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Life...

The closer you look,
the more mysterious it seems.

We can't see
the invisible forces at work.

But what if we could?

It's time to look
at our home...

...in a whole new way.

Imagine carbon
cycling through nature.

It's one of the building blocks
of life.

And it's stored
in our forests...

...oceans

and grasslands

on an incredible scale.

But we've released too much
of it into the atmosphere,

risking our future.

We can halt emissions
and draw the carbon back down.

And our best ally for that
is nature.

Restoring it to abundance

is the biggest challenge
of our time.

But we can do it.

If the future of nature
looked brighter,

so could the future for us all.

To me
personally, forests are special

because you're surrounded
by giant beings, these trees.

A forest is much more
than the individual bodies,

objects that you can see,

the trees or the soil
or the animals.

There's a huge world of
interaction and communication

beyond
our immediate experience.

And through science,

we begin to get glimpses
of that world.

Professor Yadvinder Malhi
from Oxford University,

has been studying this forest
for over 20 years.

It's a profoundly
central part of my being,

I think, being out,

realizing that
you're just one being

in a community
of species and entities

and different forms of
consciousness all around you.

Research at Wytham Woods
began in the 1920s.

It's one of the first places
where scientists came up

with the concept
of an ecosystem.

So here, we've got
this caterpillar consuming

the leaves of this tree,

and it's what makes up
a forest ecosystem -

not the individual tree
or the individual caterpillar,

but this interaction
between the two.

This caterpillar may end up
being consumed by a blue tit,

taking the food
to feed its young chicks.

And the leaf is also probably
creating chemical signals

to attract birds to tell them
that this caterpillar is here.

This is just one small example

of thousands of such
interactions

between species occurring
above the forest,

in the canopy,

and below in the ground
as well.

These connections
keep the forest healthy.

All living trees
are adorned with leaves.

Beneath every single one
are thousands of tiny holes -

stomata.

They draw in carbon dioxide
from the air,

which the trees turn into food
to help them grow.

And nowhere is carbon drawdown
more powerful

than in the great
tropical forests of our planet.

Fed by constant rain
and sunshine,

the trees grow rapidly here.

It's been like this
for millions of years.

Dense forests are
the hardest to study,

the animals often
impossible to see.

So the few places
where we can learn

about how the forest works
are invaluable.

Kibale National Park lies
on the eastern edge

of the Congo rainforest
ecosystem.

Here, our closest relatives
are under observation.

Margaret Kobusingye
is the field manager

of the Kibale Chimp Project.

She leads a team of researchers
who keep up with the chimps

from dawn until dusk.

Every detail of their lives
is recorded.

Who's grooming who.

What they eat.

And where they go.

A fig tree in fruit
brings them all together.

Chimps are fast eaters,

consuming up to ten figs
a minute.

And they can eat for up to
eight hours at a time.

By feasting on these fruits,

they provide an invaluable
service for the trees,

helping to spread their seeds
across the forest.

Animals like chimps
are critical

to the health of the forest.

Yet across the whole of Africa,

less than 250,000 remain.

Here in Kibale,

protection is making
a difference.

We cannot have the trees
without the animals.

And so we need them
to be around.

The Congo rainforest is home

to some of the largest trees
on the planet.

And when it comes to carbon,

the bigger the tree,
the better.

Giants here can tower
over 200ft tall.

But to reach
their full potential,

they need help
from another creature.

Forest elephants
are nature's gardeners.

Smaller than
their savanna cousins,

they still eat
an incredible 400 pounds

of vegetation per day...

...mostly the shrub layer
that's easy to reach...

...which gives larger trees
more space to grow.

There are
over 10,000 animal species

in the Congo rainforest.

They're all part
of a complex web of life

that keeps the ecosystem
working.

The Congo rainforest covers

more than
1 million square miles.

It is so large,

it influences the climate
across the entire region.

The rainforest causes humid air
to rise into the atmosphere...

...forming rivers of cloud

that transport billions of tons
of water north...

...where it hits
the Ethiopian highlands

as rain...

...feeding rivers which sustain

some of the driest regions
in Africa.

The influence of a forest
extends far beyond its borders.

And every forest on Earth
has its own unique character.

In the north
are the boreal forests...

...dominated by evergreens
that take time to grow.

It's quieter here.

Not so many animals and only
a few tough species of tree.

Scots pines can live
for 500 years.

They're not the fastest
at drawing carbon down,

but they are good
at storing it.

To study this,
David Coomes and Aland Chan

from Cambridge University

are using
some unusual technology.

We can map the trees

and work out
how much carbon is in them.

We've been working
with this lidar data set.

We've popped it into
one of the bits of software

that game developers use,

and then we just see it
from a person's perspective.

This helps map the forest.

And lidar can show precisely

how much carbon is locked up
within it.

In this restoration area,

David and Aland can assess
the drawdown benefits

of regrowing a forest.

We have this sort of...

If you look at the mountains
behind us,

that will be around 800m
in elevation.

So naturally,
the forest would extend

all the way back up
to 650m to 700m in elevation,

and the goal is to try to get
the trees and forest

to extend back up there
through natural regeneration.

As it grows, each sapling
has the potential to draw down

half a ton of carbon dioxide.

And what makes
the boreal forest

even more unique
is where that carbon ends up.

So as well
as understanding

what these amazing,
ancient trees are doing,

we're also interested

in what's happening
below ground.

And in these boreal systems,

the soil is mostly made up

of organic materials
like this -

leaf litter, pine cones,

but also roots

and some incredibly important
fungi sitting in there as well.

Together, they form a layer

which is incredibly slow
to decompose.

This organic matter accounts

for over half of all the carbon
stored in the boreal forest.

The rest is held in the trees.

It's the largest carbon store
on terrestrial Earth.

Looking after it in the face
of climate change is essential.

So the boreal forest,
first of all,

is a forest of cold.

The vegetation grows
quite slowly.

It stores twice as much carbon
per hectare

as any other
terrestrial ecosystem,

including the tropical forests.

I'm a member of the Innu
community of Mashteuiatsh.

But I'm also
the executive director

of the Indigenous Leadership
Initiative.

Because of my connection
as an Innu woman,

I've always known
that I would be doing work

to protect
and work with nature.

The boreal is very much home

to the iconic species
of caribou,

and it's such a fundamental
part of Canadian identity.

I mean, it's on our quarter.

It is what has allowed
my people to survive

in this landscape
for over 10,000 years.

Because the caribou
are so sensitive,

when they're present,

it's a good indication

that other species who
are a little bit less sensitive

will also be present
in that area.

They're kind of like canaries
in the coal mine

or a way of really giving us
an alarm

about what's coming
in these ecosystems.

And so
we're definitely looking,

as foresters and as people
who manage these areas,

to find caribou,
because it's a good way

of telling that
the whole system is healthy.

Caribou need
old-growth forests.

In this cold environment,

the lichens they eat
take up to 50 years to grow.

But even the slowest ecosystems
need a boost now and then

to get the nutrients moving.

Boreal is
an ecosystem of fire.

The soils in the boreal
are quite poor.

And because that organic matter
decomposes so slowly,

over time,
that soil can break down

and become less and less
productive over time.

Well, what brings back
that productivity, in part,

is fires,
because what it does is

it breaks down
that organic matter

and all the nitrogen that is
in that matter gets released

into the soil.

Natural fires are
usually started by lightning.

Big burns used to happen
once a century, giving time

for the slow-growing forest
to recover.

Fires are becoming
more intense,

larger and more persistent
than the norm.

Canada has had a long
forest management history,

so we know what is
the natural cycle of fires.

And so every once in a while,
there's a big fire.

Then there's a lot
of little fires.

But what's happening is

we're not getting a lot
of little fires anymore.

We're just getting big fires.

More frequent storms
and hot, dry weather

are causing infernos that
are actually damaging soils,

impacting
the old-growth forest,

caribou
and also local residents.

I've got a lung disease
that was probably exacerbated

by the fires last year.

Two weeks after the fire
started,

did I notice that I was having
shortness of breath.

Peter Durocher lives
in Ile-a-la-Cross,

in Saskatchewan.

I feel like I'm grounded
when I'm right here.

I don't feel grounded
in my house.

Here, I'm grounded.

It's beautiful.
Forest is healing.

Peter belongs to
the Metis Indigenous community.

The boreal forest has been
their home for generations.

Indigenous people
need forest.

I feed my family
off the forest and the water,

whether it's the rabbit,

or the deer, or the moose.

But under the pressure
of climate change,

life in the forest
is getting harder.

This fire was only
about four hectares

the first time it was seen.

Four hectares.

And it ended up burning
close to a million hectares.

That's a crazy number, eh?

The initial fire seemed
too small and too far

from habitation to be
a priority for the province.

There was no response to
the community's calls for help.

By the time action was taken,

the fire was bigger
than Chicago.

In all my life, all my 62 years
of living on this earth,

I never seen a fire behave
like that.

Fire was burning at 2:00
or 3:00 in the morning,

as hot as it was burning

at 2:00 or 3:00
in the afternoon.

By the time
May 29th came around,

the fire was uncontrollable.

In 2023,

the hot, dry spring caused
fires to burn so intensely,

they destroyed
over 70,000 square miles

of boreal forest

and sent a veil of smoke

to New York City
and far beyond.

Hundreds of wildfires continue
to burn across Canada,

many of them out of control.

An ominous orange haze envelops
the Statue of Liberty.

Wildfire smoke from Canada
has billowed across the border.

As firefighters try
to contain the fires,

officials in many US cities
warn

air quality is at code red.

100 million Americans
are under air quality alerts.

The potential health threat
posed by wildfire smoke

spanning as far south
as Georgia and Texas.

Normally, where it burnt here
would have slowed down,

but because
the fire was so hot,

look how high it burned.

Look at my hands. I mean,
this is just from one tree.

You know?
This is only from one tree.

One little... one little tree

that's probably
only 15 years old.

Now, if you look at a fire
of our size here that has

10 million trees, you know,

how much carbon
is actually being released?

If this tree released
that much carbon,

what happens if a million trees
burn like that?

What happens if a billion trees
burn like that one year?

There's a problem out there,
just nobody's listening to us.

Keeping the infernos
in check is essential

if we want the boreal forest

to help balance
the Earth's climate.

The generations
that are coming up behind me,

what are they going to see?

Change is going to happen.

The biggest worry I have is
how fast the change is coming.

I love my grandkids,
all of them,

and the forest is up there.

And I want my granddaughter
to experience it.

I call her an old soul
because she feels what I feel.

And how do you say rabbit
in Cree?

- Wapos.
- Wapos, yeah.

- See right there? Look.
- Yeah.

Yeah, wapos.

We went hunting moose,
and she came with me,

and we were sitting there,
and she says, uh, "Listen."

I said, "What?"

I said, "You hear a moose?"
"No."

She said,
"You can hear the forest,"

you know, which is the wind, right?

So... And I thought
it was just a blessing,

a blessing for her
to feel that,

to understand that.

Indigenous people
take care

of more than a quarter
of all the land on Earth.

But they need support.

In Canada, the government
has pledged $800 million

to fund that stewardship.

It's a start, but there's
an urgency for us to recognize

the value of forests.

To understand what forests do
for our global climate...

...we have to take
a more mathematical approach.

Forests are the cathedrals
of nature.

They are where most
of the biodiversity lives.

And so it shouldn't be
a surprise

that forests are central

to the carbon story
of this planet.

And we're all trying to
understand the climate system

and help society fight
against climate change.

Now, part of that fight
is understanding

precisely how carbon moves
across the planet,

in and out of our ecosystems.

Building on years
of scientific data,

the Climate Center has created
detailed maps that show us

where the carbon flows
in and out of our forests.

They show that it's not just
the tropical and boreal forests

that are significant
in the global carbon story.

One of the world's largest
managed forests is found

along the Appalachian Mountains

on the eastern side
of North America.

Temperate forests
can be extraordinary sinks.

If managed well,
they can draw down carbon

at rates that are comparable

to the other forests
of the planet.

And because we live
with and next to them,

we have
an extraordinary opportunity

to really manage them better.

The Appalachians
are 2,000 miles long,

and they're home
to 26 million people

who live amongst
the deciduous forest.

Each farmstead has
a different story.

My grandfather purchased
this property in 1943,

and we've held it since then.

Susan Benedict is
the third generation manager

of her family's land.

Today, it's filled
with over 2,000 acres

of mixed hardwood forest.

But this hasn't always been
the case.

In the early 1900s,

great swaths of it
were harvested.

There was so much
environmental damage done

with all of that clear-cutting,

the streams were all clogged
with mud.

I'm sure that species that
need trees weren't here then.

Since that initial felling,

trees have been planted
and cut several times.

Often just a single species
was used for easy timber.

But this left the trees
vulnerable

to pests and disease.

The year my father died,
in 2006,

we had a three-year outbreak
of gypsy moth,

coupled with a drought,

and our consulting forester
estimated

that our losses of timber
was in excess of $1 million.

And there's no insurance
for that.

That's just an economic loss
that we can't make up.

To hold their place
in this working landscape,

forests have to be
economically viable.

And that means healthy...

...which is where
nature comes in.

Even in those woodlands managed
for timber,

animals like black bears,

which spread seeds
far and wide,

can really enhance
forest biodiversity.

They're a keystone species

along the entire
Appalachian range.

But biologist Katie Martin
has noticed

what looks like
a worrying decline.

Bears are a pretty good
indicator of healthy forest.

Forest and the wildlife
are truly linked.

They all work together
in a working ecosystem.

For the forest to function
as it should,

we need the wildlife.

And vice versa,
the wildlife need the forest.

If one is out of balance,
the whole thing can fall apart.

Virginia bear populations
have been a huge success story,

but unfortunately,
in recent years,

we have noticed
a change in our bears

and something
that's on the landscape

that's making us pretty nervous

about what's happening
with our bear population.

The bears are unwell...

...and many are dying.

Katie is trying
to find out why.

We've actually got
these little field kits

we've developed
where you can do a skin scrape

really easily on the bear
while you've got it down,

look at it
underneath the scope.

This bear is suffering
from a severe outbreak

of mange, a painful skin
condition caused by mites.

It's something bears
normally survive,

but recently it's been getting
more dangerous.

And unfortunately,
here in Virginia,

we see a lot of
really severe cases

that do end up leading
to the death of the bear.

So it's really sad
and heartbreaking to see.

It is certainly a wide variety
of factors that we think

are probably impacting
the bears

and maybe causing
these impacts from mange.

The mites are likely
able to live longer

out on the landscape
if we have warmer winters

because they're just, you know,
not succumbing

from cold temperatures
in a den site

or out on the forest floor.

Potentially,
that's helping the bears

that are picking up mites
more frequently,

because the mites
can live longer.

A mite population
unchecked by winter

may be impacting
less resilient bears.

As we've seen winters get
a little bit warmer

over the past few years,

this obviously, when it's
70 degrees in January,

a bear is a hot animal,

they're going to get up
and start wandering about.

There's still not food
available in the forest

at that time of year.

So unfortunately, that means
likely getting into more urban

or residential areas

where garbage can be available
to them.

All of these things that are
not natural foods for a bear

end up becoming maybe
a primary source of their diet.

Junk food could be
weakening the bears' immunity,

and in the south,

they're waking early because
of rising temperatures.

To help this whole area
become more resilient

to climate change,

an ambitious project is needed.

I'm Marc Anderson. I direct
The Nature Conservancy's

Center for Resilient
Conservation Science.

My generation's spent
so much time

convincing our peers

that climate change
was real and serious,

that we didn't realise

the effect we were having
on our own kids,

who were losing hope
and not seeing a future.

But there is a future, and now
we have to focus on solutions.

And a big part of that solution

is healthy, functioning,
thriving nature.

The Appalachians are one
of the largest remaining areas

of temperate forest
in the world.

Running north to south,

they are also a major corridor
for wildlife.

We call it a climate highway,

where most of nature
will be moving northward

or upward to adjust
to a warming temperature.

It's predicted
that, every decade,

plants and animals will move
11 miles north and 36ft higher.

Mark's project aims to ensure

that they have the space
to do so.

So the key to creating
a resilient landscape

for the future is understanding
where we need to work.

That's what I've been working
on for the last 15 years.

And we've produced a map
of the results of that

which we're now sharing
publicly.

The green areas on this map
are the lands most resilient

to climate change,

and the blue areas connect
those places together

into a connected,
resilient landscape.

To create
effective wildlife corridors,

landowners in the Appalachians
will have to help out.

One of the reasons

we've created this tool
and released it

is because we need people
as part of the solution.

So we need to involve them
in the science

and involve them
in the conservation.

- That would be interesting.
- Yeah.

Susan has recently enrolled

in the Family Forest
Carbon Program,

a new market
for sustainable forestry.

So, Susan, how's the
program working out for you?

We really have benefited
from it.

This area here is part
of our mature forest

that's enrolled in the program.

Through the project,
carbon offsets can be sold

and experts help people
manage their forests better.

Right now, I think
our our biggest project

is to train the next generation

in how to steward
this property.

That's why we involve
the grandchildren.

This is the forest for them
that we're planting now.

They're the ones
that will be able to enjoy it

and benefit from it.

Riley is
our expert tree planter.

She does a good job.

I love coming up here.

It is my favourite place
in the world.

Being up here makes me think
of the future

and what I can have
and what I want to have.

I'm gonna own this place
one day.

And I just think
that it's really cool

that I have to learn
all this stuff from my family.

I think that climate change

is one of the biggest problems
in our world.

And my family is trying to help

by, like, keeping this forest
healthy.

And personally, I feel like
we're doing a good job.

Family tree farms
like this one can be part

of a connected
and resilient landscape,

enabling wildlife
to move around and settle

in newly restored areas.

Recently,
we're very excited

because beavers have come back
to our stream and our pond,

and we feel like

that is a real ecological
success for us,

that they've chosen to be here,

and we're very happy
to have them with us.

Our forests
are holding on

in the face
of climate change...

...but they're under
extreme pressure.

Keeping them strong
and resilient

is key to their future...

...and ours, too.

There are
nearly 400 billion trees

in the Amazon rainforest.

That's three times more than
the stars in the Milky Way.

But if the world continues
to burn fossil fuels,

this entire ecosystem
is at risk of failure.

How this might happen
is what an experiment

in the heart of the forest
is trying to find out.

I usually scared of heights,
but then, you know,

the first time I flew on this
was so amazing.

Here in Brazil,

Dr Carlos Alberto Quesada

runs a project called
AmazonFACE.

It stands for
Free-Air Carbon Enrichment.

The idea is to try to mimic
these conditions,

particularly with the CO2,
the best we can,

so we look how the forest
will behave

and try to understand
what's going to happen

to the Amazon in the future,
and then we can get prepared.

It took ten years
to get the funding

to build these structures
deep in the forest.

16 towers 100ft tall,

encircling 90 adult trees.

Carbon dioxide is pumped in,
simulating the elevated levels

that scientists are expecting
in the near future.

We really need
to get this right, you know,

to understand,
OK, how this will work.

This will influence your life,
my life, everybody's life.

So we really need to study
everything we can

inside of those rings.

So please don't step
off the path.

OK?

How the trees respond will help
predict the fate of the forest.

Here, we measure
the soil respiration.

And here is
the root productivity.

This machine measures
the CO2 concentration.

As well as increased
carbon dioxide

in the atmosphere,

climate change is predicted
to make the area

seven degrees hotter,

with only half the rainfall.

If this happens,

conditions couldn't support
a rainforest at all.

The tests will help to indicate

how soon this scenario
might become reality.

Without this giant forest
absorbing carbon dioxide,

the effects on the world's
climate will be catastrophic.

This great forest pump
can't be allowed to switch off.

Protecting the Amazon
should be a high priority.

But as well as suffering
climate change,

it's under
constant human pressure.

Over a million acres
are destroyed every year

in Brazil alone.

The country has pledged
to cease deforestation by 2030.

But so much
has already been lost.

The only hope for restoration
is with the communities

who know it best.

Like the Xingu people
of Mato Grosso.

When people have
to help nature,

it requires
an intimate knowledge

of the ecosystem.

Some of the seeds
the women gather will be used

by the Xingu Seed Network,

an organization funding
forest restoration.

Working for this network

is Milene Alves
de Oliveira Lima.

Since joining the Seed Network
ten years ago,

Milene's life has transformed

from a young girl
in a poor neighborhood

to a mother embarking
on a master's degree.

She's now using
her academic training

to find out
if any of these seeds

will survive
in the fast-warming climate.

Seeds that can still germinate
in heat wave temperatures

are now essential
for successful reforestation.

Some species will be lost,
but there is hope.

The tests show that the larger,
harder seeds can survive

extreme heat waves.

This helps Milene choose
the perfect cocktail,

mixed together
in a process called Muvuka.

The mixing mimics
the chaos of nature,

and it's nearly four times
more effective

than traditional tree planting.

Many of the farms here
are agricultural wastelands.

Regulation requires them
to restore forests

to a fifth of their land...

...and some farmers
have responded

with promising results.

Valmir Schneider has been
on his reforestation journey

for many years.

The seeds of over 40 species
of native trees

were planted here.

These pockets of trees will
draw down carbon as they grow,

but if they're isolated
by miles of farmland,

the biodiversity
that makes them sustainable

will never return.

These small patches
must become so much more.

Whatever challenges we face,

we are stronger
when we work together.

Nurturing a connection
with our forests

is the first step
to looking after them.

You have to think
forward to the next generations

and take joy
in the hope of the future.

Resilient forests

are the best
carbon drawdown tool we have.

Imagine a world where forests
can thrive and flourish

hand in hand with humanity.

While we still have forests,

we still have hope.

There still remains
huge opportunities

to really protect what's left.

Not only for our own benefit,

but that of
the rest of the world.

Well, we need nature to adapt
to a changing climate

because we need a living,
breathing world.

With forests
in our future,

that future will be brighter.