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Our planet has immense power,

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and for most of human history
it has dominated us.

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In the series so far we've seen
how the forces of the planet,

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the deep Earth,

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wind...

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...fire...

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...and water

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have all had major impacts
on human history.

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But now the relationship between
us and the planet is changing.

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We're no longer at its mercy.

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We have now become
a major planetary force.

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The fundamental elements of our planet
have helped shape human history,

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but now we ourselves
are a force of nature to be reckoned with.

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Even in the wildest corners
of the Earth,

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you can't escape our human influence.

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The question is
what does that mean for our future?

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If you want to get a sense of
our changing relationship with the planet,

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then this vast expanse of mud
is the place to come.

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This is no ordinary mud.

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The towering column of steam

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shows that this mud is emerging from
within the Earth at boiling point.

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I'm in Indonesia,

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one of the most volcanically
active countries on Earth.

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Which is a clue to the origin
of this strange phenomenon.

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You know, what's happening down there

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is one of the most unusual
eruptions on Earth.

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It's a volcano,
but it's not spewing out molten lava.

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That is a mud volcano.

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This volcano began erupting in 2oo6,

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and for the people who live here,
it's been a disaster.

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Around 3o,ooo people have been
displaced by the mudflow,

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and around 1 o,ooo homes
have been destroyed.

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You know, the scale of this
is truly enormous,

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and all the way around
it's surrounded by villages,

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and many of them are half flooded
with the mud...like that there.

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Look at that, completely burying
these trees here.

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Down on the ground,
there's a real sense of desolation.

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Up close, it's the sheer oddness
of the scene that strikes you most,

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like the fact that I'm walking
alongside the roof of a mosque,

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a mosque that was once
the centre piece of a village

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that now lies entombed
in solid mud beneath me.

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Such an eerie feeling.

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It's as if the planet has decided
to reclaim this place from humanity.

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Life has been completely smothered.

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But there's something
that makes this eruption unique.

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And that is what it was caused by.

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The eruption going on out there
is really special,

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because it's almost certain
it's not natural at all.

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Geologists think it was triggered
by us...by human activities,

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when an underground probe
for natural gas went horribly wrong.

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In 2oo6, developers were drilling
in search of gas,

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but at around 3,ooo metres,
they withdrew the drill.

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The pressure in the well
then dropped,

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which sucked in hot water
from surrounding rock.

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This caused fractures in the rock.

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Water burst through and shot upwards

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mixing with layers of mudstone

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to form a liquid mud
that boiled to the surface.

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Every day, enough mud emerges

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to fill more than 4o
Olympic-size swimming pools.

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To try to contain the flow,
enormous levees have been constructed.

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Wallowing machines
are still trying to channel mud

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away from the surrounding villages.

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Concrete blocks have even been thrown
into the centre of the volcano

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in an attempt to ''plug''it.

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But every effort to hold back
this relentless tide has failed.

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To me, this eruption symbolises

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our strange relationship
with the planet today.

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On the one hand, we are
an incredibly powerful force now,

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capable of triggering
volcanic eruptions.

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But on the other hand, we're not
really in control of that power.

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Much of the effect we have on the planet
even takes us by surprise.

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These days, it's easy to see
our impact on the planet

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in a negative light -
the story of an Eden destroyed.

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But our relationship with the Earth

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is far more intriguing
and surprising than that.

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We have a much longer history of

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transforming the planet
than you might think.

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And not all of those changes
have been bad news.

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To go back to the start of the story,

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I'm off to Canada's Rocky Mountains.

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This mountain scenery is spectacular,

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sculpted by one of the Earth's
great cycles,

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a cycle that's not only transformed
the surface the planet,

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but it's also been critically important
for our evolution, to our history.

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It's the cycle of the ice ages.

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For millennia, the Rockies
have been a battleground

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for immensely powerful geological forces.

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Ice has carved this landscape,
creating these dramatic peaks

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and cutting deep valleys
out of the rock.

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You know, for the past
one million years or so,

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our planet's been swinging back
and forth between long ice ages -

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when mountains like these
were embedded deep in the ice -

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and much shorter warm periods,
like we're in now.

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The ice waxed and waned according to
small changes in the Earth's orbit,

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and that influenced
the amount of heat

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falling on different parts
of the Earth's surface.

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The ice age cycle is
pretty well understood.

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I mean, it's not an exact science,

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and there are plenty of
complicating factors,

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but what it means is
that scientists can predict

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when ice ages should begin
and when they should end.

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But until recently,
geologists had been missing something.

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New data has provided
a more accurate understanding

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of temperature changes
between ice ages -

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periods known as interglacials.

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The data shows
that during past interglacials,

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temperatures steadily declined.

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If that pattern had continued
into the present interglacial,

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we would now be heading
into a new ice age.

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From here you get a good idea
of what that would have meant.

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If cooling had continued
to the present day,

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that ice would have crept down
and smothered the whole valley.

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From about 7,ooo years ago,

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temperatures would have
started to fall.

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In Europe, the glaciers of the Alps
would have spread out

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across alpine meadows.

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If the cycle of the ice ages
had continued to follow

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the same pattern as in the past,

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then human history would have followed
a very different course.

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But it didn't happen.

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It was the ice age that never was.

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If you like, a great escape.

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So what prevented the ice
from following the same rhythms

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that it always followed in the past?

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There's a clue in the timing.

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Just when
it should have been getting cooler,

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a major change to the planet
was under way.

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Farming.

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It's thought that farming began
around 1 1,ooo years ago

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in the Middle East,
in what's known as the Fertile Crescent.

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It took a while to catch on,
but by 7,ooo years ago

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it was spreading fast,
across Europe and Asia.

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Even though our numbers
were still small,

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farming had a big impact
on the planet.

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Fires were used to clear
the forests for farmland,

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which increased the amount of
carbon dioxide in the atmosphere.

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We domesticated wild animals,
which produce a lot of methane.

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Both carbon dioxide and methane
are powerful greenhouse gases.

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This new theory suggests
that the gentle rise in greenhouse gases

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meant that instead of temperatures
falling, as they had in the past,

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they stayed steady.

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The rise of farming was enough
to halt the onset of the next ice age.

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It's fascinating to think that
as far back as 7,ooo years ago

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we had already made an impact
on the planet at a global scale.

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This was the beginning of our role
as a force of planetary change.

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Since then, human progress
has been defined by our ability

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to find ever more inventive ways

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of exploiting the planet's
natural systems.

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Around 5,ooo years ago,
our ancestors discovered

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that trapped within certain types
of rock were metal ores.

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These mineral-rich rocks were formed
deep inside the Earth

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over millions of years.

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The metals they released
could be transformed into tools,

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the foundation of civilisation.

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By 2,ooo years ago,

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people had found ingenious ways
to intercept the water cycle.

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They tapped fresh water
underneath deserts

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and used it to create
some of the first cities.

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Around 5oo years ago,

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sailors learnt how to exploit the power
of the Earth's wind systems.

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They used them to develop
global ocean trade routes.

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And more recently, we discovered
that the fossilised remains

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of plants and animals,
coal and oil,

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could become major sources of energy.

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Each of these discoveries
was a landmark

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in our ability to use planetary systems
for our own purposes.

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Today, the way in which

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we use the Earth's resources
can be summed up by this...

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It's just great to be able to
get up close

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to one of these beautiful machines.
They're so elegant and streamlined.

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A kind of fusion of precision engineering
and raw power.

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It's absolutely beautiful.

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But as a geologist,
I can't help seeing these planes

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through a different lens.

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Just look at what
goes into making one...

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Aluminium, or aluminum,
comes from a mineral called bauxite.

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It's the most abundant
metallic element in the Earth's crust,

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which has been concentrated
within rock over millions of years.

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Perspex -
in its most basic form, oil.

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It's made inside the Earth
over hundreds of thousands of years

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from dead organic matter.

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And the wiring, loads of copper
from a mineral like malachite.

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Anyway, you get the picture.
This thing comes from the Earth.

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In many ways, it feels like
modern life is detached from the planet,

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but actually we're linked to it

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in hundreds of subtle
and surprising ways.

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This plane is a huge conglomeration
of natural resources

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that have all been precisely extracted,
transformed, moulded

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and connected by us.

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And what's staggering
is the scale on which we do this.

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This airbase in the Arizona desert
is home to over 4,ooo planes.

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Many of them will never fly again.

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Effectively,
this is a vast accumulation

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of the planet's minerals.

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Our impact on the planet is felt
not just in what we transform,

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but also in what
that transformation leaves behind.

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I've come here because rivers carry
and deposit sediment.

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This is what forms
the rocks of the future.

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The old geological hammer's
not much use here. Urgh!

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You know, there's a lot of things
in here that I would expect.

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There's lots of plant remains,
some pollen grains.

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I see a few snail shells.

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But in amongst all that

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there's some very odd little fragments,

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like, a-ha, just here.

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Now that...looks like a little shell,
but it's not.

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It's made of plastic...

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and what that is
is a little plastic pellet,

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the kind of plastic pellets that go into
making plastic bags, plastic bottles.

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There's more of them, there's loads
of them, there's another one.

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00:19:22,509 --> 00:19:26,582
And look at that,
it's a plastic seal of a bottle.

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Now, that may not be so surprising

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when you consider exactly
where this river is...

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I'm right in the centre of Los Angeles,

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00:19:38,669 --> 00:19:43,140
home to around four million people
and all that goes with them.

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But the impact of plastics reaches
much further than major cities.

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Globally, around 26 million
tonnes of plastic

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ends up in the ocean every year,

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where it becomes part
of something much bigger.

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In the Pacific Ocean,
plastic from America

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is swept into a large revolving
ocean current known as a gyre.

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As this current circulates, it also
picks up material from East Asia.

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Over time, these plastics accumulate
in enormous flotillas.

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One of them is so big
it's even got its own name -

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the Eastern Pacific Garbage Patch.

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00:20:45,749 --> 00:20:50,425
Eventually, the plastic is broken down
by the sun's ultraviolet rays

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into smaller particles,

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that sink to the sea floor,
where they are buried.

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It's the first stage in their
transformation into sedimentary rock.

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The Grand Canyon is a striking example

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of the scale this process operates on.

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These cliffs were once
an ancient seabed,

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formed over millions of years,
as layer after layer of sediment built up.

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00:21:31,869 --> 00:21:36,659
Under immense pressure,
these layers were cemented together

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00:21:36,709 --> 00:21:39,507
to form the rock strata we see today.

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The plastics that lie
at the bottom of the ocean

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will eventually form
part of the rocks of the future -

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our geological legacy.

239
00:21:58,069 --> 00:22:01,618
You know, it's a sobering thought
that from the planet's point of view,

240
00:22:01,669 --> 00:22:05,742
our enduring signature, the thing
that marks out the modern human age

241
00:22:05,789 --> 00:22:08,587
in geological terms,
will be the dead weight

242
00:22:08,629 --> 00:22:11,985
of millions of tonnes
of different kinds of plastics.

243
00:22:15,029 --> 00:22:17,941
Our ability to take the Earth's resources

244
00:22:17,989 --> 00:22:20,742
and transform and deposit them
in vast quantities

245
00:22:20,789 --> 00:22:26,978
means we've now made an indelible mark
in the planet's 4.5 billion-year history.

246
00:22:45,829 --> 00:22:49,504
We can slice the tops off mountains

247
00:22:49,549 --> 00:22:52,461
and dig holes big enough to bury a city.

248
00:22:57,389 --> 00:23:02,417
In a single year,
we now move more earth and rock

249
00:23:02,469 --> 00:23:05,267
than all the natural processes
of erosion put together.

250
00:23:11,869 --> 00:23:14,941
Our machines
have transformed the planet.

251
00:23:25,389 --> 00:23:29,860
So great is our impact on the Earth
that it has been used

252
00:23:29,909 --> 00:23:32,377
to define a new geological epoch...

253
00:23:37,269 --> 00:23:40,784
...the Anthropocene, the human epoch.

254
00:23:50,309 --> 00:23:53,699
If you add together
all the landscapes we've altered -

255
00:23:53,749 --> 00:23:57,537
our cities, towns, villages
and farmland -

256
00:23:57,589 --> 00:24:04,904
then 75% of the Earth's ice-free landmass
owes its appearance to us.

257
00:24:09,229 --> 00:24:12,187
This truly is a human planet.

258
00:24:34,389 --> 00:24:38,826
Sometimes our intervention
in the planet's natural processes

259
00:24:38,869 --> 00:24:41,827
can have surprising
and far-reaching consequences.

260
00:24:51,349 --> 00:24:55,581
This is South Dakota in the United States.

261
00:25:04,629 --> 00:25:08,224
It's hard to believe it,
but this was once a busy little town,

262
00:25:08,269 --> 00:25:11,306
up to 3OO people living here
in its heyday.

263
00:25:12,629 --> 00:25:16,224
It's hard to imagine it
as a jostling little farming community,

264
00:25:16,269 --> 00:25:19,022
but that's exactly what it was.

265
00:25:29,469 --> 00:25:34,304
In the early 1 9oos,
this was a boom town.

266
00:25:34,349 --> 00:25:38,262
Farmers poured into the Great Plains
of the western USA

267
00:25:38,309 --> 00:25:40,698
to develop new land.

268
00:25:42,789 --> 00:25:46,020
You'd think this place
would be fantastic for farming.

269
00:25:46,069 --> 00:25:51,018
The whole landscape is covered
in a thick blanket of silts and clays,

270
00:25:51,069 --> 00:25:53,219
blown or washed in after the last ice age.

271
00:25:57,309 --> 00:26:00,779
Soil is a mixture of minerals
from broken-down rocks

272
00:26:00,829 --> 00:26:03,218
and nutrients from organic matter.

273
00:26:05,429 --> 00:26:10,549
It takes more than 5oo years
to create just 2cm of it.

274
00:26:15,229 --> 00:26:19,188
What keeps that fine sediment here
is the vegetation -

275
00:26:19,229 --> 00:26:22,619
the grasses bind the topsoil together.

276
00:26:22,669 --> 00:26:25,866
But the first settlers
ploughed over those grasses

277
00:26:25,909 --> 00:26:30,778
and exposed the delicate soil underneath,
and that dried out in the sun.

278
00:26:33,949 --> 00:26:38,898
When the rains failed in the 1 93os,
the ploughed-up soil was exposed

279
00:26:38,949 --> 00:26:41,463
to the full force of the wind.

280
00:26:41,509 --> 00:26:44,148
The result was devastating.

281
00:26:44,189 --> 00:26:48,023
It became known as the Dust Bowl.

282
00:26:50,309 --> 00:26:54,507
Half a million people
in the Great Plains were made homeless.

283
00:26:54,549 --> 00:26:59,065
1 oo million acres of farmland
turned to wasteland.

284
00:27:06,869 --> 00:27:09,747
The homesteaders
of the Great Plains had upset

285
00:27:09,789 --> 00:27:12,223
the delicate balance of the landscape.

286
00:27:14,309 --> 00:27:19,622
8o years on, that delicate balance
is one we still find hard to keep.

287
00:27:25,749 --> 00:27:29,344
In China, deforestation and overgrazing

288
00:27:29,389 --> 00:27:33,177
means soils are being degraded
3o times faster

289
00:27:33,229 --> 00:27:36,665
than the planet's natural processes
can replenish them.

290
00:27:40,029 --> 00:27:44,625
In Australia, clearing
large areas of bush for farmland

291
00:27:44,669 --> 00:27:48,298
has allowed salt
to infiltrate the topsoil,

292
00:27:48,349 --> 00:27:51,147
damaging around 6o,ooo square kilometres.

293
00:27:58,109 --> 00:28:02,864
In total, 25% of the world's farmland
has now been degraded

294
00:28:02,909 --> 00:28:08,506
as an inadvertent consequence
of our drive to increase food production.

295
00:28:12,029 --> 00:28:14,668
There's now an extraordinary contrast

296
00:28:14,709 --> 00:28:20,227
between the Earth's natural environments
and the ones that we've created.

297
00:28:25,589 --> 00:28:27,466
To fully appreciate the extent

298
00:28:27,509 --> 00:28:31,138
of our interference
in the planet's natural processes,

299
00:28:31,189 --> 00:28:35,660
take a look at one of the Earth's
most fundamental cycles...

300
00:28:39,909 --> 00:28:41,388
...the water cycle.

301
00:28:44,829 --> 00:28:49,823
Rain that falls over mountains
makes its way into streams and rivers.

302
00:28:54,669 --> 00:28:56,466
This is the Lena River.

303
00:28:59,069 --> 00:29:02,857
Its headwaters
are in the Baikal Mountains,

304
00:29:02,909 --> 00:29:06,185
where rain and snowmelt
set the cycle going.

305
00:29:08,349 --> 00:29:12,945
It travels 4,5oo kilometres
across Siberia...

306
00:29:14,709 --> 00:29:18,418
...before it reaches a huge delta,

307
00:29:18,469 --> 00:29:21,188
on the edge of the Arctic Ocean.

308
00:29:23,309 --> 00:29:28,337
Here it returns water to the sea,
which evaporates to form clouds,

309
00:29:28,389 --> 00:29:30,949
and the cycle begins again.

310
00:29:39,389 --> 00:29:41,903
The Lena is one of the few major rivers

311
00:29:41,949 --> 00:29:45,862
that still completes the water cycle
from source to sea

312
00:29:45,909 --> 00:29:48,707
without a single
man-made interruption.

313
00:29:55,229 --> 00:29:59,017
Today, we've created
an alternative water cycle.

314
00:30:03,229 --> 00:30:06,221
This is part of
the Colorado River system.

315
00:30:06,269 --> 00:30:11,821
Along its 2,ooo-kilometre length,
it has over 2o dams.

316
00:30:14,949 --> 00:30:18,100
So much water is diverted
to the cities and farmland

317
00:30:18,149 --> 00:30:22,779
of the American West that most years,
it no longer reaches the sea.

318
00:30:27,309 --> 00:30:31,143
The biggest city it supplies
is Los Angeles.

319
00:30:34,789 --> 00:30:38,702
Fresh water is delivered across
hundreds of kilometres of desert

320
00:30:38,749 --> 00:30:42,822
via a network of aqueducts,
canals and pipelines.

321
00:30:44,269 --> 00:30:49,389
This system delivers 9o%
of the city's fresh water.

322
00:30:49,429 --> 00:30:52,148
Without it, LA wouldn't exist.

323
00:30:59,949 --> 00:31:02,417
The veins and arteries
of our water supply

324
00:31:02,469 --> 00:31:05,267
are the lifeblood of our civilisation.

325
00:31:05,309 --> 00:31:08,904
And the human version
of this planetary cycle

326
00:31:08,949 --> 00:31:12,146
operates at a global scale.

327
00:31:12,189 --> 00:31:16,501
We have altered the planet's
water cycle to such an extent

328
00:31:16,549 --> 00:31:20,986
that five times as much fresh water
is stored in reservoirs

329
00:31:21,029 --> 00:31:23,589
as flows in all the world's rivers.

330
00:31:27,709 --> 00:31:32,180
This change in the balance of power
between us and the planet is based

331
00:31:32,229 --> 00:31:37,349
more than anything on our ability
to exploit one particular resource.

332
00:31:56,469 --> 00:32:02,260
This is the Athabasca River,
in the heart of Alberta in Canada.

333
00:32:02,309 --> 00:32:06,063
It doesn't look like it,
but today this is a fresh frontier

334
00:32:06,109 --> 00:32:09,021
in one of the great geological
quests of our age -

335
00:32:09,069 --> 00:32:11,424
the hunt for oil.

336
00:32:16,509 --> 00:32:19,581
Oil is central to our lives.

337
00:32:19,629 --> 00:32:22,860
It fuels a mechanised world.

338
00:32:25,629 --> 00:32:30,623
It's a concentrated form of energy,
easily transported.

339
00:32:30,669 --> 00:32:36,027
Every year we burn
around 3 1 billion barrels of it -

340
00:32:36,069 --> 00:32:39,186
that's 1,ooo barrels a second.

341
00:32:39,229 --> 00:32:43,302
The problem is...
it won't last forever.

342
00:32:44,509 --> 00:32:47,740
The amount of oil we're burning
each year takes the planet

343
00:32:47,789 --> 00:32:50,144
over three million years to make.

344
00:32:53,989 --> 00:32:55,707
Thanks...

345
00:32:55,749 --> 00:32:58,627
Finding more oil is getting harder.

346
00:33:02,309 --> 00:33:04,777
Some say we've already reached
a peak in oil production,

347
00:33:04,829 --> 00:33:07,389
and that from now on
it's all downhill,

348
00:33:07,429 --> 00:33:10,501
with supply unable to keep pace
with demand.

349
00:33:10,549 --> 00:33:12,904
But others say
that's a load of rubbish -

350
00:33:12,949 --> 00:33:16,339
there's plenty of oil in the ground,
it's just a case of finding it.

351
00:33:16,389 --> 00:33:21,463
For those in the second camp,
one of their prime exhibits is here.

352
00:33:27,869 --> 00:33:33,023
Ah, now, this is what
I've come to find. Look at this.

353
00:33:33,069 --> 00:33:35,503
Looks like the rock's bleeding,
doesn't it?

354
00:33:35,549 --> 00:33:38,746
This place is just full of oil...

355
00:33:38,789 --> 00:33:42,020
coming out of the rock,
and if you look at it, the thing is...

356
00:33:42,069 --> 00:33:43,502
Look at that - ugh!

357
00:33:43,549 --> 00:33:46,859
You feel as if, if you just squeeze it,
it would come out.

358
00:33:46,909 --> 00:33:52,347
It's actually a sand, but all
the sand grains are just coated in oil.

359
00:33:52,389 --> 00:33:55,506
We've got a name for this -
we call it tar sands -

360
00:33:55,549 --> 00:33:59,303
and this is just about
the dirtiest oil around.

361
00:33:59,349 --> 00:34:01,260
The whole cliff is just full of it.

362
00:34:04,749 --> 00:34:08,947
This kind of oil doesn't come
shooting out in a great fountain.

363
00:34:08,989 --> 00:34:11,867
And you don't get at it
by drilling down into the ground.

364
00:34:15,469 --> 00:34:18,381
This is a very different type of oilfield.

365
00:34:20,549 --> 00:34:24,622
To appreciate just how different it is,
you have to go up high.

366
00:34:44,869 --> 00:34:49,340
Oh, my... Look at that! It's like
we've gone into a different world.

367
00:34:56,749 --> 00:34:59,422
This oil deposit is thought to contain

368
00:34:59,469 --> 00:35:02,461
almost a trillion barrels of oil.

369
00:35:02,509 --> 00:35:05,865
It covers 5o,ooo square kilometres.

370
00:35:08,869 --> 00:35:12,225
I mean, look at that.
The forest just ends there,

371
00:35:12,269 --> 00:35:17,184
and then after that, just industry
for miles upon miles.

372
00:35:17,229 --> 00:35:21,620
To get at the tar sands involves
scraping the surface

373
00:35:21,669 --> 00:35:23,864
off vast tracts of land.

374
00:35:23,909 --> 00:35:27,424
This is strip mining for oil.

375
00:35:27,469 --> 00:35:31,178
Right below me, you can see
both the huge attraction of tar sands

376
00:35:31,229 --> 00:35:33,140
and their Achilles heel.

377
00:35:33,189 --> 00:35:36,420
On the one hand,
there's just vast amounts of oil -

378
00:35:36,469 --> 00:35:39,267
those fields seem to go on and on forever.

379
00:35:39,309 --> 00:35:43,825
But on the other hand,
getting it out comes at a price,

380
00:35:43,869 --> 00:35:45,348
a hell of a price.

381
00:35:48,869 --> 00:35:52,066
Although it's at the surface,
it's much harder to extract

382
00:35:52,109 --> 00:35:53,940
than conventional oil.

383
00:35:53,989 --> 00:35:56,628
To separate the oil from the sand,

384
00:35:56,669 --> 00:36:00,628
huge volumes of steam
have to be injected into it,

385
00:36:00,669 --> 00:36:02,546
and that's expensive.

386
00:36:03,669 --> 00:36:08,504
In a traditional oil well, you'd expect
around 25 barrels of oil back

387
00:36:08,549 --> 00:36:12,224
for every one barrel of energy
you use to extract it.

388
00:36:12,269 --> 00:36:15,625
Here, it's more like
one barrel of energy in

389
00:36:15,669 --> 00:36:17,899
and only five barrels back.

390
00:36:21,589 --> 00:36:23,500
You know, tar sands may be messy,

391
00:36:23,549 --> 00:36:26,825
but we still get more energy
out of them than we put in.

392
00:36:26,869 --> 00:36:31,659
So as far as oil's concerned,
they're one of our best prospects.

393
00:36:31,709 --> 00:36:35,179
But it's not exactly
an appealing image of hope, is it?

394
00:36:35,229 --> 00:36:37,185
Can't help but think...

395
00:36:37,229 --> 00:36:40,141
that we really are scraping
the bottom of the barrel.

396
00:36:47,309 --> 00:36:52,383
The tar sands illustrate
that the oil is still out there.

397
00:36:52,429 --> 00:36:55,660
And new sources
are being discovered.

398
00:36:55,709 --> 00:36:59,668
It's just they tend to be
exceptionally hard to reach.

399
00:37:01,989 --> 00:37:07,347
For centuries, our ingenuity has
enabled us to find new forms of energy,

400
00:37:07,389 --> 00:37:09,983
so it's easy to think
that trend will continue.

401
00:37:12,309 --> 00:37:15,346
History tells us that
we don't tend to run out of resources.

402
00:37:15,389 --> 00:37:20,622
Instead, when push comes to shove,
we find new ones.

403
00:37:20,669 --> 00:37:23,979
But that is a lesson
from human history.

404
00:37:24,029 --> 00:37:28,181
The planet's history has perhaps
a more important lesson for us.

405
00:37:29,749 --> 00:37:34,777
It's a lesson about the most dramatic
human influence on the planet -

406
00:37:34,829 --> 00:37:39,744
the speed and scale at which
we're changing the atmosphere.

407
00:37:57,229 --> 00:38:01,620
Levels of carbon dioxide and methane
are higher than at any time

408
00:38:01,669 --> 00:38:04,661
in the last 1 5 million years.

409
00:38:09,829 --> 00:38:12,104
We can already see
some of the effects.

410
00:38:13,669 --> 00:38:16,866
The thickness of the Arctic sea ice
has almost halved.

411
00:38:19,509 --> 00:38:22,865
Some of the extra carbon dioxide
we've pumped into the atmosphere

412
00:38:22,909 --> 00:38:26,219
has been absorbed by the oceans.

413
00:38:27,349 --> 00:38:29,863
This has increased their acidity by 3o%,

414
00:38:29,909 --> 00:38:33,743
hindering the growth
of marine creatures, like corals.

415
00:38:34,989 --> 00:38:37,662
Over the last few decades,

416
00:38:37,709 --> 00:38:41,543
the frequency of extreme hurricanes
has doubled in some areas.

417
00:38:48,469 --> 00:38:51,779
We're at the beginning
of a dramatic period of change.

418
00:38:51,829 --> 00:38:54,741
At the heart of it
is the greenhouse effect,

419
00:38:54,789 --> 00:38:58,065
a global warming caused by
the gases we release.

420
00:39:02,229 --> 00:39:06,302
The question is, how will the planet -
and our civilisation -

421
00:39:06,349 --> 00:39:09,022
respond to this change?

422
00:39:09,069 --> 00:39:13,347
For me, the best way to answer
this question is to look back

423
00:39:13,389 --> 00:39:15,983
into the Earth's past.

424
00:39:19,509 --> 00:39:21,898
Which is why I've come
to the coast of California.

425
00:39:25,069 --> 00:39:27,822
There's something really strange
going on in the ocean over here -

426
00:39:27,869 --> 00:39:30,667
the whole water looks as if
it's fizzing away like mad.

427
00:39:30,709 --> 00:39:32,506
I've never known anything like it.

428
00:39:38,309 --> 00:39:41,381
This promises to be an unusual dive.

429
00:39:41,429 --> 00:39:44,705
The point is to take me back
to the last time

430
00:39:44,749 --> 00:39:50,187
the Earth experienced a rapid and extreme
increase in greenhouse gases.

431
00:40:12,869 --> 00:40:14,746
It's amazing.

432
00:40:14,789 --> 00:40:17,349
It's like...

433
00:40:17,389 --> 00:40:19,698
it's like swimming in champagne.

434
00:40:19,749 --> 00:40:22,309
Everywhere you look,

435
00:40:22,349 --> 00:40:26,388
wherever you are,
you're surrounded with bubbles.

436
00:40:35,349 --> 00:40:39,740
These bubbles are the key to unlocking
one of the Earth's great events.

437
00:40:43,429 --> 00:40:48,742
55 million years ago, the atmosphere
went through something very similar

438
00:40:48,789 --> 00:40:50,859
to the changes happening today.

439
00:40:55,189 --> 00:40:57,749
The bubbles are full of a gas
called methane,

440
00:40:57,789 --> 00:41:00,542
which is leaking out
of a fault line deep below me

441
00:41:00,589 --> 00:41:03,979
and heading up there
to the atmosphere.

442
00:41:06,949 --> 00:41:11,659
And it's this speed and intensity of
bubble release that's a critical factor.

443
00:41:11,709 --> 00:41:15,987
Today, only relatively small amounts
of methane bubble out

444
00:41:16,029 --> 00:41:19,146
from seeps like this
at the bottom of the ocean.

445
00:41:19,189 --> 00:41:21,749
But 55 million years ago,

446
00:41:21,789 --> 00:41:26,305
methane started to erupt
from the ocean in massive quantities.

447
00:41:26,349 --> 00:41:28,863
No-one is quite sure
why it happened,

448
00:41:28,909 --> 00:41:33,300
but huge areas of the ocean
would have been bubbling like this.

449
00:41:33,349 --> 00:41:36,068
55 million years ago,

450
00:41:36,109 --> 00:41:39,260
these bubbles
wouldn't have been fizzing out,

451
00:41:39,309 --> 00:41:43,461
they would have been belching out.
It would have had a devastating effect.

452
00:41:46,069 --> 00:41:52,099
Methane is 2o times more potent
than carbon dioxide as a greenhouse gas.

453
00:41:52,149 --> 00:41:55,698
And as it burst up
through those ancient oceans,

454
00:41:55,749 --> 00:41:59,105
it led to sudden, runaway global warming.

455
00:42:24,469 --> 00:42:28,428
That burst in methane levels
55 million years ago

456
00:42:28,469 --> 00:42:30,744
was the closest experience we've got

457
00:42:30,789 --> 00:42:34,099
of what continued global warming
might bring.

458
00:42:34,149 --> 00:42:36,379
So what was it that happened
to the planet

459
00:42:36,429 --> 00:42:40,468
during that ancient surge
in global warming?

460
00:42:42,069 --> 00:42:44,139
And what did it mean for life?

461
00:42:45,829 --> 00:42:48,138
The answer can be found

462
00:42:48,189 --> 00:42:52,740
nearly 8,ooo kilometres away,
on the Svalbard archipelago.

463
00:42:55,109 --> 00:42:58,658
It's well within the Arctic Circle.

464
00:43:00,269 --> 00:43:04,865
6o% of Svalbard
is covered in glaciers.

465
00:43:08,309 --> 00:43:11,506
It's a landscape dominated by ice.

466
00:43:15,429 --> 00:43:19,741
But 55 million years ago,
it was rather different.

467
00:43:20,789 --> 00:43:23,542
The clues are in the rocks.

468
00:43:30,149 --> 00:43:32,583
Let's see what we've got. Ooh!

469
00:43:32,629 --> 00:43:35,621
Ooh, look at this.

470
00:43:35,669 --> 00:43:38,229
It's what I was hoping to find.

471
00:43:38,269 --> 00:43:41,978
These rocks are stacked full
of ancient leaves.

472
00:43:42,029 --> 00:43:44,668
Look, there's a frond of a plant there.

473
00:43:44,709 --> 00:43:49,658
There's another one here.
There's a stem with branches going out.

474
00:43:49,709 --> 00:43:54,305
These rocks are packed full...of leaves.

475
00:43:54,349 --> 00:43:56,260
Better keep going.

476
00:43:57,589 --> 00:43:59,068
(HE CHUCKLES)

477
00:43:59,109 --> 00:44:03,660
Look at this! Would you believe it?!

478
00:44:09,029 --> 00:44:11,907
These fossil leaves originate

479
00:44:11,949 --> 00:44:16,340
from a time just after
the methane surge in the oceans.

480
00:44:16,389 --> 00:44:19,142
They're from a distant relative
of the beech,

481
00:44:19,189 --> 00:44:22,226
a broad-leafed deciduous tree.

482
00:44:23,869 --> 00:44:26,019
Some of these trees are preserved

483
00:44:26,069 --> 00:44:29,186
in the permafrost
in other parts of the Arctic.

484
00:44:33,949 --> 00:44:35,462
It's amazing.

485
00:44:35,509 --> 00:44:41,823
You can just imagine these falling down
from trees onto an ancient forest floor.

486
00:44:41,869 --> 00:44:44,144
But, I mean, today...

487
00:44:44,189 --> 00:44:48,148
you don't get trees here. You don't get
trees like this for hundreds of miles.

488
00:44:48,189 --> 00:44:51,420
It just tells you
that 55 million years ago,

489
00:44:51,469 --> 00:44:55,178
Svalbard was a very different place.

490
00:44:56,829 --> 00:45:00,139
Following the methane surge
in the ocean,

491
00:45:00,189 --> 00:45:04,626
global temperatures would have been
1 o degrees warmer than they are today.

492
00:45:06,189 --> 00:45:08,225
It caused immense upheaval.

493
00:45:08,269 --> 00:45:12,387
Plants and animals were forced
to migrate towards the poles.

494
00:45:14,189 --> 00:45:16,657
Back then,
I would have been walking through

495
00:45:16,709 --> 00:45:21,942
a completely different landscape -
subtropical swamps and forest.

496
00:45:21,989 --> 00:45:25,743
Less High Arctic -
more Florida Everglades.

497
00:45:31,389 --> 00:45:35,064
It would have been inhabited
by ancestors of creatures

498
00:45:35,109 --> 00:45:37,748
like the hippopotamus and the crocodile.

499
00:45:40,869 --> 00:45:43,303
The lesson from the Earth's past

500
00:45:43,349 --> 00:45:47,388
is that the world we know today
can change out of all recognition,

501
00:45:47,429 --> 00:45:51,820
simply by raising the level
of greenhouse gases in the atmosphere.

502
00:45:58,109 --> 00:46:02,387
But the remarkable events
of 55 million years ago

503
00:46:02,429 --> 00:46:06,502
offer another,
more optimistic, lesson for us.

504
00:46:06,549 --> 00:46:12,499
Clearly this extraordinary warm period
55 million years ago didn't last -

505
00:46:12,549 --> 00:46:15,382
otherwise,
I wouldn't be dressed like this.

506
00:46:15,429 --> 00:46:19,900
The planet cooled,
ice came to the Arctic.

507
00:46:19,949 --> 00:46:21,507
So what happened?

508
00:46:29,069 --> 00:46:31,583
What happened was the Himalayas.

509
00:46:36,909 --> 00:46:42,506
The creation of this mountain range
helped return ice to the Arctic.

510
00:46:48,749 --> 00:46:52,139
When the tectonic plates
of India and Eurasia collided

511
00:46:52,189 --> 00:46:54,419
around 5o million years ago,

512
00:46:54,469 --> 00:47:00,180
the result was a mountain range
that grew to become the biggest on Earth.

513
00:47:11,069 --> 00:47:14,425
In building the Himalayas,
the planet unleashed

514
00:47:14,469 --> 00:47:18,621
its most formidable
global-cooling weapon...

515
00:47:20,189 --> 00:47:21,668
...weathering.

516
00:47:26,709 --> 00:47:30,543
The process begins when
carbon dioxide in the atmosphere

517
00:47:30,589 --> 00:47:33,706
is dissolved in rain and snow.

518
00:47:33,749 --> 00:47:36,627
This reacts with minerals in the rock

519
00:47:36,669 --> 00:47:39,741
to form a solution
that's carried by rivers to the sea.

520
00:47:43,629 --> 00:47:47,383
Here, the carbon is absorbed
by marine creatures.

521
00:47:47,429 --> 00:47:51,138
When these die,
they sink to the sea floor,

522
00:47:51,189 --> 00:47:55,182
eventually becoming rock,
locking the carbon away.

523
00:47:59,229 --> 00:48:02,505
Because the Himalayas
were constantly rising,

524
00:48:02,549 --> 00:48:06,861
they were perpetually exposing
new rock to the elements.

525
00:48:06,909 --> 00:48:11,505
This drew more carbon dioxide
out of the atmosphere,

526
00:48:11,549 --> 00:48:13,380
cooling the planet

527
00:48:13,429 --> 00:48:18,344
and eventually leading to
the re-freezing of the Arctic.

528
00:48:22,909 --> 00:48:26,299
So the planet had
an entirely natural way

529
00:48:26,349 --> 00:48:28,704
of reducing greenhouse gases.

530
00:48:30,269 --> 00:48:34,421
But there's one obvious problem,
and that is

531
00:48:34,469 --> 00:48:38,348
it takes millions of years
to build a mountain range,

532
00:48:38,389 --> 00:48:41,187
and we don't have the luxury
of that sort of time.

533
00:48:44,629 --> 00:48:48,383
Yet the lesson from history
is not entirely wasted.

534
00:48:50,349 --> 00:48:54,501
Burying carbon has long been
the sole preserve of the planet,

535
00:48:54,549 --> 00:48:58,827
but there's no reason why we can't have
a go at doing the same thing ourselves.

536
00:48:59,909 --> 00:49:04,380
We are now developing ways
to take carbon out of the atmosphere.

537
00:49:09,269 --> 00:49:13,706
One method is to stimulate the growth
of immense blooms of algae

538
00:49:13,749 --> 00:49:18,948
that use photosynthesis to draw
carbon dioxide from the atmosphere.

539
00:49:21,789 --> 00:49:24,223
On land, there are plans

540
00:49:24,269 --> 00:49:28,740
to create artificial trees
that replicate photosynthesis.

541
00:49:28,789 --> 00:49:31,428
But the biggest challenge

542
00:49:31,469 --> 00:49:36,179
is to stop carbon dioxide reaching
the atmosphere in the first place.

543
00:49:37,389 --> 00:49:40,506
This can be done by capturing it
at source,

544
00:49:40,549 --> 00:49:44,144
filtering it from industrial chimneys

545
00:49:44,189 --> 00:49:45,861
and then burying it.

546
00:49:51,549 --> 00:49:55,861
Scientists are planning
to try this out on Svalbard.

547
00:49:57,669 --> 00:50:01,867
If you happen to have thousands
of tonnes of carbon to dispose of,

548
00:50:01,909 --> 00:50:05,026
the geology here
is particularly helpful.

549
00:50:06,509 --> 00:50:10,343
That cliff behind me is a layer cake
of sandstone and shale.

550
00:50:11,829 --> 00:50:15,538
And that arrangement is perfect
for burying carbon.

551
00:50:19,549 --> 00:50:23,258
This sandstone is ideal
for storing the carbon,

552
00:50:23,309 --> 00:50:27,382
because there's lots of spaces
in the pores between the grains.

553
00:50:27,429 --> 00:50:31,866
And this dense, impermeable shale
provides the ideal lid

554
00:50:31,909 --> 00:50:35,140
that stops the carbon escaping upwards.

555
00:50:36,389 --> 00:50:40,940
The plan is to drill a number of shafts
through the dense shale lid

556
00:50:40,989 --> 00:50:43,742
and into the sandstone.

557
00:50:43,789 --> 00:50:47,577
Carbon dioxide will then be pumped
down into the sandstone,

558
00:50:47,629 --> 00:50:50,302
where it will be locked
within the pores of the rock.

559
00:51:06,229 --> 00:51:10,825
Carbon capture won't solve
our greenhouse gas problem,

560
00:51:10,869 --> 00:51:15,226
but it might at least buy us some time
to develop cleaner forms of energy.

561
00:51:17,629 --> 00:51:22,908
Burying and locking away carbon
is an attempt to accelerate massively

562
00:51:22,949 --> 00:51:26,339
what the Earth has done
for millions of years.

563
00:51:26,389 --> 00:51:29,426
It's the beginning of
a new approach to the planet,

564
00:51:29,469 --> 00:51:31,778
deliberately transforming it

565
00:51:31,829 --> 00:51:36,425
to try and preserve
the conditions for our survival.

566
00:51:41,949 --> 00:51:46,898
Up until now, the effects of our impact
on the planet, whether good or bad,

567
00:51:46,949 --> 00:51:50,464
have been accidental and unintended.

568
00:51:50,509 --> 00:51:55,424
Whether it's a mud volcano in Indonesia
or altering the Earth's climate,

569
00:51:55,469 --> 00:51:59,064
we never set out
to create these changes.

570
00:52:04,589 --> 00:52:08,502
Science has given us an understanding
of how the planet works

571
00:52:08,549 --> 00:52:13,748
that allows us to protect ourselves
against Earth's unpredictable nature.

572
00:52:15,109 --> 00:52:18,579
But today,
we're on the brink of a new era.

573
00:52:20,509 --> 00:52:26,459
We can now take control of our impact
on the planet's natural processes

574
00:52:26,509 --> 00:52:30,980
and maintain the conditions
for civilisation to flourish.

575
00:52:32,309 --> 00:52:36,427
It's a big challenge,
which involves global co-operation.

576
00:52:37,989 --> 00:52:42,904
But there's an example of
what can be achieved here in Svarlbad.

577
00:52:52,829 --> 00:52:54,342
You know, you'd never know it,

578
00:52:54,389 --> 00:52:58,428
but locked inside this mountain
is something incredibly precious.

579
00:52:58,469 --> 00:53:01,267
And that...that's the way in.

580
00:53:01,309 --> 00:53:03,459
It's got a front door!

581
00:53:03,509 --> 00:53:06,069
(HE CHUCKLES)

582
00:53:06,109 --> 00:53:08,498
It looks like something
out of James Bond!

583
00:53:20,949 --> 00:53:26,740
To protect its contents, this facility
in Svalbard has been built high enough

584
00:53:26,789 --> 00:53:30,020
to be above any future rise
in sea level.

585
00:53:30,069 --> 00:53:33,061
It's been excavated
so deep into the mountain

586
00:53:33,109 --> 00:53:36,545
that it would survive a nuclear explosion.

587
00:53:37,709 --> 00:53:41,907
This is apocalypse planning
for our future survival.

588
00:53:51,869 --> 00:53:54,542
You know, this is a giant vault,

589
00:53:54,589 --> 00:53:58,025
but in a way it's the modern equivalent
of a Noah's ark,

590
00:53:58,069 --> 00:54:00,822
except that instead of sheltering animals,

591
00:54:00,869 --> 00:54:04,464
it's preserving the future
of the world's food supply.

592
00:54:09,909 --> 00:54:14,300
The temperature is a constant
minus 1 8 degrees Celsius

593
00:54:14,349 --> 00:54:18,103
to protect
the precious contents stored here.

594
00:54:29,149 --> 00:54:35,099
This is a shrine to over 1 o,ooo years
of agricultural development.

595
00:54:35,149 --> 00:54:38,027
It's a global seed vault.

596
00:54:40,189 --> 00:54:41,827
I mean, take this -

597
00:54:41,869 --> 00:54:44,463
this is rice. But the thing is,

598
00:54:44,509 --> 00:54:47,740
there's not just one variety of rice
in here, there's thousands,

599
00:54:47,789 --> 00:54:50,940
with different properties
and different growing conditions,

600
00:54:50,989 --> 00:54:53,457
different resistance to disease.

601
00:54:53,509 --> 00:54:57,388
This is the genetic diversity of rice
for the future.

602
00:55:02,629 --> 00:55:07,020
But of course it's not just about rice.

603
00:55:07,069 --> 00:55:08,866
This vault will one day store

604
00:55:08,909 --> 00:55:15,064
every variation of every staple crop
from every country on the planet.

605
00:55:21,069 --> 00:55:24,106
It's a heck of an insurance policy.

606
00:55:32,549 --> 00:55:36,508
You know, for me,
preserving these seeds,

607
00:55:36,549 --> 00:55:41,100
with all their precious genetic code,
makes a really important point.

608
00:55:41,149 --> 00:55:47,338
And that is, we're taking conscious
control over an uncertain world.

609
00:55:47,389 --> 00:55:50,665
And in that sense,
this whole place is like a symbol

610
00:55:50,709 --> 00:55:53,382
of what can be achieved
at a global level,

611
00:55:53,429 --> 00:55:55,624
if we put our minds to it.

612
00:56:01,549 --> 00:56:06,065
In this series, we've seen
how the fate of past civilisations

613
00:56:06,109 --> 00:56:09,067
has been shaped
by the planet's natural forces.

614
00:56:10,989 --> 00:56:16,746
The Khmers of Angkor Wat thrived on
their ability to exploit the monsoon

615
00:56:16,789 --> 00:56:18,939
until their growing population

616
00:56:18,989 --> 00:56:22,584
outstripped
their most precious resource - water.

617
00:56:25,749 --> 00:56:29,708
The Anasazi of Chaco Canyon
came to ruin

618
00:56:29,749 --> 00:56:34,869
when a change in the El Nino cycle
led to a sudden, prolonged drought.

619
00:56:37,709 --> 00:56:40,906
The Minoans of Santorini flourished

620
00:56:40,949 --> 00:56:44,066
in blissful ignorance
of the volcano beneath them

621
00:56:44,109 --> 00:56:47,306
that would one day
destroy their civilisation.

622
00:56:53,629 --> 00:56:58,225
Today, our relationship
with the planet is a different one.

623
00:57:00,509 --> 00:57:05,424
We are now a geological force
to rival the Earth's natural forces.

624
00:57:07,469 --> 00:57:11,826
The ultimate test will be
how well we use that power.

625
00:57:18,469 --> 00:57:22,382
As a species,
we like to think that we're special.

626
00:57:22,429 --> 00:57:26,217
Well, this is our chance to prove it.