♪ UMA THURMAN: Life.

The closer you look... ..the more mysterious it seems.

We can't see the invisible forces at work.

But what if we could?

It's time to look at our home... ..in a whole new way.

Imagine carbon cycling through nature.

It's one of the building blocks of life... ..and it's stored in our forests... ..oceans... ..and grasslands on an incredible scale.

But we've released too much of it into the atmosphere, risking our future.

We can halt emissions and draw the carbon back down.

And our best ally for that is nature.

Restoring it to abundance is the biggest challenge of our time.

But we CAN do it.

If the future of nature looked brighter, so could the future for us all.

Our ocean.

It's the greatest ecosystem on the planet.

♪ DAVE: Standing by.

COMMS: There might be a group going left to right.

- They just dove.

- Roger that.

Thanks.

UMA: Understanding how it works has never been so important.

- Over on the other side.

- Right by that black boat?

- Yeah, I can see dorsals.

- Yeah.

UMA: Because it's changing under the pressure of climate change.

It's getting hotter and hotter, without a doubt.

UMA: And life within the ocean affects the whole planet.

Humpback whales are ocean nomads.

It's estimated they can migrate over half a million miles in a lifetime.

(WHALES CALL) Each summer, Atlantic populations come to feed in Stellwagen Bank National Marine Sanctuary, where marine biologist Dr Dave Wiley and his team are ready to meet them.

There's a lot of activity, both commercial whale-watching boats and recreational boats.

So we have to work around them, but we're looking for a group of two or three.

UMA: Dave's team wants to know how climate change is affecting the humpbacks' feeding behavior.

To find out, they need to get much nearer to the whales.

You can't try to rush any of it.

That's why it takes sometimes, you know, long periods of time before we actually get close enough.

UMA: It's a waiting game.

There's going to be a lot of this during this trip.

After looking for whales and working on whales, eating is probably the next most common thing I do.

Such a good sandwich.

We're out here for like eight to ten hours at a time.

Of course, everybody gets hungry.

But we've noticed as soon as you start to snack, that's when the whales pop up.

(WHALE CALLS) - Oh!

- Look at that!

Whales coming up.

UMA: The scientists want to attach sensors to the whales to collect important data.

It's not an easy task to put tags on every animal in a group, but we've done it before and we're going to try to do it again.

Looks like the group's coming up over there at our one o'clock.

♪ I have 403 here.

The tags we're using are called DTAGs.

They're a really sophisticated tag that goes on with suction cups so it doesn't hurt the animals at all.

So basically with these tags, we know what the animals are doing with their body and we know any sounds they make or anything they're hearing.

And they're also equipped with GPS so when they come to the surface, they give us location.

So it's really a full suite of data.

(INDISTINCT DIRECTIONS) DAVE: OK. Mike's ready to tag, everybody.

Hold on.

TAMMY: Here we go.

(THEY CHEER) That was good.

That worked well.

It all comes together, it's perfect.

UMA: Some of the tags are fitted with cameras to see what the whales are doing.

DAVE: So we've got this great backlog of data that shows us what the ocean was like over the past 20 years, how it's changing right at this very minute.

And then as this project continues into the future, we'll know how the animals are behaving in an ocean that's going to be really quite different than the one they've been used to for the last... ..hundreds and hundreds and thousands of years.

UMA: And by deploying almost 300 tags since 2004, they've built a picture of their feeding behavior.

This gives the scientists an important reference, allowing them to see if anything unusual is happening.

Since the study began, the whales' feeding habits stayed fairly consistent... ..until this year, when Dave and his team noticed something different going on.

DAVE: The main prey item for almost everything in the Stellwagen Bank National Marine Sanctuary, and humpback whales in particular, are a little fish called sand lance.

They're maybe six inches long, as big around as your thumb, and they're here in really big numbers.

UMA: Sand lance normally stay at the surface, but this year they are keeping to the sea floor.

Dave thinks that rising ocean temperatures are causing the fish to hibernate early.

We haven't seen this before, so this is already a sign that the ocean is changing rapidly and in many ways drastically.

♪ UMA: What happens to whales matters, as they play an important role in the ocean.

So these animals are going down and they're feeding on the bottom, but they defecate at the surface.

They spread huge amounts of fertilizer all over the surface of the ocean, where the sunlight is also, so you get this combination of fertilizer and sunlight.

UMA: This creates the perfect conditions for a microscopic organism to flourish.

Phytoplankton.

Just like plants, they photosynthesize, absorbing carbon dioxide.

And when conditions are right, their numbers explode.

Carbon is now locked inside these giant blooms instead of in the atmosphere.

They can become so huge they are visible from space.

The more whales you have, the healthier the ocean is.

One of the really great things about humpback whales is how successful they've been in making a comeback from commercial whaling.

UMA: Some populations have recovered by as much as 90%.

If all the whales came back to fill the ocean, the future would be brighter.

DAVE: They're fertilizing the entire system so there's more life here that can hold lots more carbon and draw down carbon dioxide out of the atmosphere where we don't want it, and into this ecological world that we're looking at, which is exactly where we do want it.

UMA: But there's more to phytoplankton and the role they play in the carbon drawdown story.

♪ STEPHANIE: I wish more people knew about phytoplankton cos they really are the unsung heroes of life on our planet.

Dr Stephanie Henson is a phytoplankton expert at the National Oceanography Centre in England.

Hiya.

Here's a little sample.

Thank you.

So the bucket that we collected this morning of water probably contains more phytoplankton than the population of London or New York.

There's plenty of phytoplankton and zooplankton in there.

Oh, nice.

That's really great.

Oh, there's all sorts of stuff in there.

- Yeah.

- Really nice.

Great.

But of course, they're feeding the whole ocean, effectively.

They're the base of the marine food chain, and everything else in the ocean depends on them.

♪ UMA: Phytoplankton are eaten by tiny creatures called zooplankton.

And they in turn are eaten by larger predators.

STEPHANIE: If there weren't phytoplankton in the oceans, the marine food chain as we know it today would completely collapse.

UMA: As species eat each other, the carbon goes all the way to the top.

It's part of a process that scientists call the biological pump.

To understand its significance, we need to measure how much life there is in the ocean.

And that takes innovative thinking.

Marine ecologist Gael Mariani is crunching the numbers.

I know this code might look pretty boring, but in fact it reveals something really fascinating about fish, something we didn't even know about three or four years ago in science.

And this research reveals really new information about the role fish can play in transporting carbon into a safe place.

♪ So fish are able to store the carbon they eat in their own bodies.

And you might say, hang on, it's not a lot compared to a large species like some whales.

But it's biomass that matters.

How many fish there are.

UMA: By gathering data from the fisheries around the world, Gael's results give an astonishing picture of how ocean life helps us in the fight against climate change.

GAEL: So we've made some calculations, and we found out fish of commercial interest are able to draw down the equivalent to the annual emission of 50 million American citizens.

It's massive.

UMA: Fish numbers are far lower than they could be.

By taking them out of our ocean, we are reducing the power of the biological pump.

We can also work out how much carbon we've lost through fishing globally, and the numbers are quite remarkable.

We calculate industrial fisheries has reduced the carbon drawdown potential of fish of commercial interest by 50%.

UMA: As well as their carbon value, fish have a market value... ..and 60 million people around the world depend on the fishing industry.

(CONVERSATION IN FRENCH) So we really have to move toward a future where we change how we value fish.

Like this place just behind me, who really cares about how they source their produce.

♪ UMA: Most of the life we know in the ocean inhabits the surface layers.

It draws the carbon in.

But the deeper the carbon goes, the better it is for the planet.

The twilight zone is a vast part of the ocean.

It extends around the globe, from pole to pole, anywhere that the water's deep enough.

If you go into the ocean twilight zone, one of the most amazing things you'll see is the incredible what we call marine snowfall.

These tiny particles - microscopic organisms, debris of animals and plankton that have died and are drifting down slowly through the ocean.

And as it's falling, it's helping the ocean to draw that carbon away from the atmosphere.

♪ UMA: These deep, dark waters may seem lifeless.

But there are creatures here that look like they're from an alien world.

HEIDI: There are types of organisms that just look completely different than those species that we're used to seeing in the upper ocean.

Many are luminescent, so they sparkle like fireflies.

After many years of scientists slowly learning about the ocean twilight zone, we thought we had a pretty good idea how many fish might live there.

But recent methods using sonar have suggested that we may have been way off, and there may be ten times more fish than we previously thought.

♪ UMA: Researchers from the Woods Hole Oceanographic Institution are on a mission to recover an instrument that's been moored 1,800 feet down in the deep ocean.

Winch left.

Bottom depth is 2802.

UMA: It's been gathering information for the past two years, so should be full of scientific revelation.

ANDONE: So there's always a chance that something can go wrong during the recovery.

UMA: The research is led by oceanographer Dr Andone Lavery.

ANDONE: This is the mooring that's been out for two years.

We are looking at the acoustic sonars that are on the top of the...of the mooring.

There's a little bit of slime on it, but not a lot considering it's been down there for two years, so, uh, pretty exciting.

UMA: This giant acoustic ball sends pulses of sound through the water to paint a picture of what's happening in the dark.

ANDONE: We're interested in the fishes in the ocean twilight zone, and their migration from the deep waters down at about 600 or 700m of depth.

And as they come up to the surface at night to feed, we're interested in how much carbon they basically consume and draw down when they migrate back down to the deep ocean during the daylight hours.

We think that this is probably the largest migration on Earth, the largest movement of animals on this planet, which happens daily in this big wave around the ocean.

♪ UMA: We're only just discovering the secrets of the twilight zone... ..and its role in drawing carbon into the deep.

♪ I'm in a really slick area.

You got it?

Yeah.

OK. ZHAOZHONG: Finally get the data.

UMA: A simple USB stick holds the precious files.

ZHAOZHONG: All the data is here.

This is awesome.

6,000 files.

ANDONE: Could you put them up on the big screen?

ZHAOZHONG: Yeah.

ANDONE: The reason we use acoustics in the ocean to look at fishes instead of using cameras, is that you can see quite a long way with acoustics.

With a camera, you can only see fishes that are very close by.

And we use that sound and that really strong signal to count how many fish we're seeing, and to characterize what kinds of fishes they are.

♪ UMA: Studying this movement of life is a formidable task... ..but the team is making headway.

What we've learned about the Twilight Zone suggests that it may help the ocean draw down billions of metric tonnes of carbon every year.

As much as six times the carbon dioxide emitted by automobiles worldwide may be drawn down by the ocean with the Twilight Zone's help.

But it's very hard to study, and there's a lot of things that we still don't know about it.

UMA: The race is on to improve our understanding of the ocean.

But it's huge.

It covers 70% of our planet.

There's only one way to get a truly global picture of how it works.

♪ DR LAURA LORENZONI: The ocean is a challenging environment, which is one of the reasons why we don't know as much as we probably should about it.

UMA: Dr Laura Lorenzoni is a NASA scientist.

She's preparing for a historical rocket launch.

A mission that aims to see the ocean in a way that's impossible from Earth.

So important, the world will be watching.

LAURA: Right now, I'm getting ready because I'm going to be part of that broadcast tonight for our mission that we're launching to space.

This mission that we're launching is really going to help us understand that connection between the atmosphere and the ocean and that carbon drawdown.

What do I do?

Just stick it in my ear?

As this is my first broadcast, I am obviously a little nervous.

What time do we start?

JASMINE: You are looking live at Space Launch Complex-40 on Cape Canaveral Space Force Station.

It is such an honor to be here with all of you near and far and witness history in the making.

JASMINE: NASA has studied Earth's atmosphere in the past.

What is it that you hope to learn that you didn't already know?

LAURA: That is an excellent question.

So this mission is really going to be critical to nail down some of the gaps of information that we have in terms of carbon cycling.

We have a decent grasp on the physics of this carbon drawdown, but the one thing that we're not really 100% sure on is the biological part which is carried out by phytoplankton.

♪ This mission is going to be able to tell us what kind of plankton and what species, and some species are really important and can sequester a lot more carbon faster than other species.

LAUNCH COMMENTARY: Many on the PACE spacecraft team now going outside to watch this launch.

Getting down to the final seconds.

LAUNCH COMMENTARY: 15 seconds.

LAURA: This mission has been in the works for about two decades.

It has gone through the hands of many hundreds of scientists and engineers, enabling us to see the ocean in brand-new ways that we hadn't before.

LAUNCH COMMENTARY: Minus 10.

LAUNCH COMMENTARY: 10, 9, 8, 7, 6, 5, 4, 3, 2, 1.

Booster ignition, full power engines and liftoff of the Falcon 9 and PACE, helping keep pace with our ever-changing ocean and atmosphere.

♪ LAUNCH COMMENTARY: Stage one propulsion is now go.

UMA: With every orbit, this satellite will scan 30 million square miles of the Earth's surface... ..identifying different types of phytoplankton... ..and where the most carbon-rich expanses of ocean exist.

LAURA: This mission is really going to move us forwards.

Because of the new measurements that this mission is bringing, we have a lot of opportunities at our fingertips to try to mitigate some of the changes that our presence, our human presence, has induced on the planet.

LAUNCH COMMENTARY: We're about 10 seconds from the engine cut off.

♪ UMA: We can establish which parts of our ocean are most important for carbon drawdown.

♪ But they are often the most sensitive to climate change.

In the Southern Ocean, warming temperatures are affecting a very different kind of carbon system... ..one so important it's studied by scientists across the world.

♪ My name is Peter.

I'm a research director at the Flanders Marine Institute.

I'm an oceanographer.

♪ So the Southern Ocean is the most remote ocean of our planet.

Now, you can think about the Southern Ocean as a big lung.

It breathes in and breathes out carbon dioxide.

UMA: Atmospheric pressure pushes carbon dioxide into the ocean surface, a process called "the physical pump".

When it dissolves into the cold Antarctic waters, it sinks down deep... ..where it can be stored for thousands of years.

♪ We know today that the Southern Ocean is one of the most important carbon sinks on this planet, slowing down the rate of global warming this way, but what we do not really know is how this is changing, how this heat and this carbon uptake are changing over time, how variable they might be, and as climate change progresses, what we can expect in the near and far future.

UMA: There are few places on Earth more difficult to study than the Southern Ocean.

It's not for the faint-hearted.

But Peter knows someone who's always up for a challenge.

♪ Yeah, yeah, OK. Let's go.

UMA: Boris Herrmann is a professional yachtsman.

Woohoo!

Yeah, yeah.

Pause.

Yeah, I obviously love sailing and racing on the ocean.

That is my passion since my childhood, and it became my job.

I really feel at home on the ocean.

OK, let's have a look outside.

Sea state is OK. And full main!

Scientists need precise data about the exact CO2 concentration in the ocean surface.

This you cannot measure by satellites.

You need to go with some sort of vessel.

And there are no commercial ships here, no cruise ships, etc.

Here in the Southern Ocean, us racing sailors, we are the only ones.

UMA: Boris's boat gathers data as it sails.

BORIS: Here's the ocean lab.

So, basically, there's a big pump here.

I can...

If I put my hand on it, it's warm, I can feel it pumping and I can hear the water flowing through these tubes.

It comes from the keel, it goes through here and then goes back out into the sea.

So it permanently tracks water temperature, water salinity and, most importantly, the CO2 concentration.

UMA: With Boris's help, scientists will be able to assess how the Southern Ocean is changing.

And what's really remarkable about the data that Boris has collected is that he has collected data in places where we haven't... ..we've never, ever collected carbon dioxide measurements before.

I think the biggest gratitude for Boris might be that his data will be used for a very long time.

So every measurement that is taken today will not only be used tomorrow or in the next years, it will be actually used indefinitely.

BORIS: I'm very happy that we can use the attention we get around this sport to make people speak about climate solutions and hopefully inspire people around this topic and hopefully have a positive influence with this because we have no choice.

It's a race we must win.

♪ PETER: We shouldn't take it for granted, because if we don't protect those natural carbon sinks, may they be on land or in the ocean, we will not have this service in the future and will be a much bigger problem.

We want to keep a close eye on the climate system, how it behaves, how it changes, because there are so many things that we may not know, and so many changes that we might otherwise overlook, and so we want to understand our future we're heading to.

♪ UMA: Across the seas of the world, signs of what's in store are becoming more frequent.

♪ DR GIULIO BOCCALETTI: One of the great advantages of being here is that the Mediterranean is a laboratory for the world.

So the Mediterranean is undergoing remarkable changes.

Its temperature has never been hotter.

The last few years we've had extreme marine heat waves.

And so what we see when we look at the Mediterranean is a glimpse of the future for the rest of the planet.

♪ If we don't figure out how to stop the climate from changing more, if we don't figure out a way of drawing down carbon, if we don't find a way of working with nature, I don't know exactly what the future will look like, but this is the place where we will find out first.

UMA: The ocean draws down one-quarter of the 11 billion tonnes of carbon that we emit each year.

♪ Extreme temperatures are compromising this critical system.

Giulio's work models these effects to help us avoid the worst, and prepare for what is coming.

GIULIO: I actually think that nature has been trying really hard to help us.

Now, it can't do that by itself.

It can't solve all of our problems by itself.

We have to stop emitting, and we have to help nature do what it does.

♪ So the quest here is, can we transform that nature?

Can we power it up so that, while we stop emitting, it then helps us draw back down the stuff that we put up in the atmosphere in the first place?

♪ UMA: Restoring life in our ocean is a huge task.

It takes collaboration... ..determination... ..and innovation... ..and some brilliant projects are already under way.

40% of us live along the coastline...for good reason.

UMA: On this small island in Kenya, nature is still abundant.

♪ It's a favorite spot for local fisher Hassan Shee Yusuf.

What makes the catch so good here is the surrounding mangrove forest... ..an ecosystem of tangled roots that only exists where the land meets the sea.

UMA: Working alongside local fishers is marine biologist Mwanarusi Mwafrica.

What I love much about the mangrove forest is because this is an ecosystem that actually provided me with a job.

Like my daily bread, yeah!

Mangrove roots are very essential because they provide a safe haven for juvenile fish from being carried away by strong waves.

So the fact of having more trees, this means you're going to have more fish, more fish in the future.

♪ UMA: Mangrove forests grow along many tropical coastlines.

And when it comes to harnessing carbon dioxide, they are a superpower.

These are very magical trees because the services that they provide are quite diverse.

Mangroves are very efficient at drawing down carbon.

When we look at the capacity, it's almost seven to ten times compared to other terrestrial trees.

♪ UMA: The interaction between the trees, the tide and the mud creates a unique environment... ..that not only means mangroves can store more carbon per acre than any other type of forest on Earth... ..they keep it locked up for millennia.

♪ But many mangroves have been lost to deforestation and coastal development... ..including here in Kenya.

But the community here is now turning things around... ..through a new business venture.

MWANARUSI: So Vanga Blue Forest is part of a carbon-offsetting scheme.

So what happens is that individuals, companies, businesses come to offset with the project, in the essence that they are promoting conservation efforts as much as they are offsetting their own carbon emissions.

♪ UMA: If we fund nature now, these ecosystems will continue to draw down carbon long after our emissions have ceased.

Since the project started, over 4,000 mangrove seedlings have been planted.

MWANARUSI: Carbon drawdowns of Vanga mangrove forest are at 6,000 tonnes a year.

UMA: Carbon sales are also enriching the community.

The local school now has a science lab, and better facilities have helped its first student get to university.

MWANARUSI: What makes me to be very proud working at Vanga Blue Forest is the fact that I'm at the focal point of a change, the focal point of a movement that is growing globally, and that movement is changing the narrative of reversing climate change.

♪ UMA: Pioneering projects like this show how we can boost nature and carbon drawdown.

But to really transform our ocean, we need to work at scale, which requires even more investment.

♪ I'm Julie Robinson and I'm the Belize Program Director for the Nature Conservancy.

This story does not start in nature, it actually starts in a boardroom.

Belize had a long history of being indebted.

That actually became worse during the COVID-19 pandemic, and tourism came to a screeching halt.

And so, essentially, we were in an economic crisis, and we also had a debt payment looming.

UMA: But Julie and her team were working on a plan that was about to turn this crisis into an opportunity to invest in nature.

But I've spent way too much time in boardrooms like this looking over Excel sheets and on computer.

What I'd really like to do is take you out on the ocean and show you exactly what we're protecting.

♪ So right now we're in San Pedro, which is a really popular tourist destination.

It is a biodiversity hotspot, great for diving, great for snorkeling.

It was actually my childhood out here that led me to be where I am today...

Right over here looks good.

..and at six years old, I pretty much decided that I was going to dedicate my life to saving the animals in the water.

♪ UMA: In today's warming ocean, this beautiful reef needs all the help it can get.

But conservation at this scale is expensive.

Hard to prioritize when you've got a large national debt.

But Belize had a plan.

JULIE: We call it Blue Bonds for ocean conservation.

You could think of it as refinancing or remortgaging a home, whereby a bank is able to provide better terms and reduce the overall payments, and then the savings from that reduced payment is what goes towards conservation.

In this case, that was a figure of $180 million US to be rolled out over a 20-year period.

When you borrow money for your home, it's an investment, right?

You renovate, you look after it, and over time, it adds value.

The challenge was really coordinating all the various players, all the partners, because something of this scale had just never been done before.

UMA: A big team effort was needed for this ground-breaking deal to protect mile after mile of ocean.

And for its part of the bargain, Belize had to commit to some serious goals.

Protecting 30% of waters would allow nature to thrive... ..and better management would support the people who rely on a healthy ocean.

JULIE: And look at it.

When it's working, it is absolutely paradise.

Once the decision had been made to move the deal forwards, it took only 18 months to get everything in order, and now there's a model for other countries.

UMA: Around the world, more projects like this are in the works, thanks to the success of this inspirational deal.

JULIE: During a time during climate crisis, we need things like this more than ever before.

When nature wins, we win, and so does the carbon drawdown.

♪ UMA: But two-thirds of our ocean, known as the high seas, fall outside of national laws.

Without governance, fishing can be a free-for-all.

To protect nature in these unmanaged waters takes international collaboration... ♪ ..based on accurate scientific information.

Ecologist Tristan Rouyer is hoping to spot one of the world's most valuable fish from the sky.

Buckle up and let's go.

♪ UMA: Tristan is joining Scientific Angler, a fleet of recreational fishers competing to catch a tuna for science.

UMA: The Mediterranean Sea is home to one of the most important Atlantic bluefin tuna fisheries in the world... ..making it a prime spot to monitor numbers.

UMA: Demand for bluefin surged in the 1990s, which led to their rapid demise.

But against the odds, these highly prized fish are making a comeback.

Fabien!

UMA: The competition is on!

Small tuna like this are the optimum size for tagging.

The tag has been programmed to last for over four years.

It will show Tristan exactly where the tuna goes as it heads out to unprotected waters.

(CHEERING) TRISTAN: Perfect.

UMA: The resurgence of bluefin tuna can't be taken for granted.

Keeping their numbers up requires collaboration.

And Tristan's data feeds into an international coalition of over 50 countries and governments committed to preventing overexploitation in the future.

UMA: If Atlantic bluefin tuna can come back from the brink, surely there's hope we can return even more nature to abundance.

In an ocean bursting with life, carbon can be drawn away from the atmosphere.

DAVE: Carbon is it...

It's the...

It's the thing of our time, right?

It's the challenge that all of us have to face.

Climate change - it's something that we have done, but it's also something that we can fix.

UMA: No matter where we live, the nature that surrounds us can be restored.

As a project lead, it gives me the boost to always look forward to every morning waking up with an open heart, because it gives me the determination that whatever I'm doing brings change.

UMA: But it's not just down to you and me.

The world needs to act and boost our entire living planet.

It's a race against time to find solutions for climate change.

UMA: We have a choice to build the world we want to live in.

So if we can find a way of investing in nature, of working with nature...

..I think we'll be able to overcome even this, which is the greatest challenge of this century.

♪ The future I want is a future where this sanctuary is filled with whales and filled with sea birds and fish and just life, and so I want to make sure that this sanctuary stays this way.

I want this place to be like this, you know, for ever.

UMA: And for ever depends on the future of nature.

♪ ♪