All language subtitles for Breaking.Boundaries.The.Science.of.Our.Planet.2021.720p.WEB.H264-STRONTiUM-HI

[man] You could think of yourself
driving in a mountainous area

with the road circling up the mountain.

An overpowered engine
driving much, much too fast,

driving without any headlights.

Cliffs that you're
at risk of falling over.

[engine revving]

You want, of course,
to turn on the headlights,

and that is
what science tries to do all the time.

To give us the headlights
so we can see what risks we're facing.

Recent discoveries made by scientists

studying the ways
in which our planet works

are surely of the greatest importance
for all of us.

Their insights are deeply troubling.

Nonetheless, they also give us hope,

because they show us
how we can fix things.

One of those who has devoted his life

to studying
these globally important problems

comes from Sweden.

Johan Rockström.

What he and his colleagues
around the world have discovered

is perhaps the most important
scientific insight of our times.

Johan has given us hope.

Hope that there is
a way out of this crisis.

And once you too have heard it,

you may never look at the world
in the same way again.

[Johan] This is not about the planet.

This is about us. It is about our future.

We still have a chance.

The window is still open
for us to have a future for humanity.

That I think is the beauty
of where we are today.

[David Attenborough]
Our understanding of how our planet works

is always advancing.

We can now see more clearly than ever

how life's intricate complexity
is essential for our own survival.

But biodiversity is collapsing,
and our climate is changing.

Johan Rockström has focused
on what keeps our planet stable.

We're the first generation,
thanks to science,

to be informed that we may be undermining

the stability
and the ability of planet Earth

to support human development
as we know it.

This comes from ice core data,

and I think that this is
the most important graph we have today.

[David] The graph is a revelation.

It shows global temperature variability

over the past 100,000 years

since the first appearance
of modern humans.

We were jumping between plus-minus
ten degrees Celsius in a decade.

We had, to put it simple, a rough time.

[David] What's critical
is that the temperature stabilized

just 10,000 years ago.

[Johan] You can just see from the graph
that this is a remarkable,

not to say almost miraculously stable,
interglacial period.

[David] Geologists have given
this period of stability

its own special name.

It's called the Holocene.

The Holocene is remarkable.

It is a warm period
where the planet's global mean temperature

varies between
just plus-minus one degree Celsius

during the entire period.

Plus-minus one.

...is plus-minus one degree Celsius.

This is what established
the modern world as we know it.

[David] The Holocene's stable temperatures

gave us a stable planet.

Sea levels stabilized.

For the first time,

we had predictable seasons
and reliable weather.

This stability was fundamental.

For the first time,
civilization was possible,

and humanity wasted no time
in taking advantage.

We domesticated rice, wheat,

teff, maize, sorghum,

on different continents
roughly at the same time.

And off we go on the civilizational
journey as we know it.

This is the interglacial stage
that has enabled us

to develop
modern civilizations as we know it.

The Holocene is the only
state of the planet we know for certain

can support
the modern world as we know it.

[David] Since the dawn of civilization,

we have depended on
this stable state of the planet.

A planet with two permanent ice caps,

flowing rivers,

a cloak of forests,

reliable weather,

and an abundance of life.

Throughout the Holocene,

this stable planet
has given us food to eat,

water to drink, and clean air to breathe.

But we have just left the Holocene behind.

The exponential rise
in human pressures on planet Earth

has now reached a stage

where we have now
created our own geological epoch.

[David] Scientists recently declared
that the Holocene has ended

and that we are now in the Anthropocene,

the age of humans,

because we now are
the primary drivers of change

on planet Earth.

We have converted
half the world's habitable land

to grow crops and rear livestock.

We move more sediment and rock
than all the Earth's natural processes.

More than half of the ocean
is actively fished.

Nine out of ten of us
breathe unhealthy air.

And, in a single lifetime,

we have warmed the Earth
by more than one degree.

I would say that perhaps
the most dire message to humanity

is the following.

So we have, in just 50 years,

managed to push ourselves

outside of a state that we've been in
for the past 10,000 years.

Are we at risk
of destabilizing the whole planet?

It's just
a mind-boggling situation to be in.

For the first time,
we have to seriously consider

the risk of destabilizing
the entire planet.

[David] Johan's ambition
has been to see the big picture.

To draw
from a global network of knowledge,

to learn what keeps
the entire planet stable.

What are the systems
that determine the state of the planet?

And if they are five or if they were 30,

we did not know when we started.

We just open-ended asked the question,

"Can we identify the systems
that regulate the state of the planet?"

[David] Those systems
have held the planet in its stable state

throughout the Holocene.

As we increase our pressures on Earth,

there is a danger that those systems
will start to break down.

That we will
break through Earth's boundaries,

causing the stability
that we depend on to collapse.

[Johan] I was absolutely convinced
that we wanted

to dig into this challenge
of defining planetary boundaries,

and can we identify a quantitative point

beyond which we risk
triggering nonlinear changes?

And that becomes your boundary.

[David] If scientists
could define our planet's boundaries,

could they also give us the road map
to guide us out of our current crisis?

To show us not only how to avoid collapse,

but how to secure
our own thriving future on planet Earth?

The first and most obvious boundary
is well known to us all.

With global temperatures now warmer

than they've been
since the dawn of civilization,

there is a danger that we have already
crossed the boundary in Earth's climate.

Perhaps the most alarming evidence of this

is in the change of our planet's ice.

As a Swede,
Johan feels this more keenly than most.

[Johan] As a kid in Sweden,
like all children in Sweden,

we learn that the south top at Kebnekaise
is the highest peak in this country.

And it's something that is just ingrained

in the identity
of being a Swedish citizen.

So, of course, it's...

You know, with sadness,

one comes to realize that
that will no longer be the case.

[David] The south peak of Kebnekaise

has recently lost its status
as the highest peak in Sweden.

The glacier
that makes up its highest point

has been shrinking roughly
at the rate of half a meter a year

for the last 50 years.

[Johan] What we're seeing
here at Kebnekaise

on its own
will not destabilize the planet.

But having two caps of a permanent ice

in the Arctic and in Antarctica is

the very precondition
for the planet to stay in this state

that has enabled us
to develop civilizations as we know it.

And that's why
it's such an enormous concern

to see glaciers melting,

irrespective of whether
it's a small glacier at Kebnekaise,

or whether we're talking about Greenland,

because they all add together

to this fantastic capacity
of cooling the planet.

[David] This cooling effect
was fundamental

in keeping the Earth's temperature stable
throughout the Holocene.

The planet's ice was reflecting
just the right amount of the Sun's energy

back into space.

A permanent white surface
like what we can see around us here

is reflecting back 90, 95%
of incoming heat from the Sun.

When these ice sheets start melting,

not only do they shrink in size

so the fringe areas
are very dark and absorb heat,

but even just the fact
that you get liquid surface on the ice

changes the color so significantly,
so you can come to a point

where the ice sheets tip over
from being self-cooling

to becoming self-warming,

and that is
the most dramatic tipping point

in the Earth's system.

[David] A tipping point is a point

beyond which a change
becomes irreversible.

[man] It's like a train
that's parked on a slope,

and it's beginning to move.

We're losing the brakes on the train,

and so the train is accelerating,

getting faster and faster,
and at some point, we lose control.

[water splashing]

[David] We are already losing the brakes

that could prevent the melting
of the Greenland ice cap.

[man] When I first came here, aged 20,

it felt like kind of a dream,

because I was seeing landscapes
that I had only kind of seen in textbooks.

[David] Jason is one
of the many scientists around the world

whose evidence and insights
were fundamental to Johan's research.

The millennia snowfall
onto Greenland has accumulated,

produced this dome of ice.

It's two miles thick and,
you know, well up in the atmosphere.

It's really cold up there.

[David] As it melts,
the surface of the ice cap

lowers into warmer air,

speeding up the melt.

The more it melts,

the cooler the climate would need
to become in order to reverse it.

But today's climate
is already too hot for Greenland.

So in the current climate,
Greenland is already beyond its threshold,

er, where it's now losing
10,000 cubic meters of ice per second.

That's the average loss rate.

Now, that loss rate will only continue

as the climate heats up.

So is Greenland lost?

Evidently, it is.

[David] Unless we can
significantly cool the Earth's climate,

the melting of the Greenland ice cap
will inevitably continue.

[Johan] The drama here is that
one characteristic of tipping points

is that once you've pressed
the on button, you cannot stop it.

It takes over. It's too late.
It's not like you could say,

"Oops. Now I realize I didn't want
to melt the Greenland ice sheet.

Let's... Let's back off."

Then, it's too late.

When you cross these tipping points,
you can enter a point of no return

that you basically commit the planet
to an irreversible sliding away

from a state that,
in our case, can support us humans.

[David] The melting of Greenland's ice cap

would raise sea levels
around the world by seven meters.

[Jason] Imagine a world
where sea level is not static.

Where it's changing.

Cities, hundreds of coastal cities
now are threatened by rising seas.

Er, that stability in sea level was key

to the development of civilization.

It's... It's a... It's a Mad Max future
that we're facing.

[David] But Greenland
is just one of Earth's polar ice caps,

and it's dwarfed by its southern twin.

Not so many years ago,

it was thought that Antarctica
was the resilient system.

This was the ice sheet that was
not very much affected by climate change.

But today, that has changed completely.

Today we're seeing
accelerated loss of mass

and loss of ice
into the ocean in Antarctica.

West Antarctica would lead
to sea-level rise of more than five meters

if it were to melt down completely,

and then east Antarctica
actually holds the tenfold of that,

so more than 50 meters worth
of sea-level potential.

[David] Ricarda
is one of Johan's colleagues,

and she studies
how tipping points can interact.

The important point
to make here is that everything

in the Earth's system is connected.

If one part of the climate system

crosses its tipping point,

then that might make it more likely

for other parts of the system
to also cross their critical threshold,

so you can think of this
in terms of dominoes.

If you tip one of them over,

then this might lead
to a cascading effect.

What is clear is
that with ongoing global warming,

we're increasing the risk

of crossing tipping points
in the Earth's system.

When we cross tipping points,
we unleash irreversible changes

that would mean that the planet
will go from our best friend

to a position where it dampens
and reduces the stress,

sucking up carbon dioxide,

taking up heat, absorbing impacts,

and tipping over to a point
where it could self-reinforce warming

and become a foe.

[David] The climate is, of course,
being warmed by greenhouse gases,

so it's in our emissions of these gases

that we find a global tipping point.

Since long before human beings appeared,
the Earth's average temperature

was closely tracking the concentration
of carbon dioxide in the atmosphere.

During the Holocene,

this concentration
remained relatively steady,

but that all changed
with the Industrial Revolution.

In 1988, we passed 350 parts per million

of carbon dioxide in Earth's atmosphere.

This was the moment
we crossed the boundary.

Ever since then,
we've been at risk of triggering changes

that lead to runaway warming.

[Johan] You go past 350 PPM

in the concentration
of carbon dioxide in the atmosphere,

and you enter the danger zone.

[David] So 350 parts per million
is the first of Johan's boundaries,

and we're already well beyond it.

[Johan] Right now, we've reached
a point of carbon dioxide concentration

in the atmosphere
of roughly 415 parts per million.

We're starting to see the impacts of being

in the middle of the danger zone
in the climate boundary

in terms of rising frequency of droughts,

and heatwaves, and floods,

and accelerated melting of ice,

and accelerated thawing of permafrost,
and higher frequency of forest fires.

[David] Up ahead is a second threshold.

We are rapidly approaching
450 parts per million carbon dioxide.

[Johan] The planetary boundary
danger zone is defined

by the uncertainty range in science.

Today, our assessment is
that the uncertainty range in science

lies between 350 PPM,

which is the boundary

between the safe zone
and entering the danger zone,

up to 450 PPM,

which is when you exit the danger zone
and go into a really high-risk zone.

[David] If we enter the high-risk zone,

irreversible tipping points
become highly likely, if not inevitable,

and this is a conservative estimate,

given that the signs of tipping points
are all around us now.

In simple terms,
the climate planetary boundary

is equal to 1.5 degrees Celsius warming,

and it just provides all this evidence

that we take a huge risk
if we allow ourselves to go beyond 1.5.

We are at 1.1,
we're rapidly moving towards 1.5,

and our only chance to stay
within the planetary boundary on climate

is that we, you know,

reach a fossil-fuel-free world economy
within the next 30 years.

[David] While that target
for global temperature

may have grabbed all the headlines,

Johan knew that this was
only one part of a bigger picture.

For our planet's stability relies
on more than just its climate.

More research and evidence
had to be brought forward

to conclude that we also have
four biosphere boundaries.

Boundaries that are in the living Earth.

These include the land configuration.

How...
How is the composition of biomes on Earth?

Er, the three rain forests,
the temperate forest,

the boreal forest,

the grasslands,

the wetlands.

Second is biodiversity.

So all the species in water and on land.

And then the third one, of course,
the bloodstream, the hydrological cycle.

And then, finally,
the injection of nutrients

that are fundamental for the functioning
of the living biosphere.

The nitrogen and phosphorus cycles.

[David] The first
of the biosphere boundaries,

the composition of the habitats on Earth,

is concerned with how we are now
transforming those natural habitats.

We are fast approaching
a major tipping point

in one of the planet's
largest remaining wildernesses.

The Amazon.

Carlos Nobre has been studying

the rain forest's importance
to our planet's stability for decades.

He was the first to sound the alarm.

[in Portuguese] I saw the Amazon
in 1971-72 undisturbed.

I saw the forest

and the rivers.

I would swim
in the Rio Negro with the piranhas,

And nothing ever happened to me.

[David] Since that time,
large swathes of Amazon have been cleared

for livestock and soya farming.

Carlos has discovered
that this is pushing us closer

to triggering irreversible change
across much of what remains.

[in Portuguese] In 1998,
we began the largest scientific experiment

ever conducted in a tropical rain forest.

[David] Many towers
were built in the rain forest

to study how it creates its own climate.

The data shows large parts
of the rain forest are drying out.

[Carlos in Portuguese] In the Amazon,

the dry season
lasts a maximum of three months.

But with global warming

and also forest degradation,
due to human activities,

in particular, livestock and soya farming,

the dry season has become six days longer

each decade since the 1980s.

[David] As the forest is reduced
and fragmented,

its ability to recycle water

and generate rain into the dry season
is diminished.

If the dry season
becomes longer than four months,

the jungle trees die
and are replaced by savanna.

A process called savannization.

There are signs that parts of the Amazon
are already changing.

[in Portuguese] If deforestation
goes above 20 to 25% of the forest,

with global warming increasing,

we are likely to experience
an irreversible process of savannization

that could affect 50 to 60%
of the entire Amazon forest.

[David] We have already lost
close to 20% of the Amazon rain forest.

We could be about to tip the Amazon
from planetary friend to planetary foe.

As the jungle turns to savanna,
many trees die,

and carbon is released
into the atmosphere.

Carlos has calculated
the Amazon could release

200 billion tons over the next 30 years.

That's equivalent
to all the carbon emitted worldwide

for the past five years.

[Carlos] We are very, very close
to the tipping point.

Are we concerned
about fighting the climate crisis?

Are we, er, concerned
about keeping the carbon in the forest?

Or "I don't care"?

There is reason
to be deeply concerned at this point.

We're still expanding agricultural land
into natural ecosystems.

We are still cutting down the rain forest

at a pace
that puts the whole system at risk.

[David] And it's not
just the rain forests.

Trees of every description are invaluable
in maintaining planetary stability.

So much so that a loss of just 25%
of the world's forest cover

risks triggering
catastrophic tipping points.

But we have already cleared almost 40%.

We are well into the danger zone
for this boundary.

A second major consequence
of deforestation

is a loss of biodiversity.

Of nature.

Biodiversity is the second
of the biosphere boundaries,

because it underpins
our own ability to thrive on Earth.

But we are not treating it well.

Nature is being degraded
at a rate and a scale

that is unprecedented,
er, in human history.

[David] Anne Larigauderie is an ecologist
alarmed by the growing flood of evidence.

Everywhere around the world,
nature is in decline.

One million of species
of plants and animals

out of an estimated total of eight million

are threatened with extinction.

If we continue with this negative trend,

we might be headed
towards a sixth mass extinction.

[David] In just 50 years,

humanity has wiped out
68% of global wildlife populations.

It's clear that we are
in the midst of a biodiversity crisis.

Losing all of this fabric of life,

all of this biodiversity,
is threatening our own life on Earth.

With current negative trends
in biodiversity,

we are not going to be able
to feed the planet.

For that,
you need nature that functions well.

[David] For Johan,
it was a story close to home

that really hit him.

I opened the newspaper and read this story
about UK scientists coming over to Sweden

and stealing, you know,
short-haired bumblebee queens.

And it read like they had,
you know, sneaked over at night

and basically snatched
these hundred bumblebee queens

to bring them back into the UK

and to basically save
what they had been destroying.

[David] Across Europe,
short-haired bumblebees

are key pollinators for food crops.

But by the 1990s, they had been
classed as extinct in the UK.

Here, we have, you know, a country
that feels forced to go to another country

and then steal back
some of its pollinators

to have a functioning ecosystem.

That's a...
Then, you know, to me personally,

that was a moment of, er,
of realization that

this is serious.

[David] Around 70%
of the world's crop species

rely to some extent on insect pollination.

But the expansion
of intensive monoculture is leading

to a drastic decline in insects.

The irony is
that our global production of food is,

in essence,

wiping out the very thing
our food production relies on.

It was not only proof
of one of the fundamentals

in biodiversity research,

which is
that biodiversity is not something

we need to protect
just because of the beauty

or some kind of moral responsibility
from one species, humans,

to another species like flora and fauna.

Oh no, it's the toolbox
for the functioning of our societies.

It is a fundamental piece of the puzzle

to make food production,
clean air, clean water,

carbon sequestration,
nutrient recycling, to work.

[David] Scientists have tried to calculate
the benefits that insects provide

simply by going about their daily business
in large numbers,

each kind providing
a subtly different service.

But their value is mostly incalculable
until suddenly...

they're gone.

A planet without insects
is not a functioning planet.

And, of course, the decline
is not just confined to insects.

Wildlife has been squeezed out

as our agriculture has expanded
across much of Earth's habitable land.

Today, of all the birds on Earth,
only 30% are wild.

And of all the mammals on the planet,

wild species now make up,
by weight, only 4%.

So where is the boundary for biodiversity?

How much more of the natural world
can we afford to lose

before our own societies collapse?

There are many different tipping points
in the natural world,

and it's difficult to translate concretely

the planetary boundary
when it comes to biodiversity,

because life is very complicated.

[David] A single boundary
for the loss of nature

may be hard to pinpoint
because of nature's complexity,

but one thing is clear.

We've already crossed well beyond it.

[Johan] We are so deep in the red.

We are in such a dangerous point

when it comes to losing species on Earth
and destroying ecosystems on Earth

that we have to halt
the loss of biodiversity

as quickly as we ever can.

Now is the time to set as a target

for 2021, 2022,

I mean really
at the early parts of this decade,

that we must aim at a zero loss of nature.

The equivalent of 1.5 degrees Celsius
maximum allowed warming

would be zero loss of nature
from now onwards.

[David] The third biosphere boundary
relates to the planet's bloodstream,

for fresh water is
another of the fundamentals

that society depends on.

Did you know that you and I need roughly

something like 3,000 liters of fresh water
per person every day for us to stay alive?

And you say, "My God, 3,000 liters?
Three tons of water? How can that be?"

Yes, we only need 50 liters
for hygiene and drinking.

We, in the rich world,
use roughly another hundred

for washing, our household needs.

And then industry needs another 150,
so that's like 300 liters.

But the rest,
the 2,500 or so, is for food.

That's the fresh water we need to produce
everything that we have on our plates

when we eat our food.

[David] Fresh water
has a special significance for Johan.

It was the subject of his PhD

and many years of research
in the semi-arid regions of Africa.

I spent from, you know, sunrise to sunset
walking around, sweating like crazy,

collecting data, you know.

Digging profiles in the soil,

taking soil samples,
doing soil moisture measurements.

Just getting wind speed data
and rainfall data.

I've measured so much leaf area.

You don't, you won't imagine, you know,

how careful a scientist has to be
in just measuring in square millimeters

the size of all the leaves on a plant.

[David] It was the details he needed
to answer a much bigger question.

How much water
do we need to feed the world?

My tentative answer
when I was doing my MSc was,

was that,
"Yes, there seemed to be enough water."

[David] But there's
another side to the coin.

Is there a global threshold
for fresh water use

beyond which
the system starts to collapse?

[Johan] We actually scanned off
all the river basins in the world

and then, you know, defining
what's the minimum amount of runoff water

any given river basin must have
to maintain the wetness in the system

so that you have thriving ecosystems,

good supply of water,
functioning river basins.

[David] The volume of water
currently being extracted from each river

reveals why many
are now in danger of running dry.

[Johan] Globally, we're still,
as far as our assessment shows today,

in the safe zone on fresh water,

but we're rapidly moving
towards a danger zone.

[David] The last
of the biosphere boundaries

involves the flow of nutrients,
nitrogen, and phosphorus.

They are the essential components
of all living things,

the key ingredients in fertilizers.

Johan has witnessed firsthand
the impacts of their increasing use.

He spent his childhood summers
on an island in the Baltic Sea.

[Johan] We loved fishing.

Most often, I fished
with my closest friend here, Anders,

and my little brother Nicklaus. And...

So there was often the three of us.

Almost being able
to tell my mother and dad that,

"So you want some fish for dinner?"

and we would come home with a catch,
basically.

One of the adventures was going out

one, two nautical miles
out in the open Baltic,

and that's where we could,
by hand, fishing cod.

I was, at that time,
the best at rinsing the fish,

so, after one hour,
I had to abandon the fishing,

because we got so much cod
that the only way to bring it home

was that we would actually
cut up the fish on site.

So we would have
the seagulls just engulfing us,

because there was so much,
er, you know, entrails

and then pieces of fish
that I was then cutting off

just to fit in the boat.

And that was a cause of great,
great excitement as a kid to do that.

A few decades later, today,
it's a completely different situation,

and you see nobody trying
to go out to catch cod,

because, er, it's just literally empty.

It looks exactly the same, by the way,
as it did in the 1970s, 1980s

when you look at it from above,

but when you look at it from below,
it's something completely different.

[David] When Johan was a boy,
the Baltic was a healthy environment

dominated by predatory fish like cod.

But while overfishing
removed many of the fish,

it was fertilizers
washed off the surrounding fields

that tipped the Baltic into disaster.

It's now the world's most polluted sea.

[Johan] It is when you have many
Baltic Sea equivalents across the planet

that there is reason for deep concern,

because it's a...

It's a signal that the entire planet
is gradually losing its resilience

and gradually becoming weaker and weaker.

[David] Elena Bennett is an expert
on the impacts of fertilizers.

We take nitrogen out of the air
and chemically convert it

into a form
that is able to be used by plants,

or, in the case of phosphorus,
we dig it up out of the ground.

We mine it.

We developed these chemical pathways
or ways to mine phosphorus

that were much, much more efficient,

and that basically doubled, tripled,

or even quadrupled
the production of food around the world.

[David] This was invaluable
in feeding a growing population,

but we got into the habit
of applying far more fertilizer

than the crops could actually use.

The unused nutrients wash into rivers,

over-fertilizing them too.

A process called eutrophication.

What we see are these algal blooms.

Sort of looks like a blue-green scum
on top of the lake.

They often smell terrible

because we're smelling
the rotting of that algae.

As it's decomposing, it uses up oxygen.

[David] Reduced oxygen
changes the chemical composition

of the sediment on the bottom of the lake,
causing it to release more phosphorus.

[Elena] Soon as you have
a eutrophication problem,

the lake sort of says,

"Oh good, we're gonna make it worse,"

and it just creates
a positive feedback cycle

that creates
more and more and more phosphorus

going into that lake
and essentially keeps it in that state.

We also have the same issue
of eutrophication in oceans,

where we get what are called dead zones
from the same nutrients,

and we see those dead zones now

in a few hundred places around the world.

[David] Eutrophication in the ocean
may have been an important contributor

to one of the world's
five previous mass extinction events.

Already today,
some dead zones have expanded

to cover tens of thousands
of square kilometers.

Our overuse of phosphorus and nitrogen

is one of the least known,
but most critical impacts

we're having on the biosphere.

We are already deep into the danger zone.

[Elena] We are well across
the nutrient boundary.

It's... It's not a thing
that we think about very often.

I think we need to be taking this boundary
much more seriously than we currently are.

[David] Nutrients, water, our forests,
biodiversity, and the climate.

Five big components of our planet
that regulate stability

and underpin our own survival.

But Johan and his colleagues knew
that this still wasn't the full picture.

They hadn't yet accounted
for a little-known drama

that's playing out in the oceans.

Its impact on our planet's stability
could outplay all others.

When we emit CO2 into the atmosphere,

about a third of that emissions
has ended up in the ocean.

[David] Terry Hughes
has been a close collaborator with Johan

over many years.

[Terry] That has changed
the chemistry of the ocean.

It has changed the pH

and made it less alkaline, or more acidic.

Hence the name "ocean acidification."

[David] When carbon dioxide
dissolves in water,

it creates carbonic acid.

[Terry] The vulnerability
is in colder waters.

[David] Over the past few decades,

the world's ocean
has become 26% more acidic,

and, for as long as
carbon dioxide concentrations

in the atmosphere remain high,

the ocean will continue acidifying.

The acid reacts with chemicals
in the water called carbonate ions,

reducing their concentration.

[Terry] It affects
a broad suite of organisms,

particularly those that need

carbonate to grow their skeletons.

Things like mollusks, oysters, mussels.

[David] Ocean acidification
has an ominous history.

Global changes in the acidification,

the pH of the ocean,
can actually cause mass extinctions.

We've seen that repeatedly
in the geological record.

So as we manipulate

the planet's climate,
we're literally playing with fire

in terms of the unforeseen consequences

of moving past these planetary boundaries
into uncharted territory.

[David] We are still in the safe zone
for ocean acidification,

but we're pushing towards the danger zone

and potentially
a catastrophic mass extinction.

For all the complexities of Earth,

Johan and his colleagues discovered
that there are just nine systems

that keep our planet stable.

But they've not yet identified
where the boundaries lie for two of them.

The first one is an assortment
of human-made pollutants.

We call it "novel entities,"
and it is everything from nuclear waste

to persistent organic pollutants

to loading of heavy metals

to microplastics.

[David] Humans have created
100,000 new materials,

any number of which could interact
with the environment in catastrophic ways.

As of yet,
this boundary is not quantified.

We simply don't know the long-term
or cumulative impacts

of these polluting substances.

But most have the potential
to cause planet-wide disruption

if not controlled in some way.

There's one form of pollutant
that is already having a global impact.

So much so
that it has a boundary of its own.

Aerosols are basically particles
in the atmosphere.

They are what's called
air pollution particulates.

75% of the aerosol pollution
is from fossil fuel combustion.

We see them as hazy sky,

because they intercept sunlight
and just scatter it like mirrors.

And they cause
what's called "global dimming."

[David] Veerabhadran has spent a lifetime
studying the air around and above us.

The other way aerosols impact climate,

because you're cutting sunlight,
which is the major energy source

for driving the temperature of the planet,
these aerosols have caused some cooling.

When you hear climate scientists like me
say that aerosols are cooling the planet

and mask the warming,
you may think, "That's a good thing."

But unfortunately, it's not.

Because of this masking,

we are still not seeing
the full greenhouse beast.

[David] This cooling effect
from aerosols is masking

about 40% of the effects
of global warming.

And it comes at a high price.

Air pollution kills
over seven million people every year

and takes, on average, three years
off the life expectancy of each one of us.

Where the boundary for air pollution lies

has not yet
been scientifically determined.

Just based on the 7.5 million deaths
by these particles,

I would say we have already
crossed the boundary

as far as aerosols are concerned.

[David] Finally,
the ninth boundary is the ozone layer.

It has the unique distinction
of being the only boundary

where we're moving in the right direction.

[Veerabhadran] The ozone intercepts
harmful ultraviolet radiation,

which directly impacts our DNA

and causes deadly diseases
like skin cancer.

That is why,

when the Antarctic ozone hole
was discovered in the 1980s,

there was a global panic.

[David] The discovery of the ozone hole

caused by chemical pollutants
being released into the atmosphere

persuaded nations
to phase out these chemicals.

[Johan] It was quite fantastic
how the scientific warnings

translated into political action.

This is the first and only example

that we can actually
manage the whole planet.

We can actually return
into a safe operating space

for a planetary boundary that we had
seriously gone into the high-risk zone,

and we returned back
into a safe operating space.

It was indeed fantastic to witness.

Scientists raised the alarm,
and the world acted.

Thanks to Johan and his colleagues,

we now know the planet has nine boundaries

and the risks we face by crossing them.

Together with the ozone layer,
we are, at least for now,

within the safe zone
for ocean acidification and fresh water.

We don't yet know how close we are
to the danger zone for air pollution,

or for all the other pollutants,
the novel entities.

But most worryingly,
we have already exceeded

at least four of the nine boundaries.

Climate, forest loss,
nutrients, and biodiversity.

We are now crossing
irreversible tipping points,

and we are perilously close
to tipping the Earth

into a state that is unable
to support our own civilizations.

What we're seeing in the world today
verifies the planetary boundary framework.

We can see so clear evidence that,

because we're in the danger zone
on climate,

because we're in the deep high-risk zone
on biodiversity loss,

we start seeing increased drought,
impacts on the rain forest,

the forest fires
in Australia and in the Amazon,

the accelerated ice melt,
the collapse of coral reef systems.

[David] For the scientists bearing witness
to these planetary changes,

the loss is much more than just numbers.

Terry Hughes has spent a lifetime
studying coral reefs.

[Terry] A bleached coral
is very, very sick.

[David] Corals bleach
when the waters around them get too warm,

something that's happening
with increasing frequency and intensity

as a consequence of global warming.

In big thermal extremes,
like we've been seeing

during mass bleaching events
in recent decades,

they can actually die very, very quickly.

They cook.

The footprint of a bleaching event
is ten times bigger

than the most extreme
Category 5 tropical cyclone.

So they're off the scale
in terms of the size of the impact,

and in terms of how frequently
they are occurring.

[David] Terry studies
the Great Barrier Reef,

the largest reef system in the world.

Bleaching events
used to be localized and rare,

but over the past two decades,

marine heatwaves
have caused widespread bleaching.

Three of the five biggest bleaching events
have occurred in the past five years.

[Terry] We're worried
about that shrinking gap

between one bleaching event
and the next one.

We've already seen
back-to-back bleaching events

occur for the first time
on the Great Barrier Reef

in two consecutive summers
in 2016 and 2017.

[David] Those gaps are critically
important if the corals are to recover.

Half the reef's corals have already died.

Terry's work involves
conducting aerial surveys

to record the extent
of each bleaching event.

[Terry] When we do our aerial surveys,
we fly as slowly as we can,

as low as we can,
so we can see individual corals,

and we can assess how many of them
are bleached white or not.

[Terry] All the coral's bleached.

[man] Yeah, that's bad.

[Terry] You can actually see
a bleached reef from kilometers away,

because it virtually glows.

There's so much white coral on it.

[Terry] So I've got very broad crest,
and just about everything's bleached.

Those surveys have now been done
five times,

and I have led three of those.

The last three in 2016, 2017, and 2020.

It's, um...

It's a job I'd hoped I'd never have to do,

because it's actually,
um, very confronting.

Sorry.

[David] We're heading for a future
in which the Great Barrier Reef

is a coral graveyard.

[Terry] The climate modelers
are telling us, the biologists,

that business-as-usual carbon emissions

will result
in back-to-back bleaching events

every consecutive summer
by the end of this century.

We've gone past
the tipping point for coral bleaching.

Scientists and ecologists like myself

have been talking for decades now
about global warming,

and it has been frustrating,
um, that we haven't been listened to.

I get angry.

I don't get depressed. I get angry.

There is a real reason to be frustrated,

because the science is clear

and has been communicated
for the past 30 years,

and still
we're not moving in the right direction.

I want you to panic.

I want you to feel
the fear I feel every day.

And then I want you to act.

I want you to act
as you would in a crisis.

I want you to act
as if the house was on fire.

Because it is.

[woman] The bush fires in Australia
have raged for months,

destroying so much
of the country's east coast...

[David] In 2020,
Australia endured a summer from hell.

[man] And our only way out is now

a treacherous gauntlet
of fallen trees and flames.

[David] Fueled by record-breaking
temperatures and months of severe drought,

50 million acres of lands
were incinerated.

People fear
this will become the new normal.

But the science says
there will be no normal.

Daniella Teixeira studies
glossy black cockatoos,

one of Australia's most vulnerable birds.

[Daniella] Glossy black cockatoos
let you get really close to them.

They will learn who you are,
and, in places where you visit regularly,

they actually, I think,
get to know who you are,

and so you can actually go up to them,

sit underneath the tree
where they're feeding,

and get to know the individual birds.

[David] As soon as it was safe to do so,

Daniella returned
to one of her main study sites

on Kangaroo Island off South Australia.

It's February.
Nesting season for the cockatoos.

[exhales]

There's no sign of any wildlife at all.

Um...

There's nothing left here.

It just looks like

complete carnage.

It's almost like I'm not looking
at the spot that I know.

Like it's almost like
this can't be the same spot,

because it's so starkly different.

Yeah, I've spent the last four years

working in this very location, so this is...

This is about, um...

Yeah, this is about as hard as it gets.
This spot was really, um...

Like there was a big commotion
every evening.

We would have had young chicks
by this point.

[sighs]

This is... This is heartbreaking.

Jesus.

[sighs]

[sniffs]

I know this nest

pretty well.

It's absolutely horrible
to see it like this.

And all that's left is...

Is the iron collar
just burnt on the ground.

Like, the iron collar is...

Is what we put on the nest trees
to save them.

To stop the possums

from...

From predating on the chicks.

And just to see all around me
these iron collars just

open on the ground.

You know,
they weren't enough to save them.

This is an ecological catastrophe.
There's no doubt about it.

[David] The 2020 bushfires

were the most devastating
in Australia's history.

[Daniella] Climate scientists
have been talking about these events

for a long time,

and we were expecting
that this might happen,

but I don't think
anybody expected it to be so soon

or so severe.

[David] Scientists estimate that the fires
killed or displaced three billion animals.

[Daniella] 1.43 million mammals,

2.46 billion reptiles,

180 million birds,

and 51 million frogs.

These figures are so enormous,

so consequential...

I don't know how to make sense of them.

That's not what we should be dealing with
as conservationists.

I think this is a wake-up call.

These black summer fires
really showed us that it's now,

it's affecting us today,

and this is gonna have
long-lasting consequences.

Like, where can he go?

[David] Wildfires and coral bleaching

are caused
by us overstepping the climate boundary.

But it is the destruction of nature
that lies behind what has been by far

the most far-reaching impact
of our destabilizing planet.

The COVID-19 pandemic.

It affected your life as it affected mine.

COVID-19 was a planetary impact
we were ill-equipped to deal with.

It overwhelmed health services

and brought the global economy
to its knees.

Though it surprised many,

the World Health Organization
had forewarned that it was coming.

I think it was a question of time.

Er, we were destroying nature.
We were destroying our ecosystems.

We have been doing
very aggressive agricultural practices.

We were doing an incredible,
very aggressive deforestation.

If you add to that the fact
that we live in very polluted cities

with a very high population density,

I think all of those elements
were kind of contributing to create

the perfect scenario
for any new virus to spread.

[David] Zoonotic diseases emerge
and spread into the human population

when nature's resilience is weakened.

It's not healthy nature
that causes pandemics.

In terms of transmission of the diseases,

it's only with certain species
under certain circumstances

and when we invade their environment
in a very aggressive way.

So, for the human health,
animal health, and environmental health,

the three are so much linked.

Exposure to nature is good,

provided we do not destroy nature

and we not destroy the ecosystems
where other species are able to live.

COVID-19, I feel, has made us understand

for the first time that,

"Oh my God, something that goes wrong
somewhere else on the planet

can suddenly hit the whole world economy

and can change my life,
like, immediately."

The appearance of COVID-19

was a clear warning
that all is not well with our planet.

But it's also given us an opportunity
to rebuild in a new direction.

Now that Johan and his colleagues
have turned on the headlights,

we can clearly see the boundaries.

We can see the path back to a safe space,

to a more resilient future.

It is achievable.

It's not a question anymore
of doing economic growth here

and then do some
environmental impact reduction over here.

Oh no, now it's a question
of framing the entire growth model

around sustainability,

and have the planet
guide everything we do.

[David] An immediate priority
is to reduce carbon emissions to zero

and stabilize global temperature
as low as we possibly can.

The window is still open for us
to be able to avoid passing two degrees.

It's even open to come to 1.5.

But the window is really just...

It's... It's barely open.

[David] Since the beginning
of the Industrial Revolution,

we have emitted
2,400 billion tons of carbon dioxide.

To stay below 1.5 degrees,

we must emit
less than 300 billion tons more.

If we continue to emit
40 billion tons each year,

our budget will run out
within seven years.

Of course, we cannot shut down

all energy utilities in the world
overnight,

so the only orderly way to do this

is to bend
the global curve of emissions now,

because that's what all science shows.

Now is the last chance we have
to bend the global curve.

What is the most rapid pace
of emission reduction

that we can accomplish?

Well, there's no study that suggests
that we can go faster than 6, 7% per year,

because 6, 7% per year,
that is cutting by half in a decade.

[David] Cutting our emissions
in half every decade

is an exponential rate of change.

[Johan] Anyone can adopt this pace.

I mean,
you and I can do it as individuals.

We can say,
"Okay, from now on, myself and my family

will try to cut emissions
by half every decade,"

which would mean
that you would be fossil fuel-free

in one generation, in 30 years' time.

And a company can do it,
or a country can do it,

or the world can/must do it.

[David] Phasing out fossil fuels
will, of course,

begin our journey
back towards the safe space

within the climate boundary.

And it will also
substantially reduce air pollution

and also slow down ocean acidification

as well as reduce pressure
on biodiversity.

But zero emissions are not enough.

We must also draw down the carbon
that's already overheating the planet,

and there's one very effective way
to do this.

Plant more trees.

A global effort to plant billions of trees

could be one of the most cost-effective
and achievable solutions

to the climate crisis.

And growing more trees is vital
to offset the carbon we continue to emit

as we strive to reach zero emissions
as fast as we can.

Of course, capturing carbon

is only one of the benefits
that trees provide.

Cheikh Mbow has collaborated with Johan
for many years.

He's an advocate for trees.

[in Wolof] Trees prevent soil erosion.

Without trees, there will be less rain.

If we plant trees in the fields,

the fertility of the fields
and, therefore, production will increase.

We want to bring the tree back
to its place

at the center of sustainable development.

Our job is to make sure
that wherever a tree can grow,

we plant one.

[David] Planting trees
and restoring our natural world

will, of course, have huge benefits
for our planet's biodiversity,

but it will also help
to stabilize our climate, our fresh water,

and have enormous benefits
for our food production

and all the other services
that nature provides for free.

Just imagine, for the first time
since the dawn of humanity,

we could wake up one morning

on a planet with more wildlife
than there was when we went to sleep.

There's another transformation
that is almost unbelievably simple,

but it's key to staying
within our planet's boundaries.

It can be adopted by you or me.

In fact, by anyone with the freedom
to choose what food they eat.

[Johan] Now, the exciting thing
is the diet that is more flexitarian,

less red meat, more plant-based protein,

more fruit and nuts, less starchy foods,

if you take that diet

and assume that all people
would eat healthy food,

we could actually come back
within a safe operating space,

not only on climate,
but also on biodiversity,

on land, on water,
on nitrogen and phosphorus.

Quite exciting that eating healthy food

might be the single most important way
of contributing to save the planet.

There's one more transformation
that is vital.

It would bring us
back towards the safe zone

within all our planet's boundaries.

Imagine a world without waste,

with nothing to throw away.

Our waste is created by design.

When we make products,

we rarely build in the means
to recover the raw materials.

If we turn that linear system
into a circular one,

designing products
so that the raw materials

can all be recovered,

our use of resources could be infinite.

[Johan] So more and more evidence
shows that circular economies

are fundamental
if we are to stand a chance

of providing good lives
for all citizens in the world.

[David] Eliminating waste would bring us
closer to the safe zone for climate,

biodiversity, and especially nutrients,
novel entities, and air pollution.

The planetary boundaries
have given us a clear path ahead.

Simple things,
like choosing renewable energy,

eating healthy food, planting trees,

saying no to waste.

Together, these could transform
our future on Earth.

And the magic in this
is that these transformations

would also improve
all our lives right now.

[Johan] Even if you don't care at all
about the planet

and even if you don't care too much
about equity in the world,

but rather are selfish,
just focusing on yourself

and your family and your own life,

which I think
is a very respectful position to have

as a human being
struggling with everyday life,

still you would want to come back
to a safe operating space.

Everyone would benefit immediately
of having clean air,

giving more healthy
and longer life expectancies.

Your children would be healthier.

Coming back within planetary boundaries

also means you are more likely to live in,

in societies with, you know,
stable markets and stable jobs,

which then reduces risks of conflict
and instability where you're living.

So, all in all,

you want to be in a safe space,

rather than being in a danger zone
where everything is just in flux.

What we do between 2020 and 2030,

from the evidence we have today,
my conclusion is,

it will be the decisive decade
for humanity's future on Earth.

The future's not determined.

The future is in our hands.

What happens over the next centuries

will be determined
of how we play our cards this decade.

[David] It's a remarkable time
to be alive,

but it also carries great responsibility
to act decisively.

We have no time to lose.

[Johan] What would we do
if we had had a report tomorrow morning

saying that an asteroid
is on its way to Earth?

Well, I'm sure that we would
just put everything else aside

and just focus then
on solving the problem.

Cost whatever cost it takes.

[David] It is now clear from the science

that the planetary crisis we are facing
requires the same united response.

[Johan] I would say that we do not have

environmental problems
in the world anymore.

Destabilizing the planet...

The risk of destabilizing the planet
is a question of security and stability

for all societies in the world.

Therefore, it is a question
for the Security Council.

I think one should put the planetary
boundaries right at the center

of the most strategic top governance level
we have in the world,

which is
the United Nations Security Council.

[David] Such a global response
is now within reach as never before.

There's something bigger
happening right now,

which is that one species, we humans,

are such a dominant force on the planet

in a way
that we haven't seen across the eons

over the past four billion years.

Mother Earth is under continuous diagnosis

and continuous observation.

The digitalization
and the hyper-connectivity

in the world of science
and in the world of observation

now means we've covered
the whole planet with knowledge.

What if we're now entering

a new, unique geological epoch

that is not only geophysically defined,

but also defined by the fact that we have

a new consciousness
embedded inside the planet?

Thanks to the work
of scientists like Johan Rockström,

we now have the capacity to act
as Earth's conscience, its brain.

Thinking and acting
with one unified purpose

to ensure that our planet
forever remains healthy and resilient.

The perfect home.