Boiling Earth Fierce Earth

Iceland, the clue is in the name. It's a bit chilly.

Chilly? It's absolutely freezing.

100,000 square kilometres

of snowy rock close to the Arctic Circle.

Whichever way you look at it, Iceland is icy,

but how do you explain this?

Wow! It's boiling Earth!

Get ready to feel the heat on today's Fierce Earth.

'We're exploring Iceland,

'the country created by volcanoes.'

Wish me luck.

Leah is plunging over a kilometre down into Britain's deepest mine.

The heat is overwhelming.

And Leo is taming the power of the geyser.

Let's do it.

Hang on for the ride, it's going to get hot.

What happens when the ground shakes,

the seas rise up

and the air tears itself apart?

The Fierce Earth team move in,

taking on the most powerful forces on the planet.

Get ready for Fierce Earth.

The Earth and how to survive it.

The fierce heat from deep within our boiling planet Earth

creates incredible sights for us to enjoy up here on the surface.

Geysers, volcanoes,

spectacular lava flows.

These volcanic wonders can be found dotted all over the world,

but there's one very special country where you can see them

all in one place - Iceland.

A geyser.

Boiling water and steam blasted

straight from the depths of the Earth.

This one is called Strokkur

and close by is Geysir, which in Icelandic means to 'gush'.

It doesn't erupt any more,

but it's given its name to the rest of the geysers across the planet.

And it's the planet that gives geysers their power,

just look at this thermal camera.

I'm picking up nearly boiling

temperatures at the surface.

That means that, beneath our feet,

a few miles, the Earth is a raging furnace,

a nuclear power reactor generating heat.

Now, it's hard to imagine that when you're standing in the cold

and the snow of Iceland, unless you make a snowball.

Imagine this rock is the core at the very centre of our Earth.

Now, the solid part in the middle is over 5,000 degrees Celsius.

That's about as hot as the surface of the sun.

Most of the rest of the Earth,

nearly 85% by volume,

is made up of the mantle,

and that's going to be represented

by this red snow I've dyed here.

The mantle isn't as hot as the core,

but it's still a searing heat over

thousands of degrees in places.

A thick, toffee-like hot rock that moves very slowly.

So there we have it,

there's our Earth.

But almost all of it,

apart from one tiny thin layer

on the top.

The Earth's outer layer is incredibly thin

in relation to the rest of the planet,

much thinner than I can roll in the snow.

Imagine a postage stamp stuck on a football.

And it's this thin top layer, where we live,

that's cold, sometimes freezing,

but just beneath the surface...

..it's boiling.

Wow!

Geysers are spectacular proof that there's heat just beneath our feet.

Geysers are formed when water,

boiled by the heat from within the Earth,

bubbles up through cracks

towards the surface.

If cold water is above,

this stops the hot water escaping.

The hot water gets stuck

and churns around

warming the cold water

until finally it gets even hotter,

flashing to steam with enough pressure

to burst through the colder water above.

Whoosh!

And we have our geyser.

And there's a reason for all this volcanic activity.

The land round here is constantly growing -

Iceland is alive.

It's down to plate tectonics,

the large-scale motion of the Earth's outer layer.

This layer is made up of giant rocky slabs called plates

that float on top of the underlying hot rock,

like a huge jigsaw puzzle.

Iceland is an island in the Atlantic Ocean,

slap-bang where two tectonic plates meet -

the American and the Eurasian.

These plates are moving apart

at an incredibly slow rate,

about 2.5 cm a year,

but that's enough to open up tears in the Earth

that let the hot mantle seep out as magma.

The result is an incredible landscape with volcanoes,

geysers and lava flows

powered by the hot volcanic rock,

formed from an otherwise freezing country.

And it's the mix of fire and ice that makes Iceland unique.

And what's more incredible is that you can see the very point

at which two giant tectonic plates tear themselves apart.

With Europe over this side

and America over here.

But the very point at which those plates touch,

one slight problem,

it's at the bottom of that icy lake.

This is Silfra, a lake formed from melting glacier water flowing into

the actual tear between the two tectonic plates.

The water in Silfra is just above freezing.

I wouldn't last more than a couple of minutes in a standard wetsuit,

so I'm wearing a dry suit

that will keep as much water as possible away from my body.

'Silfra is beautiful, but diving here is serious business.'

Whoa, he-he.

This is quite cold.

A constant two degrees Celsius.

The water is so fresh,

you can drink it straight from the glacier.

Wish me luck.

You should never normally drink straight from lakes,

but the water in Silfra is crystal-clear

and the sights hidden below the surface are spectacular.

They call this area the Silver Cathedral.

All around me are the rocks left behind

as the two giant tectonic plates pull apart.

Look carefully and you can see that these rippled boulders

were once red-hot flowing lava.

And here's what I've come for,

the point where you can actually touch

two continental plates at the same time.

I can put my hand on the Eurasian plate and then the American plate.

Eurasian,

American,

what a thrill.

I can feel the power of the planet coursing through my fingers,

even with mittens on.

Wow! That's amazing.

I've actually touched two different continental plates.

With the Earth splitting apart like that,

no wonder Iceland is the home of boiling Earth.

Later in Fierce Earth,

Clare and I will be trekking deeper into Iceland's volcanic heart

for a very special picnic.

Back in the UK, Leo is on his own quest for adventure

inspired by geysers.

An ordinary day, an ordinary lake.

No sign of the boiling Earth here,

but have no fear, geyser lovers.

Today, we're going to turn the power of the geyser on its head.

Geysers can shoot thousands of gallons of water

up to 60 metres into the air.

The Jetovator is part geyser,

part Jet Ski and uses high-powered jets of water

to propel a rider over seven metres in the air

at speeds approaching 25 mph.

It's the nearest thing you can get to riding the boiling Earth.

So, Mark, how does this thing work, mate?

Well, Leo, basically, the Jet Ski, which we've got back here,

is acting as a water pump and it pumps water through the hose

-and kicks it back at the Jetovator.

-OK.

You've got thrust coming out in the middle bottom there.

And then, you've got water jets coming out of these as well, right?

Yeah, these give you stability and aid in the hard turns.

This is going to be fun. Let's do it.

Yeah. Let's go.

Seems simple enough.

What could possibly go wrong?

This is it - the moment of truth.

Riding the power of the geyser to the max.

HE LAUGHS

Miles harder than I thought it was going to be.

Never mind. They say practice makes perfect!

-Right, are you ready?

-Yeah.

Well, they say that...

Taming the power of the water geyser is not going to plan.

Time to regroup.

Oh, that was difficult!

That was miles harder than I thought it was going to be.

It's like... There's a lot of power in that jet.

But it's really subtle,

the difference between having control and not having any control.

I didn't feel like I had a lot of control.

Oooh!

This time, I take things slowly.

Easy on the water jets, steady with the thrust.

And suddenly, finally, I'm flying!

Wooo-hoo!

What a thrill. Zooming through the air on nothing but jets of water.

I am the geezer on the geyser!

We've already seen spectacular proof that the Earth below our feet

can boil water.

But exactly how far do you have to go down below the surface

before things start heating up?

Leah is digging for clues in North Yorkshire.

Boulby mine, Cleveland.

Every year, it produces over a million tonnes of the fertiliser,

potash, as well as half a million tonnes of rock salt.

And to get to it, you have to dig deep.

Almost 1.5km into the Earth.

It makes Boulby the deepest mine in the UK

and the second deepest in Europe.

I'm about to experience for myself how the Earth heats up

under the surface and all that means travelling down to the deepest,

hottest corner of the mine.

Millions of tonnes of rock above me,

the boiling heat of the Earth not too far below, it sounds scary.

I feel a little bit scared.

The closer you get to the Earth's hot mantle, the hotter it gets.

On average, the ground heats up by 25 degrees Celsius

for every 1,000m you travel into the Earth.

They call this the geothermal gradient.

In a mine as deep as Boulby,

that should mean a temperature in excess of 40 degrees Celsius.

Sahara desert temperatures on England's chilly North Sea coast.

And there's only one way in or out.

The mineshaft.

A token system checks that everyone who goes down into the mine,

comes back up.

It's a six minute journey down the lift shaft,

which is 1,100 metres deep.

Enough for three London Shards with room to spare.

It's a bit like being on an aeroplane

when you're going high, your ears pop.

Well, it happens when you go deep underground, too. They've popped!

Feels really weird.

I think we're almost there.

So I've made it to the bottom.

I can't believe how windy it is down here.

But that's because they're blowing air right through this mine.

That's to keep everyone breathing, of course,

and the machinery nice and cool.

But, my journey has only just begun.

It's another 10km out to the hottest part of the mine,

and I have to go even deeper into this sweltering, underground city.

Up to 300 miners are down here at any one time.

And they all have a personal supply of iced water. My guide is Carl.

He manages the potash mining

and has over 30 years' experience underground.

I want to know how he copes with the heat.

I don't think you ever get used to it,

but you have to certainly think about what you're doing

in respect of taking water on board and keeping yourself hydrated.

That's the key to it all, is hydration.

HOOTING

There are over 900km of tunnels in the mine.

That's about the distance from Land's End to John O'Groats.

As well as inland, they also stretch 7km out under the sea.

-It's feeling a lot warmer now.

-You've still got a fair way to go, yet.

-Yeah.

-I mean, this is actually still very, very cold.

-It's going to get warmer?

-It's going to get significantly warmer.

Along the way, we pass towers of wooden blocks.

They look like giant stacking games,

but are actually helping hold up the roof of the tunnel.

You can see how the wood is slowly being crushed by the vast weight

of rock just above our heads.

After half an hour driving, we finally arrive at our destination.

The heat is overwhelming. The sweat is incredible.

I don't know if you can see that.

And now, I'm going to head for the face of the mine.

The mine face is where the actual mining takes place.

Giant machines cut through the Earth, collecting potash and salt,

24 hours a day.

What sort of machine could create tunnels like this

through solid rock?

This sort of machine!

The Heli Miner, a 90 tonne state-of-the-art mining monster.

Costing £1.5 million,

it's the most powerful remote-controlled toy on the planet.

They're just moving it forward now, and it needs constant air and water

to cool it down because it's so hot here.

The monster goes back to sleep.

Time to check out the Heli Miner's handiwork.

So this is the deepest, hottest part of the mine. This is the mine face.

And you can see the grooves that that beast of a machine

has been spinning against the hard rock. It's really hot here.

And I've been all over the world for Fierce Earth,

including the Sahara Desert, and it's way hotter here.

It's really stuffy and dry. But let's check out just how hot it is.

What I want to do is touch the rock here and see how hot it is.

And that feels like touching a radiator.

The heat is all coming from the rock itself.

Let's just get an exact temperature.

Just put it there.

So that's flicking. Yeah. 42 degrees.

Now that is incredible.

42 degrees is around as hot as it ever gets in Thailand, Brazil,

or the Caribbean.

The average temperature above ground here is just ten degrees Celsius.

Down in the mine, it's four times hotter,

all thanks to the boiling Earth.

Amazing though it has been down here, I'm ready to head back up

and get out of this heat!

But I couldn't leave without mining a little bit of rock salt.

Now, it's a long way to come for a bit of salt,

but I'm on a mission for Dougal in Iceland.

Whatever could he want with this? All will be revealed!

Sometimes the heat from the ground isn't just a hazard

that miners have to put up with when mining rocks.

Back in Iceland, it's the very heat itself that's being mined.

So far, the boiling earth we've seen in Iceland has given us

spectacular geysers.

Pretty, but not very useful.

I'll give you useful.

Woo! SHE LAUGHS

This vast blue lagoon contains hot spring water

from deep within the Earth.

There are over 170 of these hot spring

pools across Iceland for the 300,000 people who live here.

To bathe with friends and family is a big part of Icelandic life.

The hot springs are fun,

but they also show us that Icelanders take their boiling Earth seriously

because it's the source of endless, more of less free, power.

The hot water in the Blue Lagoon hasn't come directly from the Earth.

It's passed through this huge power plant first.

The water is actually the leftovers.

This steaming heat is all that remains of the energy

that has been extracted by the power station.

When it comes to power, Iceland is the ultimate eco-friendly nation.

In Iceland, the five geothermal power stations provide

an incredible 25% of the energy needs for the country.

In fact, they've got so much power,

they even heat their pavements to stop the ice collecting in winter.

And the source for all that power?

Well, it's right beneath us, deep within the boiling Earth.

This is a bore hole, forming a man-made geyser.

It's pretty straightforward to make

in a landscape as volcanic as Iceland.

The hot volcanic rock is underground, just beneath our feet,

and all you need to do to get to it is drill a bore

hole down to around 2,000 metres,

and up shoots endless boiling water and steam.

The bore hole is really amazing.

You can hear it bellowing steam out and you can smell the sulphur.

But by itself, it's not really very practical.

However, if I attach a pipe, like you can see over here,

I can bring the steam all the way round to here.

And if I drill loads more bore holes, and I attach lots more pipes,

I can take the steam absolutely anywhere.

Yeah, perhaps even down to that brand-new,

state of the art geothermal power station,

right down the hill there.

-I was just about to get to that.

-Come on.

These pipes are full of water and steam as hot as 370 degrees

centigrade, nearly four times hotter than a boiling kettle.

They transport the heat from three volcanic systems in the hills

all the way to Hellisheidi,

the second largest geothermal power station in the world.

The final destination for the steam is to power these giant turbines.

The turbines look like jet engines, but work like windmills.

The high pressure steam spins hundreds of blades inside,

which generate electricity.

This is geyser harvesting on a giant scale.

There are five turbines behind me and the combined power is

enough to produce electricity for 50,000 people.

Now that is amazing, isn't it, Dougal?

Dougal?

As the energy around here is more or less free,

I don't think they'll mind if I borrow a little of it.

Here I've got a miniature turbine -

it's a bit like a windmill -

attached to a motor which is, in turn, attached to this little light.

Now hopefully, if I can use some of this steam,

I might get some electricity.

Wow. There you go.

Free electricity.

And with the steam here being generated by the boiling

Earth beneath us, this is energy that will never run out.

Wow!

The power stations of Iceland show how human beings never stop

inventing, and it's the same story all over the planet

wherever there is geothermal activity.

We're heading to the far north of Iceland now,

right on the edge of the Arctic Circle,

but if anything the ground is hotting up.

We're surrounded by some of the most amazing columns and turrets of rock.

These were once all red hot lava.

How could this have happened, up here in the north of Iceland?

It's so cold and icy. What was going on?

As ever, the clue is in the boiling Earth.

This is Krafla, the closest you can get to the origins of the planet.

It's terraforming in action.

Iceland's splitting at the seams and growing year by year.

-Wow!

-That is amazing.

This is where all that lava's coming from...

giant cracks in the Earth's crust.

This is the Atlantic ridge.

It's incredible to think that this tear actually runs all

the way from the top of Iceland right down to the very bottom.

You have that piece.

So I've got the American plate...

And I've got the Eurasian plate...

And there you have it.

Iceland literally tearing itself apart.

Have you ever wondered what planet Earth

was like millions of years ago when it was just forming?

Before people, before dinosaurs, before anything.

The living landscape of Iceland is your answer.

Fumerals are natural vents that constantly belch

steam from under the ground.

The steam brings up sulphur that dyes the rocks yellow.

Whoa!

That stinks of bad eggs! You don't want to be near that.

Now all the ground around us here, even up on the hill,

has melted the snow.

It's as though it's alive.

It's an awesome sight.

And for the first Viking settlers,

who arrived over 1,000 years ago, the hot land was a real gift.

And I know some people can show us why.

Iceland was first inhabited by Vikings,

who travelled from Scandinavia over 1,100 years ago.

They left a country where life was tough

and arrived somewhere even more hostile.

But the boiling Earth helped them survive,

and some of their traditions are still around today.

Daniel, Lurvic, Margaret

and Ragnaheida are Icelanders who have grown up in and around Krafla,

direct descendents of the Vikings who settled all those centuries ago.

What are you guys up to?

We're baking bread in the Earth...

using just natural heat.

So, basically, you're using the ground as an oven.

-ALL:

-Yeah.

-How hot does it get in there?

-It goes about 90 degrees.

How long does the bread take to bake?

-24 hours.

-Oh! Well, I'm starving!

Well, that's OK. We put some in for you yesterday.

-That's a relief.

-Well, that's good news.

I brought some eggs as well.

-Maybe we can bake those?

-Yeah.

-OK, let's do it.

This one's broken already, so I think that might have been Dougal.

LAUGHTER

Put the eggs in there then.

How long do you think the eggs are going to take?

They're going to take about ten minutes.

-So what do we do?

-Well, we'll wait.

-We will wait.

-We'll wait.

'Instead of an egg timer, the girls give us

'a rendition of an Icelandic song.'

BOTH SING IN ICELANDIC

'And then it's the moment of truth.'

Are we ready to see if our egg and our bread are cooked?

A big moment.

-There's the eggs. You take hold of them.

-Here's the eggs.

-Is the bread cooked?

-Put it down like a sand castle.

-Wow!

-Look at that!

I get the honour to cut it - brilliant.

-Wow!

-That is perfect.

Bread cooked from inside the Earth.

'The bread looks good,

'and Dougal's brought a little surprise along to season the eggs,

'courtesy of Leah.'

This is Fierce Earth rock salt from the deepest mine in the UK.

'Let's just hope our eggs are done.'

-Yeah.

-It's boiled!

-A little bit of salt...

Right then, let me just taste it. I'm going to go for it.

-Is that good?

-Lovely.

That is beautiful bread, and it's really nice and warm.

This is fantastic.

A volcanic picnic, courtesy of boiling Earth.

What do they say in Icelandic?

THEY SPEAK ICELANDIC

-Or, in British, good health.

-Good health.

Our amazing planet is alive with wondrous volcanic sights.

We've seen fumerals,

geysers,

and touched the giant tears in the very fabric of the Earth.

The heat from below can make life tough for miners in the UK,

but give the gift of unlimited energy in Iceland.

With such an incredible resource under the ground,

the country will be surviving and thriving for thousands of years,

all thanks to the boiling Earth.

Next time on Fierce Earth...

things get wet as we discover the power of waves and tides.

Clare and Leo get a surf lesson,

and Leah witnesses one of the fastest tides in the world.

It's starting to get a little bit scary, actually.