NOVA

The Arctic...

the Antarctic...

our planet's ice worlds.

Vast, frozen, and empty.

Yet hidden in these rocks,

buried under the oceans...

Control, boulder board.

...and trapped in the ice

are clues that reveal a totally different past.

Oh my God, look at this.

Full of surprises...

It's like a whole forest.

I'm Kirk Johnson

and I'm headed out on an adventure back in time...

Just walking around, carrying a mammoth tusk.

...and around the globe,

from one polar extreme to the other,

to discover an Earth totally different...

It just looks like Mars.

...from the planet we know today.

This place, this is so totally amazing

An Arctic that was once a warm, humid swamp;

Antarctica full of dinosaurs;

and a time when ice sheets extended from pole to pole,

turning earth into a giant snowball.

What powerful forces drove the poles to such extremes?

And what does it mean for our planet's future?

Find out the true power of ice.

This is amazing out here.

"Polar Extremes,"

right now, on "NOVA."

Major funding for "NOVA" is provided by the following:

We're right at the mouth

of the Ilulissat Icefjord.

This place is a dream.

It's almost unimaginable to think

that I can paddle a kayak around in a landscape

of floating, frozen ice.

Think about all the other places you could be right now,

then think about where you actually are.

These icebergs are amazing,

and they come in all sizes,

from the size of little, tiny ice cubes

all the way up to the size of mountains.

Believe it not,

we live on a planet whose fate is determined by ice.

You wouldn't think it living at mid-latitudes,

but here in Greenland, it's really obvious.

There is so much ice in glaciers and ice caps,

mostly up here in the Arctic

and down in the Antarctic.

When you add it all up,

it's 70% of Earth's fresh water.

I'm paddling towards two of the most spectacular icebergs

I've ever seen in my life.

This stuff looks so solid,

so vast, so permanent.

But looking around at these giant floating mountains,

you've got to wonder, "How did all this ice get here?

How long did it take to form?"

And, of course, "How long will it last?"

For the whole time that humans have been on this planet...

around 300,000 years...

there's always been ice at the poles.

But if you look at the entire history of Earth,

Homo sapiens' existence has happened

in just the blink of an eye.

If we could travel back in time...

hundreds of millions of years...

what would the Arctic and Antarctic look like?

Ice at the polar extremes

is vital to the health of our planet.

If it disappears, what can the past tell us about the future?

How close are we to a tipping point?

That took me by surprise.

To answer these questions,

I'm joining scientists working around the world...

Oh, yeah!

Digging... Oh!

There's a perfect three-million-year-old clam!

This is like a window to the past.

Drilling...

You can actually see

the annual layers, even at this level.

And probing...

First we're going to lower the probe. Probe deployed.

To unlock the hidden history...

Okay, so it's cold.

You're better than me, I'll tell you.

...of the polar extremes.

Oh, yes!

I'm a paleontologist.

Get-get this edge right here.

Yes, sir.

I love finding fossils of all kinds,

but I have a special place in my heart for fossil plants.

Oh, my God.

Like this palm frond I found in Alaska a few years ago.

Whoa.

My first stop on this journey is one

of the most remote places on Earth,

with some surprising secrets locked in its rocks.

I'm on my way to Ellesmere Island,

high in the Canadian Arctic, next door to Greenland,

and it's only 800 miles from the North Pole.

We just crossed over latitude 77,

and we just left Grise Fiord,

which is the northernmost town in North America,

and we're going north.

There's just clouds and ice and rock.

It just looks like Mars, it's a magical place.

This far north, there are no roads, no airports,

and definitely no runways.

He's coming in right now.

Landing on uncharted ground is a nail-biting experience.

Hold tight, hold tight.

Even for a seasoned Arctic guide

like Jason Hillier.

There we go.

That's what we call an...

That's an Arctic landing right there.

He hit the brakes pretty hard.

Whoo!

That was awesome.

Terra firma.

Ellesmere!

You got to have a really good reason

to want to land a plane here.

It's a great place to be; I mean,

this is a most beautiful spot.

There's always the moment when that Twin Otter leaves,

and you're standing here realizing that

there's nobody for hundreds of miles around.

You're all alone out in the amazing, wide world.

Time to get down to business.

I know.

I've come here to try and figure out

what life was like in the Arctic millions of years ago.

There's a two-month-long window in summer

when conditions are right for fossil-hunting.

This is also a trip back in time for me.

I first came here in 1984, when I was only 23 years old.

My first trip to Ellesmere Island

changed the way I looked at planet Earth.

It sealed my fate.

After that trip, I knew I had to become a paleontologist.

Yeah, these are good memories.

It's great to be back here.

In addition to Jason,

Dave Briggs is here to protect us

from any stray polar bears.

Okay.

And completing the team

is fellow paleontologist Jaelyn Eberle.

Once camp is set up,

Jason is going to help me find a special site

that I never got to see the last time I was here.

It's just straight northwest

for four kilometers. Right.

Just a little bit of a hike.

Then we, uh, sort of head northwest, I guess.

The beds are dipping pretty steeply here.

Yeah, it's definitely something we have to be careful of

with this mud.

There's a bit of a precipice over there,

although it's generally in the direction of where we're going.

Our target is several hours' hike from our camp.

This frozen tundra may look barren,

but for me as a paleobotanist, this is geologic heaven.

There are a few small Arctic wildflowers

and some scrappy ground cover.

But the nearest living tree is a thousand miles south of here.

You know, the coordinates are, they're,

our best guess are somewhere in this vicinity.

Finally, we reach what I've been looking for.

Wow!

Oh, my God, there's some amazing stumps here.

Look at this.

Sticking out of the hillside are a bunch of weird brown rocks.

These are petrified tree stumps.

Wow.

One, two, three, four,

five, six, seven, eight, nine, ten, 11, 12,

13, 14, 15, 16, 17, 18.

In one view, 18 trunks in place.

Ah, this is incredible, man.

This is, this is amazing. It's like a whole forest.

Look at that one, that one is just perfect.

You can see the whole shape of the trunk.

It's quite an amazing thing... just insane.

This is a stone tree trunk, it's a petrified tree.

It used to be a growing tree,

then it got buried and turned into stone.

Geologists have dated these trees

to around 50 million years ago.

Back then, this treeless hillside

would have been completely different.

There's a lot of clues here

to how this forest got to be the way it is.

The first is that all these stone trunks are surrounded