[music playing]
Narrator: Before humans even walked the earth,
The forces of nature shaped our world.
Ours is the blue planet, bathed in water and teeming with life.
[music playing]
Without water, plants, animals, and the human race
Would not exist.
Early civilizations are drawn to the water.
They settle along rivers,
Making bricks from water and earth
To build their homes.
As societies grow, the use and distribution of water
Become a driving force in state building.
Settlements by the sea grow into cities of wealth and beauty.
They become symbols of progress and prosperity
Around the world.
We've even built cities in the desert,
A feat made possible only by bringing in water
From hundreds of miles away.
We're drawn to water and instinctively love the sounds
And smells of the sea, perhaps because our bodies
Themselves are 60% water.
Yet as our population has exploded across the globe,
We've put earth's water in danger.
We're living in what some scientists call the age
Of humans, a time when our impact is the defining force
That's shaping planet earth.
From glaciers to aquifers, shallow reefs to deep seas,
We are putting more stress on earth's water
Than at any other time in history.
Human ambition and ingenuity are how we got here and may also
Be how we reverse the damage and guarantee clean water on
Our blue planet in the future.
[music playing]
Water covers 70% of the earth's surface.
It's all around us in many forms, from rain and clouds
To snow and ice.
The overall amount of water on earth never changes.
It merely shape shifts from one form to another
To exist in every corner of land, sea, and sky.
It circulates from the air to the ground
And then through plants, animals, even ourselves.
It never truly dries up.
The heat of the sun makes water evaporate and form clouds.
As clouds cool off, they produce rain since cold air stores
Less water than warm air, and then rainwater on earth
Is used by plants and animals.
This is the water cycle, and it never stops.
[music playing]
The immense rainforests of the amazon basin
Are about the size of america's lower 48 states.
What water does here is a fascinating story.
In 2017, it was discovered that trees in the amazon
Release enough moisture through photosynthesis
To create low-level clouds.
In other words, the forest makes its own rain.
Around the world, trees keep moisture in place.
Without them, water would escape into the air
And to lakes, rivers, and oceans.
The overall amount of water on the planet remains constant--
About 330 million cubic miles.
[speaking german]
Interpreter: There's ample water on earth.
Most of it is saltwater.
If we put all the water into a liter bottle,
Then just a few sips, about an ounce, would be freshwater.
And most of that would be ice or snow.
So we have very little freshwater
Available for all living beings.
Narrator: Part of earth's freshwater
Is stored in aquifers, water-containing layers of rock
Up to three miles below the surface.
This so-called fossil water has been there
For thousands, even millions of years,
And renews itself very slowly.
Mostly hidden to ancient humans, modern technology makes
That water accessible today.
In the 1970s, groundwater made it possible for saudi arabia
To become one of the biggest wheat exporters in the world.
But in the space of a couple generations,
The country depleted its aquifers,
And today, they're almost empty.
Groundwater also gives life to the mar de plastico,
The world's largest plastic greenhouse
Complex in southern Spain.
The buildings here span 134 square miles,
So massive that they're visible from space.
It's been called europe's largest winter
Garden, providing about 3 million
Tons of greenhouse vegetables.
Groundwater from northern Spain makes it possible.
But here too, the supply is almost gone.
Consumption of water per capita varies greatly
From country to country.
In large parts of africa,
For example,
It's considerably lower than in most industrialized countries.
Not surprisingly, the world's megacities consume
Water on a massive scale.
In new york city, 8.3 million residents
Use a staggering 1 billion gallons
Of fresh water every day.
It comes to them from upstate reservoirs.
The new croton dam, 22 miles north of the city,
Was built in the early 1900s to increase
The water supply for a rapidly growing population.
At the time, it's the tallest dam in the world,
A masterpiece of engineering.
The water is carried by aqueducts
To huge reservoirs in the city.
Today, the new york city water system
Is a massive infrastructure, 6,800 miles of iron
And steel pipes stretching beneath the city.
From its sources, water reaches the sixth floor of buildings
By natural pressure alone.
And the quality of the water is famously pure.
But back in the middle ages, water quality
Was an undiscovered science.
Men carried drinking water from public wells,
Delivering it directly to the people.
No one knows that the water they need for life
Can actually make them sick.
[speaking german]
Interpreter: During the middle ages,
People had no idea of the actual origins of diseases.
They suspected parasites or the so-called miasma,
Polluted air which contained and transported germs.
There was a general notion that something within these fumes
Caused illnesses.
However, they didn't yet know what this was.
Narrator: By the 17th century, it
Becomes possible to discern what's hidden
In a single drop of water.
A lens grinder by the name of antonie van leeuwenhoek
Creates a microscope that can magnify an object
By 270 times its original size.
Among other things, he discovers bacteria, though he doesn't
Yet understand its importance.
[music playing]
By the late 1800s, waterborne diseases plague european cities
On a regular basis.
In hamburg, germany, the city's last cholera outbreak
Kills almost 9,000 people who have been
Drinking polluted river water.
[speaking german]
Interpreter: In hamburg, there's an additional problem.
The ebb tides of the elbe river may take the sewage with them.
At high tide, however, they are pressed back into the canals,
So the dirt gets stuck and causes bacterial pollution,
Which in turn causes cholera.
Narrator: Robert koch is a world-famous bacteriologist who
Finds humburg's living conditions to be appalling,
Even for the time.
He identifies that water is the key to stopping the outbreak.
And this motivates local government
To install filtration systems for the first time.
[music playing]
In 2010, access to clean water is recognized as a human right
By the assembly of the united nations.
But even today, it's not always available around the world.
We'll need more and more technology
To make that right a reality.
Desalination is one that holds promise--
The process of making saltwater into fresh.
[music playing]
At this plant in carlsbad, california,
Desalinated seawater supplies 300,000 homes.
It's done using high pressure and fine-poured membranes.
Water purification is another process in widespread use.
In a suburb of los angeles, sewage water
Is purified in several stages, first by microfiltration
Followed by reverse osmosis and disinfection
By ultraviolet light.
More technologies like these are key to meeting
The needs of the world's growing population,
And we're not there yet.
Today, more than 2 billion people do
Not have access to clean water.
It's particularly limited in parts of asia and africa.
A big threat to water around the world is, of course, pollution.
Its effects are easily measured in the waters off big cities.
In new york, only a handful of traditional fishing boats
Still ply the harbors.
They're the last of their kind.
In decades past, the hudson river was a rich and productive
Marine ecosystem, thanks in part to millions
Of oysters that helped to keep the waters clean.
Today, almost all the oysters are gone due to overfishing
And pollution.
But a group of conservationists is
Working to turn back the clock.
Their goal is to bring back a billion
Live oysters to these waters.
New york harbor used to be full of oysters,
200,000 acres of oyster reef.
It was the dominant habitat type in the harbor.
And back at that time, 500 years ago,
The harbor was also full of fish and other marine life.
And the oysters are the keystone species in that ecosystem.
So when europeans first arrived in new york harbor,
There were so many fish that you could catch them
Just by lowering a basket over the side of the boat
And pulling it back up.
So the harbor is actually literally full of live animals.
Narrator: Oysters are remarkable filter
Feeders that act like living sewage treatment plants.
A single oyster can filter 60 gallons of water every day.
Along with clams and shellfish, they also
Remove excess nitrogen that they use to grow
Their shells and tissue.
The billion oyster project collects oyster shells
From local restaurants and plants
Them in floating cages on artificial reefs.
If all goes as planned, oyster larvae
Will nest on these old shells and reproduce.
We hope that by restoring oyster reefs,
We can return those ecosystem functions, the services that
They provided traditionally.
The oysters filter the water.
They provide food and habitat for thousands of animals.
They stabilize the bottom.
And they can protect the shore from storm
Events and wave action.
Narrator: If this project succeeds,
Then the tiny oyster will return to its role
As protector of a megacity.
It's one solution.
But in the age of humans, we'll need many more.
Throughout the age of humans, people have found myriad ways
To use water in all its forms.
Harnessing the power of water for energy
Opens a world of possibilities.
300 years ago in the upper harz mountains of germany,
Residents reshaped land across 80 square miles
To support local silver mines.
Both above and below ground lies an immense, sophisticated
System of dams, ditches, tunnels, and canals
That's unique in the world.
It's preserved today as a unesco world heritage site.
Interpreter: This is groundwater that's coming in here.
The amount is practically the same in summer as in winter--
Almost 80 gallons a minute.
That's roughly 100,000 gallons a day.
Narrator: In the 1700s, silver is mined here in deep shafts,
But groundwater gets in the way.
At first, it's removed by hand, a slow and backbreaking
Process, until engineers make an ingenious discovery
And turn that water into power.
They install wheels which drive mechanical pumps,
Creating hydraulic energy.
[speaking german]
Interpreter: This is called a reversible wheel.
It's a water wheel that can switch
Its direction of rotation.
A rope is wound up.
The pit cage is drawn upwards, while at the same time,
A second rope uncoils, and the other cage goes downward.
Narrator: The water wheel helps this region
Become the biggest mining area of germany in the 18th century.
[music playing]
Elsewhere in the world, people are experimenting
With more ways to harness the power of water in its form
As vapor.
Steam power has been known about since ancient times.
In the late 1600s, a frenchmen named
Denis papin discovers that steam can
Be used to speed up cooking.
He experiments with a pressure cooker,
A process of trial and error.
Only when papin inserts a safety valve does his invention work.
Papin's valve opens up new possibilities.
Steam engines and turbines are the driving
Force of the industrial age, but progress often comes at a cost.
Steam power requires huge amounts of energy
To produce, typically from power plants
Running on fossil fuels--
Coal, oil, and gas.
Polluting the air and feeding the greenhouse effect,
The legacy of these fuels is being felt around the globe.
Melting glaciers are among the most alarming legacies.
Since 1961, glaciers have lost billions of tons of ice,
Contributing to rising sea levels around the world.
Sea level will rise, and what this will do
Is it will absolutely undermine agricultural productivity
In most parts of the world.
It will adversely affect water quantity and quality.
It will affect our natural ecosystems.
It will displace millions and tens
Of millions of people who live in small island
States, deltaic areas.
Deltaic areas are also called wetlands,
Like the florida everglades, home to a unique variety
Of plants and animals.
A staggering 85% of all wetland areas on earth
Have already vanished.
In the united states, the everglades are already feeling
The effects of sea level rise.
Water throughout the state has been dammed and diverted
By humans since the middle of the last century,
And more and more groundwater is needed to support
An ever-growing population.
Now there's an added pressure.
Sea water is pushing inland, and the freshwater everglades
Are being invaded by saltwater.
The everglades is the aquifer replenishment
Zone for all of south florida.
We rely on one main aquifer.
That's the biscayne aquifer.
The biscayne aquifer, however, has become inundated,
Year after year, during the spring king tides.
When that happens, miami beach the last several years
Has been underwater, under saltwater, because of how
High the king tides have been.
When that happens, that saltwater
Has to trickle down through the substrate and into the aquifer.
What connects the everglades to the ocean
Is the aquifer under the ground.
When the sea level rises and the everglades does not come up
Equivalently, saltwater comes underneath
And infiltrates our aquifer.
[music playing]
Narrator: Freshwater plants and animals
Can't survive in saltwater.
And that's not the only harm being caused by rising seas.
[music playing]
All around the world, oceans are eating away at the coastline.
In the united states alone, real estate worth $500 million
Has been lost to erosion.
Countermeasures have had only limited success.
Two thirds of all beaches in southern california are doomed.
Coastal cities are facing submersion all over the world.
Disastrous floods are becoming more and more frequent.
Yet despite the threats, humans still love living on the water.
[music playing]
Cities like sydney, new york, shanghai,
Tianjin, venice, these are all cities
That are attached to the sea.
Their infrastructure abuts right up to the sea.
There's no space there for the water
To come in the city to retreat.
And so a lot of these places are building barriers or thinking
About building barriers.
But barriers can really only protect up to a point.
Narrator: It's not just that seas are rising.
They're becoming ever more polluted in the age of humans.
One substance in particular is doing a great deal of damage,
Though, like many inventions, it started out innocently enough.
The story of plastic begins in unusual surroundings--
An american pool hall.
In the mid 19th century, billiard balls
Are made of ivory.
They're not just expensive, they're fragile
And break down over time.
Chips come off the ball surface and affect
The accuracy of shots, which the players don't like.
Michael phelan is a renowned billiards
Player and promoter who thinks there must be a better way.
$10,000 to anyone to find a replacement for ivory.
Narrator: The man who comes up with a solution is an engineer
Named john wesley hyatt.
He succeeds in producing a mass from cellulose nitrate
And camphor which he calls celluloid.
Hyatt, however, has no formal training in chemistry,
And celluloid has properties he doesn't yet know.
It's both flammable and explosive,
Causing alarm in the saloons, according
To reports from the time.
[music playing]
I'm sure we'll overcome this problem in time.
[music playing]
Narrator: Plastic develops quickly and becomes
A staple of the age of humans.
Lightweight, inexpensive, and durable, plastic
Has changed much for the better.
But the bad news is that these days, about 40
Million tons of plastic end up in our rivers and oceans
Every year.
Its durability is a double-edged sword.
Plastic bags alone account for much of the waste.
Hundreds of billions of plastic bags are used just once
And then discarded.
But it's the plastic we don't see that's actually
The bigger threat.
Plastic in our oceans floats on the surface.
As it's exposed to sun and waves, it breaks down.
Eventually, it decays into tiny particles called microplastic
Which finds its way into the food chain
With troubling consequences.
Its effects can be clearly seen here
On a tiny island called lord howe about 350 miles off
The coast of sydney, australia.
Out here in the pacific ocean lies
The southernmost tropical coral reef on our planet.
A mere 400 people may visit the island each year.
And at first glance, it looks like a paradise.
But biologists are troubled by the health of birds
Here, particularly one called the pale-footed shearwater.
Each day, biologists find dead fledglings along the beaches.
Even before an autopsy, they have a good idea
Of its cause of death--
Plastic in the bird's stomach and intestines.
Looks like we've got one piece of plastic right there.
Shearwaters hunt in the sea and will
Devour anything that floats.
The birds can die from internal wounds caused
By sharp-edged particles.
But more often, they starve because they're unable to pass
Plastic, so their stomachs become full
And can't take in nutrients.
Plastic threatens all marine animals, including
Turtles, fish, and mammals.
It contributes to climate change and threatens
Ocean health, food safety and quality, and coastal tourism.
[music playing]
This beautiful island covered in plastic.
People on that island, it's not even their plastic.
It's just plastic washed around the world.
And yeah, I don't think there's any place that
Isn't covered with plastic now.
Narrator: As night falls on lord howe,
The scientific team is moving on to a special rescue mission.
They're collecting shearwater fledglings hiding in the scrub
While their parents are out looking for food.
Ok.
Next one, alex.
Narrator: Lord howe is the only breeding site
For these migratory seabirds along the eastern coast
Of the continent, and their numbers
Are declining year by year.
We collect the feathers from the birds--
It takes only a quick moment--
Because these couple of feathers can tell us a lot of really
Important information.
When plastic is out floating in the ocean,
It acts like a magnet or a sponge,
And it concentrates pollutants onto its surface.
And so when a seabird like this consumes that plastic
Or a whale or a turtle, those chemicals
Leach out into the bloodstream and inevitably into the
Tissues, including feathers.
And so I can send these off to the lab
And figure out what chemicals this animal has been exposed
To and whether or not that relates
To the amount of plastic that I then find in the stomach.
So something that is only a little bit painful
And takes a brief second is actually
Incredibly informative for a scientist like me.
40.1.
Narrator: To save as many fledglings as possible,
The team performs an unusual operation.
[music playing]
They pump their stomachs.
Tonight, every one of the birds has plastic in its belly.
This chick alone has swallowed 13 pieces.
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 plastic
And a huge piece of hummus.
Look at that.
Narrator: Then it's off into the wild
Again, where unfortunately, more plastic awaits,
Even out here on a faraway island.
Every ocean in the world contains plastic.
More than 9 billion tons of it have been produced worldwide
Since 1950, 18% in north america, another 18% in europe,
And most of it from china, which produces the majority
Of the world's consumer goods.
Interpreter: Plastic has had unforeseen consequences
During the history of mankind.
As a young student, I always thought
That if we divide historical periods
According to certain metals--
The copper age, the bronze age, the iron age--
We ought to talk of the plastic or synthetic age
If we refer to the era from the early 20th century onwards.
Narrator: Back in australia near the great barrier reef,
Students of the australian institute for marine science
Are searching the beaches for microplastics,
Tiny particles which are almost invisible to the eye.
Research confirms that both humans
And animals are ingesting more and more
Microplastics every year.
One indicator species is the tiny clownfish,
An animal that lives on the reef by the thousands.
Scientists want to know how much microplastic the clownfish take
In and how much of it accumulates
In their stomach and tissues.
They also want to find out whether the fish
Are able to discriminate between food and plastic.
I was very surprised, when I first started this work
On the great barrier reef, that we did find
Microplastic contamination in every water sample
That we took and in most of the fish that we analyzed.
Narrator: Today, most of the plastic eaten by fish
Consists of microfibers that enter the oceans as residues
When we wash our clothes.
10,000 microfibers weigh less than a fraction
Of a single ounce and they're just one source of the problem.
The microscope confirms that the intestines of the clownfish
Are filled with microfibers.
We know that microplastics come from sewage
Treatment plants, for example.
But importantly, it also comes from larger
Plastic waste that ends up in the oceans and on the beaches.
And specifically on beaches, they become very, very brittle
Very quickly due to being exposed
To the sun and the salt, and they break down very quickly
Into smaller and smaller bits until eventually,
They turn into microplastics.
Narrator: Plastics are everywhere,
Infecting every single form of marine life.
Yet as bad as the problem is, it's not even the biggest
Threat to our oceans.
Oceans absorb heat and gases from the atmosphere.
As carbon dioxide emissions increase,
The oceans are absorbing about 30% of them,
Making the water more acidic.
Add to that rising sea water temperatures,
And you get coral bleaching.
It's a process that changes the algae
That corals rely on for food.
Eventually, the reefs starve and die.
The first thing you see on the reef that has bleached,
That has been exposed to higher temperatures,
Is all of the individuals going white
And all of these other fluorescent colors.
So in the early stages of a bleaching event,
It's quite a spectacular and beautiful phenomenon.
But these colors are the colors of death.
[music playing]
The fish life has disappeared.
All the small damselfish that typically
Live within the branches of living coral have gone.
So it really does feel like swimming
Through a graveyard with the tombstones still intact.
What our study shows is the corals,
They're not being replaced.
And so if they're not replaced, eventually, they'll
All die out.
Narrator: Too big to fail--
That's what people long thought about the great barrier reef.
But some scientists are working on new and novel remedies
And hoping for a cure.
At the australian institute for marine science,
They've managed to develop corals that can withstand
Higher water temperatures, which may reduce
The impact of coral bleaching.
Corals in the study reproduce by releasing
Larvae that drift in the sea until they settle down.
At the lab, they provide the corals with pieces of limestone
As their new settlements.
The experiment can't be verified by the naked eye.
It takes an electron microscope to do that.
Each new coral that settles on the limestone
Promises an option for saving the reefs.
The tiny white dots are rays of hope, corals in the earliest
Stage of growth.
Despite these gains, whether the scientists here
Can ensure the survival of the great barrier reef
Is doubtful because the survival of a reef
Doesn't depend on local conditions alone.
Over on the west coast of australia in the east
Indian ocean, scientists are studying
Another reef called coral bay.
It's part of the ningaloo reef, another unesco world heritage
Site.
Its corals are among the most beautiful and intact specimens
In the world.
Healthier than the great barrier reef,
It's also fighting coral bleaching.
Biologists regularly check sections of the reef
To see how it's doing.
They're heading to a problematic spot
To see how bad the damage is.
Whatever they find, they know it's
Likely to get worse in the future due to climate change.
I'm afraid the ningaloo reef will follow the same trajectory
That we're seeing in coral reefs around the world--
The collapse of corals in the great barrier reef,
In the caribbean.
The corals here in a pristine state.
There's little impact locally.
But what's happening in europe, what's
Happening in north america--
Increases in atmospheric co2-- is going to lead to increases
In ocean temperatures, and that's going have an impact
Right here at ningaloo.
Narrator: The team finds their study area
And marks the location.
They'll compare photos of today to those
That were taken in the past.
Coral bleaching can occur in phases.
If there is sufficient time between phases,
It's possible for reefs to regenerate,
Though it can take up to a decade.
So far, coral bay has managed to recover
From periods of bleaching.
The team is also studying coral reproduction.
They want to know how many larvae attach to the reef
After spawning, a number that may indicate life or death.
After the corals spawn, we've got all these coral larvae that
Go up into the water column that might swim around for a couple
Of days or a few weeks.
And then they find a nice bit of habitat and settle on it.
And what we used to count how many
Corals are actually setting are these little settlement tiles.
So we've had them out there from before the coral spawn,
And we've just gone to pick them up.
We'll take them back to the lab, have
A look at the tiny little corals that are on there,
Look at what species they are and how many there are.
Narrator: First results are encouraging.
In this area, corals are producing
Enough offspring that are taking hold and growing as hoped.
But the ningaloo reef stretches for more than 160 miles,
And not all of it is doing so well.
Scientists studying the ningaloo reef in western australia
Are finding that parts of the reef
Are lacking healthy numbers of young corals.
It's not growing as it should.
Its future may depend on worldwide co2 emissions,
Though some, like the united nations group unesco,
Are already predicting the worst.
The unesco prediction of ningaloo ceasing
To have a functional reef system by 2041
Is indeed extremely alarming. We need to
The important thing for us at the moment
Is to build resilience in these systems.
The world is going to change.
The climate's going to change.
We want to make the systems we've
Got at the moment as resilient as possible to those changes.
Narrator: It won't just be an underwater tragedy to lose
The earth's coral reefs.
Reefs around the world are barriers
That protect the coasts.
They help waves break offshore and prevent
Beaches from washing away.
Without those barriers, the beaches
Erode and must be replenished, a costly and only
Temporary solution.
Still, waterfront development continues, and more and more
Sand is forced into the water.
Erosion and sand loss are very real problems for many beaches
Around the world.
The more we build, the more sand we need.
And that sand can be hard to get.
Building is one of the main activities
In the age of humans, and it requires sand.
But not all sand is the same.
And for building, it must be coarse enough
To provide grip and cohesion.
In the desert, for instance, grains of sand
Are ground into spheres by the wind.
They're not suitable for concrete or mortar.
Our world is literally built on sand.
On average, a single family home requires about 200 tons of it.
The gigantic construction projects in the arab world
Actually depend on sand from other areas of the planet.
Within the past 20 years, demand for sand and gravel
Has tripled.
By some estimates, we use about 40 billion tons of sand and gravel
Annually to produce concrete, an amount
Sufficient to erect a wall around the world
88 feet high and wide.
In ethiopia, it's actually being extracted illegally
Because the worldwide demand is so high.
The sand trade has become big business
With profits in the billions.
The workers on the front lines profit the least.
The extraction of sand around bodies of water
Has grave consequences.
Rivers transport sand to the sea, and by doing so,
Regularly fill up the beaches.
Around the world, some 850,000 dams
Are also interfering with sand flow,
Changing the course of rivers and harming
The animals that live in them.
Yet we make this trade with nature because humans
Need food, water, and energy.
Changes in ecosystems-- greater sedimentation rates,
Intense rainfall, global warming--
All of these things have happened
All together many times in the history of the planet.
But we know what the cause of our perturbation is.
It's us.
Narrator: As we continue to rely on earth's water to live,
The age of humans is marked by questions
Of priorities and balance.
What's at stake is graphically illustrated
By those reefs which are still intact,
Such as the ningaloo reef.
Coral reefs, like the rainforests,
Are the most biodiverse regions of our planet,
And biodiversity is essential.
It's our life support, fueling the ecosystems that supply us
With clean air and water, pollination of plants,
Pest control, and much more.
The very technology that allows us to see and record
These natural wonders was developed
In an age that's changing the earth at a rapid pace.
As humans, we've used our natural gifts
To create and invent in order to take care of ourselves.
At first, any damage we might have done
Wasn't well understood.
But now science is giving us all kinds
Of indicators that the planet is suffering
And that we're the cause.
Without the environment, there is no culture.
Without the environment, there is no human history.
And certainly, without a viable environment,
There is no human future.
And we're in a dance together.
Narrator: Humanity's will and decision-making
Are being tested.
Will we heed the warnings of our planet,
Or will we keep pushing to a point of no return?
We have the power to bring about either result.
What we do in the next few years is
Critical to how the story of the age of humans will be written.
[music playing]