♪ 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.

(RUMBLES) Imagine a world where nature thrives... ..ecosystems are functioning... ..and the carbon cycle is stable.

Paradise.

If we want to live here too, we must find ways to be a force for good throughout the natural world.

ALEX: Maple and Willow were found five days after their mom was found dead on a highway here on the peninsula in California.

UMA: Dr Alex Herman works at the Oakland Zoo Veterinary Hospital.

She's overseeing the arrival of a pair of orphaned mountain lions.

When they came in, they were tiny, about four to six weeks old.

They were very hungry, very dehydrated.

Willow very soon after that developed pneumonia just from the trauma of the whole situation.

She was really, really sick.

We were very concerned that we could lose her.

UMA: Thanks to the team's expertise, Maple and Willow have both survived.

ALEX: It's really nice to see them moving around, climbing, playing.

UMA: These kittens may be safe, but they're not the first the team has rescued.

ALEX: Here at the Oakland Zoo, we've treated 26 orphaned mountain lions since our program began in 2018.

Mountain lions bring hit by cars is a common, big problem.

UMA: Without their mother, the future for these youngsters is limited.

None of the orphaned mountain lions that we've seen so far here at the Oakland Zoo have been able to be rewilded.

They need to stay in captivity because they're just too young when they lose their mother.

So normally they'll hunt with their mom, be mentored, taught, protected by their mom until they're two years old.

Because their mom was killed, they've lost that opportunity.

♪ UMA: In the wild, mountain lions are found from Canada to southern Chile.

They're so widespread, they have different names - pumas, cougars, even Florida panthers.

But the more their ranges overlap with ours, the more they hit a dead end.

(HORN BLARES) JEFF: So the freeways in our study area are extremely busy, some of the busiest in the world.

The 101 Freeway sees over 350,000 vehicles a day.

Roads in our area are definitely a deathtrap for our local mountain lions.

UMA: Jeff Sikich and the National Park Service team have been studying mountain lions here in LA for over 20 years.

It's been a tough ride.

JEFF: Last year we had 15 get struck and killed by vehicles.

Some of our animals that we've been following, we mark as kittens at three weeks of age.

I have followed them their whole life.

And to see these animals, you know, struck by a vehicle is just awful.

UMA: LA may seem an unusual place to find North America's biggest cats, but they're smart, adaptable, and stealthy.

JEFF: We rarely get sightings of these animals, and it really speaks to their elusive nature.

In this environment we have here, they can be 20 meters in front of me and we won't see them.

So we do a lot of looking for signs.

So looking for tracks, um, scat.

And then also our greatest tool, we use our remote cameras in areas where we think we might get a mountain lion to walk by.

♪ And we have been studying them by capturing them, placing GPS radio collars on individuals.

UMA: By charting the mountain lions' movements, Jeff can see the limits of their territory.

JEFF: So we're just north of the 101 Freeway right at Liberty Canyon.

This is a natural pinch point for them, this natural habitat on either side leading up to the freeway right at Liberty Canyon.

UMA: This human barrier is having a devastating impact on the population.

JEFF: These mountain lions aren't crossing the freeways often, and this has led to very low genetic diversity in our population and also close inbreeding.

And recently we've started to see the physical effects of that low genetic diversity in our population.

We have documented mountain lions with these physical abnormalities, um, a distal tail kink.

And we've also seen some reproductive abnormalities as well.

UMA: The longer they stay trapped, the bleaker their future.

If inbreeding depression sets in to our Santa Monica mountain lion population, there's pretty much a 99% chance of extinction within 50 years.

♪ We get asked often, well, what if we lose mountain lions from this area?

What will happen?

And we like to say that's an experiment we don't want to conduct.

You know, the mountain lion being an umbrella species, that if mountain lions are doing good in an area, if that population is healthy, that equals healthy prey populations and a healthy ecosystem overall.

UMA: The more nature there is, the more effective the ecosystem is at drawing down carbon.

But remove the apex predator, and it can fail.

Mountain lions are facing a disastrous future.

They need a hero.

Ten years ago, conservationist Beth Pratt was inspired by the tale of a mountain lion living in LA.

BETH: I read about P-22, a mountain lion shows up in Griffith Park, and I was like, is that true?!

You know, is there really a mountain lion in LA?

He had to cross two of the busiest freeways in the nation, the 101 and the 405, and then he ends up on a dead-end area of eight square miles, the smallest known home range ever recorded for a male mountain lion by science.

And he makes it.

Lives under the Hollywood sign.

In fact, he became a celebrity in a land of celebrities.

We had the P-22 Day Festival, a festival for a mountain lion.

15,000 people showed up to honor this cat.

And so I think P-22 has really evoked something magical in us that even in the second-largest city in the country, nature had not been fully banished.

If a mountain lion could live under the Hollywood sign in the middle of LA, what else was possible?

♪ UMA: Inspired by P-22, Beth is part of a campaign that's aiming to change the fate of all mountain lions.

BETH: It's launched a movement.

The science has always been there.

The public support is now there.

It really got people to reconsider, like, "OK, we can coexist with large predators," and indeed, it's not just that we can.

We have to.

We have to save these cats.

It involves people having the will to do something visionary.

All my work is about coexisting with wildlife, and there's lots of angles to that, but the biggest is infrastructure, right?

The biggest is, animals need to get across roads.

UMA: Determined to help them, Beth has spent a decade raising nearly $90 million for a seriously ambitious project.

BETH: This is where we're putting a wildlife crossing.

♪ UMA: Stretching 210 feet long and 165 feet wide, the Wallis Annenberg Wildlife Crossing will be the world's biggest bridge for animals.

BETH: This is science come to life.

This is hope.

I've stood here at 2am and I wouldn't even try to cross.

So you can imagine an animal just isn't going to make it.

You know, the Wallis Annenberg Wildlife Crossing is truly one of the most significant conservation projects of our time, not just because it's going to be the world's largest crossing, but because what it represents - that we are doing this.

We are making way for wildlife in one of the most populated areas in the country.

JEFF: The wildlife crossing right at Liberty Canyon couldn't have come at a better time for our population.

Once the wildlife crossing is built, we really only need one mountain lion every two years or so to come down and successfully breed to make a difference in our small population here.

ALEX: These are beautiful, iconic, important animals that are a part of California.

The wildlife corridor is being recognized as a key to coexistence, I think is the future that we should all work towards.

♪ BETH: Maintaining our ecosystems, and fully functioning ecosystems, are key to the climate crisis.

That is what's going to save us.

How can we stop with one?

UMA: The more we build nature into our lives, the more carbon is drawn down.

If we become ecosystem engineers, we can help nature thrive everywhere.

Mangrove forests live along coastlines and can draw down ten times more carbon than plants on land.

♪ But they're fragile, and vulnerable to pollution.

On Hainan Island, China, Dongzhai mangrove forest is an important nature reserve.

Life's been flourishing here for millions of years, undisturbed - until recently.

It's on the doorstep of Haikou city.

In just over four decades, Haikou has grown from less than half a million to over two million people.

And whatever flows along the city's river ultimately impacts the health of the mangrove forest downstream.

(KONGJIAN) UMA: Kongjian Yu is an architect with a radical vision.

♪ UMA: Kongjian believes modern engineering practices make the problem worse.

UMA: Kongjian was inspired by his childhood on the rice terraces of central China.

UMA: The rice paddy landscape is like a giant sponge, not just slowing the water, but filtering it and cleaning it too.

At his office, Kongjian has the solution to Haiko's problem.

UMA: Kongjian has taken this vision for a healthy landscape and supersized it.

♪ He's turned Haiko into a sponge city... UMA: There are even benefits for the city.

For Kongjian, this is only the start.

UMA: Re-engineering our cities is better for the future of nature.

It could even be better for us.

(HORNS TOOT) Freetown in Sierra Leone, West Africa, is one of the most vulnerable places in the world to the impacts of climate change.

♪ In August 2017, resident Idrissa Conteh experienced just what that means.

(IDRISSA) UMA: Everyone lost someone.

ERIC: I was getting ready to go off to the office in Mali when I heard about the landslide in August of 2017, and the immediate effect of 1,000 people losing their lives, and immediately there was thinking about how to support Sierra Leone.

UMA: On hearing the tragic news, senior climate adviser Eric Hubbard was compelled to make a difference.

A few months later, I was here.

Listening, trying to understand how people that live in the community understand risks.

UMA: Working with the city council, Eric learned that climate change caused crops to fail, forcing thousands of people to move here.

And this had severe consequences.

Urbanization in itself is not a problem, but what we have is unsustainable and unplanned.

And what that does is create a level of deforestation that is also unsustainable for the city.

UMA: Over two square miles, or 500,000 trees, have been lost annually since 2011.

♪ ERIC: When you remove trees systematically, you disturb the soil dynamics.

So what happens to the loose soil?

First of all, it becomes destabilized.

The landslide of 2017 was directly caused by that level of removal and the destabilization of that slope.

UMA: The Freetown tragedy highlights the dangers of removing trees.

But the effects of deforestation spiral further.

What we are probably even more concerned about are the rising temperatures.

UMA: All across the city, people are feeling the heat.

(ISHA) ERIC: Outdoor work is a critical component of how we live.

There will be a point at which it will be biophysically impossible to do any of those things if we don't figure out a way, you know, to cool the environment.

UMA: Eugenia Kargbo is the chief heat officer for Freetown.

EUGENIA: You can experience the heat, you can feel the change when you talk to communities and you talk to people, they can tell you that something has changed.

But in terms of data, that's a challenge.

And that's why we did the first heat mapping, was conducted in January, which gave us a baseline of what the current situation is.

♪ UMA: Eugenia's data shows Freetown rarely cools down, and the forecast is worrying.

EUGENIA: Projection from different studies have predicted that if nothing is done about the situation, temperatures will rise to about 30, 35 degrees by the end of 2030.

UMA: This heat, combined with intense humidity, will be unbearable.

A solution is urgently needed.

ERIC: In our approach, we want to cool the air-scape and stabilize slopes, and what we have found is that trees have the propensity to do both.

UMA: As well as preventing landslides, trees can reduce city temperatures by as much as 15 degrees Fahrenheit.

The solution may be to simply plant more, but wherever they grow, they need long-term care.

A survey of 176 new plantations showed that after five years, half the saplings had failed.

Growing trees in a fast-developing city like Freetown seems an impossible challenge.

ERIC: "Freetown The Treetown" is a community-led, community-owned, community-driven restoration process.

♪ UMA: The Treetown project pays residents like Sinneh Turay to not just plant trees, but also be their long-term guardians.

Literally pay to grow.

(SINNEH) UMA: Sinneh's planting a mix of 52 different species chosen for their environmental and also economic benefits.

And technology is ensuring as many of these saplings survive as possible.

ERIC: We've integrated digital technology into the process to ensure that we get a digital footprint of every tree, and that way we can use the digital space to track the life and the health of the tree.

And so that creates the ability for the city to do something that most cities have never been able to do, and that is to guarantee an 80% tree survival rate.

The tracking happens four times a year, but the critical piece is that we have created a care economy.

UMA: Whenever a tree is tagged and in the database, its digital footprint can be traded on the worldwide carbon market.

And thanks to the ongoing monitoring, companies that need to offset their carbon footprint can guarantee the tree's continued health and lasting value.

ERIC: So we have built a natural capital investment strategy with corporate and institutional partners that are looking for carbon offsets.

That are... That have made net zero pledges, right?

That have supply chains into Sierra Leone.

UMA: Carbon offsetting is not a license to emit, but it could be a short-term solution to some urgent challenges.

ERIC: The ecosystem services from those trees will really manifest around 2030.

But they have already begun to sequester carbon.

UMA: Such big ideas could make a real difference to the people living here.

♪ (IDRISSA) (SINNEH) UMA: The legacy of the project could extend far beyond this city.

ERIC: The thinking was Freetown The Treetown and what we like to call Treetown Africa.

And so we've been doing a lot of work to build out our model.

- We've got one over here.

- I see it.

ERIC: This has created a context for us to share broadly, step by step, with cities across Africa and across the Global South what we've been doing and how we've been doing it.

UMA: If we can embrace nature, carbon can reinvigorate our livelihoods... (SHEEP BAA) ..from fast-growing new cities to some of the oldest rural communities.

♪ - (WHISTLE) - JOHN: Meg!

Come by.

Come by.

Away, away, away.

(JOHN) No, Meg.

Meg!

(WHISTLE) There, sit.

UMA: For farming families like John's, one particular gift from the land made the difference between survival or failure.

UMA: Peat is waterlogged, oxygen-depleted soil filled with slowly decomposing plant material.

♪ UMA: Small-scale cutting for families has never been the problem.

But large-scale commercial peat extraction has had devastating consequences.

Dr Guaduneth Chico works with WaterLANDS, an EU environmental initiative aiming to restore the peatland.

(GUADUNETH) ♪ UMA: On top of the Black Mountain, Guaduneth can see why degraded peatland is such a problem.

UMA: Years of accumulated carbon make peat the largest store on land.

But this ancient landscape is extremely fragile.

♪ UMA: Peatlands cover nearly 3% of land on Earth, but 15% of them are degraded, turning them from carbon sinks... ..to carbon sources.

In Ireland, just a fifth of peatlands remain.

But Guaduneth's showing the community how to restore them.

- About... - Yeah, two meters.

Two meters.

Yeah.

UMA: Despite the damage to the environment, commercial peat-cutting was only banned in 2022.

But more recent uses of peatland still impact the carbon cycle, as well as the communities trying to live alongside.

(JOHN) UMA: But there's a plan to help communities thrive here - and support the peatlands, too.

- That one over there?

- Yeah.

UMA: Guaduneth is working with local farmer Sean McGovern on a particularly prickly problem.

There's a couple up there, Guaduneth, I think.

Yeah, yeah.

I can see them.

Yeah.

(SEAN) GUADUNETH: No, no.

There's no chance on that one.

SEAN: It's amazing how fast they grow in a few short years.

(SEAN) - One less.

- One less.

There's a couple more up here.

(SEAN) UMA: By restoring peatland for carbon drawdown, Sean is eligible for an environmental grant from the government.

The better the condition of his land, the more money he'll be paid.

(GUADUNETH) So what we can do is, you know, invest on the farms and improve the quality of the land.

It's opportunity to actually restore habitats.

We train you... We pay for the training and then we pay also for the labor.

So you can actually have some people full-time job, I think.

If you measured the black area, where that's bad, it would probably cover about...

It would cover about three acres, four acres?

- Oh, more, more.

- More.

- Yeah, yeah.

- Oh, would it, yeah... (GUADUNETH) ..to do this because obviously this is a very big job.

Oh, yeah.

Of course.

UMA: It IS possible to see a future and live a better life with carbon.

And we can even do this in the face of the most immediate challenge of all.

♪ For at least one month every year, nearly two-thirds of the world's population face a severe scarcity of water, and supplying enough of it to our growing cities is increasingly difficult... ..even in some of the lushest places.

Rio may be Carnival City, but beneath the glittering surface there are big challenges.

Most of its water is supplied by the Guandu River, but heavy industry and intensive farming along its banks have left the river polluted and silt-ridden.

With the city's water treatment plant working overtime, the cost and reliability of the water supply is a growing problem for Rio's 14 million residents.

But there's a simple, free solution right on the doorstep.

(OTAVIO) UMA: Otavio Barros has lived here all his life.

(LAUGHTER) ♪ UMA: The Enchanted Valley community has enough clean, free water because it's alongside a crucial natural resource.

The Tijuca forest.

Forests are like sponges, collecting and filtering rainfall, which drains into streams.

As the streams flow from the slopes of the valley, they're channeled into rivers.

And the region where the water accumulates is called a watershed.

The Tijuca Forest is a small remnant of a once-giant watershed ecosystem.

The Atlantic Forest.

Spanning the length of Brazil, it was twice the size of Texas.

But today, farming and industry has made it one of the most depleted ecosystems on Earth.

Barely 15% remains, and the region's water supply is in trouble.

But 60 miles south of Rio, conservationists at REGUA Reserve are piecing this giant watershed back together again.

They can only do it with the help of Brazil's largest gardener.

(MARON) Professor Maron Galliez is returning tapirs to their natural environment.

UMA: The tapirs have come from zoos, so to prepare them for life in the wild, they'll first spend time in an outdoor enclosure.

♪ UMA: Weighing over 650 pounds, tapirs feast on large fruits and seeds, which become large trees, and the larger the tree, the more carbon it can store.

While the tapirs acclimatize, REGUA manager Raquel Locke is evaluating how to best restore the health of the watershed.

RAQUEL: We must think of the forest as this live entity, where every little form of life is necessary and has to be added when possible.

All that diversity will have communities of insects, animals coming back in due time.

Certainly some bigger animals won't be able to come back by themselves.

UMA: The more wildlife can be returned, the better the chance of restoring the watershed.

Having spent a month acclimatizing in their enclosure, the tapirs are ready to go to work in the forest.

The promise of a treat is enough to lure one of them into its transit box.

But the other one is not so easily fooled.

♪ The team will need all their skill, and a lot of patience, to lure this one in.

STUDENT: We are using his favorite foods, but he's too clever.

UMA: And just when the team think they've got the better of him... STUDENT: We decided to try it later because it's too difficult.

So maybe he can get in then.

UMA: After some time, and with a fresh bag of treats, they're ready for one more attempt.

- (DOOR SHUTS) - (LAUGHTER) I'm relieved now.

UMA: Relocating large animals is ambitious, expensive work.

And making projects like this happen means we must all make some tough choices.

Refauna's biggest financial backer is a fossil fuel company.

♪ (MARON) ♪ I'm happy.

It's nice to see all the stages and everything for this.

♪ UMA: The tapirs will expand the watershed, and Rio could save nearly $80 million in water treatment costs.

Abundant nature benefits everyone.

(OTAVIO) UMA: All across our planet, people are making changes to build a future with nature.

RAQUEL: Without people's involvement, care of a conservation project, it just wouldn't work.

The more people involved, the better for nature.

UMA: Just imagine what could be achieved... ..if every one of us was part of this.

A global movement for nature.

ERIC: If we want to have a flourishing future and be thriving in 2050 and beyond, we have to do this.

We have to make changes.

We have to make a trade-off.

The trade-off doesn't necessarily mean we lose, and this kind of dynamic will actually win.

That's all I got.

UMA: The brighter the future of nature... ..the brighter the future for all of us.

♪ ♪