[static crackling] [static crackling]
[indistinct muffled radio chatter]
[David Attenborough] Just 50 years ago,
we finally ventured to the moon.
For the very first time, we look back at our own planet.
Since then, the human population has more than doubled.
This series will celebrate the natural wonders that remain,
and reveal what we must preserve
to ensure people and nature thrive.
When human beings built their first settlements
some 10,000 years ago,
the world around them,
on the land and in the sea,
was full of life.
For generations, this stable Eden nurtured our growing civilizations.
But now, in the space of just one human lifetime,
all that has changed.
In the last 50 years,
wildlife populations have, on average, declined by 60 percent.
For the first time in human history,
the stability of nature can no longer be taken for granted.
[ice cracking]
But the natural world is resilient.
Great riches still remain.
And with our help, the planet can recover.
Never has it been more important to understand how the natural world works,
and how to help it.
[birds calling]
[waves crashing]
Wildlife still flourishes in astonishing numbers
in a few precious places.
Along the Peruvian coast of South America,
seabirds congregate in colonies millions strong.
They come here to breed.
[birds calling]
Every morning, the birds leave their colonies
to fish in one of the richest seas on Earth.
It is an astonishing daily migration
of five million birds.
The huge flocks of cormorants and boobies are all seeking one thing:
anchovies.
[water rushing]
The boobies carpet-bomb the shoals.
More and more birds join the feeding frenzy.
[water splashing]
[classical music score plays]
All in this immense assembly are here
because a powerful oceanic current, the Humboldt,
sweeps up from the Antarctic,
bringing with it rich nutrients from the ocean's depths.
90 percent of the life in the oceans
is found in the shallow seas close to the coast.
Away from the land,
the seas, for the most part, are a blue desert.
But even these distant waters may be enriched
by a most unexpected connection to the land.
Some deserts,
often hundreds of kilometers from the ocean,
provide the raw materials for life.
[wind blowing]
Every year, winds sweep up two billion tons of dust into the sky.
At least a quarter of it eventually falls on the sea,
providing nutrients needed by the microscopic organisms
that are the foundations of ocean life.
[water splashing]
Dolphins explore the vast, open ocean
in search of the riches that distant deserts may have nourished.
[dolphins spouting]
A shoal of mackerel has discovered a swarm of krill...
the small crustaceans
that feed on the ocean's floating microscopic plants.
But the mackerel themselves are food for the dolphins.
[dolphins whistling]
[water rushing]
They drive the mackerel towards the surface,
and into the range of birds.
Shearwaters.
The wings that normally propel the birds through the air
now drive them six meters down through the water.
[water rushing]
Whilst the birds pick off the top of the shoal...
the dolphins attack the underside.
[water rushing]
[dolphins whistling]
[water rushing]
After 20 minutes of feasting,
the predators from both the sea and the air
have had their fill.
The stability of life on our planet
relies on such connections between different habitats.
Water evaporating from the surface of the sea
condenses to form great clouds.
And these eventually release the fresh water as rain.
But these life-giving rains are not evenly spread over the land.
This vast salt pan in Africa
is all that remains of an ancient lake.
It's totally waterless and oven-hot.
Few places on the land are more hostile to life.
A few tracks cross it, made by animals searching unsuccessfully for water.
[snorting]
But very occasionally, this whole landscape is transformed.
[thunder rumbling]
[thunderclap]
A huge deluge drenches the salt pan.
[rain pouring]
[thunder rumbling]
Triggered by some unknown signal,
flocks of lesser flamingos arrive from thousands of kilometers away.
The algae that the flamingos feed on
have lain dormant as spores in the dust.
But most importantly,
the birds are here to breed.
Perfect conditions might occur only once in a decade.
[flamingos squawking]
The birds nest on an island far from the shore.
[mud splashing]
They build mounds of mud that raise up their eggs
and so keep them just marginally cooler than they would be at ground level.
[flamingos chattering]
The water surrounding the island is so salty
that predators do not venture into it.
So the nests are safe.
[squawking]
Thirty days later, thousands of chicks start to hatch.
But there is no shelter from the scorching sun.
The water that once surrounded their island, protecting them,
has now dried up altogether.
[cheeping]
The last to hatch step out into a desperately harsh world.
-[chicks cheeping] -[squawking]
[squawking]
Somehow or other, the growing chicks must find fresh water to drink.
-[cheeping] -[squawking]
They cannot yet fly, so they must walk, guided by some of the adults.
They may have to trek for 50 kilometers.
[frenzied cheeping and squawking]
Some... cannot keep up.
The salt has solidified around their legs.
[cheeps]
-[squawking] -[splashing]
Most of the chicks, in spite of everything,
and having walked for days,
eventually reach fresh water.
[frenzied squawking]
It is the end of a long journey...
but only the first of the trials that will be imposed on these flamingos
by the irregularity of the rains.
-[rainfall] -[snorting]
If rainfall is more predictable and certain,
then life can flourish more richly,
both in numbers and variety.
The Serengeti plains in East Africa support over a million wildebeest.
[grunting]
The herds follow the seasonal rains,
grazing on the newly-sprouting grass that comes in their wake.
[grunting continues]
Each year, within a three-week period,
the females give birth to over a quarter of a million calves.
[bleating]
This youngster is just a few days old.
Playing strengthens its legs for the long journey that lies ahead.
[grunting]
The calf must stay close to its mother.
Without her milk, it would starve.
-[snorting] -[grunting]
And the herds are always traveling,
following the rains as they drift across the plains
in order to find fresh grazing.
Eventually, they reach woodlands.
[birds chirping]
[grunting]
Hunting dogs.
Wildebeest calves are a favorite prey.
And the dogs are hungry.
The calf must stay with its mother, protected within the herd.
[wildebeest snorting]
The dogs have incredible stamina...
but the calf is defended by the herd.
They need the calf on its own.
[snorting]
[hyenas panting]
The mother blocks the dogs, shielding her calf.
It makes a run for safety.
And it just manages to get back to the herd.
The future of this whole migration depends on the regularity of the rains,
but also on the continued existence of the great open grasslands
across which the herds make their immense journeys.
-[insects chittering] -[birds calling]
In places where rains fall abundantly throughout the year, forests grow,
and in the warmth of the tropics,
they support an unparalleled richness of life.
[overlapping animal vocalizations]
Half of all the species of land-living animals
live in these stable worlds.
[bird whistling]
The sheer diversity is breathtaking.
We still have not catalogued
all the species that live in the tropical forests.
The relationships between them all are multitudinous and complex.
[wings buzzing]
Plants often depend on animals to pollinate their flowers.
And these intimate connections
are just as important as the great global ones.
[buzzing]
These are traps.
Flowers shaped like buckets,
produced by an orchid.
[buzzing]
Each red bucket is filled with an oily liquid that drips from above.
Male orchid bees need a rich perfume with which to impress their females,
and the orchids provide it.
But the bucket is slippery,
and the liquid into which the bee has fallen is sticky.
The only way to get out
is through a narrow tunnel.
As it emerges, the bee is gripped tight.
And that gives enough time for the plant
to glue pollen sacs on the bee's back.
So the orchid has its pollen taken to another plant...
and the bee is rewarded with a perfume,
with which, when it recovers its strength,
it can woo a female.
[water crashing]
There are no pronounced seasons in a rainforest.
It produces food in one form or another the year round.
It's so rich that the females of some birds
are able to raise their young entirely by themselves,
and that allows the males to spend their whole time attracting females...
[cheeps]
...as manakins do.
There are over 50 different species,
each with its own highly elaborate dance routine.
[cheeps]
The golden-collared manakin
starts by clearing his dance floor.
[cheeps]
A female arrives and he starts his routine,
rocketing from one perch to another.
[fluttering]
[cheeping]
She checks out every detail.
Finally, he performs his signature move.
[tweets]
The back-flip...
[calls]
...with twist.
[calls]
Perfection.
-[cheeps] -[whir of wings]
The red-capped manakin has a very different act.
[cheeps]
It's a kind of slither.
[cheeps]
[feet pattering]
[cheeps]
With wing snaps.
[snap]
[calls]
-[cheep] -[snap]
[wings snapping]
But it doesn't seem to be working.
[cheeps] [tweets]
[wings snapping]
She's seen enough.
[chirruping]
The most complex routine is that developed by the blue manakin.
The lead male is supported by three junior dancers.
[calling]
They practice together almost every day.
During rehearsals,
a young male in juvenile plumage stands in for the female.
[twittering]
The dance has to be perfectly synchronized.
[high-pitched tweets]
[chirrups]
With the lead male happy...
they're ready to present their dance to a female.
-[calling] -[fluttering]
In a carousel of movements, each male takes his turn at the front.
-[calling] -[fluttering]
The lead male performs the final move.
[high-pitched tweets]
Have they done enough?
What's her decision?
[chirruping]
It's...
a yes!
A great team effort.
[chirruping]
Tropical forests cover only seven percent of the planet's lands.
Away from the tropics, where the weather is seasonal and cooler,
they're very different.
The greatest of all is the boreal forest
that extends right across North America and Eurasia.
It cannot grow during the frigid grip of winter.
The forests are a crucial refuge
for the relatively few species that are able to survive here.
[wind howls] As winter approaches,
caribou grazing on the open tundra to the north
head south to the forest to seek food and shelter.
Out here, temperatures may fall below minus 40 degrees centigrade.
The forest will give some protection from the worst of the weather.
But now the caribou are not traveling alone.
Wolves.
They live in the forest year-round.
And in the winter, they specialize in hunting caribou.
They must find the freshest tracks.
They move fast by avoiding the deep snow,
sticking to the hard-packed trails made by the caribou.
This wolf has found fresh scent.
The caribou must be close.
The herd chooses to stop to rest on a frozen lake.
Out in the open, they will be able to spot approaching danger.
[faint grunting]
And sure enough, the wolves catch up.
[caribou bleating]
They start to test the caribou,
probing for any weakness.
[rapid bleating]
Out on the open lake,
the caribou can outrun the wolves...
so the wolves drive them back into the forest.
Here, in the deep snow, progress is much harder and slower.
[bleating]
And, hidden by the trees, the wolves can get closer.
The hunt is on.
[bleating]
[snorting]
[bleating]
The pack must decide which particular caribou to target
and which trail to take.
As the caribou scatter,
the leading wolf takes a wrong turn.
It's a crucial mistake, and the wolves abandon the chase.
With the coming of spring, the caribou will head north once more,
leaving the wolves and the forest behind.
They will travel 600 kilometers, crossing mountains to reach the tundra,
where the spring grass will be sprouting again,
and they can give birth.
But these migrations are a shadow of what they once were.
The herd has lost nearly 70 percent of its numbers
in the last 20 years.
Their world and all of our planet is now changing fast.
At the furthest polar extremes
lie the frozen wildernesses of Antarctica and the Arctic.
Though they may seem remote to many of us,
the stability of these icy wastes is crucial to all life on the planet.
But in just 70 years, things have changed at a frightening pace.
The polar regions are warming faster than any other part of the planet.
The Arctic in the north is a frozen ocean,
and the sea ice, on which all life here depends,
is disappearing.
[panting]
Polar bears
specialize in hunting seals out on the frozen ocean.
But that world is now, literally, melting beneath their feet.
The sea ice breaks up every year,
but now this is happening earlier,
and the bears' limited hunting season is getting shorter.
This is already having a profound impact.
[gentle snorting]
Cubs are growing up underweight, which reduces their chances of survival.
[snuffling]
Within the lifetime of these cubs,
the Arctic in summer could be largely free of sea ice.
[gentle snorting]
It's not just the sea ice that is vanishing.
The ice that lies on land is also changing fast.
This is Greenland,
a vast expanse of ice one-fifth the size of the United States.
This glacial ice, together with the sea ice,
protects our planet by reflecting solar radiation away from the surface
and so preventing the Earth from overheating. But the Arctic is warming dramatically.
The leading edge of the Store Glacier may appear to be motionless,
but glaciers can move at up to 45 meters a day.
[ice rumbling]
Where this one meets the sea, it towers 100 meters above the water,
and continues downward for another 400 meters
beneath the surface.
[ice cracking]
[waves rushing]
Over the last 20 years, Greenland has been losing ice.
And the rate of loss is accelerating.
[ice rumbling]
[crashing]
These massive icefalls from the top of the glacier
are just the beginnings
of a far greater event.
[icefalls crashing in distance]
A stretch of the front face of the glacier over a kilometer long
is starting to break away.
[ice rumbling]
[ice crashing]
From 400 meters beneath the surface,
the hidden ice is surging upwards.
[waves rushing]
[crashing]
The breakaway of an iceberg the size of a skyscraper
generates a colossal tidal wave.
[wave rushing]
-[crashing] -[rumbling]
[classical music score plays]
Within 20 minutes, 75 million tons of ice break free.
Glaciers have always released ice into the ocean,
but now this is happening nearly twice as fast
as it did ten years ago.
Around the world, ice is now feeding vast amounts of fresh water into the sea,
raising sea levels, changing salinity, and disrupting ocean currents.
Without the Humboldt Current, the coast of Peru would fall silent.
The seabird spectacle would be no more.
All across our planet, crucial connections are being disrupted.
The stability that we and all life relies upon is being lost.
What we do in the next 20 years
will determine the future for all life on Earth.
The rest of this series will explore the planet's most important habitats,
and celebrate the life they still support.
We will reveal what must be preserved
if we are to ensure a future where humans and nature can thrive.
Please visit ourplanet.com to find out how our planet can thrive again.
[Ellie Goulding: "In This Together"]
♪ I can hear the whole world Singing together ♪
♪ I can hear the whole world say "It's now or never" ♪
♪ 'Cause it's not too late If we change our ways ♪
♪ And connect the dots to our problems ♪
♪ I can hear the whole world say "We're in this together" ♪
♪ We're in this together ♪