♪ As a continent, Africa has contributed the least to global climate change, and yet it is suffering and will continue to suffer the most.

Its people will suffer the most.

I grew up on this continent.

I've been coming to actually this landscape for, like, 3 decades.

And right now, this should be green as far as the eye can see, and the grass should be, like, waist high, and it isn't, because the rains are late again.

And when it does come, it comes in dribs and drabs-- a little bit here, a little bit there, sporadic, episodic, and clearly not enough.

And the big question I have is can it survive?

You know, can the people and the iconic wildlife, the big things like elephants that we associate with this continent can it survive what's coming?

And I really don't know.

It really feels like a place on the brink.

♪ Sanjayan, voice-over: On this leg of my journey, I'm in Africa joining the teams protecting Kenya's largest elephant herds... ♪ and the local people building themselves a sustainable future.

[Cattle lowing] We'll be in Brazil to meet the ranchers who defend the jaguars attacking their cattle and in Cambodia to find out how the people living on Southeast Asia's largest lake are adapting to a major fishing crisis.

♪ This is Kenya in December.

It's supposed to be the wet season, but the rains still haven't arrived.

♪ This year's drought is one of the worst on record.

♪ I'm in Tsavo National Park, home to the single largest population of elephants in Kenya.

♪ In the last 4 months alone, 62 elephants have died because of the drought.

♪ I'm joining Christine from the monitoring team as she gathers information about the seasonal movement of big tuskers-- elephants whose exceptionally large ivory makes them particularly vulnerable to poaching.

Sanjayan: So we're now outside the park on communal land.

You can see signs of cattle grazing, and I actually did not expect to be tracking elephants outside of the park.

And its green over here, which is why they're here, because it's recently rained.

I mean, the truth is that even for a park as gigantic as Tsavo, it's not big enough for elephants.

♪ Oh, my goodness.

Holy cow.

[Clucks tongue] Ugh, I could smell it from a long way away.

A dead giraffe.

Drought?

Christine: I guess.

♪ Sanjayan, voice-over: Christine's boss is Joseph Kyalo, in charge of monitoring and protecting the world's last viable gene pool of elephants with this kind of big ivory.

Kyalo: The big tuskers are important.

They're an iconic species, and also, like, use them to highlight the plight of elephants in the Tsavo Conservation Area.

Sanjayan, voice-over: The big tuskers know poachers want their ivory, and they've learnt to conceal themselves as best they can.

Kyalo: Whenever you approach with a vehicle or a plane, they normally try and hide their tusk in bushes.

We have the ground teams, and also there are some areas in Tsavo that we can't get by road, so we also depend on the aerial unit.

[Engine starting] ♪ Sanjayan, voice-over: To cover this vast area quickly and locate the concealed tuskers is much easier from the sky.

There are only perhaps 25 left on the entire planet-- most of them here in Tsavo.

The biggest of the big tuskers are known as super tuskers, whose giant ivory can weigh up to 100 pounds each.

♪ Sanjayan: The elephant we're tracking is actually collared, and it's only a kilometer away, but it's taken us a long time to cover that kilometer because it's really thick in here.

What's the name of the elephant we're looking for?

Christine: Wide Satao.

Sanjayan: Wide Satao.

Sanjayan, voice-over: As we track Wide Satao, I'm shocked to come across so much evidence of trees that have been cut down and burnt to make illegal charcoal.

People don't have energy.

This is what--the fuel they use to cook and yeah, to eat.

This is a massive threat to landscapes across Africa.

Charcoal and charcoal burning is like a major contributor to climate change because it puts carbon dioxide into the atmosphere, it destroys trees.

Sanjayan, voice-over: It's a reminder to me how this drought is really a crisis for both people and animals in competition for scarce resources.

Sanjayan: You know, they say that if you want to do conservation in Africa, you got to understand 2 things-- you got to understand cattle and you got to understand charcoal because both are such massive habitat modifiers.

And I'm going to add a third "C" to it, and that's climate change.

So now you've got charcoal, you got cattle, and you've got climate change.

And that's what you're going to wrestle with if you're trying to really protect this landscape.

♪ Sanjayan: Straight ahead, straight ahead.

Just see a little dust.

Sanjayan, voice-over: After 4 hours of tracking we're rewarded.

Sanjayan: There's definitely an elephant over there, at least one.

♪ Another.

Ah, there's another one under that tree.

Yeah, and there's another one moving over there.

Oh, wow.

They're all around us, huh?

Mm-hmm.

♪ Look at the tusk on that thing.

Oh, my goodness.

Just like that-- huge tusks.

Huge tusks!

[Christine speaking Swahili] ♪ There's a collar.

Sanjayan: It has a collar.

That's the one, eh?

Christine: Yeah.

It's right ahead of us.

100 met--150-- no, a bit more, 200 meters.

♪ Wow!

Sanjayan, voice-over: Wide Satao gets his name from the big gap between his massive tusks.

♪ Poachers with poisoned arrows have already targeted him 3 times.

The signal from his collar can alert Christine to unusual activity.

♪ Christine: Collar sends signal after every hour.

then when you see a--like a strike without him stopping, you know that something is bad and you go and check on him.

When he gets shot, he runs back to the park closer to where the camps are, where people are, and after observing, he can be rescued.

And what do you do, you basically treat him?

You medically treat him?

Yeah.

He medically treated.

It's amazing that he knows that, that there's so much intelligence and knowledge that he knows if he gets there he's going to be safe.

♪ It's such a privilege to see big tuskers like this.

This elephant has, you know, a 50-year memory.

It's got a memory bank.

It knows where water is.

But even for them, with climate change, the unpredictability of the rains and the drought are something they've never seen before.

It forces them to move out of the park, which is where they come into conflict.

If they go, the era of super tuskers is gone.

Big elephants like this will be a thing of the past.

♪ Sanjayan, voice-over: Just 3 days after we filmed him, Wide Satao was dead.

♪ He may have died of old age, but his condition had severely deteriorated during the long drought that has ravaged Tsavo in recent months.

In the last decade, local anti-poaching organizations have had growing success bringing elephant deaths down by 70%, but Kenya's big tuskers face an uncertain future.

The drought continues to be a national disaster for people and animals alike.

[Animal squeaking] Sanjayan: What's the impact it's having on wildlife?

The elephants go to those traditional places to dig for water.

The water table is that much less because the drier spells are that much longer, which means that all the other animals that rely on the elephants to dig that water can't get to it.

Do you think I'll see the tuskers, if I come back here 5, 10 years from now?

The answer is yes, you will.

Even through the hardships that Tsavo has endured in major droughts to poachings, still there are elephants dying of old age in Tsavo today.

And that in itself is a massive conservation positive.

♪ Sanjayan, voice-over: From Africa to the Amazon, the two "C"s of climate and cattle are bringing humans into conflict with some of the planet's most iconic wildlife.

The Pantanal in South America is the largest tropical wetland on Earth.

The area, the size of Florida, is home to the continent's top predator--the jaguar.

Like many wetlands around the world, the jaguar's habitat is under threat from development and agriculture, in particular, the extensive cattle ranching that the area is so famous for.

Its 4 million cows make Brazil the biggest beef exporter in the world.

Roberto is one of the largest landowners in the Pantanal.

For him, the recent changes in the ecosystem have been dramatic.

Klabin: We have been noticing that rains have been diminishing in the Pantanal for the last years, and this is something that we have never experienced such droughts as we are experiencing now.

Sanjayan, voice-over: Climate change is compelling Roberto to adapt, making cattle and conservation work together.

Klabin: My vision for the future is having the idea of putting together wildlife observation tourism and cattle raising in an area in the Pantanal.

You can accommodate wildlife observation, and you can accommodate cattle.

There is space for everybody.

And so why not combine these activities?

This is the future.

Sanjayan, voice-over: The Pantanal has one of the world's highest densities of jaguars, making it ideal for ecotourism.

Habitat loss, however, is putting its star attraction on a collision course with the cowboys, whose cattle jaguars kill for food.

♪ Lili Rampim is working to reconcile this conflict between ranchers and the jaguars.

Rampim: Our idea was extremely simple-- to show people that jaguars are much more valuable alive than dead through the ecotourism, so that was our thing, you know.

This is the best place for you to have a great experience of our jaguar because you'll not only see a jaguar, but you will know their entire natural history.

Sanjayan, voice-over: Lili and the team have now been tracking jaguars since 2011, using a combination of camera traps and radio collars.

Rampim: We know exactly their relationship and their behaviors.

So it's not just exciting.

It's a very special experience.

♪ Sanjayan, voice-over: A signal from one of her collared jaguars leads Lili to a recently killed calf.

[Lili and man speaking indistinctly] We just found a really fresh carcass.

You can see clearly, right, that there's scratch marks here right on the head, and it's clearly that was a jaguar that killed, right?

They can die hitted by lightning.

Sometimes they get stuck in the mud, bitted by a snake.

In this case, it's clearly that there's a jaguar.

You can see bite marks, you can see this messy, and this is typical of a jaguar.

Sanjayan, voice-over: The toughest part of Lili's job is to change what are deeply held attitudes because every time a jaguar kills a cow, a rancher is losing money.

Rampim: Cowboys--they always take notes of the death, and they always say that "It was a jaguar, and this number represents 30%."

Can you imagine if 30% of cows being killed by jaguar?

It's just impossible.

So by studying in this place, we were able to study every day and every carcass, and we reached to a number that is less than 3%, actually.

So people got wrong quite often.

It's like jaguar is a killing machine, and it's not.

♪ Sanjayan, voice-over: The cowboys are beginning to see how ecotourism makes the jaguars more valuable alive than dead.

[Men speaking Portuguese] ♪ Sanjayan, voice-over: The big cat we're tracking is a dominant male in this region... ♪ and goes by the name "Tupa."

♪ He's a massive jaguar.

See?

And as you can see, he's completely relaxed.

If you habituate an animal mostly every day, it gets to a point that they don't mind our presence, just like Tupa right now.

And the good thing about this place here is that they are so habituated that we can actually follow them, see them behaving normally.

We already have guests that, they stood for 4 days and they saw 7 jaguars.

This is not unusual.

So that's the beauty of ecotourism.

That's the beauty of habituation, in my opinion.

That's the salvation of the jaguars in Brazil.

I'm very proud to be part of this project.

We are changing a bad scenario, and we are transforming to a good future for them and for people, as well, because we are not only working with jaguars.

We work with jaguars, we work with people, and we are trying to make some difference here, and I think we are achieving.

♪ Sanjayan, voice-over: Tupa is probably 8 or 9 years old, relatively old for a jaguar.

His reign as top cat might be nearly over.

♪ I'm interested in following how this relationship between the cowboys of the Pantanal and the jaguars evolves over the coming years.

♪ Back in Kenya, I'm approaching the southern boundary of Tsavo East National Park.

This is a hotspot for poachers hunting everything from the ivory of super tuskers to small birds for the pot.

I'm going on patrol with Tembo 1, one of 7 units made up of park rangers from the Tsavo Trust and armed members of the Kenya Wildlife Service.

♪ ♪ Sanjayan, voice-over: Tembo 1's beat spans all 8,500 square miles of Tsavo.

♪ But as we advance, it soon becomes clear: that out in the bush, you're never alone.

♪ Sanjayan: What do you have?

Lions.

It's--it's here, right?

This is the print?

Man: Yeah.

How recent is it?

Is it yesterday?

Man: 2 days ago.

2 days ago.

Man: Yeah.

Sanjayan: So the lions patrol these?

They go through here?

Those are hunting.

This is a very big landscape.

How do you know where to go?

The poacher is looking where it's very bushy, where he can hide himself, and where those animals come to graze there.

Have you seen an increase, or have you seen a decrease, or is it the same?

Because of the drought, normally the number rises.

There is no rain, so people are trying to-- Sanjayan: Get some food.

Get some food, yeah.

Are they selling the meat or are they just eating it?

Yeah, eating and selling.

Sanjayan: Both.

Yeah.

♪ Sanjayan, voice-over: Every night, poachers set up traps to kill wildlife.

It's one of the jobs of Tembo 1 to find these snares and arrest the culprits-- over 100 last year alone.

So these are confiscated snares?

Yes.

Can you show me how-- how they would set this up?

So they tie it like this, in a good way, and then... they open it out like this one.

Sanjayan: It's just a noose.

Like this one, depending on the size of the animal.

OK.

So they can get trapped at the neck, and then, when they use force, it tight like this.

Sanjayan: Yeah, yeah, yeah.

But is it alive or is it dead when they find it?

Man: It's dead.

Sanjayan: It's dead.

Yeah.

Because it struggled.

Yeah.

And it suffocated.

It struggle and try to remove it, and it can't.

Yeah.

This is so easy to set up.

How many can a poacher put out in an hour?

You can put out more than 50.

Just put out 50 of them in an hour.

In an hour.

Even from, you know, couple meters away, I can barely see it.

That's just so effective.

From this distance, it's gone.

♪ Sanjayan, voice-over: In my mind, there really isn't any doubt.

This year's drought is increasing the human misery that leads to burning trees for charcoal and killing animals.

More poachers have been caught here this year than in any other year in the last decade.

The work of Tembo 1 has never been so urgent.

♪ [Man calling animals] ♪ My next stop is a place full of hope for the next generation.

♪ The goal of the Voi Elephant Orphanage is to re-integrate these rescued youngsters back into the wild.

Wow.

That's so cool.

Sanjayan, voice-over: It's time for their mid-morning break.

♪ Sanjayan: Wow.

These are the youngest ones.

I can't even imagine how big the older ones are.

Sanjayan, voice-over: These orphans develop relationships with individual keepers that can last an entire lifetime.

Sanjayan: How old are these guys?

Man: These ones are-- these ones are 5 years old.

They're 5 years old?

Oof!

Yeah.

Sanjayan, voice-over: In his 22 years as a keeper, Joseph Sauni has been the first responder in the rescue of dozens of young traumatized elephants.

Sanjayan: Have you had these elephants since they were babies?

Sauni: Yes, some of them very tiny.

So most of them came when they were a few months?

Only a few days old, they came to us.

♪ Sauni: Water now.

Go and drink water.

Molly, let's go.

Sanjayan, voice-over: The orphanage was established 50 years ago when poaching was rampant and climate change, well, it wasn't even on our radar Sanjayan: Today, the big challenge that you're facing, is it poaching, or is it drought?

Mostly is drought because poaching has been controlled.

Now the challenge is--is when the drought situation.

Does the mother just abandon them?

No, the baby collapse, and then the mother wait there for 1 or 2 days.

The baby can't come up, and then they give up because they have to go look for water.

They go and leave their baby.

Sanjayan, voice-over: Right now, the orphanage is home to some 30 traumatized orphans, including drought victims aged 3 and over, transferred from the Nairobi Nursery.

Sauni: When a baby is younger than 6 months, we start from the Nursery first, where we have a little bit tender care there.

They've given up, they've lost their parents, they're depressed.

So we give them that love, as keepers, to show them that they've gotten a new life.

They are given that care until when they're 1 1/2.

That's the time they're brought here.

Look at--look at this over here.

They're all piling up on one another.

Sauni: They're all happy.

Sanjayan, voice-over: Allowing the orphans to mix with the wild herd prepares them for return to life back out in the bush.

Sauni: This area has hundred of wild elephants coming around.

So this a wild herd that they know best because they're interacting with them in daily basis, and they're happy to go with them.

Our duty here is to reintegrate them into the wild.

These are only a few that have been sighted.

Exactly.

Many others are dying out there, so When we don't have elephants, I-- my heart calm down, because I know that they have enough food there, no collapsing issues.

So that's my dream.

♪ Sanjayan: The thing that gets you every time you come to Tsavo is how big this landscape really is.

I mean, this is one of those really rare ecosystems.

♪ It's massive.

I mean, it's the size of Switzerland.

And when you look at this and you think about climate change and the impact it's already having on this landscape and how close to the tipping point this place really is, and that's what really struck me today is that whatever we come up with, dealing with a problem like climate change in a landscape like this, it also has to be a really big solution.

[Gulls crying] ♪ This is the Pacific coast of Northern California.

♪ I've seen for myself the devastating impact of rising temperatures on its great redwood forests.

In the last decade, the sea here is warming fast, too.

These nutrient-rich waters are home to over 1,000 species.

What's happening is shows removing a single species can throw the whole ecosystem out of whack almost in the blink of an eye.

♪ On land, California redwood trees up to 1,000 years old can remove and store more carbon from the atmosphere than any other tree on the face of the Earth... ♪ but hidden beneath the waves is another forest that does an even better job.

Thick stands of bull kelp run along most of California's coast, and they can store 20 times more carbon per acre than forests on land.

These giant algae also act as a barrier against storms and erosion.

The Yurok showed me how a healthy coastal ecosystem isn't just some catchphrase.

It's vital for sustaining whole communities that ultimately rely upon it, and in this part of California, too, fishermen are fighting back.

Insatiable purple sea urchins have devoured more than 95% of California bull kelp forest in the last 10 years.

Disease brought on by rising sea temperatures has destroyed the sea urchins' main predator, the sunflower sea stars that eat urchins and keep the population under control.

I haven't seen a sunflower star in years.

Sanjayan, voice-over: Grant Downie is working with dozens of conservation groups to catch and measure these unappetizing and largely inedible purple urchins.

He's experimenting with different ways of baiting traps.

Here you can see the kelp that I just pulled off of that trap.

The urchins were completely covering it.

And you can see all the little bite marks from them chomping all night long.

They're definitely hungry, and the kelp is what they want.

Sanjayan, voice-over: The loss of the kelp has badly damaged Grant's business.

His family spent 40 years catching the red sea urchins, which are much larger and juicier than the purple ones and can be sold to high-end restaurants as sushi.

Downie: It's always been me and my dad diving.

I was averaging about 1,200 pounds of red sea urchins a day, and now that we've come into a collapse, I'd say I'm averaging about 300 pounds a day.

Sanjayan, voice-over: Grant is spearheading the local efforts to improve the marine habitat and encourage the red sea urchin by clearing as many of the purple urchins as possible.

♪ Before the urchin invaders are discarded, Dr. Frank Hurd wants to see how successful the trapping has been.

Hey, Frank, good to see you.

Hurd: Hey, how'd it go out there?

Ah, it was good, you know?

Sanjayan, voice-over: He is working with fishermen like Grant to collect data on the purple sea urchin population that has exploded to 60 times its usual size.

But here's a subsample from what I got.

Hurd: Oh, great.

Slide 'em up to you.

Oh, this is great.

Pretty good haul?

♪ Hurd, voice-over: I've dived up here for over 15 years now, and having witnessed firsthand the catastrophic loss of kelp on this coastline has been devastating We know that we need to drop down that purple urchin population, and so we are exploring multiple ways of doing that at scale.

We want to restore these kelp forest ecosystems to a resilient state so we can ensure that they continue to thrive into the future.

♪ Sanjayan, voice-over: Out in the bay, Frank goes out to take a look at some "urchin barrens"-- dead spaces on the sea floor where the urchins have eaten up all the kelp.

Hurd: This is a site that was cleared of urchin.

We're seeing kelp come back in where it had previously disappeared.

The animals that depend on the kelp for food, like the abalone, are looking healthy and whole.

It's not quite what we would say is an average year prior to the purple urchin population explosion, but it does reaffirm the notion that given a chance nature can bounce back.

Sanjayan, voice-over: It's terrifying when you see large, complex ecosystems like this changing so fast.

Our vulnerable kelp forests cover a quarter of the world's coastlines, and conserving them by hand can't be the only answer.

We just can't afford to lose one of the most powerful tools we have for storing greenhouse gases and fighting the effects of climate change.

My hope is that in the coming years we'll see other solutions at scale that we need to stop the total collapse of our coastal habitats.

Hurd: I think our job in all of this is to give these kelp forests that fighting chance to be able to turn the tables and re-establish that balance in the ecosystem.

There's still a lot of work to be done here.

♪ Sanjayan, voice-over: I'm leaving the dry, lowland savannas and heading for another precious ecosystem.

140 miles southeast of Nairobi in the shadow of Mount Kilimanjaro is one of the last great landscapes for East Africa's most iconic wildlife.

♪ Mzima Springs in Tsavo West National Park pumps out over 20 million gallons of ice-cold water each day, supplying Kenya's second-largest city Mombasa with nearly 1/3 of its fresh water.

♪ When you're standing in this oasis with thousands of gallons of water bubbling up, this is truly unexpected after completely dry, desolate Tsavo.

And all this water is actually coming from the Chyulu Hills, filling up these springs and then from here onto Mombasa.

It's so lush and green here even in the drought, but how does all this fresh water get here?

♪ To find out, I'm heading from the springs up into the hills.

♪ [Man speaking native language] My guide is Samson Parashina, a Maasai warrior and community leader honored by the U.N. for his commitment to developing a sustainable green economy.

Sanjayan: It's a great view from up here.

Parashina: Very.

You see the entire 300,000 acres.

That's a community-owned Maasai land?

And it goes all the way to the slopes of Mount Kilimanjaro.

This really is kind of amazing...

Very.

being in here, to be honest.

I mean, these are massive trees.

Sanjayan, voice-over: Today, Samson and his community are battling to save this forest from the growing threats of livestock and conversion of land for agriculture.

Sanjayan: The soil looks black.

Trees look big and thick, and the forest looks, you know, not--"dense" is not the right word.

It looks alive.

Parashina: This forest is very, very unique to us.

You don't find such forest in other places.

They are very rare.

Called a cloud forest.

Sanjayan, voice-over: Just 1% of all the woodland on Earth can be called cloud forest.

Parashina: In the morning, you get the condensation of cloud that drips water to the ground, then slowly, slowly forming the river underneath.

The Maasai get water below in the plain from these forests, and that's what our livestock and the people depend for living.

If this goes, it means no life, no life or livestock, no water for them.

And also wildlife will disappear.

What are the big threats to this forest?

Because of the growing population, people will encroach to the forest, and then they'll start burning charcoals.

Making charcoal?

Making charcoals, yes.

From trees like this?

From trees like this, yes.

Sanjayan, voice-over: Even though it's illegal here, charcoal burners continue to take wood from this protected forest.

Sanjayan: And why is it protected now?

What's changed?

We've start receiving carbon credit funding, and this has supported the community to understand more on protecting this forest.

Understanding that this forest was not just giving you water but also was full of carbon.

It's said to have 600,000 tons of carbon every year.

Sanjayan, voice-over: Protecting and restoring forests that can absorb and store vast quantities of carbon dioxide from the atmosphere is part of a growing and sometimes controversial multi-billion dollar credit system.

It allows companies, governments, even individuals to offset some of their environmental footprint.

♪ Parashina: It's hard to explain to the community members, but what we usually tell them-- real benefit in terms of health, in terms of education, access to water, creating employment.

So those benefit all built together, the community have seen a real, real benefit of keeping this forest.

These trees have saved our life.

Sanjayan, voice-over: The sale of carbon credits in Chyulu generated more than $3 million in 2020 alone, funding vital conservation projects for the local Maasai people while protecting our global atmosphere.

It's clear that in the last few years with the drought and what it's done to their lives and of course with the pandemic that that revenue has been a lifesaver.

To meet a ranger who's a Maasai who used to cut down this forest for charcoal and then have him tell me that "I make more money protecting these trees "than cutting it down.

"I make more money from carbon and protecting carbon than "burning it for charcoal.

And that's how I get to send my 5 kids to school," that kind of sums it up.

♪ Sanjayan, voice-over: At the foot of the Chyulu Hills lies the Kibwezi Forest.

2 decades, due to people illegally cutting down the trees in this cloud forest, the natural spring here entirely dried up.

Man: Around the year 2000, this area had extremely reduced water volumes.

In fact, you could hardly see any water flowing.

Sanjayan, voice-over: In response, the Kenya Forest Service helped to set up over 30 plant nurseries to sell to local people wanting to re-green their community.

Maneno: When the water disappeared, the seedling production here really diminished.

Currently, we have 50,000 seedlings.

Now, when the water went down, the amount of seedlings dropped to around 5,000.

So you can see the difference.

I believe that the conservation of Chyulu Forest has increased the water infiltration and subsequently flow here.

♪ Sanjayan, voice-over: The Thange Tree Nursery is part of a global network to conserve forests and other important carbon stores through community action.

Woman: We started it because we are doing nothing at our home.

So that we come here, we join the group.

We started working together as women, and it helps us very much.

[Continues in Swahili] Sanjayan, voice-over: As well as an income for the women, every single tree planted here under the Chyulu Hills also helps absorb carbon dioxide in the atmosphere.

♪ Maneno: The area has realized a lot of enrichment planting with the seedlings from Thange Tree Nursery and even on their farms.

So this is likely to continue improving their livelihood.

♪ Sanjayan, voice-over: The 2 million carbon credits that have so far been sold in return for funding projects like this will be re-invested in schools and community projects.

[Children singing in native language] The Kuku Wildlife Warriors Club are passionate about nature.

Recently, they dedicated some of their school playground to planting trees.

Each kid has chosen a tree to take care of, but they cooperate in planting it.

Sanjayan: Thank you for doing this.

And I really mean it, you know, because when you guys, when you plant these trees, you're not only taking care of your community and your area, but you're also taking care of the atmosphere for all of us, you know, the air for all of us.

So even though I don't live in Kenya and I live--I live in Washington, D.C., by the fact that you are planting and taking care of trees here, you're actually making my daughter-- you're making her life better, as well.

Thank you.

Thank you.

Thank you.

Asante sana.

Child: You're welcome.

♪ Sanjayan, voice-over: In Asia, the next generation is going to be big... like, really big.

By 2050, its population is expected to have exploded by up to 20%.

That's almost a billion more people than today.

We've come to Cambodia.

Nearly 2 decades of economic growth here is lifting millions of people out of poverty, but all that growth comes at a cost.

We're here to see what impact the demand for energy and natural resources is having on one of southeast Asia's most important wetlands.

♪ Cambodians call the Mekong the mother of all rivers.

Flowing through 6 countries from China to Myanmar, Thailand, Laos, and via Cambodia to Vietnam, it's sustained human growth for millennia.

♪ At the heart of Cambodia's flooded plains lies the Tonlé Sap Lake, where every year a miracle occurs.

Between May and October, the monsoon rains swell the river, and instead of draining the lake, the Mekong waters pour back in--a reverse pulse expanding the lake to 5 times its usual size.

♪ This normally heralds the arrival of an unimaginable quantity of fish in one of the world's great animal migrations.

♪ More fish get hauled from the lake each year than from all the lakes and rivers in North America combined.

♪ However, recent fish numbers are declining, provoking a crisis for the millions of fishermen who depend on this lake for their livelihood.

♪ Floating communities like Meychrey have thrived for generations living an entirely aquatic life on the lake-- with floating schools, floating offices, floating shops, but its inhabitants now face an uncertain future... ♪ as community leader Mr. Leur explains.

[Leur speaking native language] Mr. Leur is adapting to the new reality.

He's even created a floating vegetable garden and a fish farm attached to the side of his house.

♪ And yet how can these local solutions be enough when some of the problems are truly big and located thousands of miles away upriver?

♪ Dredging, irrigation, and overfishing have all played a part in weakening the Mekong River system.

Some experts predict within the next 5 years the entire system could collapse.

And the most damage is being caused by the insatiable demand for electricity.

13 hydropower dams straddle the main Mekong stream.

The so-called clean electricity that they produce is fossil-free and improving the quality of life for people across Southeast Asia, but with it comes catastrophic environmental consequences that surely were not intended.

The annual flooding of the Tonlé Sap Lake has been reduced by nearly 60%.

This isn't just worrying for the Cambodian people.

The dams block fish from migrating and trap more than half of the rich sediment that fertilizes the other countries of the lower Mekong: Myanmar, Laos, Thailand, and Vietnam.

A further 100 dams are planned or are in construction.

It's a threat hanging over the lives of millions living in the entire Rice Bowl of Asia... and to some of its most biodiverse ecosystems.

If the fish populations continue to shrink, over the next 7 years, the pressure is really on for Mr. Leur and his community.

♪ The economic boom of developing nations consumes more energy, more food, more resources, but groundbreaking technology could help reduce the environmental cost.

Brad Murg is combining satellite imagery with data from the ground to model the impact of hydropower on the wider Mekong Delta system.

♪ Murg: This is the first time that we can see the movement of the river as a whole, and not just the river itself, but also looking at its tributaries, really the entire Mekong River watershed.

And this gives us a perspective that we've never had before, and that is game-changing.

Sanjayan, voice-over: The computer model shows how the once regular annual flood has been growing increasingly unpredictable.

Murg: We see a very large number of dams basically becoming active and opening 2012.

The argument that's presented in the data that's shown here really demonstrates that dams are the primary cause.

Sanjayan, voice-over: In California, we've seen how the Yurok are working with federal agencies to tackle the damage caused by hydroelectric dams.

Governments around the world are beginning to understand the importance of balancing the growing demand for energy and protecting the environment.

In terms of the future of dam construction, there has been a change.

This really goes to the renewed interest and focus on--on the Mekong and the realization among governments um, that, uh...time's up.

So I think throughout the region, it's incredibly difficult to find support or even acceptance for the construction of new dams.

Sanjayan, voice-over: With 6 countries involved, a diplomatic solution is not going to be easy or quick.

I'll be back to see how this story in Cambodia develops.

Hopefully this is just the first indication of real positive change.

♪ The water crisis in East Africa is not so easy to pin down, but it's suffering just the same from human-made climate change.

Today, however, in the Chyulu Hills, there's more than just a glimmer of hope.

♪ The global trade in carbon credits has helped conserve 1 million acres of this forest, preventing the release of around 37 million tons of carbon emissions.

It's also provided a "sweet" alternative to charcoal burning and poaching.

♪ I've come to meet Wilbur Mutua, who teaches beekeeping to local Maasai women.

He says that the evening light makes the bees a bit drowsy, but I'm not so sure.

Mutua: Now we are doing an inspection of this hive to see how is it doing.

Sanjayan: Oh, my God.

OK.

These are African bees.

Sanjayan: Yes, sir.

Yeah, so with these-- I'm puffing this like my life depends on it.

Yeah, which is OK.

I am actually surprised that you are able to get local communities to adopt this because it is unnerving to be here.

It's very easy when you get used to it.

Yeah.

Sanjayan, voice-over: 800 hives and counting from the carbon project provide an environmentally friendly economic alternative to the local women.

Mutua: Our aim is more hives to empower the women.

Many were neglected by their men.

Why?

Men normally--they're after livestock.

Livestock generates money, which goes straight to the men.

Put it in their pocket, not thinking of the women.

Sanjayan, voice-over: A hive can cost as much as a goat but can deliver a regular income, supplying up to 22 pounds of honey twice a year.

Sanjayan: Do you use the honey, or do you sell it?

♪ Sanjayan, voice-over: Of course bees really do matter not just to the Maasai but to all of us.

Mutua: Bees--they're good for pollination.

All over the world, it's by bees.

So without bees, no pollination and no food.

At the end, no life.

[Buzzing] ♪ Sanjayan: As an ecologist, as a scientist, I've been sort of trained to think of nature changing in very slow ways, barely perceptible, but what's really striking about the journey that we've been on is that the changes that we're now seeing in the natural world are fast.

The speed, the unpredictability of it is shocking, and it's frightening to me, but the other side of it is that along this journey, we've met incredible people who are doing extraordinary things.

I mean, you think about the Yurok, and this is a community that is restoring an entire river basin, and the Maasai protecting the carbon-rich forest, the Chyulus, that provides water here, but it's also changing the global climate equation.

I mean, when you run into indigenous communities that are willing to do so much, it leaves you with this giant question about why?

Why our politicians, our corporate leaders, our communities, our religious leaders, our schools, when those of us with real power, why we're not doing an awful lot more.

♪ Changing Planet is available on Amazon Prime Video.

♪ ♪