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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.