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The Arctic.

Its vast frozen ocean
cools our planet

and impacts weather
around the globe.

But the Arctic is changing...

warming at least twice as fast
as the rest of the planet.

Exactly what's happening,

and how it will
affect life on Earth,

has not been fully explored.

But now,

a global team of scientists
is setting out

on the biggest polar expedition
ever attempted.

We have hundreds of people

from 37 different nationalities
on board.

It's a massive operation

on a scale that we have never
seen in the Arctic before.

We're creating
a benchmark of measurements

that we may never be able
to repeat

in the future because there
won't

be sea ice for us to study.

The plan is a world first:

to take a high-tech
research icebreaker

and freeze it into
the Central Arctic ice

for an entire year.

We're taking

a whole new level of
sophistication with us.

All right? Onboard the ship
will be instruments

that have never been installed
in the Central Arctic.

Locked in place, they'll explore

every aspect of
the Central Arctic

as never before,

through the constant darkness
of a polar winter

and some of the harshest
conditions on Earth.

Their mission:
to investigate why the ice

is melting so fast

and help us better predict
how its rapid change

will impact the rest
of our planet.

It's about taking stock of what
we've done to the Earth...

and what we can still do.

"Arctic Drift,"

right now, on "NOVA."

After more
than ten years of planning,

an international team
of scientists is heading north

on the journey of a lifetime.

This mission is
the modern climate science

equivalent of going to the moon.

If you asked me if
I'd ever imagined myself

working in the Arctic, going to
polar bear safety training,

handling a rifle,
I would have laughed at you.

I would have been, like,
"You're crazy, there's no way!"

Coming from a place where

people have never seen snow
or ice

for the past thousands of years,
Arctic, for me,

is something out of this world.

The expedition will definitely
give us a new perspective

about the changes happening
in the Arctic environment.

Making scientific observations
in the Arctic is very difficult.

Relative to the rest
of the globe,

we have very few observations
of the Arctic system,

especially in the wintertime.

We're going into a frontier,
really.

I mean, the Arctic
is still a frontier.

The mission, dubbed MOSAiC,

and led by
Germany's polar institute,

is heading deep into
the Arctic sea ice.

A place like nowhere else
on Earth.

A vast, frozen world floating
on a deep ocean.

It's thin and treacherous
in summer,

and almost impenetrable
in winter.

It means the Central Arctic
remains

one of the least understood
places on the planet.

But now, the team plans

to establish a cutting-edge
research camp

by allowing their icebreaker,

the Polarstern, to become frozen
into the ice itself.

This looks great, I think,

as far as size.

We're going into the sea ice

to try to find an ice floe.

An ice floe is
a discrete chunk of ice.

It's maybe a couple of
kilometers across.

Ideally, our floe will be
thick enough

so that it can support
all of our equipment

that we want to put out
on the ice.

And yeah, this stuff
that's right there

is the rotten layer
that's underneath...

And this
will be our home for the next year.

So this is really

a crucial moment in
our whole expedition.

The success of the mission

depends on taking advantage
of a natural phenomenon.

The plan is to hitch a ride on
the Transpolar Drift,

a constantly moving belt of
sea ice

that's driven by prevailing
winds and ocean currents.

If they freeze-in near Russia,

it should carry them for
hundreds of miles...

close to the North Pole,
then towards the Atlantic.

If we pick the right ice floe,

then we'll stay in the ice pack
for a full year.

If we pick the wrong ice floe,

it might drift out to the ice
edge faster than we anticipated.

It might break up.

And so we're walking
a thin line here.

So we are standing by.

Copy that, I will take off now.

Okay, door's closed.

The team has
spotted several potential ice floes.

To find out if they're suitable,

they need to explore them
on foot.

Our dream
would be an ice floe that is

thicker than one meter 20.

Just a stable island of ice.

The team searches for days.

But the
ice floes are all too thin.

They're running out of options.

This, this is interesting.

This whole area here looks...
somewhat...

- Yeah.
- We'll look over here.

See what we can find. Yup.

Eventually, they spot a floe

that looks like it could
be thicker.

So it first goes out
50 meters that way,

and then we go,
try to walk parallel

to Polarstern over there.

There are quite a
few potential hazards out there.

How thick is the ice?

Is it stable?

Is it safe?

Matt, this is Markus,
Matt, this is Markus.

Markus... Matt.

I think our, our thinnest ice
was 70 centimeters,

and we've seen some up
to multiple meters.

And there's quite an extensive
area of that thicker ice.

All right, Matt, thanks.

That sounds great.

After days of uncertainty,

it's an enormous relief.

They've found their ice floe.

Now, as the ice starts
to freeze around the ship...

the real work can begin.

The team needs to unload

around a hundred tons of
equipment

and set up bases out on the ice.

With just days remaining
before the perpetual darkness

of Arctic winter arrives,

the pressure's on.

Every day, we're
looking out the window

and light is diminishing.

And it's a race against time.

The plan is to build

five research stations
they call ice cities

up to a half-mile from the ship.

The cities and their
cutting-edge equipment

will allow scientists to explore
every aspect

of the Central Arctic
at the same time,

and crucially, constantly
monitor how each piece

of this complex puzzle affects
all the others,

from high in the atmosphere

to the ice and
the deep oceans beneath.

A mile-and-a-half of data cables

and over three miles of
power lines

connect the cities to the
Polarstern.

Beyond is a network of more
distant science sites,

as well as almost 250
remote monitoring stations.

The entire operation

stretches across an area
of around

two-and-a-half thousand
square miles.

While the scientists work,

others keep watch.

There's one thing
they're all concerned about.

I'm standing
there on this small hill at Met City,

on my very first polar bear
guard duty.

Bridge,
bridge... pack your stuff together.

You have to evacuate.

Suddenly, I hear from the bridge

two polar bears
are approaching us.

They are 1,000 meter away,
900 meter away,

and we all have to go
back immediately.

In that second,
I start to shout...

Stop doing what you're doing

and come to the Ski-Doo!

Polar bears, if they are hungry,

they would hunt for a person.

These huge animals can reach

speeds of 40 kilometers
per hour,

and everybody has to have
that in mind.

Once a polar bear is close,

it can be at the person
in seconds.

I am
the only person who have a rifle,

and am I going to be able
to use it,

protecting all the people
around me?

And that's a lot of people
there.

Bridge, bridge... Matt.

We are actually really
full here.

We are going to try to load
everybody on these.

It's going to be really full,

but we'll try to make it out
with what we have here.

Guys, hurry up!

In my mind, I don't care

how small the sleds are...
everybody has to fit.

We all have to go back now.

As we all got on board...

Bridge,
bridge, this is Gaute, over.

That was when I saw them.

This is bridge.

Polar bear
are at a hundred meters.

I will inform you when you have

the shot with the flare guns,
yeah?

Where is Trude?

She is right next to me.

The main goal is to have
everyone safe

and then scare
the polar bears away.

We are invading their space.

I don't want to harm them.

So it is

so nice when they understand

that we are making too much
noise for them.

The darkness
of Arctic winter arrives.

The team will not see
the sun again

for almost five months.

It's an incredible
experience to live, exist, and work here

in the wintertime.

It looks unreal.

It feels like we are somewhere

else in the universe,
this is not the Earth,

this is something
completely different.

The darkness?

Working in the dark
for months on end,

not really being
able to see beyond

where your head lamp shines?

That's scary.

Yeah, that's pretty scary.

After three weeks on the ice,

one of the most complex
research camps,

Met City, is up and running.

All systems green.

The tower is alive today.

Our tower here is about
11 meters tall,

and this can tell us about the
turbulent exchange of heat,

of energy,

of moisture at the surface.

Such detailed data

has never been
captured year-round

in the Central Arctic before.

We need to
understand what the sea ice

is experiencing and how that
affects

the melting of the sea ice or
the freezing of the sea ice.

The Arctic ice

is melting, it's retreating,

and we want to understand why
that ice is changing.

Today, sea ice in the
summertime covers only half the area

it did just 40 years ago,

and the decline is accelerating.

Only some of the reasons
are known.

Decades ago, when
there was more extensive ice cover,

a lot of the sunlight that comes
in in the summertime

would just reflect back off that
really bright, white surface

and go back to space.

Now we have progressively less
and less sea ice,

and that exposes more ocean.

And that open ocean is dark.

It absorbs the sunlight,

and therefore warms up the ocean
and melts even more ice.

This feedback
loop is a major reason

why the Arctic is now warming

at least twice as fast
as the rest of the planet.

But it's not the only factor.

Already,
Met City is shedding new light

on another potentially powerful
warming influence.

Clouds are a big
player in the Arctic system,

as they are in the
whole global system.

On the one hand,

they shade the surface
from the sun, right?

So they cool the surface.

On the other hand,
they serve as a blanket

and they trap the energy
at the Earth's surface.

And it gets really
interesting in the Arctic,

because during parts of the
year, there is no sun.

It's dark for
four months straight.

And so the clouds are
only serving as a blanket.

What we're seeing is that
in polar winter,

there's actually a lot more
thick cloud than I expected.

It's slowing the winter
sea ice growth.

That means less ice going
into spring and summer,

which in turn makes it more
vulnerable

to the melting season.

The clouds are
one piece of the complex puzzle

the expedition is trying
to put together.

Another is the hidden world
under the ice.

It doesn't look like
much, I mean, right, at the surface?

You're, like, it's just snow,
it's quiet.

But actually, below the ice,
there's a flurry of activity.

I'm used to making
lab experiments

with a pipetter and...
delicate work.

And here I am with a
60-centimeter-long chainsaw.

Some of the big outstanding
questions are,

what are the activities
of organisms in polar night?

From the Central Arctic,

there are basically
no measurements whatsoever.

So this would be the first
chance in history

for us to do that work.

This device
can collect water samples

at specific depths,

down to just above the
ocean floor...

Two-and-a-half miles below.

What?

At this place in the world,

at this time of year,

there's never been data
like this.

And that's incredible,
and so every time

we put a piece of equipment out

and we collect
a sample successfully,

we're the only people
that have been able to do it.

Okay, so Jien, you're done
for D.I.C. on one.

Uh, Haylun, that means you
can do salinity on number one.

What they're
finding is a huge surprise.

I think
winter in general is thought of

as a time of hibernation
or low metabolic activity.

But what we're seeing is that
organisms

have adapted over millennia
to this,

what we consider
an extreme environment.

In one milliliter of seawater,

which is basically,
like, a teaspoon of seawater,

are one million bacterial cells.

And from there,
the diversity is extraordinary.

The team
finds that phytoplankton,

plant-like organisms that rely
on the sun for their energy,

are still present in winter,
primed and ready for spring.

They also discover tiny
zooplankton in their thousands...

far more abundant
and active than they'd imagined.

This thriving ecosystem
is vital for our planet.

Globally, phytoplankton
produce around half the oxygen

we breathe and absorb
vast amounts of carbon dioxide,

while the zooplankton
that feed on them

help lock that carbon away
in the depths.

It's partly why the oceans
absorb

around a quarter of the
CO2 produced

by the burning of fossil fuels.

For our climate, these tiny
creatures play

a crucial role.

Given that the Arctic is
experiencing so much change,

we need to understand
what impact

reductions in sea ice
and global warming is having

on these organisms
and how these components

of the climate interact.

Almost two
months into their yearlong mission,

the Transpolar Drift
has carried the Polarstern

over a hundred miles deeper
into the Arctic.

Bridge, bridge, Trude.

Trude, go ahead.

I'm in position, stern.

Thank you, enjoy your watch.

Do we have a ladder here?

. Oh, my God.

The ice is moving a lot.

Bridge, bridge,
for your information,

the ice here has really started
to move.

We noticed by the sound and are
monitoring it now.

We managed to save the ladder,
which is now on our side.

It's so loud.

It sounds like a,
an engine as it starts.

It is like an
earthquake under your feet,

but there is nowhere to run.

You really feel
how fragile you are.

It's a frightening experience.

Let's hope we find a way over.

Oh, it's stopped.

Bridge, bridge, Trude.

Go ahead, Trude.

Ice has stopped moving

and it's completely silent here
in the Arctic again.

This is stress on the ice.

This is the winds
and the currents in the ocean

causing pressure in the ice, and
eventually,

the ice just lets go.

There's internal pressure
and it breaks.

And those
stresses are intensified

by the arrival of a violent
storm.

Cracks in the ice open up,

some big enough
to wreck the entire base.

There is
one crack behind Met City.

We've lost the power, huh?

Yeah.

It's knocked
out our power supply.

It's taken down our measurements
at Met City.

We have to get back out there.

We have to get the power hooked
up again, so that we can

continue making our
measurements.

Goal of operation, really,

is to rescue

the cables so thatwe don't

lose them.

So we prepare the kayak?

Yep.

All right!

All good? Yeah.

Team Kayak?

The first thing they need to do

is find out if the cable

is still connected to the
ice cities.

All right,

the connectors have been
ripped off,

so the other half is probably
in the water.

We can't reach it,
we can't see it.

Copy that.

With the power
cable hanging deep into the ocean,

they'll need to retrieve it

by hauling it out with
a snowmobile.

Slowly, slowly!

Hey, stop, stop!

There is something else
hanging here.

Yeah.

Okay, we are very close.

Ah, this is the end.

This is the end.

Well done, guys!

Excellent.

With the cable
saved, the team can restore power

to the ice cities
and get the science

back up and running.

I don't know if I am

the first Indian to walk on
frozen ocean waters,

but, at least,

for this expedition,
I am the only Indian.

My name is Vishnu Nandan.

Vishnu means
preserver of the planet,

and that's my goal.

I'm here to protect the planet.

To every, to protect everyone.

Let's pull it across.

We don't want to
block the way with this.

Okay, yeah, I mean,

we can at least
bring the cables this direction.

I've been going up to the Arctic region

for almost 30 years now,

but it's always been
during daylight.

Doing it over winter,

yeah, that's
a really unique experience

that many people,
even if you're a scientist

working in the Arctic,

you don't get
to experience that.

And honestly, you feel like
you're walking on the moon.

That's amazing!

Hi, fox!

That is very cool.

My first polar fox.

That's exciting.

Yay.

Okay, check if
my instrument's working now.

Julienne and Vishnu
are running the Remote Sensing City.

They're here to answer
one of the most

fundamental questions of all:

Just how much ice
is in the Arctic Ocean?

We have over 40
years of satellite measurements

telling us how much of
the Arctic Ocean

is covered by sea ice,

but what we've really lacked

is knowing how thick the ice is.

The problem is that satellites

can't differentiate
between the ice

and what's
just snow on top of it.

By testing the same technology
at the surface,

where they
can compare the results

against physical measurements,

they hope to revolutionize
our ability

to monitor sea ice from space.

It would allow
us to actually map not just

the spatial extent of the ice,

but the actual ice volume in
the Arctic every single day.

As they
begin to analyze their results,

it confirms what they suspected:

satellites have been vastly
overestimating ice thickness.

It will take time
to turn their data into new,

more accurate predictions,
but it's a major breakthrough.

Collecting
the data is really key,

and will hopefully help
the public and policymakers

understand how quickly
the Arctic is transforming

and that we need to do something
before it's too late.

As a new year begins,

the team is less than 200 miles
from the North Pole.

They're due to receive
vital supplies, equipment,

and a new team of scientists

before the ice becomes
too thick to reach them.

But the Russian icebreaker
entrusted with the task

is hundreds of miles away,
struggling through thick ice.

As soon as the
icebreaker started to move through the ice,

I got the sense of how remote
the area we're going to is.

I mean,
we're traveling for weeks

to get to this
miraculous haven in the north.

No icebreaker has
ever tried to venture so far north

in the middle of winter before.

If the supply
ship has to turn back,

the team here could
be stranded for months,

and they'll be dangerously low
on fuel for heat and power.

It's affecting the morale of
the scientists onboard.

We are kind of stuck here.

There, there to the east.

Is that the Dranitsyn?

After a
grueling monthlong journey,

and with the first signs of
sun returning,

the supply ship, Dranitsyn,
finally makes it.

Okay, team, we walk.

And we follow them.

At one point,

I didn't think we'd be here.

But it's happened.

It's incredible.

With the new
scientists and supplies on board,

the mission is back on track.

As the sun returns,

the Arctic begins
to transform once again.

For the scientists,

it brings a whole new world
to explore.

Welcome to the office.

For me, snow tells a story.

We're trying to understand,
in this scale,

how it's changing,
and eventually link it

to the whole of
the Arctic snowpack.

We start
one snowflake at a time.

So at the surface today,
we have -20 degrees.

But then just
17 centimeters below,

we have minus nine degrees.

So it has
a really big influence.

Oh!

The snow here
is acting as a major insulator,

trapping heat from
the warm ocean in the ice

and slowing its escape
to the atmosphere.

With scientists predicting
that a warming Arctic

will see more precipitation,
which means more snowfall,

understanding why it's
having such a dramatic effect

is crucial.

Using a CT scanner,

the team can study
the structure of Arctic snow

in minute detail.

So, at the top,

these are all really compact
and tightly together.

And then
as you move further down,

you come across these
large crystals.

I've never seen these
crystals quite so big before.

You can start
to see more and more air.

The blue would be an air gap.

The scans reveal
how during winter and early spring,

large crystals in the snow

trap more air,
keeping the ice warm

and inhibiting
the growth of new ice.

This may seem strange,

but under certain conditions,
more snow can mean less sea ice.

The Arctic is now in
full transition.

With just over two weeks
between first sunrise

and 24-hour daylight,

every day
there's more opportunity

for one team
to take to the skies.

Let's do this.

Let's do it!

Three, two, one, go!

Hell, yeah!

Whooo!

Way to go, team drone.

We did it, whooo!

First flight, success!

The plane will spiral up

from near the surface
up to 1,000 meters.

And we're measuring
the state of the atmosphere,

so that's the temperature,
pressure, humidity, and wind.

It is flying really well.

I am so happy.

And right away,
there are exciting findings.

Here we have a plot of

the temperature,
and the wind speed. Yeah.

And you can see that we have
a really strong inversion

in the temperature around 200

to 300 meters, or...

The first flight we did

had this real sharp
temperature inversion,

where the temperature
increases with height.

It's the opposite
of what we normally see

where we live.

This phenomenon,
characteristic of the poles,

is caused by the icy surface
cooling the air just above it.

What's interesting to me is that

the temperature inversions
are often associated with

this core of really fast winds
right near

the surface of the Earth,

where sea ice or ocean or snow

exchange energy and moisture
and different gases.

And so the wind is really a
critical part of understanding

how the atmosphere is coupled

to these other parts of the
climate system.

NARRATOR Along with
these crucial surface winds,

there are other polar winds,
much higher,

that have a powerful effect
on the climate

far beyond the Arctic.

The jet stream is
a band of high-altitude wind

that whistles around our planet
at over 100 miles an hour,

influencing much of the weather
in the Northern Hemisphere.

It's driven by
the temperature difference

between the warm Equator
and cold Arctic.

Many scientists think
the faster-warming Arctic

may be weakening the jet stream,

causing it to become unstable.

It's a controversial theory,
but if true,

it could have
catastrophic results.

Cold air is able to escape
out of the Arctic

and cover parts of Europe
or North America

and give us
really cold winter weather.

Or if the jet stream
pushes very far north,

and you get these intrusions
of warm air up into the Arctic.

The weaker jet stream
might also be causing weather patterns

to get stuck over
the same area for longer,

prolonging droughts and floods.

It impacts everything we do.

It impacts farmers
and where they can grow crops,

where rain falls,

how often droughts occur,
how often heat waves occur,

how often blizzards occur...

I mean, all of the weather
that we experience.

In addition to altering

weather patterns
in the Northern Hemisphere,

the warming Arctic

is also speeding up
global warming,

which will affect
weather everywhere.

And as ice on land
also melts faster,

it accelerates
global sea level rise.

What happens in the
Arctic affects us all.

The Arctic is far away.

You know, 'cause you think,

"Oh, it's so far away,
who cares?"

But it has such a critical
impact

on the, the global environment

that we all have to care.

Six months in,

the Transpolar Drift
is carrying the Polarstern

and its ice cities
around eight miles each day,

as the rest of the world

faces a pandemic.

The coronavirus is

the biggest threat this country
has faced for decades.

All over the world,
we are seeing

the devastating impact of
this invisible killer.

The scientists may be

more isolated
than anyone else on Earth,

but as spring turns to summer,

they face their own challenges.

The thinning ice
is increasingly treacherous.

Large cracks form,

and huge ridges of
colliding ice bury equipment.

Both are made worse by
violent storms.

And as they drift ever closer

towards the edge of
the ice pack,

the favored hunting ground
for bears,

their work is
constantly interrupted.

By mid-June, much of the Arctic

is in the grip of
a record-breaking heat wave.

In July,

the ice is disappearing fast,

leading to the smallest area
of Arctic sea ice

ever recorded
for this time of year.

The question on everyone's mind

is, how long
will their ice floe last?

So this one, can you see it?

- It's kind of...
- Ooh, yeah, yeah.

There's a few, like, lines.

This is undergoing melting. Yes, I see.

The water in the snow,

it's just trickling down
and pooling on the ice.

And the ice starts to become,
we call it rotten.

The processes and changes
have been really quick,

a lot quicker than I, I thought
they were gonna be.

So, how long have we got?

That's a good question.

While the floe is
becoming increasingly fragile,

the thinner ice is also
moving faster than expected.

The team had hoped to stay
locked in until September,

but by mid-July,
the Transpolar Drift

has already brought them
close to the ice edge,

where the waves
of the open ocean

will finally destroy their floe.

It could be

a very dangerous situation,

where the ice floe
breaks into small pieces.

It could be any day now.

You know, sea ice,

it has a lifetime of its own,

and so we watched it grow
when we arrived,

and now we're watching it decay.

Good morning, everybody.

We are at a distance
of nine nautical miles

from the ice edge,
and that is the distance

where we need
to take things down.

It's time to say goodbye
to our research camp.

We measured right up to the end,

and actually, that feels great.

To me, this feels like
a huge accomplishment.

So, I wake up,
and I go to the bridge...

and there's nothing.

Our floe is gone.

It's totally gone.

It's disintegrated
into a thousand pieces.

Overnight, we went from
having a floe that we could work on,

that we were moving
heavy equipment on,

to literally shambles of ice.

It was incredible.

Soon after their
ice floe melts away into the ocean,

2020 is confirmed as having

the second-smallest extent
of summer sea ice on record.

Across the Arctic,

vast areas are ice-free.

There are even patches of
open water

at the North Pole itself.

We don't
have that much time left.

If the Arctic Ocean is going to
lose its summer sea ice,

that's a big climate shift.

The problem is that

climate change is
this gradual, creeping change.

I think eventually, we're
going to cross a, a threshold

where the weather and
the climate become so different

from what
we're able to deal with,

that it will become a crisis.

That it will become urgent,
like COVID has been for us.

Here's the
question I would like to pose:

why not act now?

Humans are very resilient,

we're very innovative.

We can come up with ways
to solve this,

but we need to start working
together more than we are.

MOSAiC is a symbol of

what we need to deal with,

the challenges we face.

It's a global problem.

And you solve global problems
by acting as a global community.

We're leaving the Arctic now

with a tremendous amount of
new knowledge,

and it's going to be available

for everyone around the world
to use.

What each team has found

has been really extraordinary.

The implications are huge.

From thousands
of feet above the Arctic ice

to the ocean deep below it,

the team has gathered
more than 150 terabytes

of vital new data

and countless samples
still to be examined.

As scientists
around the world work together

to analyze
and combine the findings,

they'll piece together
a new picture

of our changing Arctic,

transforming
how we see our future

and what can be done about it.

The world is changing,

and there is something
that we can do about it,

but it takes us
making better choices

about our everyday lives.

I hope that what you've seen

encourages you to believe that,
as we continue to

be curious about our world,

it will help us protect it.

What is at stake?

Everything, I would say.