Our Changing Planet

Four and a half billion years old.

An astonishing planet.

We know it's changing -

faster now than at any other time in human history.

But do we understand exactly what the future holds?

Over the next seven years, this ambitious series will chart

the health of six of our planet's most vulnerable habitats

through a time of great change for our natural world.

From Iceland's frozen wilderness...

..to the rainforests of Cambodia.

These habitats have been chosen

because they're changing at breakneck speed.

In seven years' time, life here could be very different.

I'm one of six presenters who will witness first hand

the scale of the transformations ahead.

We're going to be following the scientists and local communities,

each working hard to find solutions and to make a difference.

And we'll follow animals learning to adapt

over these next seven critical years.

I'm in California, on the front line of climate change,

to find out how wildlife and people are being impacted.

I'm standing on a glacier in Iceland.

Witnessing the devastating effect of global warming.

This is Kenya.

Now, it's supposed to be the wet season,

but it's as dry as a bone.

I'm in Brazil to find out how deforestation is threatening

the largest tropical wetland anywhere on Earth.

I'm in Cambodia.

Home to one of the fastest growing economies on the planet.

Uncovering the hidden cost of economic development.

I'm here in the Maldives, in the Indian Ocean,

which is a place in immediate and present danger

from the effects of climate change.

Together, we hope to better understand the future

for our changing planet.

Nestled in the heart of the Indian Ocean,

the Maldives is far more than just white sands and palm trees.

Beneath the waves...

..lies a world of wonder.

Nowhere is life in the ocean more complex, or colourful,

than our coral reefs.

And this is one the greatest coral reef systems on the planet.

The coral reefs here are a biodiversity hot spot

and one of the natural wonders of our world.

But there's trouble in paradise.

Change here in the Indian Ocean is not just something far off

in the future. It's something that's already happening.

Ocean warming is killing coral reefs at an astonishing rate.

We've already lost half of our reefs.

And without action, it's predicted that over 70%

of the world's remaining reefs will be damaged by ocean warming

and acidification by the end of this decade.

With the Indian Ocean heating quicker than anywhere else

in the tropics, the reefs surrounding the Maldives

are set to see some of the most dramatic changes.

We're here to find out what effects that will have on the wildlife

that relies on the reef.

Animals come to reefs for a range of reasons,

one of which is food.

The more varied the food offering, the more varied the visitors.

For scientists here in the Maldives, one of the clearest markers

of a thriving reef is the presence of these - manta rays.

These reefs support the greatest concentration

of reef mantas on Earth,

making it the ideal place to study these giants.

This boat is a floating base camp for the Manta Trust.

They're at the cutting edge of manta ray science and conservation.

Right here in the Maldives is their most important study site.

This international team of marine biologists will be studying

changes in the Maldives' manta population.

Niv Froman is a project leader.

Manta rays heavily rely on coral reefs.

Coral reefs is where food is produced.

Because manta rays rely heavily on what the reef generates,

they can be used as an indicator of how healthy the reef is.

Despite being one of the bigger animals in the ocean,

they feed on one of the smallest - plankton.

Billions of tiny plants and animals, including baby corals,

that form the base of the ocean food chain.

Plankton is abundant because of coral reefs -

that generates that productivity that the mantas rely on.

Researcher Hannah Moloney is investigating the impact

rising sea temperatures will have on the mantas' food supply

in the coming years.

So, you've created a PhD topic that involves you

swimming alongside mantas all day, every day. Tough break!

What is it you're hoping to find out?

What evidence are you hoping to gather from this study?

Even the smallest amount of sea level temperature rise

is predicted to have more than 50% of a decline

in zoo plankton biomass in tropical regions worldwide.

And with these changes in the smallest animals in the ocean,

it's going to have an impact on manta rays here in Maldives.

So, we're going to swim beside the manta rays

and actually collect some of the food that they're feeding on.

Manta rays are solitary animals.

However, they can be seen feeding with friends,

and this is a strategy to be able to get the most amount of plankton

in the shortest amount of time.

So, basically, lazy feeding.

It's like picking apples from a tree compared to

going to a buffet dinner.

To understand how changes in their food supply affect the mantas,

first we need to work out how much plankton they're eating and where.

And a remote inlet, called Hanifaru Bay,

just happens to be their favourite dining spot.

When you look out to the blue, you can see the dark shape of wing tips

carving the surface from the mantas beneath.

Right here, right now is probably the best place on the planet

for a wildlife encounter that has to be seen to be believed.

Weighing as much as a buffalo,

these graceful giants eat around five kilos of plankton a day,

carefully funnelling it through their paddle-like head fins.

Although they look like flying carpets,

they're actually one of the smartest fish in the sea.

Their large brains enable them to create mental maps

of the reefs around the Maldives

and hold long term memories of the best feeding spots.

Oh...

There is nothing quite like diving with manta rays.

It is a deeply emotional experience,

something that really hits you in the heart.

But these iconic ocean animals - like whales and dolphins

and sharks and mantas -

they're incredibly important to ocean ecosystems,

and they can tell us so much about their health.

Initial analysis reveals the plankton here

is exceptionally rich in nutrients.

Over the next seven years, Hannah will be able to show

exactly how the quantity and quality changes as temperatures rise.

The more we understand about where the mantas are feeding,

what they're feeding on, how they're feeding,

the more we'll be able to protect these gentle giants into the future.

The manta population here is currently stable,

but as their food supply declines over the coming years,

Niv predicts it'll have a big impact on the next generation.

He's already noticed the reproductive rate of these mantas

is a third of that of populations in Hawaii and Mozambique.

To help ensure they keep breeding,

he's become something of a manta gynaecologist.

That is some fancy looking kit, Niv. What is all this?

We're using this equipment to take ultrasound examinations of manta rays.

Mantas have very slow growth rates.

Here in the Maldives, actually, they only reproduce once every five

to seven years, and gestation lasts 12 and a half months.

You don't have to take many mantas out to have

a big impact on the population.

Absolutely, and that's why issues like climate change

can really drive the species quickly to extinction.

Understanding how well the populations are doing,

how often they are reproducing,

we can then determine how well our reefs are, also.

Do you have a business card saying "Manta midwife"?

If not... I don't, but I probably should get one made.

You definitely should!

Once in the water, we head to a popular manta cleaning station

and cross our fingers.

Here one comes.

We have a manta!

Look at that.

Niv's heading in with the ultrasound.

I think he's got it.

That is insane.

I can't believe I've just seen a manta midwife in action!

I think that may just be the coolest bit of science I've ever seen.

While he processes our images,

Niv shows me a future addition to the reef.

Niv, when I first heard that you were going to try

and scan a moving manta, I have to admit,

I was sceptical, but you nailed it.

So, what you are seeing here is a baby manta,

and it will come very clear in a moment.

Right there.

That's the baby. It's a pretty big baby, actually. Wow!

So, this marvellous, magical manta is an expectant mum.

It is. She is, yes.

That is just fantastic.

This is the most visual proof you could ever need

of how important these seas are to the mantas, right?

Absolutely. One pregnancy term is a huge investment.

So, it requires a lot of energy, requires a lot of food.

And that's why with climate change - and the reduction in nutrients

and plankton availability - the animals will be weaker

and will not have enough energy to invest in reproduction.

They might decide to skip a reproductive year

until food is abundant enough.

So, understanding what factors affect their ability to reproduce

might allow us to then mitigate those negative effects.

So that's why the work you're doing here is so important.

This is the most important time of their entire life cycle,

and they're relying on these reefs.

Lose the reefs, and they have a very uncertain future.

Exactly.

Niv has confirmed that the manta we scanned is pregnant.

Such great news for this manta population.

These pregnant females tell us the reefs here are still producing

enough food to sustain mothers and their growing pups.

But if plankton concentrations halve, as predicted,

mantas in the Maldives could be in serious trouble.