All language subtitles for S38E07 - Secrets Beneath Ice

It's a mystery continent at the bottom
of the world and the largest single mass

of ice on Earth.

For longer than humans have walked the
planet, ice

has dominated Antarctica.

But what about the future?

Ice melt from the continent.

Sea level goes up.

As Earth gets warmer, what will happen
to Antarctica?

We're going into uncertain lands,
uncertain future.

How will the Earth respond?

Today, a pioneering team is searching
for answers with a bold new plan and a

revolutionary new machine.

No one has ever drove through an ice
shelf.

And they present these challenges.

They must drill down nearly a mile and
more than 20 million years deep into

Antarctica's ancient history.

In this unforgiving place, it's never
been done before.

It's quite amazing when you think about
where we are and what we're doing.

Anything can go wrong at any minute.

The stakes are high because the secret
to Earth's future...

lies buried in Antarctica's past.

Right now on NOVA, Secrets Beneath the
Ice.

Major funding for NOVA is provided by
the following.

In 1968,

As whaling continued worldwide, the
first recordings of humpback songs were

released.

Public reaction led to international
bans, and whale populations began to

recover.

At Pacific Life, the whale symbolizes
what is possible when people stop and

think about the future.

Help protect your future with Pacific
Life, the power to help you succeed.

I would love to have been a musician,
but I knew that I was going to need a

job. We actually have a lot of
scientists that play music. The

innovation, there's definitely a tie
there. One thing our scientists are

on is carbon capture and storage, which
could prevent CO2 from entering the

atmosphere. We've just built a new plant
to demonstrate how we can safely freeze

out the CO2 from natural gas.

It looks like snow.

It's one way that we're helping provide
energy with fewer emissions.

And David H. Koch.

And HHMI.

Howard Hughes Medical Institute.

And the Corporation for Public
Broadcasting and viewers like you. Thank

Major funding for Secrets Beneath the
Ice is provided by the National Science

Foundation, where discoveries begin.

Additional funding is provided by the
Earth Science Program at NASA.

It's the coldest, windiest, driest, and
most desolate landscape on the

planet, with few permanent residents
except penguins and seals.

This frosty continent appears locked in
a perpetual ice age.

A colossal cloak of ice covers almost
every inch of land, and in some places,

The ice is so thick and so heavy, it
depresses the Earth's crust almost half

mile.

Some people call it Earth's freezer, but
scientists call Antarctica the ice.

Antarctica plays a fundamental role in
the way the Earth functions.

For polar researchers, Antarctica is a
giant laboratory more than one and a

times the size of the United States, and
home to 90 % of all the ice in the

world. Anything that happens down here,
anything that changes, will affect the

rest of the world.

Most people don't think that change in
Antarctica matters to them. But when we

look at New York City, and we look that
it's in front of the ocean, it matters.

What would happen if all of Antarctica's
ice were to melt?

The Antarctica milk sea level goes up 12
stories in New York City. Sea levels

would rise by more than 150 feet.

Flooding coastal cities, displacing
hundreds of millions of people.

That would be a change that you could
see from space. Earth would look

different. In any case, even a loss of
just 10 % of Antarctica's ice would be

catastrophic.

It would raise the sea level over there
in Manhattan, about 19 feet, right up

along the edge.

Big sections of Brooklyn would be
underwater.

Certainly the Mediterranean, some of my
favorite cities like Venice, would look

very different.

Tens of millions of people would have to
be relocated. It would be almost a

different planet.

If sea level changes and the climate
around the coastal regions change, it's

going to affect the climate where you
live, it's going to affect the things

can grow, it's going to affect how you
live.

There may be a list of things in store
that come as a result of

raising sea levels that we haven't even
thought about yet.

Could this be our fate?

Is Antarctica heading for a major
meltdown?

If so, it may happen over centuries.

But it could already be starting,
because the climate is changing.

And it's changing because burning fossil
fuels has increased the level of carbon

dioxide in the atmosphere.

Today, we have something that's
completely man -made, and that is the

of carbon dioxide being put into the
atmosphere by humanity, by us.

Carbon dioxide is a greenhouse gas.

It prevents the sun's heat from
escaping.

I'm in the Brooklyn Botanic Garden in a
greenhouse.

Greenhouses, they're basically like heat
motels where the sun's rays can come in

and they get trapped inside the
greenhouse. They can't get out.

So like glass in a greenhouse, gases
like carbon dioxide trap solar energy in

our atmosphere.

But now those levels are increasing.

The result is our Earth is now warming
up.

And the ice is melting, both in
Antarctica and the

Arctic.

In the north, there's two clear signals.
In the Arctic Ocean, you have lots of

floating ice and not sticking around
through the summer.

That's one sign of it getting warmer.
The other sign, the edges of the

ice sheet are changing.

And the loss of Greenland's ice is now
speeding up.

In August 2010, an iceberg four times
the size of Manhattan broke off the edge

of Greenland.

But Antarctica has nearly ten times as
much ice as Greenland. And in the past

decade alone, rising temperatures have
caused giant pieces of coastal ice to

shrink or crumble.

Polar researchers fear that this could
be just the beginning of a chain

reaction.

But have Antarctica's ice sheets ever
collapsed before?

That's what an international team of
geodetectives wants to find out.

Here we actually have some running
water, some melt water coming out of the

To get a more precise picture of
Antarctica's future, they plan to dig

answers in the past with a giant drill.

By drilling into areas around
Antarctica, we're able to perceive a

has an impact for where we're headed as
a planet.

Antarctica was not always locked in a
deep freeze.

160 million years ago, it was part of an
enormous supercontinent closer to the

equator. At the time, Earth was much
warmer than today, and fossil evidence

suggests this giant landmass was a
tropical habitat teeming with dinosaurs.

Eventually, the supercontinent broke
apart, and Antarctica drifted south.

As Earth was getting colder, falling
carbon dioxide levels and powerful ocean

currents cooled the isolated continent
even further.

And then, around 34 million years ago,
ice slowly began to form.

It would take millions of years for
Antarctica to finally lock into a deep

freeze. And during that time, it
remained warm enough for plant life to

Evidence of that was recently unearthed
in a relatively ice -free valley in the

interior.

Here, geologists Alan Ashworth and Adam
Lewis find a remarkable fossil.

Oh, a leaf. It's a leaf.

There's a leaf right there.

That leaf fell into the mud maybe 20
million years ago.

That may be the best leaf yet.

That's a sweet leaf.

And then...

they find something extraordinary.

This is like a peat moss.

And then if we take teeth some of this
out, they're like freeze -dried.

Under the microscope, these brittle
mosses are in pristine condition.

These moss fossils are not rock, but
actual plant tissue, the last vestiges

vegetation from a time when Antarctica
was still warm.

They were found under a layer of
volcanic ash that dates back millions of

This is the original moss tissue, and
even the cells are preserved in these

fossils. These plants were flash frozen
when Antarctica plummeted into a deep

freeze that preserved them until today.

It's mind -boggling. The only way is to
say the climate remained very, very

cold, it remained very, very dry, and it
did not warm up.

for even relatively short periods of
time in this location.

Otherwise, these things are gone.

Now, as Earth is heating up, what will
happen to Antarctica?

Will it melt, raising sea levels all
over the planet?

How sensitive is this frozen land to the
temperature changes we currently face?

But before researchers can investigate
in Antarctica...

Last -minute testing is taking place
here, over 2 ,000 miles away, in the

countryside of New Zealand, with a brand
-new drill.

Yeah, it's a shakedown. We've got a few
leaking connections and things that

don't quite fit as well as they need to,
a little bit of modifications required.

Pretty common with a brand -new piece of
equipment.

Weighing in at a whopping 40 tonnes,

This mechanized marvel is as heavy as a
humpback whale, and just as large.

Towering some five stories high, the
giant rig will soon dwarf everything in

sight, except the ice.

This will be the largest drill rig in
Antarctica that's used on land.

And this mammoth rig can drill in more
than one place.

That's because it's mounted on a sled.

I think it probably is unusual.

All of the equipment is on sledges, so
in Antarctica we pull it all with big

bulldozers. It's been specially designed
to drill from the ice in order to

extract hidden secrets from beneath
Antarctica itself.

This unique multinational enterprise is
called Andril, the Antarctic Drilling

Project.

For team leader David Harwood...

It's a dream come true.

As a scientist, there's a passion.
There's a passion that comes in trying

figure this out, trying to identify what
has been the past history of the ice

sheet and wondering what the future
might hold.

Soon, the giant drill will be dismantled
and ready for a long sea voyage.

But now, the Andril team gathers at

Christchurch, New Zealand.

for the six -hour flight to Antarctica
in a C -17 cargo plane, jam -packed with

people and gear.

Their flight passes over the
Transantarctic Mountains, which divide

continent into two regions, with
colossal glaciers called ice sheets

both.

The giant East Antarctic ice sheet is
ten times the size of the West.

It's frozen firmly to bedrock high above
the sea.

And in some places, the ice towers
almost three miles into the sky.

The smaller West Antarctic ice sheet is
less stable.

That's because it rests on land well
below sea level, and it extends hundreds

miles over the ocean in floating ice
shelves.

It's likely East and West Antarctica
will respond very differently to a

world.

The Andril team touches down in the west
on an icy runway at McMurdo Station,

the largest U .S. research base in
Antarctica.

As David Harwood and Richard Levy step
out onto the ice, the first thing they

notice is the weather.

It's a bit chilly, but it's beautiful.

It's good to be back.

It's October, springtime, and it's minus
20 degrees.

The earliest I've ever been down to
Antarctica, and it's very cold. When the

wind picks up, it's rather an unpleasant
place to be working. When the wind

isn't blowing and the sun's shining,
it's actually really quite nice, but

cold.

But even a sunny afternoon can turn
nasty at a moment's notice.

It's a beautiful day!

McMurdo Station has been a vital hub of
research for over half a century.

What began as a tiny outpost has over
the years grown into a small town.

McMurdo houses a population of 200
people year round.

But during the research season, it
becomes home base for over a thousand.

Every year, McMurdo supports scores of
research projects.

providing lab facilities, food and
supplies, and survival training for

scientists who will head out to remote
field camps.

This season, those numbers include the
ANDRIL team of over 50 technicians and

researchers from the U .S., New Zealand,
Germany, and Italy.

ANDRIL is funded by their governments
and the National Science Foundation.

There's probably a week at least of work
in McMurdo where we have to get all of

our gear sorted out, getting everything
we need in order to be able to work and

survive out in the field.

As they gather supplies for more than a
month on the ice, one item is in high

demand.

Sugar actually heats your body. It gives
you quick energy, especially if you're

freezing and we expect to be very cold.

We don't really know how much chocolate
is enough. We can take up to 560 candy

bars. But I'm looking at this, and I'm
already getting queasy. I'm like, oh, I

don't know if I can eat this or not.

As Andrew researchers prepare for life
in the field, they join hundreds of

scientists spanning out across
Antarctica.

And many are focused on the same
question.

Could Antarctica be headed for a
meltdown?

Over here is Mount Boreas.

We're going to have a lot of scientists
working together. There is a little bit

of volcanic ash. And challenging each
other's theories, challenging what we

know.

Look at that.

As a community, we're going to find the
answers.

But the continent won't give up its
secrets easily.

The stark beauty of Antarctica masks a
treacherous nature.

More than 70 % of all the fresh water in
the world is harbored here.

But most of that water is frozen.

And with less precipitation than the
Sahara, Antarctica is the driest desert

Earth.

Raging winds of up to 200 miles per hour
sometimes blast the frozen terrain,

where temperatures can drop to 100
degrees below zero.

Only during the short Antarctic summer
can most researchers gather precious

scientific data from this giant mystery
continent.

A four

-hour flight and 400 miles from McMurdo
is the center of the West Antarctic Ice

Sheet.

And for one team,

This is the best way to find out about
the fact.

This is the side of a snow pit. It's a
thin wall between two pits. The other

side is open so the light can shine
through.

And you can really see the different
layers in the pit.

So this is one year's worth of snow
accumulation.

And there's a second year's worth of
snow accumulation here below it.

Two years of record right here in the
snow pit.

Of course, we want to go back a lot
further in time than that.

In order to do that, we can't just use
shovels and chainsaws like we did here,

so we have to use a drill.

Ken Taylor's team is drilling through
ice.

Their goal is to gather samples from the
nearly two -mile -thick West Antarctic

ice sheet.

And the deeper they go, the further back
in time they travel.

We're at about 480 meters deep right
now. This is right around the time when

Jesus lived. It's right about 0 A .D.,
right when B .C. years turned into A .D.

years. These ice cores contain tiny
bubbles of ancient atmosphere that were

trapped each year as the snow was
compressed into ice.

Nice bubble for this one.

There's ancient air in there. When we
crush samples like this, it'll get the

out of there, and we can sample the
ancient atmosphere.

We can also get a record of how things
like temperature and sea ice changed in

the past. And by combining these
different records, we can understand how

climate system has operated in the past.

But the ice record, valuable as it is,
only goes back about 800 ,000 years, a

tiny fraction of geologic time.

To get a more complete picture of
Antarctica's climate history, you have

drill farther back in time.

And that's what the Andril team is
trying to do.

They want to paint a picture of
Antarctica as it changed from warm to

millions of years ago.

In order to do that, Andril will have to
drill deep into the earth.

But finding the right location is a
major challenge on a continent covered

ice. And even in those few places where
the ice has receded, it's still not

easy.

Andril's David Harwood and Richard Levy
are searching for places to drill.

But as they fly over a field of rubble,
they see that gathering evidence for a

chronological history is not possible
here.

Something has stirred things up, and
that something is the ice itself.

That's because ice moves.

For tens of millions of years, glaciers
have slowly scoured the land, gobbling

up rocks and debris and spreading them
all across the landscape in random

This we call glacial paleontology. Some
call it garbage pile paleontology

because we're looking and sorting
through these moraines to try to get

information that the ice sheet has
brought to us.

A moraine is the chaotic accumulation of
rocks and debris deposited by glacial

movement. This one here actually has
abundant shell fossils.

This shell, brought here by a glacier,
comes from a time when the continent was

warmer and water ran through these
valleys.

This landscape is a treasure trove of
Antarctica's climate history.

But the ice has scrambled all the clues.

We're looking at a jigsaw puzzle.

Yet there's one place where the evidence
remains intact.

That's in the seafloor beneath the
Antarctic ice shelf, where the glacial

movement has also deposited layer after
layer in chronological order.

Drilling gives us an opportunity to get
a serial history in time.

Each layer goes back in time, and we
know that a rock above was younger than

rock below, so we can put it into
history.

The Andril team aims to drill through
the Antarctic ice and the sea below.

Then, like a straw thrust through a
layer cake, they'll bore deep into the

floor in order to recover millions of
years of rock and mud that trace

Antarctica's climate history.

Even after ice began to form in
Antarctica around 34 million years ago,

continent remained warm enough for plant
life to survive, a lot like areas of

New Zealand today, where ice can be
found bordered by trees and plants.

But when did Antarctica plunge into a
solid deep freeze, and how did it

Was it gradual or abrupt?

Will the story of how Antarctica changed
from greenhouse to ice house reveal new

clues about the continent's climate
future and our own?

Charlie, Charlie, I am David Harwood.

The Andril team will spend the next few
weeks searching for drilling locations

from the surface of the ice.

But David Harwood remains focused on
what lies below.

When I'm driving across there, I'm
always thinking about what's beneath us.

over about 15 feet of ice, and over that
I'm over about 1 ,500 feet of water,

and then to the sediments below that.

Here at the bottom of the world, the sun
never sets in the summer.

And as night blends into day, the work
begins in earnest.

The team heads out to McMurdo Sound, a
place where the ocean freezes annually,

creating a precarious platform of
floating sea ice that will only last a

months.

We're standing right now in the southern
part of McMurdo Sound.

Seasonally, this region will break out.
The sea ice that we're standing on will

melt out.

It's now strong enough, perhaps 20 feet
beneath us is the thickness of ice.

and then 1 ,500 feet of water beneath
that as well.

Just to be sure they're in the right
place. Fire in the hole.

The team blasts powerful sound waves
through the sea ice and into

the sea floor below.

The result is a sonic street map of
layer after layer of rock and mud, each

representing a different era of the
past.

By looking into the past, we can maybe
project into the future how dynamic has

been the behavior of the ice sheets.

Have they been static and slowly
changing?

How active a player have they been?

Finally, it's time to tow the giant
drill out onto the ice.

to ensure that the weight of the rig
isn't supported by the sea ice alone.

Divers attach flotation devices to the
drilled pipe, and at the end of that

is a whirling tool with a unique cutting
edge, a drill bit made of diamonds that

can bore through almost everything in
its path.

The diamond core system that we have,
it's almost like melting the core down

through the rocks. It just cuts through
whatever's there.

If you hit a big boulder, you'll just
end up with a cylinder of that boulder,

and it'll just keep going.

Now the real drilling begins.

There's not a minute to waste, because
the Antarctic research season is so

short.

The crews work around the clock.

to recover cores of rock that trace
Antarctica's ancient past.

The powerful drill bores down over three
quarters of a mile, bringing up 12 feet

of core at a time, each foot averaging a
thousand years of climate history.

It's an astonishing feat.

It's quite amazing when you think about
where we are and what we're doing.

We've got a drill rig, a 60 ton to 90
ton with all the equipment on a drill

sitting behind us here on eight meters
of sea ice, about 380 meters of water.

And then we're drilling down into the
seafloor below that with a three to four

inch diameter pipe that's turning round
and round like a piece of spaghetti

hanging down through the water and into
the ground and it's wobbling around a

bit and we're turning around and
bringing core up from deep within the

Anything can go wrong at any minute with
this process.

And all too soon, it does.

Sometimes even a drill bit made of
diamond can run into trouble.

We haven't been getting particularly
good quality core, and we're suspecting

that the drill bit has been damaged in
places that are a little bit narrower

than it should be for the size of the
diamond bit.

And that means we have to pull all of
our pipe out.

about 1 ,700 meters, and replace the
bit, and then put the pipe back down the

hole, and that's going to take us about
24 hours to 36 hours.

Removing and replacing nearly a mile of
pipe is no easy task, especially when

it's your job to change it all out,
piece by piece.

But for other members of the Andro team,
it's a welcome break.

In an extreme environment like
Antarctica, nobody's on a diet.

Your body is working so hard to stay
warm. Packing away 6 ,000 calories or

a day is not an indulgence.

It's a necessity.

And because Antarctica is drier than the
hottest desert,

dehydration is a constant concern.

And keeping the drill up and running.

is another.

Finally, after a day and a half of hard
work, the new bid is in place.

And drilling is back on track.

They recover a 12 -foot length of cord
wrapped in a protective cover.

Workers carefully carry it back to the
lab to be examined.

When they crack it open, It's in perfect
condition.

This mud and rock is more valuable than
gold because each core is a time

machine. We're currently down at a depth
of about 440 meters.

That's about a quarter mile down,
corresponding to a time at least 15

years ago when Antarctica was still
warm.

As the cores are recovered,

Each section is sliced lengthwise, x
-rayed, and scanned in labs at the drill

site and back at McMurdo.

These cores came out of the ground three
days ago. They were split yesterday.

They were imaged yesterday.

Sedimentologists worked the night shift,
12 hours, describing these cores

millimeter by millimeter, looking at the
color, size ratios, any kind of

structure they see in a core, trying to
understand how these sediments were

deposited.

Each core tells a story, depending on
its texture, color, and contents.

And some of those stories are
spectacular.

We're seeing some macro fossils, some
large shells.

These shells are evidence of warmer
times, even as Antarctica is icing up.

This is one of the most spectacular
fossils found within Andrea this season.

This is a scallop. Now, this kind of
scallop simply do not live in extreme

waters.

And there are other clues, some of them
nearly invisible.

Hidden inside these cores are shells of
microscopic algae called diatoms.

For androclimate detectives, these tiny
diatoms create a highly revealing

picture of the past.

Because not all diatoms are alike.

Some species are adapted to colder
conditions, while others flourish in

waters.

We use them as biological markers, index
of different environmental conditions,

cold or warm, frozen waters or open
ocean waters.

Again, the Andral team examines cores
from around 15 million years ago.

They find smooth green sands containing
diatoms that thrived in relatively warm

water, confirming this was the time
before Antarctica finally froze over.

This is a very well -defined warm
period.

iceberg -free waters, open waters where
diatoms are growing and thriving.

You can see this persisted for quite
some time.

A picture is beginning to form of a long
period of transition, starting 34

million years ago, when a cooling
climate led to the formation of ice.

But even so, conditions remained
relatively mild.

But when did Antarctica finally slip
into a deep freeze?

The answer lies in cores from around 14
million years ago.

Instead of smooth and green, these cores
are rocky and gray, and some contain

diatoms that thrived in cold glacial
waters.

This amazing discovery reveals a rapid
change from cool to frozen.

It fills in what has always been a blank
page in Antarctica's climate history.

Next season, they'll attack another
crucial question.

After Antarctica froze 14 million years
ago, did the ice ever melt?

Or has it remained a frozen wilderness
right up until today?

That answer will have to wait.

Cracks in the sea ice tell the team it's
time to return to base.

We've seen the ice break in quite a bit
in the last month, but it's not broken

in anywhere further south than it is
right now.

We can only be on this site for so long
before the sea ice starts to melt,

before the conditions change, and for
safety reasons we have to get off the

ice.

The precarious sea ice of West
Antarctica may come and go with the

But what about the giant East Antarctic
ice sheet?

A mountain of ice so high, it covers
mountains.

This is like an MRI of the ice sheet.
Some places it's really thick, two miles

thick, and pretty flat and boring.

But then there are other places where
what we discovered were hidden mountain

ranges the size of the Appalachians, but
totally hidden by the huge East

Antarctic ice sheet.

There's ten times as much ice in the
east as in the west.

But a small portion of the east has
almost no ice at all

It's an unearthly location

that defies the very image of Antarctica

These

are the dry valleys cold barren and
except for

a few scientists

almost completely devoid of life.

The landscape is so alien, NASA has used
it as a test site for space programs.

It's a fantastic place.

You can't find this anywhere else on
Earth.

Its closest analog is the surface of
Mars.

Mullins Valley is the ultimate remote
field camp.

It serves as home base for a pioneering
band of glaciologists led by Dave

Marchant.

Marchant and his team are conducting
research the rugged, old -fashioned way.

They'll live in tents and won't be
picked up for two months.

They need to be self -sufficient, and
for the most part, They like it that

Good day.

The good

thing about working out here is it's

actually a double -edged sword.

You come out here, you have no contact
with the outside world, no email, no

telephone contact, so you can totally
immerse yourself in the science.

And that allows you to think 24 hours a
day about what you're doing. The other

side of that is you have no idea what's
going on outside.

Hi. At the beginning of the season, I
didn't like it when you would breathe

the frost would form on the outside of
the sleeping bag. But it's warmed up

and it's a little more comfortable in
the morning.

Small set -ups like we have, which are
helicopter -supported, are isolated.

They're among the most isolated in the
region.

And as a result, we have to check in
daily with McMurdo.

I'm trying to heat the batteries up so
that we can get a signal out right now.

There appears to be no satellite
coverage, and the batteries are a little

cold, so I'm trying to warm it up.

Sometimes you have to contort your body
in various ways to get the signal.

No, we don't have enough signal yet.

Well, here we go. We've got something
that might work.

MacOps, this is Gulf 054 Mullins Valley.

We have seven on board.

And all is well. Over.

Ah, we lost transmission.

This valley holds an incredible record.
This area is so dry and so cold that the

landscape is pristine. The rocks we see
here are millions of years old.

Marchant believes that little has
changed here for millions of years.

What? to me is exciting, is that we're
walking on an ancient landscape.

Imagine living 10 million years ago in
Antarctica. This is what you'd see,

exactly as it is today, hardly modified
at all.

But when Marchand's team drilled beneath
this rubble, they found something

totally unexpected.

A hidden glacier.

that extends hundreds of feet below the
surface.

This is, in my opinion, the oldest dated
buried glacier on Earth. Is it all out?

Yep, it's all out.

Are you getting it? Yeah.

The evidence comes from volcanic ash.

The dry valleys are surrounded by
extinct volcanoes that erupted millions

years ago.

We're finding ash deposits on top of
ice.

Ash dates are coming back as old as 8
million years.

And according to Marchand,

This volcanic ash shows this hidden
glacier, once frozen, has never melted.

This volcanic ash that erupted from a
volcano and has been sitting there for

millions of years.

It shows no chemical alteration which
you'd expect if there were any amount of

liquid melt water over that duration.

The fact that it's dry and pristine
tells me it's always been here, which is

incredible.

Equally astonishing.

and just 300 miles away, there appears
to be a completely different picture.

Exploring East Antarctica, closer to the
South Pole,

Andrews David Harwood found leaf fossils
and pieces of wood.

Surprisingly, according to Harwood,
these date to a relatively recent time,

Antarctica was not only warmer than
today, there were plants and trees.

This is a piece of southern beach.

This wood is not fossilized in the sense
that it is petrified. It could still

burn. To find the wood and leaves
together is pretty phenomenal.

It's really phenomenal for Antarctica,
particularly for Antarctica in this time

period, about 4 million years ago.

This season, the drill is set up to find
evidence of what happened in Antarctica

during this period, 3 to 5 million years
ago.

It's a time known as the Pliocene. Now
what's important about that is that the

Pliocene was globally warmer than today.

The same temperatures as our Earth may
be headed for at the end of the century,

if climate change predictions are
correct.

If we go back three to five million
years into the geological past, we know

that was a time when Earth's climate was
warmer than it is today, perhaps by

three to four degrees.

So it's the best example we have of
where the climate's heading in the next

hundred years.

The drill's new location is on the giant
Ross Ice Shelf, which extends out and

over the ocean.

It's the largest ice shelf in the world.

And it helps hold back the massive
Antarctic ice sheet from flowing into

sea. These ice shelves are very
important. What they do is hold back the

ice. It's actually trying to flow out
into the ocean.

We call that buttressing.

If warming oceans caused the Ross Ice
Shelf to break up and melt into the sea,

the West Antarctic Ice Sheet would
eventually follow right behind.

The Andral team is looking for the
answer to a critical question.

When Earth was warming during the
Pliocene, what happened to the ice?

Did the Roth's ice shelf melt, taking
the giant ice sheets with it?

Drilling on an ice shelf brings with it
a unique set of technological

challenges,

including constant

problems with mud and water.

Unlike drilling through sea ice, which
is just 26 feet thick, the ice shelf

is 400 feet.

We're looking at at least doubling or
trying to double our capability below

sea floor and penetrate to 1 ,000 meters
or better into the sea floor.

But that's only the beginning.

No one has ever drilled through an ice
shelf. And they present these

The ice shelves, they float up and down
with the tide. So you've got to deal

with this vertical elevation change.

They move sideways. They flow.

So eventually your drill pipe's going to
get bent.

Can the drill bore through a thick layer
of ice that's constantly moving without

breaking or getting yanked out of the
sea floor?

To confront this unique challenge head
on, the Andril team invents a new tool,

hot water drill.

This marvel of engineering is a moving
ring of heat that blasts jets of

water to melt a wide hole so the drill
can operate freely through 400 feet of

shifting ice.

And once again, time is so precious, the
team must work around the clock, not

only retrieving cores, but also
analyzing them.

It's 2 a .m., but you wouldn't know it.

Geologists are busy logging cores like
it's early afternoon.

We're laying out the cores in a proper
sequence, from top, the highest point of

the core, all the way to the very
slowest point of the core here.

An 80 -foot core that dates back about 3
million years is closely examined.

It contains microfossils of single
-celled animals known as sphorums.

They're from the crucial warm period
called the Pliocene.

And these tiny shells are precise
indicators of ocean temperature.

These guys are about the size of a grain
of sand.

Because the same species lived through
time, we can use the chemistry of modern

examples to allow us to calibrate, if
you like, the chemistry of the ancient

examples.

What Gab's doing here...

is he's measuring the amount of two
metals, magnesium and calcium, that are

the ocean and get incorporated into the
shell of the foram when it's growing in

that ocean. And that process is
dependent on the temperature of the

we know the magnesium, we know the
calcium, we can determine the

the ocean at the time that foram lives.

And because of that, Andrew researchers
can now calculate Antarctic water

temperatures during the Pliocene.

What this is telling us is temperatures
with three to four, perhaps five degrees

above present.

Even just one degree rise in ocean
temperatures in the waters surrounding

Antarctica will attack and begin to melt
the ice cells from below very quickly.

The air temperatures will stay cold
enough to keep things frozen at the

but what we're worried about is the ice
being attacked from beneath, not from

above.

And the cores reveal that this is what
happened during the Pliocene, when

climate was warming.

But they display even more change than
expected, revealing not only a patchwork

of glacial rubble, but also smooth mud
from open seas, indicating that ice both

froze and then melted many times.

There's a really important change right
here. This interval shows us quite a

dramatic change in the environment.

There was ice.

And then there was no ice.

The ice sheet has gone backwards and
forwards. It's advanced and it's

As they examine core after core from the
Pliocene, they continue to see

surprising signs of change.

The results of the drilling are simply
spectacular.

They give us a picture of a dynamic ice
sheet coming and going regularly more

than 60 times.

What we're seeing in this record is
telling us that Antarctica is not just a

benign spectator.

It's a player.

What this means is while it was
generally warm during the Pliocene,

also brief periods of cooling, and the
ice was exquisitely sensitive to even

small changes in climate.

Just a few degrees could tip the scale
from ice to no ice.

So what's in store for our future?

As Earth continues to warm, how much
Antarctic ice will melt, and how high

sea levels rise?

Andro scientists turn to computer models
by Rob Ducato and Dave Pollard.

We developed these climate models based
on our best understanding of the physics

of the climate system, and in this case,
ice sheets.

And now, information from Andril is
added to the climate model.

This is a computer model simulation of
the Antarctic ice sheet over the last

several million years and covers a good
chunk of the interval that was recovered

by the Andril sediment core. So we're
looking for the same kind of behavior in

our model that we're seeing in the
geological record.

As the model simulates the warming
periods of the Pliocene, all of the ice

shelves disappear.

followed by the entire West Antarctic
ice sheet and edges of the east.

And as temperatures change, the ice
refreezes and melts again and again.

And that's important because the changes
in the ice sheet that we're seeing here

reflect pretty significant changes in
sea level.

According to DeCanto's model, sea levels
rose about 23 feet during the Pliocene.

Temperatures back then were 3 to 5
degrees higher than now, just what's

projected to take place by the end of
the century.

But there's a lag time in the way ice
responds that may delay the impact for

hundreds, if not thousands of years.

Regardless, coastal cities all over the
world would be at risk, potentially

displacing millions.

We would be remapping.

Places like Boston and New York, the Bay
Area.

Not to mention, of course, places like
Louisiana, Miami, New Orleans, of

But even that might not be the worst
case scenario.

Things were very similar to today in
terms of our climate.

Tim Naish brings Rob DeCanto to New
Zealand to look at a possibility that's

more frightening.

This is the first time I've seen the
actual direct evidence for what the

are doing.

You're seeing a deepening sea level rise
up through here.

We're going to look at some rocks that
are the same age as rocks that were

drilled in Antarctica that give us the
record of global sea level changes.

Here along the Rangitiki River, tectonic
forces have razed the land and the

river has cut into the earth to expose
layer after layer of sediment that once

was the sea floor.

What they find are shells dated to the
warming era of the Pliocene.

These shells provide a way to chart sea
level in the past because some of these

species still exist today.

Many of these shells you see in here
actually live today.

So they live around the coastline, and
we know the water depth they live in

today.

So by breaking them out of these rocks
and identifying them, we can say the

depth they were living in over 3 million
years ago.

Because these shellfish live on the
seafloor and can only survive in water

specific depths, they suggest that sea
levels in the Pliocene were much higher

than even the computer models predict.

This is really it, Rob.

This is where we would say we have the
evidence for sea level being up to as

much as 20 meters above present.

That's over 60 feet.

In order for sea level to have risen
that high, an enormous amount of ice

have melted.

And this raises a startling possibility
that a large part of the vast East

Antarctic ice sheet melted along with
the West.

And if it melted once...

Could it melt again?

That could be a very bad thing because
that would actually produce a

contribution to future sea level change
that we really haven't been thinking

about.

This presents an even more dangerous and
unpredictable picture of Antarctica.

What's been surprising is... Even
geologists thought that glaciers and ice

sheets were these large static features,
which we would never really see change

in our lifetime. But glacial processes
are no longer quite as glacial. Things

are moving faster than we had thought.

What's driving these changes are rising
levels of greenhouse gas.

In the next five years, greenhouse gas
levels will be like they were in the

Pliocene. But we're not just going back
to the Pliocene. Some of the projections

put CO2 levels at twice the
concentrations of the Pliocene by the

next century.

We're essentially going back to the time
of the dinosaurs when there was very

little ice on the planet and there were
forests covering Antarctica.

And signs of change are already here.

Scientists were completely caught by
surprise when in 2002, the Larson Ice

shattered apart without warning in just
a few weeks.

And today, the Wilkins Ice Shelf, a
block of ice approximately the size of

Connecticut, barely hangs on.

I would say it's inevitable that West
Antarctica will disappear.

How long it will take East Antarctica to
engage is something that's not yet

known. In the coming years, the Andro
team will continue to explore

climate history in order to gain
valuable insight into Earth's future.

new core, we gain new knowledge about a
continent that's always been shrouded in

mystery. But its fate remains very much
tied to our own.

A date which will live in infamy.

The United States of America was
suddenly and deliberately attacked.

Do we know the whole story?

After almost 70 years, can scientific
detectives solve the mystery of a

secret weapon?

It's almost like a CSI situation where
we have a crime scene. There was a hunt

for these submarines.

Killer Thubs in Pearl Harbor, next time
on NOVA.

Major funding for NOVA is provided by
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Well, let's grow some algae.

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ExxonMobil and Synthetic Genomics have
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productive strains of algae.

Algae are amazing little critters.

They secrete oil, which we could turn
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And to do this at a large enough scale
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