All language subtitles for NOVA.S47E15.Can.We.Cool.the.Planet.1080p.AMZN.WEB-DL.DDP.2.0.H.264-GNOME_track3_[eng]

Are rising temperatures driving

Earth's ecosystems
past a point of no return?

We can't go back.

There is no path backwards.

Every
year, the damages are worse.

We have promising technologies

that put solutions
within our grasp,

but are we reaching far enough?

We have to have emissions

cut to zero.

Even if we stop emitting CO2,

we still have the CO2
we've already emitted.

So scientists
are building a new toolkit...

It has power.

To ensure a prosperous future.

Our society has to survive.

We
need to reduce the heating effect.

Cutting-edge solutions...

It's going to be revolutionary.

It's like science fiction.

And
there's the balloon up there.

And high-risk measures...

I really hope we'll
never have to do this.

It's really important that
humanity has a backstop.

in a race to discover:

can we cool the planet?

Right now, on "NOVA."

It's a new
time in the Earth's history

in which we are not
just inhabiting our planet,

we're operating as
stewards of the very thing

that we're living on.

Since the Industrial
Revolution, humanity has been running

an unintentional experiment

in Earth's atmosphere,

pushing the climate
to new extremes.

Things are going to get hot.

Boy, you can feel the heat.

This is insane!

Oh, my God.

Attitudes have changed rapidly

because everyone
can see for themselves

the climate change
that is occurring.

A child born today
will witness, across her lifetime,

a planet transformed
by rising temperature.

I got you, I got you.

How did we get here?

Every time you get in your car,

every time you fly a plane,

every time you turn the heat on,

all of those things are
putting carbon dioxide

into the atmosphere,

and if there's more carbon
dioxide in the atmosphere,

there's a higher temperature.

And now
temperatures have started to spike.

If we keep pumping
billions of tons of CO2

into the atmosphere each year,

we really will cook
ourselves, literally, in the end.

To stop the worst impacts

of planetary heating, we
need rapid emissions cuts,

starting now.

The developed
nations of the world

need to go from the energy
system they have now

to one that emits nothing,
zero, in 30 years' time.

The good news is, we
know how to do that.

Renewables now are the
cheapest form of electricity

on two-thirds of
the Earth's surface,

and it's going to be everywhere.

But climate impacts
are coming faster.

Lasers are at power.

There it is.

So scientists are
opening a second front in the battle...

Sweet. It has power.

Bringing new technologies

to bear on the way we
fight climate change...

We now have so much data.

This is going to be
a game-changer.

There are a
whole class of solutions

to actually get this
job all the way done.

By removing CO2 from the air...

This little guy,

this is just the beginning.

Converting CO2 from a waste

to a resource...

We see
this kind of as a testing ground.

Even extreme measures,

like shielding us from the sun.

There's been
a technical revolution

in the last few years

that's unlike
anything we've seen

in the previous hundred.

This is a problem
with a solution.

Can a new wave of
climate tech take us the rest of the way

to turn down the
global thermostat?

We need to look
at everything that's out there...

natural solutions,

CO2 sequestration,

solar geoengineering.

There may be this idea out there
that nobody has come up with yet

that could be really
transformative.

Cooling the planet
means, first, stopping more CO2

from entering the atmosphere

and then finding
ways to remove it.

But just how much CO2
are we talking about?

Imagine you filled the
National Mall all the way

from the Lincoln Memorial to
the Capitol steps with coal...

and you piled it up all the way

to the top of the Washington
Monument ten times.

That would be a gigaton of coal.

"Giga" means billion,
so that's a billion tons.

Now, we actually burn ten times
that much carbon every year.

People actually go dig that
stuff up out of the ground,

ten billion tons of it,

and set it on fire in
power plants, in engines,

in factories all over the world.

And then because that
carbon has reacted with oxygen,

ten gigatons of
carbon is burned,

but it creates 37
gigatons of CO2.

At our current rate,
that's just one year of CO2 emissions.

To blunt the impacts
of heating the planet,

we need to shrink that number,

to zero.

But there's another problem...

the gigatons that came before.

The single most
important fact about climate change

is that the carbon dioxide that
we emit into the atmosphere

stays there for
thousands of years.

Year after year,
we live with the carbon dioxide

we've added over time...
nearly 1,000 metric gigatons

since the Industrial
Revolution began.

Almost everything
we emit stays there,

and it's staying there

until you do something
about taking it out.

Pulling CO2 out of the air.

It sounds futuristic,

but it's a problem we've
encountered before.

Remember Apollo 13?

It was all about
CO2 filtering, right?

That was the big problem,
how to get the CO2 out of the air.

In 1970, following an accident,

the crew of Apollo 13 aborted
a mission to land on the moon.

Houston, we've had a problem.

Forced to return
to Earth in a smaller capsule,

the astronauts
faced a big problem.

You're in confined spaces.

People exhale CO2.

You need to remove that CO2.

Every exhale
caused carbon dioxide to build up,

making the air
increasingly toxic.

Okay, now,
let's everybody keep cool.

Let's solve the problem

but let's not make it
any worse by guessing.

The astronauts
survived by modifying their air scrubber

to remove more carbon dioxide.

Inside the scrubber,
negatively charged sites

on the filter polarize
and bond with the CO2,

removing it from the air.

Could something like this
work in Earth's atmosphere?

There's not a lot
of CO2 in the air compared to

nitrogen and oxygen.

Imagine a box with
10,000 ping pong balls in it

and four of them
are painted black...

those are the CO2 molecules.

Trying to find those four
balls out of that big box

full of ping pong balls is hard!

Removing CO2
from a spacecraft is one thing.

Removing it from our atmosphere
poses a much bigger challenge.

Is it realistic?

Most people to
whom we told we are taking CO2

out of the air would
say, "You're crazy."

But here you see a full-scale
direct air capture plant.

You see it consists of
12 individual modules

capturing the
CO2 out of the air.

Jan Wurzbacher is a co-founder

of Climeworks, a Swiss
start-up specializing

in what's called
direct air capture.

Through this side, we suck
in ambient air with 400 PPM...

that's 400 parts
per million CO2.

And on the other side, we expel
about 100 PPM CO2 content.

So three-quarters
are kept inside.

A filter with highly
reactive chemicals called amines

catches even small
concentrations of CO2.

Heating the filter
then breaks the bond.

You release the CO2
and you can extract pure concentrated CO2.

And then you
start all over again.

But generating the
energy to do this can produce its own CO2.

Their solution for that

is garbage.

Here we are on top of the
waste incineration plant.

The reason why we're here
is the main energy source

for our process of CO2
capture from the air,

waste heat from the
incineration process.

Heat that would have
been wasted instead heats the filters

inside the array,

which capture nearly 1,500
metric tons of pure CO2 a year...

about what's expelled from
the tailpipes of 300 cars.

Once you've pulled

CO2 out of the atmosphere
with a direct air capture machine,

the question is
what to do with it.

The big picture is taking

one percent of CO2
out of the atmosphere

within the next
five to ten years...

that is roughly 400 million
tons... and store it underground.

Could we put
carbon right back where we found it...

underground?

There are lots of
rocks near the surface of the Earth

that would want to bond
spontaneously with CO2.

There's enough of these
kinds of minerals that you could

remove all of the atmospheric
CO2 many, many times over.

One of the best
places to try that out is Iceland.

Here we are...

the land of ice and fire.

We have eruptions.

We have earthquakes.

Iceland is an island
formed out of volcanic rock called basalt.

We see the basaltic
mountains here around me

and actually extending
several kilometers downwards.

Basalt is porous
rock that readily bonds with CO2

over centuries.

Sandra Snaebjornsdottir's
team has found a way

to speed up that process.

CarbFix is the method

of capturing CO2 and
turning it into stone.

It's magic, but it's magic
that already occurs in nature.

CarbFix is turning
one-third of the CO2 from this power plant

into solid rock in
less than two years.

The key is water.

Inside this scrubber, gaseous
CO2 is dissolved in water

to react with
basalt more quickly.

This scrubber is actually

just a giant SodaStream.

The fizzy water is
then pumped into injection wells.

This is
actually my favorite part of it all.

From here, the magic
starts to happen.

This pipe extends
to over 2,000 feet.

And there, we finally
release this fluid to the rock.

Once inside the basalt,
the dissolved CO2 reacts with metals

in the rock to form new solid
minerals like calcium carbonate.

Once we have injected
the CO2 into the rock,

it's there forever.

And Sandra
is looking beyond Iceland.

She is test-driving

a direct air capture unit that
can suck up CO2 anywhere.

We don't need the power plant.

This can be done

anywhere where you have a
formation to store your CO2.

What that means
is, you can go backwards.

You can reverse the process

of emitting carbon
dioxide into the air.

Negative emissions
technologies like direct air capture

could play a role
in reaching net zero,

the moment when humans remove
as much CO2 from the atmosphere

as they put in.

So why isn't this the ultimate
answer to our CO2 problem?

These technologies are

very hard to scale up
to a meaningful amount.

The base
module of our direct air capture plant,

that's a 40-foot
shipping container.

In order to take one percent of
global emissions out of the air,

we would need 750,000
shipping containers.

All to remove just
half a gigaton of our annual emissions.

Direct air
capture is very expensive

and it takes energy to
suck CO2 out of the air.

So I hope you're not imagining

direct air capture vacuuming
up the entire fossil fuel emissions

of the world, because
it ain't gonna happen.

We'll need
lower-cost clean energy everywhere

before the promise of
direct air capture can meet

the scale of the problem.

M7 is on.

So some are exploring
another idea: recycling our emissions.

Correction factor 0.7.

We need to think about
this problem very pragmatically.

We can electrify
a lot of things.

But there are certain
parts of the energy system

that are extremely
hard to decarbonize.

A good example is aviation.

You couldn't
build today a commercial airplane

for long distances which
could fly on batteries.

You would just carry
way too much weight.

This is physically impossible.

There is no way around jet fuel.

We need to be producing
fuel that, when you burn that fuel,

it doesn't emit carbon dioxide.

Remo, go ahead and rotate.

Aldo Steinfeld
thinks he's found a way.

Perfect. We are on target.

We have demonstrated that we
can produce liquid hydrocarbon fuels

from two ingredients.

Sunlight

and ambient air.

It may sound like
science fiction or magic...

But it is chemistry,

it is heat transfer,

and also, it's a
lot of engineering.

Aldo captures
CO2 and water from the air

and feeds them
into a solar reactor.

Solar radiation is reflected

and concentrated at the
focus by a factor of 5,000.

It is like the intensity
of 5,000 suns.

Concentrated solar energy

drives a reaction that
generates a synthetic gas,

which can then be
converted into fuels.

And here in my hands,
I have an example of

solar methanol.

When it's burned,

the carbon in this fuel
returns to the atmosphere.

But since it was harvested
there, the net CO2 is zero.

This is called carbon-neutral,

and hundreds of scientists
like Aldo are working to make

carbon-neutral fuels a reality.

If they succeed, annual
net emissions would drop

by as much as one billion tons.

It's going to be
something revolutionary.

But with these fuels up
to six times the cost of standard fuel,

it's a revolution that
has only just begun.

But it raises the question:

what else can we
make by recycling CO2?

Carbon is this
incredible building block.

Think of it like

those little sort of Lego
toys that we used to have,

only there's four
little plug-ins for it.

So you could bond carbon
to carbon to carbon to carbon

to build all kinds of stuff.

Imagine a world
where everything around you

is made from carbon emissions,

from the products
you use everyday

to the clothes you wear.

This ad from
the XPrize Foundation pitches

a future where recycled
CO2 shapes our world...

and a $20 million bounty
to make that a reality.

We announced, "Hey, there's
a $20 million prize out there,

"we're looking for
innovators around the world.

"If you know how to convert
CO2 into a useful material,

consider entering this prize."

We are trying to help
catalyze the whole ecosystem

of companies, of investors,

of people that can
deploy these technologies.

The Carbon XPrize
has brought five of the finalists here

to put their
innovations to the test.

They're setting up shop next
to a plentiful supply of CO2.

They've
got to take the emissions

from a natural gas power plant

and convert those into
whatever material they like.

From toothpaste...

to yoga mats...

to watches.

Each team will be scored
on its net CO2 reduction.

You could have a process

that uses up a lot of
CO2 to make its product,

but in the end, just produces
more CO2 than it uses up.

Okay.

We don't want that. Yup.

We want things that actually
are reducing CO2 overall.

We just moved to
site about two weeks ago.

A day later, and
I think we'd have

snow in here
that we'd be shoveling out, so...

Apoorv Sinha is the
C.E.O. of Carbon Upcycling Technologies,

or CUT.

We're a carbon tech company
which takes carbon emissions

and converts them into
solid nanomaterial products

for use in anything
from cutlery to car parts.

But to make the biggest
impact on CO2 and win this competition,

Apoorv is focused on cement.

Cement is an essential
component of concrete...

the glue that binds it together.

But producing it
creates a lot of CO2.

Cement production accounts

for over eight percent of
the world's annual emissions.

If all the cement-producing
companies were a country,

they would be the
third-largest emitter in the world.

Apoorv's process converts CO2

into a needed
ingredient for concrete.

And he believes it will also

reduce the amount of cement
that concrete manufacturers need.

He starts with an
industrial waste powder

left over from burning coal

called fly ash.

With the reactor that
we have behind us,

we're scaling up
and commercializing

an enhanced fly ash,
where the fly ash has been

chemically activated
to capture CO2.

As the reactor spins the
fly ash, we inject CO2.

Ball bearings
coated with a catalyst

speed up the chemical reaction.

As the ball bearings
rise and fall,

the motion breaks up the fly ash

and roughs up the surface, so
that more CO2 can be absorbed.

As the CO2
penetrates the fly ash surface,

it forges tunnels along the way.

In effect, carbon dioxide
has bonded with fly ash

to create a nanoparticle with
more reactive surface area,

which can bind concrete together

and strengthen it
with less cement.

If concrete producers
are able to use less cement

in their production, they
could considerably reduce

the emissions that
come from their industry.

The question remains:

is it strong enough for
concrete makers to buy it?

We just want to make sure
that the technology is good,

and that it works really well.

One of our local partners
is a family-owned Calgary-based

concrete business called Burnco.

Burnco is testing
the strength of concrete held together

using Apoorv's nanoparticle.

When the cylinder breaks,

we will have our final
pressure read up there.

These are impressive results.

In normal production,
you're looking for changes

of three to four percent,
and these are showing

results in, in double digits,

which is very encouraging.

We're very
confident that we can get

up to a ten percent reduction

in the amount of
cement used today.

But our real target is to get
that number up to 20% or 25%.

Then we start talking about
significantly moving the needle

on the 37-gigaton-a-year number.

But even if these
new technologies can scale

to their full potential,

they could only lock away
a fraction of our emissions.

The total volume of CO2
that we create in the atmosphere

is so much bigger than
the volume of any product.

I think people are losing
track of the central issue,

which is, we have to
reduce net CO2 emissions.

The easiest thing,

believe it or not, is to
burn less carbon, right?

To, to not generate the
CO2 in the first place.

Carbon-free energy
like wind, solar, and nuclear power

can drive down most
of our annual emissions.

And the rest could be offset

with negative-emissions
technologies

that remove CO2 from the air.

We will do it.

We will get to the day...
there'll be global celebrations

when we get to net zero day,

where we brought human
CO2 emissions to zero.

I think it'll happen
in my lifetime.

It is doable.

But on that day,

we have not solved
the climate problem.

All we've done is
stop making it worse.

The problem
that remains is heat.

The temperature of the
Earth is determined by heat coming in

from the sun

and heat going out by
radiation out to space.

Every single
day, CO2 from our past emissions

traps energy in
the Earth's system...

the same amount of energy
as 500,000 of the bomb

dropped on Hiroshima
detonating at once.

That heat is
altering our climate.

What's it going to be
like when, you know,

three months of the
year are 115 degrees?

When vast ecosystems
have died out?

People are going to push for,
for doing something about this.

And many fear
Earth is approaching a tipping point

that will trigger rapid change.

The uncertainties
that keep me up at night are,

what if we aren't doing enough,

and there's some monster
lurking behind the door

that all of a sudden comes

out into the world among us?

It's a good idea that humanity

has some sort of a
backstop technology,

something to do if we
get surprised in a way

that is very, very dangerous.

Some think that
backstop could be solar geoengineering.

It's a way to intercept
sunlight coming into the planet

to cool the planet.

The core idea is that
humans might deliberately alter

the Earth's energy
balance to compensate for

some of the warming
and climate changes

that come from greenhouse gases.

Geoengineering
the climate is a controversial idea.

But nature can show us
examples of where we might start...

clouds.

A cloud is just
water that's condensed down onto particles

into small droplets.

These collections
of droplets are, in effect,

floating sun reflectors.

Clouds play a huge role
in controlling the climate

because they control the
reflectivity of the planet.

Especially over the ocean,

you go from sunlight
hitting a very dark surface,

where a lot of the
sunlight is absorbed,

to sunlight hitting an
extremely bright surface,

reflecting a lot of that
sunlight back to space.

Sarah Doherty of
the Marine Cloud Brightening Project

is working on a way
to boost that effect.

Can we add really
small sea salt particles to clouds

in a way that significantly
increases their brightness,

and do so over enough of
the ocean that we would have

a significant impact on
the global temperature?

But how do
you make saltwater particles

and launch them up into clouds?

What we need is a nozzle

like you'd see in a
sort of a snowblower,

except that the particles that
we want to produce are about

a thousandth the
width of a human hair.

So Sarah's
working with an engineer

who knows all about machines

for spraying
super-fine droplets...

a concept developer of
the earliest ink-jet printers.

In a different
life, I was an engineer and a physicist.

I couldn't enjoy retirement
anymore and just sit there

and watch what's going on.

Once you know what's going
to happen or might happen,

you can't sit down and say,

"Yeah, I'm just
going to enjoy life."

Armand and
his team of retired scientists

have been developing a
cloud-brightening machine

for over ten years.

They have been self-funding
this research in borrowed lab space.

PARC is a really
good place for them

because of our
history with aerosols.

PARC, or
Palo Alto Research Center,

has infused the Marine
Cloud Brightening Project

with fresh expertise
and cutting-edge tools.

Here, Kate Murphy
can make aerosols

from just about anything.

This is our deep conditioner.

Aerosols are
tiny particles suspended in air.

This is ketchup.

For clouds,
they're not going to spray ketchup.

But Kate can help the team

design a nozzle for
spraying saltwater.

Let me just give it
a little water, okay?

Okay.

Kate's
expertise will help optimize

the size and speed
of the particles

to propel them
into marine clouds.

So you're
going to be redesigning the nozzle

based on your
computational fluid dynamics?

Well, we hope to be able
to understand the effect

of multiple nozzles,

so we would want
to measure things

like velocity and direction.

These crisscrossed
laser beams can help reveal

whether Armand's
nozzle will hit the mark.

The lasers are at power.

Um, it looks like our
signal's pretty good.

So can you
measure the vertical velocity?

Do you have a
measurement of that? Yes.

That would be of
great interest to us.

PARC will be working
on developing a full spray system.

And then we would
want to move outside,

into real atmospheric
conditions.

On the other side of the world,

outdoor research
has already begun.

Armand and the team have shared

their insights with
researchers in Australia

who are testing cloud
brightening as a way to cool

the waters surrounding the
threatened coral of the reef.

That project is
targeted and local,

but some estimate that cloud
brightening on a global scale

could offset all the heat
trapped by our CO2 emissions.

It will probably
take a good 15 to 20 years

to do all of the research
involved with understanding

how big of an effect we can
have by brightening clouds

and also what all of
the side effects might be.

Those side
effects are not well understood,

and could include disruptions

to ecosystems
and rainfall patterns.

Further research is needed.

We have kids, we
have grandkids...

We're doing it
for their futures.

You know, and frankly,

we are all in this together,
whether you have kids or not.

We're more than individuals.

Our society has to survive.

We're facing a
problem that's getting worse, not better.

Do we need to consider
more extreme measures?

In 15 years or 20 years,

humanity may
find itself at a point

where impacts are so big that

there's a very large
demand for fast action.

To prepare,
Frank Keutsch is starting now,

by researching a
controversial technology

that goes further than
brightening clouds.

It would brighten
the entire planet.

Putting
particles in the stratosphere

could reflect back
some sunlight to space,

reducing the amount of
sunlight that hits the surface

and cooling down the planet.

The effect would be immediate.

We know this works,

because every time
a big volcano goes off

and it injects aerosols
into the stratosphere,

the planet cools down.

That's the idea
behind solar geoengineering.

It's like drawing a curtain
over the face of the Earth.

The first
time you hear about this,

you think, well, "That
sounds like a really bad idea.

How could that not go wrong?"

But what we're doing
to climate as humans,

that really to me starts
seeming also quite scary,

and crazy, and really worrying.

The fact is, the CO2
is in the atmosphere.

Without a time machine,
we can't make it go away.

We want to, in the long
run, do carbon removal.

But during the time that
concentrations are high,

we might want to do
solar geoengineering

to reduce the climate risk.

All that is hard-mounted to us.

That is exactly what I was...

And then there's
the balloon up there.

Frank and
David's team is designing

a first-of-its-kind experiment,

called SCoPEx,

to investigate the impacts
of solar geoengineering.

The only place I see that
conversation getting sticky

is where we do risk
assessment on it.

If you put these particles out,

what happens when
these come back down?

What happens when it
gets into the environment?

Are we endangering people?

where the existing
experimental background is bad.

You actually have to go
out and make measurements.

The plan is to launch

a 100-foot balloon
into the stratosphere

and release a plume
of reflective aerosols.

We want to put out

the particles of calcium
carbonate, for example,

and then go back
through this plume

and see whether
the evolution of the air

is the way we predicted
based on our laboratory results.

This is an experiment
on a very small scale.

And in fact,

the amount of material
we're putting out

is less than a normal
airplane flight puts out.

SCoPEx may be small,

but many fear a
large-scale manipulation

of Earth's atmosphere
could trigger

a cascade of dangerous,

unintended consequences
that ripple across the planet.

Nothing
in our scientific capability

actually enables us to
understand the complexity

of the interactions
that would be set loose.

It's not just that it
lowers the temperature,

but what are some
of the other effects

on the hydrologic cycle,

or on heat waves and droughts?

This is a manipulation
of the Earth's atmosphere

on a huge scale.

What happens if things go wrong?

SCoPEx is designed to

start answering those questions.

But there may be effects,
beyond the physical,

that no experiment can predict.

If we think that
there's this solution out there,

then people may think

it doesn't matter if
you're polluting the planet.

The root of the concern

is that solar
geoengineering research,

however well-intentioned,
will be used as an excuse

for big fossil fuels to
fight emissions cuts.

It's just like a sci-fi
dystopian novel or something,

where we continue to just

belch all this CO2
into the atmosphere,

but hey, it's okay, because
we got these little umbrellas

that are, you know,
hiding us from the sun.

Solar
geoengineering does not get us

out of the ethical and physical

requirement to cut emissions.

But with so much uncertainty,

some think we're better off

investing in a different
kind of machine:

one developed in
nature's own laboratory

over millions of years,
and with a proven record

of safely drawing
down gigatons of CO2.

Trees.

When I'm
going on a hike through a forest,

I have a tendency
to look up and say,

"Okay, oh, that tree's
about 60 feet tall."

And then I try to
calculate in my head, okay,

how much carbon
is stored in that tree?

I think this is good.

Lola Fatoyinbo Agueh

is a research scientist

at NASA's Goddard
Space Flight Center.

Sweet. It has power.

I love it when things work.

She and
her team are about to see

these century-old
trees in a new light.

Green lights all
around, if you want to do the honors.

There's carbon all around us.

If you think of
trees as a machine,

then trees would be a
carbon capture machine.

When we're looking at trees,

about half of that
weight is carbon.

Lola and her team want to know

how much carbon is
stored in this entire forest.

To measure each and every tree,

they're using a
special kind of tool...

Lasers.

We're
using a terrestrial laser scanner

that shoots out billions of
laser pulses every second

and then measures the
distance from the instrument

to whatever is around it.

The data that we get
back generate a point cloud.

Billions of data points

form a 3-D measurement
of forest volume...

and the carbon stored within.

It's so dense
that it almost looks like a photograph.

It's like science fiction.

This scan may look like reality,

but this is data.

It reveals that in an area
the size of a football field,

these trees are storing roughly

150 tons of carbon,

all pulled out of thin air.

Which prompts
Tom Crowther to ask:

could we enlist trees in
the race to draw down CO2?

Our lab is
urgently trying to figure out

how we increase the area
of forest across the globe

to capture as much
carbon as we possibly can

in the fight against
climate change.

Tom's findings
began with a surprising discovery.

We thought there was
around 400 billion trees on the planet.

But we showed that

there is in fact around
three trillion trees.

There's more trees on
the surface of our planet

than there are
stars in the galaxy.

The big question is,

how many more
trees could we add?

In order to
understand the global forest system,

we need to map a lot of things,

we need to know
where forests are,

where forests could be.

We collect our data from

millions of locations
around the world,

where scientists have
been on the ground

evaluating those ecosystems.

Data like leaf fall
patterns in forests around the world.

I'm trying to understand the
seasonal rhythm of plants.

Microscopic organisms like

the tiny worms that feed
the soil beneath the trees.

JOHAN VAN DEN
HOOGEN: In just this clearing,

there is millions and
millions of nematodes

living in the soil.

And decades of satellite data

on factors like rainfall
and temperature.

When I look at ecosystems
most of the time,

I'm looking from the top down.

And with all of that data,

we can start to see the
patterns across the globe.

Using remote sensing
information from satellites

and machine
learning technologies,

we can generate maps that
can predict which regions

can support new trees
and which ones cannot.

This really is a
data revolution.

The detail is astonishing.

And the potential for
new forests is vast.

Outside of
urban and agricultural areas,

there's room for about

2.5 billion acres of forest.

The area we identified equals

the size of the United States.

So there is a huge area
available for restoration.

Enough space for

1.2 trillion new trees,

all sucking CO2 out of the air.

If we were
to restore a trillion trees,

the right types of trees
in the right kinds of soils,

and have them
grow to full health,

they could store an additional
205 gigatons of carbon.

To put that into context,

we've released nearly

660 gigatons of carbon
into Earth's systems

since human
industrial activity began.

Restoring global forests

and conserving the vital
forests that we currently have

could take a huge chunk
out of that excess carbon.

This is a really massive
carbon drawdown solution.

And we knew that this was
going to make an enormous splash.

But these
findings also made waves.

That
study is causing a lot of debate.

On the one hand,

a lot of people
are talking about

the potential of
restoration of forests.

On the other hand,

I would say, um, a lot of
people are very upset about it.

The uncertainty around
the amount of carbon

that's stored in
trees is so high

that we can't really make
any informed recommendations

on how many trees
we need to plant.

Lola wants to
use new technology from NASA

to fill those areas of
uncertainty with hard data.

We have
over 20 Earth-observing satellites

right now from NASA alone
looking at our planet Earth.

But what we're seeing
is all in two dimensions.

What we're missing here
is the third dimension.

Enter a
powerful new tool called GEDI.

With the same laser technology

used in her
terrestrial scanners,

Lola can get a three-dimensional
measure of forest carbon

from the International
Space Station.

GEDI stands for

the Global Ecosystem
Dynamics Investigation,

which is what you're
seeing right here.

This is about the
size of a fridge.

You can see the
lasers shooting down

out of the bottom
of the instrument

towards the
surface of the planet.

We actually can see

a full profile of
plant materials.

The game-changer here is that

this is going to
be, for the first time,

a near-global data set.

GEDI will give clearer insight

on the carbon new
forests could store.

But equally important,
it can pinpoint

the old forest carbon
we must preserve.

Forests are really important

for our water supply,
forests protect us from heat,

forests breathe.

They breathe in some
ways just like we do.

When you lose a lot of

the ecosystem services
that forests provide,

that has a direct impact
on the well-being of people.

But on an
increasingly populated planet,

trees are not the only living
things competing for land.

We already use all
of our agricultural land

to feed our existing population,

and over the next 30 years,
food demand is going to double.

If you take land to solve
the climate problem,

you create another problem.

So, is there a solution

that can solve more than
one problem at a time?

Some people are looking at ways

in which forests can
help slow climate change.

Our research is
somewhat different

in that we're looking
at grasslands.

I want to have enough so
that we can do experiments.

In California,
Whendee Silver is looking for a way to

pull down CO2 right where

we grow our food...

Earth's grasslands.

This is a classic,
beautiful annual grassland.

Grasslands grow in places

where there's drought
for part of the year.

And these grasses have developed

great tools for getting water,

particularly by
growing more roots.

And any time plants invest a
lot of their energy into roots,

it's like injecting
carbon into the soil.

But tilling releases
that carbon and degrades the soil.

And producing our food

creates even more problems.

We all eat food every day.

We have to grow that food.

And we create a lot of
organic waste in the process.

When
organic waste sits in a landfill

or slurry pond,

it creates an
oxygen-deprived environment

favorable to certain microbes,
which in turn produce methane,

a greenhouse gas 34
times more potent than CO2.

We're trying to tackle
three big problems:

waste, degrading soil
health, and climate change.

We came up with
something relatively simple:

composting.

In composting,

food waste is regularly turned,

adding oxygen to the
mix and keeping the

methane-producing
microbes at bay.

It creates this organic
and nutrient-rich resource,

like a slow-release fertilizer,
that helps plants grow.

By turning
a waste into a nutrient,

compost can boost plant growth

and potentially turn vast
stretches of Earth's food crops

into a carbon-storing
juggernaut.

Can you grab that?

We now have ten years of data

showing that just a
one-time dusting of compost

onto the soil surface

can have a long-term
impact on plant growth

and increase carbon
storage in soils.

Whendee's research shows that

a single layer of compost

can increase plant
growth by up to 78%

and increase soil carbon
by up to 37% for three years.

The real challenge is

to extrapolate from little
tiny soil samples in the field

to big chunks of
California or the globe.

That's a huge challenge.

As the hunt for solutions

continues in the decades ahead,

stopping our emissions remains

the most urgent
challenge of today.

If we really didn't do
anything to limit carbon emissions,

we would have climate
changes as big as the changes

from the glacial
to inter-glacial state

and do that in one
human lifetime,

with huge potential impacts.

The more of a mess we make,

the bigger of a mess
we'll have to clean up.

We today get to decide

whether to continue
along this path...

Or to dramatically shift

our economy off
of coal, oil, and gas.

Every big
transformative solution starts small.

It starts with a couple
of people talking.

They make a small version,

they make a bigger
version, more people pile in.

This is one solution,

but we need
thousands of solutions

if we want to tackle
climate change.

There's no one magic

silver bullet that will
solve this problem.

The main challenge that we have

is that these transitions
don't happen overnight.

We have the tools already,

but we really have
to start moving.

We need better
transportation systems.

We need solar
power and wind power

and water power, and
probably nuclear power.

We need to plant trees.

We need to manage
our farms better.

We need direct air capture.

I think we probably need it all.

We have to start really
looking at what can scale up

and be maintained... for
decades, if not centuries.

That's the challenge here.

But it's an incredibly
important challenge.

15 years ago,

no one would have predicted that

the emissions in developed
countries around the world

would be dropping.

Not fast enough yet,

but that gives me hope

and should give everyone hope

that with the combined
might of human ingenuity,

we can actually
solve this problem.