A Year on Planet Earth (2022-…): Season 1, Episode 3 - Summer - full transcript

The sun.

93 million miles away...

..but powerful enough
to blast our planet

with the energy of five million
nuclear bombs every day.

As we journey around it,

it fuels extraordinary change...

..and transforms the lives...

..of all it shines upon.

Now, as we enter our summer,

we begin to feel its full force.

By June, we are already
half way through the annual orbit,



and the North Pole
is basking in 24-hour sunlight

while the South
is frozen in 24-hour darkness.

But things aren't so simple
as hot and cold.

Over the next three months,

while some race to make the most
of the time of plenty...

..others will be pushed
to the very limits of survival.

And as our planet
gets ever hotter...

..the sun can forge hell on earth.

Filmed in more than 60 locations
around the globe,

this series reveals a year on Earth
as never seen before.

And it's from June to August...

..when the world
is at its most extreme...

..that many animals
face their greatest challenges yet.

The sun is not only the architect
of the seasons,



it's also the fundamental fuel
for almost all of life.

And to tap into the sun's bounty,

life will go
to extraordinary lengths,

and indeed...

heights.

These sequoias, or giant redwoods,

are the most massive trees on Earth

and can reach up to 80m tall.

Or they can weigh
more than 20 blue whales.

That's almost more than me.

At that height, there is
no competition for the sunlight.

And in June,
they're absorbing more energy

than at any other time of year.

A similar story is playing out
across the Northern Hemisphere.

Where the sun blazes directly
overhead,

it triggers phenomenal growth.

These aren't trees.

They are the world's tallest grass.

Bamboo.

It can grow up to 3ft a day
during summer.

So, this is a pretty good time
to be an animal who eats...

almost nothing else.

The giant panda.

This cub wants to play
hide-and-seek.

But Mum's busy...

..making the most
of the seasonal feast.

Pandas give birth in summer...

..to coincide with the boom
in bamboo.

This cub is one of only
2,000 giant pandas in the world.

Now 11 months old,
he's become more of a toddler.

And such a handful
that Mum's only too happy

to let him go off on his own.

The urge to explore is only natural.

But if it all gets a little
too daunting...

..he can always escape
to higher ground.

We may not think of pandas
as tree-dwelling creatures...

..but it's believed
their black and white coats

provide camouflage
against the dark branches

and bright mountain skies.

Meanwhile, Mum's still eating.

Bamboo is so unnutritious

that she consumes around half her
body weight of the stuff every day.

Pandas have evolved a unique
thumb-like lump on their wrist

to better grip bamboo.

She spends 14 hours munching away.

Few things in life are more boring
than waiting for Mum.

Might as well get comfortable.

This could take a while.

Summer here is long.

And the bamboo will keep growing
until winter.

But further north...

..the productive season
only lasts a matter of weeks...

..and animals must make hay
whilst the sun shines.

This is a pika...

..a relative of the rabbit.

By June, her home
in Canada's Rocky Mountains

has just come into bloom.

But at 2,000 metres,

the growing season
is extremely brief.

Even now,
there's still snow on the slopes.

Pikas don't hibernate.

So, if she's going to have anything
to eat during the long winter...

..she'd better start storing now.

She makes up to 200 journeys between
here and the meadow each day.

But not everyone's
been quite so industrious.

This pika's hay pile
is woefully sparse.

But there are shortcuts,
if you're prepared to cheat.

He has to pick his moment.

Wait till the coast is clear.

Then steal
from his neighbour's stash.

Thieving saves time and energy.

But what goes around, comes around.

A ground squirrel is also trying
to cash in on the spoils of summer.

And the master thief's growing hay
pile has not gone unnoticed.

So, while the pika's out pilfering,
the squirrel helps himself.

How dare he?!

No honour among thieves.

During summer,

water in the Northern Hemisphere
heats up and evaporates.

Directly beneath the sun's path,
evaporation is so intense

it forms a band of rain
around the globe.

For the last six months, this band
has followed the sun northwards.

And in Africa...

..a legendary gathering
of animals...

..is hot on its heels.

This three-month-old zebra foal

has spent all of her short life
on the move.

And she's not alone.

There's a reason this is known
as the Great Migration.

Each June,
over a million wildebeest and zebra

follow the seasonal rains north
from the Serengeti in Tanzania...

..to the Masai Mara in Kenya.

They ravage the plains
like a giant plague of locusts.

The grass can't grow fast enough
to sustain such numbers...

so the herds keep moving.

It's the largest land migration of
animals anywhere on Earth.

Little legs have got to keep up.

Her mother knows she is safest
in the centre of the herd.

Each year, hundreds of thousands
will die on migration.

The young foal has only a 50% chance

of surviving her first year.

By June, the tropical rain band
is at its most northerly,

and now Southern Africa
is baking under cloudless skies.

As the dry season intensifies...

..life is defined
by an ever more desperate search

for water.

At six months old,
this elephant calf

is approaching its toughest test
yet.

They need to drink every two days,

but it may not rain here
for another four months.

The matriarch leads them
deeper into the desert.

She's built a mental map
of the landscape...

..and she knows it holds a secret.

Right in the middle of one
of the largest deserts on Earth

lies a true wonder of the world.

The Okavango Delta.

Rather than flow to the sea,

the Okavango River
carries rain from distant mountains

into this parched land...

..and transforms it
into a vast wetland paradise.

It's a lifeline
for all sorts of animals

at a time when they need it most.

These waters
allow 18,000 elephants to survive

here in the heart of the desert.

Snorkelling is turning out to be
more difficult than advertised.

Learning to swim together
will help the cousins bond.

They could be playmates
for another ten years,

until adulthood.

If they both make it that far.

For now, at least,

the delta provides a welcome break
from hardship.

June the 21st...

is the summer solstice.

For the plants and animals
of the Northern Hemisphere...

..the longest day of the year
brings light, warmth...

..and growth.

But in the Southern Hemisphere,
this day marks midwinter.

In the Southern Ocean,

isolated on this tiny island,

tens of thousands
of king penguin chicks...

..are enduring their darkest days.

It's been two months since this
chick's parents left to find food.

In all that time,
she hasn't eaten a thing.

All she can do
is wait for their return.

This seasonal famine leaves
her development frozen in time,

which is why king penguin chicks
take up to 13 months to fledge.

Longer than any other bird.

Parents are starting to return.

Many will have travelled over
a staggering 4,000 miles

from their winter feeding grounds
at the polar front.

Their bellies bulging with fish...

..ready to share
with their starving offspring.

The chick searches for her parents
among the new arrivals.

She can pick out
their individual call

amongst hundreds of thousands
of others.

But still nothing.

Each winter, half of king penguin
chicks starve to death

waiting for their parents.

She won't survive much longer.

Closer to the equator,

winter months
in the Southern Hemisphere

are not so much about extreme cold
as extreme drought.

North Australia is experiencing
a particularly punishing dry season.

This male hooded parrot

is not only one of the most
colourful birds of the outback...

..he's also one of the smartest.

He and his partner have found
the perfect place to keep cool.

A termite mound.

Built up to eight meters tall,

and expertly designed
to keep the heat out

and the moisture in.

Their chicks
are almost ready to fly the nest.

Just a few more meals of grass seeds
and they'll be off.

But there's something troubling
on the wind.

The tinder-dry grassland

is dangerously vulnerable
to bush fires.

Many of the plants contain flammable
oils, which supersize the inferno.

Bush fires can reach
more than 1,000 degrees Celsius,

destroying everything in their path.

The parents fly away
while there's still time.

The chicks have one last chance
to follow.

But now it's too late.

The winds carry something
equally deadly.

Fire hawks.

They follow bush fires,
picking off animals as they flee.

There's no escape.

Australia is ravaged
by more bush fires

than anywhere else in the world.

And as our planet warms,

they're increasing in frequency
and ferocity.

Fires can claim over a billion
animals in a single year.

But these clever parrots
have an advantage.

Termite mounds are fire-proof.

And this scene of desolation

is all the chicks need
to tempt them out.

The scorched grasses...

have dropped their seeds.

Far from a disaster...

..bush fires are an essential part
of the parrots' survival.

The winds
that fanned these flames...

..are the trade winds.

Huge air currents carried west
by the rotation of the Earth.

As they rush over the Indian Ocean,

their impact is even felt
beneath the waves.

The Maldives is dotted
with small coral reef islands,

home to thousands
of different species.

And this particular patch

is perfect for travellers
looking for a bit of a pampering.

It's a cleaning station...

..where creatures come to have dead
skin and parasites removed

by cleaner fish.

A new member of the service crew
has arrived.

He looks much like all the others.

But don't be fooled
by his cheeky grin.

This brilliant mimic
is a false cleaner fish.

Rather than clean...

..he bites chunks
out of fins and flesh.

But once bitten, twice shy.

He must wait till some new,
unsuspecting victims pass by.

Each summer,
the arrival of the trade winds

causes the currents beneath
the water to change direction.

Plankton arrives on the reef
like a blizzard.

And something gigantic
is right behind it.

A reef manta ray...

..with a four-metre wingspan.

And it's not the only one here.

By swimming in formation,

they catch plankton from the
slipstream of the manta in front.

As the leader turns,
they follow...

..creating what's known
as a feeding cyclone.

The downside
of swimming through this soup

is that it's also home
to drifting parasites.

Lucky there's a cleaning station
nearby.

For the trickster, this new arrival
is a huge opportunity.

He'd be wise not to bite too hard.

Mantas remember
good cleaning stations.

So, if he doesn't push his luck,

he'll have regular giant clients
for the rest of the summer.

But old habits

die hard.

As the trade winds
continue overhead...

..they pick up evaporated water
from the Indian Ocean...

..and carry it north.

Eventually, the moisture-laden winds
hit the Himalayas.

With their path blocked...

..the clouds build...

..creating the biggest weather event
of the year...

..the South Asian monsoon.

It stretches for 5,000 miles...

..drenching everything in its path.

In Southwest China,
the summer deluge

can dump almost a metre of rain
in a single month.

The same as the UK gets
in an entire year.

A toddler climbing in the rain.

What could possibly go wrong?

Now over a year old,
his confidence is growing.

But he still has a lot to learn.

Like what to eat.

Or what to wear.

And how to scratch
those hard-to-reach places.

But today's most important lesson...

..getting down
can be harder than climbing up.

Thankfully, Mum's still there...

..for moral support.

But she won't always be by his side.

So, the last summer days
spent together...

..are all the more special.

As the sun sets...

up above
a heavenly light show begins.

The annual Perseid meteor shower.

Tiny fragments of debris burn up
as they enter our atmosphere.

On clear August nights,
just look up...

..and you can see
as many as 100 shooting stars.

As long as you have an hour
to spare.

Some have more pressing matters.

For these migrating wildebeest
and zebra...

..this is the beginning
of the hardest day of their year.

Many won't survive
to see the sun set.

The zebra mother and foal
have endured months on the move.

But now,
a huge obstacle lies ahead.

The Mara River.

This is a day the crocodiles
have been waiting for.

Some may not have eaten
since the last migration a year ago.

Mum's been here before.

Best to hang back.

Let the wildebeest
make the first move.

Each August, the great migration

of wildebeest and zebra face
a terrifying obstacle.

The crocodile-infested Mara River.

Despite the risks,
everyone must cross.

Crocodiles aren't the only danger.

The Mara River
has a deceptive current.

Too much for short, tired legs.

The wildebeest mother tries to help.

But the flow is so strong...

it's hopeless.

She has no choice
but to abandon her calf...

..and save herself.

It's now or never for the zebras.

Staying close to Mum
is the safest way.

But the foal's lagging behind.

Her mother reaches the bank.

But she can't find a way out.

Life in the Great Migration
is a lottery.

These are the winners.

And this is their prize.

As the rain belt returns south,

it brings fresh grazing
for weary travellers.

The foal has put the most
challenging time of its life

behind it.

Further south,

some are still struggling.

It's been 150 days since
the penguin chick last ate.

She's lost 70% of her body weight,

and is too weak to go on.

And then,

there's one late arrival.

It's time to pick up a penguin.

When it's your first meal
in five months,

regurgitated fish slips down
a treat.

In a few months,
she'll follow the call of the ocean

and discover a world
where penguins can fly.

As our journey around the sun
enters a new phase,

there will be a shift in fortunes
across the globe.

Some will see a brighter tomorrow.

While others will have to face
their darkest fears.

Since the June solstice,

the sun has slowly
been creeping lower in the sky

until, in a few short weeks,

and for the first time
in six months,

it will illuminate
the Southern Hemisphere

more than the Northern.

The whole planet is building
to a season of intense change.

In autumn,
life has to be ready for anything.