲物を探している

South Georgia supports an extraordinary quantity of life.

ここはスヴァールバル諸島の 凍ったフィヨルド

All these creatures ultimately depend on the krill

狙いは食べごたえのある アザラシだ

that develops under the sea ice around the Antarctic peninsula.

猟場が溶けてなくなる前に―

With sea ice disappearing,

１年で食べる量の３分の２を 食べなければならない

so South Georgia's future is far from certain.

ワモンアザラシの母親は 子供を陸に置いて 海に入る

At the other end of the planet, in the north,

かつては 氷の峰に穴を掘り 子供を隠したが―

the effects of climate change are being felt even more intensely.

今では氷になる時期が遅く 大地は平らだ

The Arctic is not a continent surrounded by sea

子供を隠す場所もなく 海に潜るしかない

but a frozen ocean ringed by land.

この変化は現時点では 北極グマに有利かも知れない

Here, in spring, the sea ice is still at its maximum extent.

しかし 長期的には

It's a vast, firm hunting ground for the planet's largest land carnivore.

主食であるアザラシの数は 減少してしまうだろう

A male polar bear in search of his next meal

最近平らになった大地は 北極グマにも都合が悪い

on the frozen fjords of Svalbard in the high Arctic.

アザラシに 忍び寄ることができない

He's looking for seals, which make up the bulk of his diet.

子連れならば なおさらだ

He must eat two-thirds of the food he needs for the whole year

子グマがアザラシに 近づこうとしても―

before the ice melts and his hunting platform disappears.

慎重さに欠ける

The ringed seal mother had no choice but to leave her pup alone on the surface.

穴に隠れるアザラシが減り―

In the past, she would have built a den inside a ridge on the ice,

かつては役に立った スキルも使えない

but now the sea freezes so late that the ice is flat,

アザラシの穴について 学んだから良しとしよう

and she had to leave her pup out in the open.

狩りには曇りが 絶好であることを―

These changes in the ice may benefit the bears for now,

母は知っている

but in the long term,

母が真剣な時を子は知ってる

a crash in their most important prey will follow.

大人のアザラシの方が 食料として好ましい

This new, flatter ice makes life difficult for the bears, too.

子グマは母の計画を 台無しにしないよう―

There's nowhere for them to hide in order to creep up on a seal.

慎重に跡をついていく

And for a mother with a young cub in tow, being stealthy isn't easy.

ここからの進み方が重要

The cub doesn't yet appreciate the need for care

息の合った行動が大切だ

when sneaking up on a seal.

アザラシ狩りの成功率は低い

With fewer seals hiding in dens,

次の獲物を見つけなければ

learning this pounding technique, once so useful,

子グマが母から離れた時―

is now almost pointless.

別の機会が訪れた

Still, at least he's discovered what a seal hole looks like..

アザラシの子供が一頭でいる

His mother knows that overcast conditions are good for hunting,