All language subtitles for Worst.Weather.Ever.2013.1080p.DSNP.WEB-DL.DDP5.1.H.264-playWEB

MAN Oh my god,
oh my god.

The world's
weather is going wild.

MAN Oh man.
Oh my god.

From
record floods in India

to devastating
drought in America.

It was just
a large boiling cloud of… dust.

From
deep freezes in Europe

to scorching heat in Australia.

MAN Yeah. He's
not looking too well really.

The largest
Atlantic hurricane on record…

and the widest
tornado ever known.

GEORGE It
got so big, so wide.

Even if you tried to flee, you
wouldn't have been able to.

Scientists
are getting worried.

It's the first time ever
we ran out of letters in the alphabet

to name our storms.
Unprecedented.

BRIAN People
were freezing.

It was very unusual.

But extreme weather
has happened in the past.

It was a dreadful
terrible climate disaster.

With camera phones,
the internet and 24 hour news,

are we simply seeing more
wild weather more often?

Or is the weather getting worse?

And if it is, what
could be the cause?

In the
last ten years,

America has experienced
its two most active

tornado seasons on record.

MAN Yep, there
goes the roof off the house.

Is tornado alley becoming
an even more dangerous place to live?

MAN Oh my gosh,
look at that!

Destruction. Holy crap.

May 2013, two monster
twisters terrorize Oklahoma.

The nightmare
begins on May 20th.

A small tornado touches
down in a field.

MAN This
is freaking beautiful.

It grows rapidly
and moves towards Moore.

A city of over 50,000.

Storm chaser George Kourounis
watches the tornado develop

on his radar screen.

And it looks horribly familiar.

GEORGE We couldn't
believe what was going on,

we saw this hook echo on
the radar, debris ball,

we knew that something very
bad was happening in Moore.

And we're thinking
oh, no not again.

How can this town possibly
get hit one more time?

Oh my god.

In just 15 years,
Moore's been hit four times.

MAN Yeah, here comes the
debris, we'll get out of here. Hold on.

I can't get my window up. Phil I
can't get my window up!

For those
on the front line,

it feels like tornadoes
are getting worse.

WOMAN There's so
much debris in the air.

Fifteen minutes
after it touches down,

this monster tornado is already
one and a half kilometers wide

with wind speeds up to
320 kilometers per hour.

It reaches the edge of town

and plows through
several neighborhoods.

MAN Alright…
tearing up the buildings.

It's coming but right at us.
Oh my gosh that's violent.

Then, it makes a turn

and heads straight for
Briarwood Elementary School.

Jamie Maples is a teacher there.

You could
just hear it coming,

like a jet plane was
right over your head.

It was just super, super loud.

The
tornado intensifies,

until it's one of the most
powerful twisters in America's history.

The teachers and
children take shelter.

WOMAN Calm
down. We're in a brick building, it's ok.

JAMIE Finally
the electricity went out

and they realized that
this was serious, um,

so they started to get scared.

There was a lot of
crying and screaming.

The next thing you
knew the roof was gone.

And then that's when
everything started to fall.

The walls started to fall
and the teachers got trapped

under some beams that fell.

WOMAN
Keep your heads down.

And
then it finished,

and then when it was
over it started raining.

WOMAN Wow.

Oh my god. Oh my god.

Oh my god, oh my god.

Oh my god.

Amazingly,
everyone survives.

There were parents
coming trying to find kids

and kids screaming
and kids crying.

They all just needed to be
hugged and told, you know,

we made it.

It was a miracle that we were
able to give all the kids back

to their parents that day.

But the
tornado's not finished yet.

It strikes another elementary
school one and a half kilometers away,

killing seven children.

In 40 minutes of carnage,

the tornado takes
a total of 24 lives.

And destroys a town.

MAN It's on the ground, on
the ground! there look it's on the ground,

There, there it is, there it is,
there it is.

Dangerous tornado. Holy crap.

But the 2013
tornado season

has more horrors in store.

Just over a week later, an even
larger twister hits nearby

El Reno, Oklahoma.

MAN Oh,
it's a tornado.

It's a tornado, power flashes.

Again, storm chaser
George Kourounis is close by.

GEORGE
The tornado was so big

it filled the entire windshield.

It wasn't pretty in any way.

It was a dark mean smear,

a smudge across the horizon

that just looked like
it meant business.

That was a powerful tornado.

The wind speed reaches
a terrifying 475 kilometers per hour.

Among the fastest ever recorded.

MAN
Strong tornado.

And even more
surprising is its size.

The tornado is rapidly
getting bigger.

MAN Uh,
to our east, 200 yards to our east.

The twister
quickly grows from one and a half

to over four kilometers across.

Large enough to stretch from one
end of New York's Central Park

to the other.

MAN Holy shit.
Go man, go. Hit the gas.

It plows
across interstate 40.

Eight people are
killed in their cars,

including three
experienced storm chasers.

GEORGE It was the
first time that any storm chaser

has ever been killed by the
storm they've been chasing.

It got so big, it
got so wide so fast.

Even if you tried to flee, you
wouldn't have been able to.

This is the widest
tornado on record anywhere

in the world.

And other remarkable tornadoes
are appearing around the globe.

In Portugal, a raging vortex
tears apart a stadium.

And in Bangladesh, a violent
twister takes 23 lives as it

rips through hundreds of houses.

Is this just a coincidence?

Or are tornadoes taking
a turn for the worse?

MAN Look
how big that thing is!

To find out,
meteorologists like Josh Whurman

investigate how powerful
they were in the past.

The tornado which
killed the most people

was way back in 1925,
called the tri-state tornado.

America's deadliest
tornado leaves the longest trail

of destruction ever known -
carving a path through three states.

And kills nearly 700.

The deadliest tornado in history
strikes Bangladesh in 1989.

Killing around 1300.

But death tolls aren't
an accurate measure of a tornado's power.

Comparing violent
tornadoes from different decades

is very, very difficult.

The average number of
deaths has been going down.

We think that's because people
are more aware of tornadoes,

because we have better
warnings and better education.

So it's very hard to compare

tornadoes from past
decades to new ones.

Death
tolls are falling.

But the number of reported
tornadoes is rising.

Records indicate there have been
more than three times as many

tornadoes over the last decade
than in the fifties.

But even this is not as
clear cut as it seems.

In the past, fewer people
were looking for tornadoes.

When
I started 15 years ago,

there were very few storm
chasers, not very many at all,

and everybody knew
everybody else.

Oh there it is,
it's right there,

quick that large
tornado right there.

But now, anyone
with a cheap camera

can be a storm chaser.

…I got amazing video.

GEORGE Now, there
are more people out there.

And there are times when you're
in the middle of nowhere,

on some rural country road
and there's traffic jams

with storm chasers.

This is a bad situation here.

We've got large tornado coming
behind us and everybody's stuck

on this road right now.

And the more we
look, the more we find.

MAN There it is.
Oh we're in perfect position. Hahaha…

Most tornadoes
simply touch down in a field.

In the past, this tornado
might have passed by unseen.

These days, it becomes
another statistic.

GEORGE So of
course there's going to be more

of these tornadoes reported.

Are there actually
more of them happening?

We're not so sure yet.

Bu what experts do
know is that the atmospheric

conditions that cause
tornadoes are changing.

They know, because of millions
of precise measurements

painstakingly collected
over the last hundred years.

Twice a day, every day,
weather balloons all over the world

take the atmosphere's
temperature.

They're part of a vast network
monitoring the weather.

Peter Stott is head
of climate monitoring

at the Met Office in England.

We have
measurements of temperatures

from many, many thousands of
weather stations over the land.

And we also have measurements
uh, of sea surface temperatures.

And we're also increasingly
using satellite data as well.

And what the
data reveals is shocking.

Over the last century,
the world has heated up

by just under one degree
Celsius on average.

This is global warming.

PETER So we
have very clear evidence

that the world has warmed.

And with that has come many
other changes in weather as well.

The extra heat is
transforming the atmosphere.

In the skies above us,
the weather is changing.

But is it getting worse?

Climatologist Scott Denning is
one of thousands of scientists

trying to figure out exactly
how higher temperatures

affect the weather.

The climate system
is driven by heat coming in

from the sun, and by heat
streaming back out into space.

And the more heat you
put into the system,

the, the faster it runs,
the harder it runs.

It changes all kinds of things.

It changes temperature,
it changes rainfall,

it changes clouds.

The system is a
system, it's linked.

But when it
comes to tornadoes,

it's… complicated.

MAN Check it out.

JOSH In order
to get a strong tornado

from a supercell thunderstorm
we need two ingredients.

One is energy, warm moist air
to get the thunderstorm going

in the first place.

But that's not enough,
we also need rotation,

which is differences in wind
speeds at different levels

in the atmosphere, to make
that thunderstorm spin.

We need both of those in order
to have a rotating supercell

thunderstorm that can
make a violent tornado.

As the world warms,
these two factors change

in different ways.

More heat could mean
bigger thunderstorms.

But at the same time,
high altitude winds could be changing,

which may cause less
rotation in the atmosphere.

We don't know whether
we're getting more tornadoes,

stronger tornadoes
or whether there are

any changes in where the
tornadoes are occurring.

With global warming, we might
have more thunderstorms

in tornado alley,
but they might rotate

and make tornadoes
less frequently.

We're just gonna have to wait
until we get several years

of data to even out the spikes
that we see year to year.

Tornadoes may
get smaller and rarer.

Or climate change could create
the conditions

for a new breed
of super twister,

making the monster
that struck Moore

a sign of things to come.

While the jury
is still out on tornadoes,

if thunderstorms
intensify as predicted,

other extreme weather phenomena
could get worse:

Including hail.

MAN Oh man.

And it's
not just car windshields

that can take a battering.

Hail can ravage
vast areas of crops.

Every year, it inflicts over a
billion dollars' worth of damage

in America alone.

MAN …very large
hail… Holly…

It can even be deadly.

MAN Oh my god,
oh my god dude.

My truck is getting
hammered.

This is ridiculous.

In 2010, the world's
largest recorded hailstone

falls in South Dakota, America.

With a circumference
of over 46 centimeters,

it's as big as a
large grapefruit.

The last decade has seen a
torrent of fatal hailstorms.

Southern China, March 2013.

Severe thunderstorms
spawn giant lumps of ice.

Catching residents unaware.

They destroy homes and vehicles.

And kill more than
twenty people.

The next month, a freak hailstorm
kills three people in Afghanistan.

Could these killer hailstones
be a new phenomenon?

Deep in the Himalayas is a clue.

Around the shores of a crater
lake hides a nightmarish scene.

Hundreds of skeletons. Men,
women and children.

Who, or what, killed
them, is a mystery.

A National Geographic expedition
sets out to investigate.

As soon as we
got up close we could see

that the whole landscape there
was littered with bones and skulls

and pieces of flesh.

You could hardly take two steps
without stepping on a piece of flesh

or a bone or a
skull or something.

For most of the
last 50 years or so,

I think most scientists have
assumed that they died

in some kind of a landslide
or avalanche.

Bone samples reveal
these people lived, and died,

over a thousand years ago.

The group was traversing
the mountains,

when the unexplained
disaster struck.

It's very clear that
they didn't die of any disease.

they were not murdered,

they didn't kill themselves
or die in a landslide.

Then, on
closer inspection,

many of the skulls reveal an
even more horrifying demise.

Death from powerful blows to
the head by a blunt object.

What the bones reveal is
the fractures

of the skull that could have
killed them.

That incident must have
occurred at the time of death.

It's a
complete mystery.

Until investigators hear
a local folk song…

a legend about ice
falling from the sky.

The song helps the experts
reach a shocking conclusion:

With nowhere to hide,

the travelers were brutally
struck down by giant hail.

Hailstones big enough to kill
seem to have been around

for centuries…

But could they get even bigger?

To find out, meteorologist
Kelly Mahoney

has come to an indoor
sky diving center.

Its vertical wind tunnel can
simulate the conditions

at the heart of a storm,
where hail is made.

We're standing here
inside an indoor sky diving wind tunnel,

trying to feel what it would
be like inside a thunderstorm.

Just
like this chamber,

thunderstorms contain powerful
vertical winds that blow upwards

called updrafts.

A 100 kilometer per hour updraft
can support tennis balls.

So hailstones
form when a piece of ice

starts to collect water.

It gets tossed around
enough like these balls are.

Starts to collect supercooled
water and it grows and it grows

until it becomes damaging.

Like these tennis balls
would certainly be

if they were to fall
to the ground.

As soon as
hailstones grow any heavier,

they fall from the sky.

So in a storm like this, you
won't find any hail heavier

than a tennis ball.

Once you start
to grow bigger and bigger

hailstones you need stronger
and stronger updrafts.

This grapefruit sized hailstone
doesn't stand a chance

in just 60 miles per hour.

For grapefruits,
you need wind speeds

of almost 200 kilometers
per hour.

Storms with updrafts this
powerful are very rare,

but that could change.

So as the global
temperature and moisture increases,

we like to think
we'll have a lot more energy

to fuel thunderstorms.

So if all other things are
equal, and you pump up updrafts,

like what's holding up
these grapefruits behind us,

you can grow more damaging
hailstones potentially

and face a lot more damage.

But storms have
an even deadlier weapon

in their arsenal.

Lightning.

JOSH If
the climate changes,

we would expect that there would
be changes in how much lightning we get.

If we get more
deep thunderstorms,

then we expect more
lightning strikes.

Yet paradoxically in some places
the number of lightning deaths is falling.

In Japan, Europe, North
America and Australia,

lightning killed ten times more
people in the 1800s, than today.

It might seem that lightning
is striking less often,

but there may be another
reason for this decline.

People are living
more urban lifestyles

and people are getting warnings
of thunderstorms,

or people have access
to shelter more easily.

So the chance that I'm gonna be
out here when a big lightning

strike happens, is pretty low.

As a result, there
are fewer deaths from lightning

today in the developed world.

But that doesn't mean lightning
is striking less often.

In other more remote
parts of the world,

lightning is still
a major killer.

Taking 24,000 lives across
the world every year.

The most dangerous place
to be is in Central Africa.

With thunderstorms
all year round,

this is the lightning
capital of the world.

In 2011, a colossal
storm forms over Uganda.

People run to take shelter.

But for one school
class, that isn't enough.

A single powerful bolt
strikes their classroom

and kills 19 children.

It's a terrible demonstration
of lightning's power.

And if rising global
temperatures trigger more lightning,

there could be even more
tragedies like this.

The best way to find out
if lightning is increasing,

is to count the bolts.

MAN Oh! Fuck yea!

Every second there
are around 100 lightning strikes

somewhere in the world.

Some are powerful enough to
light a hundred million light bulbs.

So they can be easily
detected by satellites.

JOSH It's hard to
get measurements everywhere

over the tropical jungles,
unless we just fly over them

from way up in space.

And we can see the lightning, we
can see the light it gives off,

we can see radio signals it
gives off and basically count up

the thousands of lightning
strikes that happen

across the globe every day.

Satellites record
the number of lightning strikes

during cold years
and warm years.

And they found that hot
years have more lightning.

Even small changes
in temperature can cause more

and deeper thunderstorms which
make very much more lightning.

So if the planet
continues to warm up as expected

scientists think that by
the end of the century,

we could see hundreds of
millions more lightning strikes per year.

And with many of these in
tropical lightning hotspots,

they're likely to
be more deadly.

We have concern
that in more remote areas

of the world, particularly
farming areas of the world,

where that shelter isn't available
or that warnings aren't available,

that increased lightning
could result in

more direct lightning deaths.

With global
temperatures rising,

experts predict
thunderstorms will intensify,

unleashing more hail
and lightning

in many parts of the world.

Such as America's North East.

By the late 21st century, it
could face more intense storms

than ever witnessed before.

With extreme hail,
lightning and winds,

life for over 50 million people
could be changed forever.

A small shift in temperature can
have a massive effect on storms

and the extreme
weather they produce.

But this extra heat has
a more direct impact on our lives.

Over the last decade,
high temperature records

have been shattered around
the world, from Las Vegas…

MAN I've got here an egg
and a saucepan which has been heating

up the whole day in the sun.

We'll see what happens.

Literally just ten
minutes later, and it's,

it's actually perfectly cooked.

To Siberia.

Inspiring some creative
solutions to keeping cool.

In 2013, Australia endures a
heat wave of epic proportions,

lasting over two weeks.

So even though we
call it ice cream for dogs,

it's actually yogurt.

Yummy.

The Bureau of
Meteorology has to redraw

their weather charts
to illustrate

the unprecedented temperatures.

Nick Klingaman is an expert
on Australia's climate.

NICK They had to
add a new color onto the maps

that they produce for the maximum
temperatures in Australia every day.

I think the highest
it went was 52 Celsius

and uh, it was projected
to be above that.

So it was extraordinary levels
of heat that we saw in Australia

this, this summer.

2012 is America's
hottest year ever known.

2010 brings Russia's
hottest summer on record.

And in 2003, a mega heat wave
smashes records across Europe.

Killing tens of thousands.

There has been record
breaking weather in the past.

In 1976 much of Europe swelters
through its hottest summer

since records had begun.

And back in 1933, America's
warmest June ever known.

But in the past, there were just
as many new records set

for the coldest days, as there
were for the hottest ones.

So over time,
temperatures balanced out.

Now there are far more
hot records set than cold.

Climate expert
Radley Horton studies heat waves.

RADLEY If we look
at the period from 2000 to 2009,

in the US there were twice
as many extreme heat events

as there were
extreme cold events.

So we're seeing more records
getting broken on the heat side

than on the cold side.

The evidence
is indisputable.

The world is getting hotter.
The question, is why?

Professor Scott Denning
is trying to find the answer,

by using data from a network of
super-tall towers that collect

gases from high
in the atmosphere.

SCOTT This tower
is about uh, 300 meters high,

almost a thousand feet.

And there are these plastic
tubes that you can see here

that uh, run all the way up the
tower, they're collecting air,

simply, uh, through inlets.

The air is diverted to
an instrument at the bottom of the tower,

which precisely measures
carbon dioxide levels.

SCOTT These
measurements show that just recently

the carbon dioxide has
reached 400 parts per million,

400 molecules of carbon dioxide
per million molecules of air

a higher level than the
carbon dioxide has been

for millions of years.

Most of this extra
carbon dioxide comes from

the burning of coal, oil
and gas to power our homes,

vehicles and cities.

And now it's heating the planet.

SCOTT Carbon
dioxide is a greenhouse gas,

which means that it absorbs
heat radiation from the earth.

As the heat radiation is
trapped by these molecules,

it can then get re-emitted.

And the part that gets
re-emitted downward

will actually warm the surface.

So, carbon dioxide emits
heat, heat warms things up,

so if we add a lot of carbon
dioxide molecules

to the atmosphere, it'll warm
the surface of the earth.

Greenhouse gases like
carbon dioxide act like a giant

invisible blanket,
holding in the warmth.

Because of this, over the last
century the world has got

just under one degree
Celsius warmer.

That is why we're seeing more
extreme heat waves, more often.

As well as
causing deadly temperatures,

heat waves may also cause
catastrophic effects

in the countryside.

WOMAN Oh my god,
I gotta get out of here.

MAN All the way down
the hill, dude, look at this. We gotta go!

Experts are
investigating whether

extreme heat is linked to
more wildfires.

MAN I've never
seen anything like this.

I can't stop shaking. Look at
that. All those homes.

Over the
last few years,

they've collected valuable
evidence from some of America's

most destructive fires ever.

June 2013.

A fire breaks out in
Black Forest, Colorado.

Daphne Knight and Ryan Butler
are on their way to work

when they see smoke.

On the day it
started, everything was fine,

everything was green,
you just barely saw

a little plume of smoke
off to the side there.

DAPHNE Really we didn't
think it was going to be that big,

we were just going up
this road and filming the smoke.

RYAN Holy shit, that looks
like a damn explosion cloud, ya know?

Fanned by high winds,
the fire spreads rapidly through

the hot, dry undergrowth.

Before fire-fighters
can control the blaze,

it reaches a homestead.

DAPHNE I'm pretty
sure it was the houses burning that,

it just created this big
black plume of smoke.

And it went
from day to night

for a good couple of
hundred yards maybe.

Oh, we're in it.

The fire
burns out of control…

…tearing through
whole neighborhoods.

Within two days, it's already
the most destructive

in Colorado's history.

Nearly 40,000 people
are evacuated…

as well as hundreds of animals.

As they try to escape,

two residents burn to death
in their garage.

DAPHNE That's
where those people lived.

RYAN Aw, jeeze.

DAPHNE
The ones that died.

RYAN That's the
house?

That's where the
people lived that died?

They had come home to get their
belongings 'cause they had heard

about the fire, and that was it,
they didn't have time to get out

It was in their own driveway.

In the garage they were
packing up their stuff.

Yeah, they didn't make it.

There's another one of these
cars that just is completely burnt out.

After a
week and a half,

the fire is finally contained.

Over 500 houses
have been destroyed.

RYAN I think I'm
still in a state of shock.

A lot of my friends'
homes, all they are is uh,

just chimneys now.

Colorado's three
most destructive wildfires

have all burned in
the last two years.

Both years also had
record-breaking heat waves.

Climate scientist Jeff Lukas
is investigating

the link between the two.

He's searching for
answers inside trees.

They contain a record of every
forest fire over their lifetime.

This cross-section
here is from a Ponderosa Pine.

And during its lifetime, uh,
fire was a frequent visitor

to that forest, and the tree
experienced and recorded

through scarring eight
separate wildfires, uh,

each of which we can precisely
date uh, to the exact year.

Tree rings also
tell him whether each year

was hot and dry or cold and wet.

He finds that the hottest,
driest years all coincide

with the most wildfires.

Throughout history, heat and
wildfires go hand in hand.

Even though each
of these eight years was warmer

than the average, uh, none of
these eight years is as warm as

the last few decades
we've experienced.

Particularly the last decade,
which has been the warmest

in the uh, instrumental record
of over a hundred years

in Colorado.

Making the region's
forests more vulnerable than ever.

JEFF Every degree
of warming will tend to dry out

the soils; will dry out
vegetation; will dry dead fuels

and make fires more likely,
make their spread more severe

and make their
impacts more severe.

Higher temperatures
are already taking their toll,

around the world.

In Australia the record-breaking
hot summer of 2012 to 2013,

sets off devastating wildfires.

This thirsty koala is
caught up in the blaze.

MAN He's not
looking too well, really.

Russia's hottest
summer on record also triggers

hundreds of wildfires
across the country.

Thousands flee from
burning villages.

These men escape the inferno.

54 others were not so lucky.

Hotter, drier conditions
are causing more wildfires.

As the climate changes,

experts predict more forest
fires in the years and decades ahead.

JEFF Unfortunately
I think we can expect that

the fires we've been
experiencing in the last three years

to be a harbinger
of the future.

Research suggests
that by 2050, in some areas,

wildfires could be five times
more destructive than today.

As temperatures rise and
the land heats up and dries,

more forests will burn.

But as the sea warms up,
something truly terrifying

could be unleashed.

The biggest, most destructive
storms on the planet, hurricanes.

At their worst,
they can generate winds

of over 300 kilometers per hour
across a vast region

hundreds of kilometers wide.

GEORGE Every
single raindrop feels like someone

hitting you with a needle.

Every piece of gravel
feels like a bullet,

pieces of metal will fly
around like helicopter blades.

You just can't be out in it,
it's like being in a blender

for hours and hours and hours.

Hurricanes, also
called typhoons and cyclones,

form and grow over oceans,
feeding off warm water.

Which is why many scientists
fear warmer seas could already

be making these monster
storms even more destructive.

JOSH There's
pretty good reason to believe

that stronger hurricanes will be
more frequent with global warming.

That's mainly because the
source of energy for hurricanes

primarily is very
warm ocean conditions.

But we still need to learn
some important things about

how hurricanes intensify,
how they extract their energy

from the ocean.

And we can only do that
by getting right up close

to the surface and watching
what happens in the winds

in the eye wall.

October 2012,
a swirling mass of air

is gathering high above the warm
waters off the Nicaraguan coast.

A killer is born.

This is Tropical Storm Sandy.

In its eight day life,
Sandy will kill people in eight countries,

and cause over 60
billion dollars' worth of damage.

MAN Wow.

At two days old, Sandy
becomes a full-blown hurricane

raging across the Caribbean

Raging across the Caribbean

with nine meter high waves and
nearly 200 kilometers per hour winds

killing at least 70 people.

Sandy moves north, passing
over an unusually warm stretch of water,

swelling into a superstorm.

A monster hurricane, over
1,500 kilometers across.

It then takes a sharp left turn,
directly toward

America's most densely
populated coastline.

OBAMA All of us
across the country are concerned about

the potential impact
of Hurricane Sandy.

Uh, this is a serious
and big storm.

Sixty million people
brace for the superstorm about

to make landfall in New Jersey.

Climatologist Heidi Cullen
can hardly believe its size.

HEIDI This
was an enormous storm.

We're talking 900 miles wide,
roughly 1500 kilometers wide,

which means that when
it made landfall,

it stretched across an
enormous swathe of the country.

October 29th.

The largest Atlantic hurricane
in history makes landfall in America.

MAN Wow!

Storm chaser
George Kourounis is on Rockaway boardwalk

in New York to witness the
extraordinary event.

As the storm
was intensifying it became

very clear to us that this
was no ordinary hurricane,

this was gonna be
really, really bad.

There was a mountain of waves
that was just being held there

by the wind.

And then eventually
it changed direction,

and all that water came flying
in, taking all the sand with it,

totally destroying
this neighborhood.

New York has
weathered hurricanes before,

but never this big… or with
such a high storm surge.

The sea level rises up
four meters,

nearly a meter higher
than ever before.

GEORGE The surf
was as violent as I've ever seen

in seventeen hurricanes
that I've been in.

All the pieces of the boardwalk
got completely ripped up by

the waves, dragged inland, I
don't know where they ended up,

but not a single one
survived, nothing, none.

Just the concrete.

The Big
Apple is not prepared.

John Mattiuzzi captures the
chaos in Manhattan on video.

JOHN I started
walking down to the water,

the flood was
starting to come up.

It got pretty
dangerous over here,

because there were these metal sheets
that must have weighed like 30 pounds.

They were just woop woop woop!
Flipping through the air.

Car alarms, they're singing.

Water levels
rise relentlessly,

pouring into buildings.

MAN Oh my god, oh
my god. The door break open.

The door just break open.

Oh my god.

The subway floods.

And seawater gushes into
electrical substations,

which short circuit and explode.

Then all of a
sudden, my camera just lit up.

Then we get another huge flash.
A blue blast.

WOMAN I
think it just exploded.

As the power fails,

explosions continue
to light up the sky.

JOHN And
throughout the night,

you'd see these blue
explosions in the distance,

which became extremely spooky.

It looked like something out
of, you know, Independence Day.

By the next day,
the hurricane reaches

over 1100 kilometers inland.

It was so big, it
was causing 20 foot waves.

People were surfing on Lake
Michigan outside of Chicago

from a storm that was
pounding the east coast.

Finally, Hurricane
Sandy runs out of steam.

It leaves behind a vast
trail of destruction,

and takes over
two hundred lives.

In New Jersey and Long Island,
entire neighborhoods

have been washed away.

Meteorologists use
a scale called the integrated

kinetic energy scale to measure
the overall energy of a storm,

And Sandy had the second
most ever on that scale.

It had the energy equivalent
of two atomic bombs,

that's how powerful it was.

Sandy was dubbed
Frankenstorm by the media.

A powerful beast of a hurricane.

Was it a freak of nature?

Or, like Frankenstein, could
mankind have brought

this monster to life by
changing the climate?

One hurricane is not
enough to say for sure.

But experts are also studying
other remarkable hurricanes

from the last decade.

2005 produced more
Atlantic tropical storms

than any other year on record.

Including America's costliest
weather disaster ever,

Hurricane Katrina.

MAN Holy cow.
That was the roof!

In 2005, it's the
first time ever we ran out

of letters in the alphabet
to name our storms.

We actually had to go
to the Greek alphabet,

that's how many we had!

And we had seven category
three or stronger storms, unprecedented.

2010, second
busiest season ever.

And it's not just
Atlantic hurricanes

that are behaving strangely.

In the Pacific, the strongest
super typhoon ever known to hit

the southern Philippines forms.

And in the Bay of Bengal,
three destructive cyclones

make landfall in just two years.

These recent events suggest
hurricanes are changing

in frequency, strength
and location.

But it seems they are
killing less people.

In 1900,
a hurricane destroys Galveston,

at the time the
biggest city in Texas,

and kills 6000 people.

More than any hurricane
in American history.

In 1970, Cyclone Bhola kills
over half a million people

in what is now Bangladesh.

The deadliest
cyclone ever known.

These hurricanes weren't
necessarily more powerful

than today's, the people
were less prepared.

JOSH When
hurricanes hit 30, 40, 50 years ago,

they pretty much
happened by surprise.

People had almost no time
to prepare to get to safety.

Forecasting didn't exist.
Satellites didn't exist.

Communication was primitive.

MAN (over loud speaker:: The Mayor
of the city of New York has ordered

a mandatory evacuation of
the island of Broad Channel.

Hurricanes kill fewer
people today because we have

better technology, not because
they're getting weaker.

JOSH Now, pretty
much anywhere in the world,

if a tropical storm is
coming towards the coast,

those people know a storm is
coming and while still you can

have a huge tragedy, it is
not the monumental tragedies

that happened decades ago.

To find out if
hurricanes really are changing

in strength… or frequency,

the most reliable data
comes from satellites

and weather radars.

They record every hurricane
around the world

and can measure
their wind speed.

And they seem to be picking
up a disturbing trend:

There are more of the
most extreme hurricanes.

The strongest
tropical cyclones are becoming

more frequent uh, globally it
seems based on the limited data

that we have.

It's tricky though because
we've only had satellites

for about three decades.

In some parts of the world we
have observed an upward trend in

the number of extreme cyclones.

To be certain that
the most powerful hurricanes

are striking more often, we need

reliable records over
a longer period.

But the recent trend does match
what some scientists expect

to happen as the mercury rises.

Warmer oceans provide
more fuel for hurricanes.

SCOTT So every
half a degree Celsius

or one degree Fahrenheit
warming of the ocean,

you're going to increase

the wind speeds in these storms
ten to 20 miles per hour,

or 16 to 32 kilometers per hour.

And so Sandy clearly was
energized by the warm oceans

and researchers believe that at
least one degree Fahrenheit,

or half a degree Celsius of the
warming of that water was due

to man-made global warming. So
clearly, that had an impact.

But there
are other factors

that could actually
weaken hurricanes.

RADLEY We can't
say for sure that hurricanes are

gonna get stronger because
there are other things

that affect hurricanes as well.

Wind shear, differences in wind
height throughout the atmosphere

for example, but the balance
of evidence suggests that

the strongest storms are gonna
get stronger as those ocean

temperatures rise.

Another effect of
global warming could make

hurricanes even deadlier.

Melting ice and warming oceans
are raising sea levels

and that will mean more
devastating storm surges.

Scott Mandia explains.

Well, a storm surge
is a like a basketball dunk

in that it doesn't happen
very often, but when it does,

it's an extraordinary event.

As powerful winds
push seawater toward the coast,

the water piles up.

So you can imagine
as that storm gets higher,

it's kind of like somebody
jumping up and slam dunking.

That water gets up over the
defense …and does its damage.

Only the most powerful
storms can push the water

high enough to cause floods.

Just like only the tallest
players can reach high enough

to slam dunk.

So now imagine if
we raise the basketball floor a foot.

Now the average
basketball player can make

a dunk where before only
the tallest ones could.

That's what's going on
in the oceans right now.

Humans are warming the planet,
we're making the water expand,

we're melting a lot of ice.

The ocean's physically
one foot higher.

This higher sea level
means that less extreme storms

can now cause flooding.

So now average
storms are causing surges

that inundate our
coastal defenses.

So we have worse damage
from the extreme storms,

and damage we never had before
from what you call the average

storm, like an average player
normally can't dunk, now he can.

Nice one.

Storm surges are most
damaging to places that aren't

prepared for them.

And as the climate changes,
cyclones may start appearing

in parts of the world
they've never been seen before.

Hurricanes, particularly
the strongest hurricanes,

are confined to very
specific parts of the world.

And that's because there
are certain conditions

which enable them to form
and become quite violent.

In a globally warmed environment
those areas might change.

We might get new hurricanes

where they've never
happened before.

And we might have some areas
that have hurricanes now,

which don't have them with
global climate change.

In fact, this
may have already happened.

Hurricanes had never been known
to form in the South Atlantic.

Never, until 2004 when
a hurricane appears out

of the blue and slams
into South America.

JOSH Several years
ago, a hurricane formed

in the South Atlantic, much
to our surprise, and hit Brazil.

MAN

Fortunately no densely
populated cities are hit,

so the death toll is just four.

Next time, Brazil
might not be so lucky.

JOSH One of
the biggest risks with climate change

is that it can bring violent
weather to places

which aren't experienced,
who aren't hardened,

who aren't practiced to defend
themselves against that type

of violent weather.

In Brazil the hurricane
that hit was fairly close

to Rio de Janeiro which probably
doesn't know what to do

if a hurricane comes.

Those areas could be
particularly at risk.

In the future,
Rio could be right in the firing line.

Trees uprooted, black-outs
across the city,

and homes destroyed.

With a population of six million

and over a million in poorly
constructed favelas,

a direct hit would
be a catastrophe.

Hurricanes may
dominate the headlines,

but the weather that has
the biggest impact on lives

is far more ordinary:

Rain.

Too much rain can have
extraordinary consequences…

bringing flash
floods and mudslides.

Destruction on a grand scale.

More rain would affect
people all over the planet.

So scientists are searching for
changes in rainfall patterns.

They're monitoring the world's
biggest drenching:

The yearly monsoon in India.

Trillions of gallons of
water fall from the sky…

Transforming the landscape
from brown and dry…

To green and fertile.

Professor Sir Brian Hoskins
is one of the world's leading

experts on the Indian monsoon.

BRIAN The monsoon
in India is just an amazing thing.

It happens every year
with great regularity.

And it produces all water that
can give them their agriculture

and their whole life.

This densely populated
country has over a billion people.

And they all rely on the monsoon
to provide food and water.

But India has a
love-hate relationship

with its rainy season.

As well as sustaining
life, it can also take it.

June 2013.

Hundreds of thousands of people
make their annual pilgrimage up

these narrow Himalayan valleys.

They plan to return before the
monsoon arrives here in July.

But this year is different.

The monsoon was running
several weeks ahead of schedule

and people likely
were not prepared

to have such intense rainfall so
early in the monsoon season.

The rainfall is three
times heavier than normal

for this region.

The rain rushes down
the steep slopes,

causing the river
to rapidly overflow.

And stranding thousands of
pilgrims in mountain villages.

Local villager Kundilal
witnesses the chaos.

- The river started
turning ferocious at around- 00.

I saw everything.

I was looking down
and I saw everything

being washed away by the river.

All buildings were drowned
by the might of the river.

The river swells
to a dangerous level.

Submerging or sweeping
away hundreds of houses.

KUNDILAL Now where
the river flows is where all the houses

used to be.

Further downstream,
Suraj Singh is working

in a restaurant
when the flood hits.

SURAJ There was
a massive amount of water

so we had to quickly escape.

We ran up a mountain
and stood on a rock.

When we looked down, it
was a horrific sight.

Out of seven of us who
worked in that restaurant,

four of us had drowned
there and then.

The river sweeps
hundreds of people

to their death, many
of them pilgrims.

SURAJ Maybe 2% or
3% of them managed

to save themselves, but there
wasn't much hope of survival.

By the time
the flood subsides,

over 5,000 lives are lost.

SURAJ I had
no hope of coming out alive.

I kept thinking I'd never
see my children again.

Even now I'm home, I sometimes
break down into tears on my own.

We never thought such
a disaster could happen here.

I am 61 years old and never
have I seen such fury of nature.

The 2013 monsoon
floods are the deadliest

in India's history.

Over the last decade,
destructive flash floods

have struck around the world

from Canada

MAN Oh my god.
Oh that's destroyed the back of his car.

To Mauritius.

MAN
Hey, be careful!

To Australia.

Here the most destructive floods
in the country's history cause

over 20 billion dollars'
worth of damage.

MAN Oh my
goodness. There's another one. Oh no.

The rest of them are gone.
Oh that is horrible.

A canoeist manages
to see the funny side…

When a drive through
becomes a paddle through.

MAN Would
you like fries with that?

Yeah all right I'll
have a hamburger.

In Russia, water
sports enthusiasts make the best

of the heaviest rain there
in living memory.

It seems nowhere is immune.

Even in Saudi Arabia,
almost twice the average annual rainfall

drops in just a few hours…

taking many by surprise.

And in Brazil, flash floods
strike so quickly that people

don't even have time to escape
their houses before they're

surrounded by raging water.

A daring leap saves
this woman's life.

But she loses her
dog to the deluge.

700 people die in Brazil's
worst ever natural disaster.

In some parts of the world,
it seems clear that floods

are killing more
than ever before.

There's a better way to discover
if the heating up of the Earth

is contributing to more
destructive floods.

By measuring how much
water vapor is in the air.

PETER
There's 3% or 4% more moisture

in the atmosphere globally
than there was in the 1970s.

And this is an entirely expected
consequence of a warming

atmosphere that evaporates
more water off the oceans

and leads to more
atmospheric moisture.

And with more
water in the air, when storms develop,

there's extra rain to fall.

PETER With
that has come changing rainfall patterns.

So if you look globally, there's
a clear tendency for a greater

intensity of heavy
rainfall events.

In the future, more
moisture in the air could mean

even heavier rain and
more intense flooding.

Particularly in tropical
regions like India.

Here, the monsoon could drop up
to 15% more water than today.

Raging floods could
overwhelm the country.

So we're
getting more rain.

But weather experts are
struggling to solve a cruel enigma.

As much of the world gets
wetter, other parts get drier.

Why?

In
the sub tropics,

think the desert
parts of the world,

there's actually less rainfall.

The parts of the world that are
already very dry

tend to get drier.

And possibly the only
thing worse than too much rain,

is not enough.

Drought.

A shortage of water
creates a big problem.

SCOTT As the vegetation
becomes stressed in a drought,

the roots die off.

The soil is then loose um,
and the wind can come along

and lift little
grains of soil up.

And you get these rolling
billows of dust that blow

across the landscape.

When these build
up, they can grow into one

of nature's most spectacular
phenomena: A dust storm.

Phoenix, Arizona.

July 5th, 2011.

After nearly 14 consecutive
dry years

a strong wind picks up

vast amounts of
loose parched soil.

MAN Holy Cow! Massive
dust storm coming towards us!

Arizona has
dust storms every year,

but this one is different.

People stop and stare at the
160 kilometer wide wave of dirt.

MAN Seriously
Wendy, get out of the pool.

The biggest
in a generation.

MOTHER
What the hell is that?

CHILD Mom I'm
scared! Daddy! Oh my god!

MOTHER
It's alright guys.

John Melton is new
to Arizona and its weather.

As I walking
around to the truck,

I opened the door
and happened to look up

and see a gigantic dust cloud
come through the neighborhoods there.

I could taste the
grit in the air.

It was just a large
boiling cloud of dust.

The tidal wave of grit
grows over a kilometer and a half high

and swallows Phoenix whole.

As the dust wall
passes overhead,

the entire city
plunges into darkness.

MAN It's gone
from day to night!

The blanket of
dust blocks out the sun.

As I turned
onto the main road here,

I was just engulfed
in the storm.

This is a very regular
route that I drive,

uh, it just felt so
alien and unfamiliar.

Almost unrecognizable.

It's just a crazy
pitch-black dust storm.

Can't see more than ten feet.

It's like some kind of
apocalypse movie, I swear.

The spectacle
is all over in 40 minutes.

But the biggest dust storm
in decades

has left Phoenix
filthy and stunned.

The usually silent,
invisible drought

has made its presence felt.

But a lack of water can have
even more terrible consequences.

America knows the perils of
drought from bitter experience.

SCOTT There
was a prolonged drought

in the central part
of the United States

which is historically referred
to as the dust bowl.

In the 1930s,
over 70% of the topsoil

was blown away across a vast
swathe of the United States.

Destroying crops,

causing livestock to starve

and triggering one of the biggest
migrations in America's history.

Millions left their homes and
farms in search of work and food.

SCOTT There are these
classic photo montages of that period

with farms just
being buried in dust.

It was a dreadful,
terrible climate disaster.

Yet the recent drought
in America's southwest

has been even worse.

Particularly
parts of Texas, and,

and Kansas and Oklahoma uh,

have actually been more impacted

in the, in the 21st century
than they were in the 1930s.

Some estimates put
the cost of the North American drought

at over 100 billion dollars.

MAN I just looked
at my thermometer and got

105 in the shade.

Look at the bottom of that,
it's all turning yellow.

Leaves are dying on it. So I
don't know.

Stalks are kind of puny.

This, along with
other unusually extreme droughts

around the world, has been
described as a mega drought.

In South America, mega
droughts are affecting

the world's biggest rainforest.

SCOTT There was
a 2005 drought in the Amazon

that broke all the records.

Hundred year event.
Happened again in 2010!

In 2010 there was a drought that was
even bigger than the 2005 drought.

Ah, you do the maths.

How many 100 year droughts
can you have in ten years?

The unusual severity
of these droughts could be

down to another factor.

As well as less rainfall,
more heat from global warming

could be drying
everything out even more.

As the air gets
warmer, it evaporates more water

It evaporates from the plants,
it evaporates from the soil,

it evaporates from
irrigation ditches.

You can see the
plants drying out.

The consequences
can be catastrophic.

As drought
increases of course,

there's less forage
for livestock,

less water for cities
and for people.

Uh, in our part of the world,
we're reasonably adapted,

we have reservoirs and
we have water sources.

But in uh, the developing
world it can be absolutely

catastrophic for the
people that live there.

There are huge swathes of Africa
already incredibly vulnerable

to drought, areas where millions of
people subsist on a pastoral economy,

grazing cattle on
very sparse grass.

2011.

The worst drought in 60
years devastates East Africa.

Crops fail across a vast region,

leading thousands
to flee their homes.

Drought leads to famine.

The very severe
drought and the severe weather

meant that many, many
people starved and many,

many people were displaced in
search of food as a result

of that extreme weather.

One estimate
puts the death toll at

over a quarter of a million.

Making the drought one of
the deadliest weather events

of this decade so far.

The drought and famine prompts
climate expert Peter Stott

to investigate if climate change
contributed to the disaster.

He uses a supercomputer that completes
100 trillion calculations a second,

to simulate the drought

and to analyze the factors that
could have been involved.

The results are bleak.

What we found with that study
was human induced climate change

had increased the risk
and therefore had increased

the vulnerability significantly
of those people uh,

greater than what
it would have been

if we had not altered
the climate.

Climate change
has already made droughts even drier,

with deadly effect.

In the future, they'll
get drier still and dustier.

SCOTT Models
project that actually southern Europe,

the Mediterranean
region, North Africa,

they're probably going to
suffer the most from drought.

Just devastating droughts.

By mid-century,
southern Europe could face

more extreme droughts.

Parts of Italy, along
with Greece and Spain,

could turn to semi-desert.

Experts are close to solving
the riddle of how some parts

of the world can get drier,
while others get wetter.

But there's an even bigger
mystery in climate science.

As the world heats up, some
places seem to be cooling down.

Spring 2013.

Britain is in the
midst of a big freeze.

Temperatures are up to
10 degrees below average.

Usually any snow
has thawed by now…

Instead, deep snowdrifts
bury much of the country

MAN Give
it a try then boys.

BOY Ok daddy,
here we go!

BRIAN The
month of March in particular

was extremely cold, and it was I
believe a record in England

and Wales and we have a
long period for that record.

And Easter was just terrible.

So people were freezing.
It was very unusual.

The holiday weekend
is the coldest for 50 years.

But not everyone has time to
enjoy the un-seasonal wintry scenes.

Farmers, like Gareth Wynn
Jones, are hard at work.

At his farm in Wales, the snow
has come at the worst possible time.

It's lambing season and
thousands of pregnant sheep

have been trapped under
a meter of snow for four days.

This snow
has come very late.

My father's 77, he's never
seen anything to touch it.

This time last year, we were
in shorts and T-shirts

and this year, we're digging
sheep from massive snowdrifts.

Many of his sheep
succumb to the freezing temperatures.

It's just frozen
solid you see.

But then,
his dog picks up a scent.

Have they found
this one in time?

She's cold and stiff, but alive.

Unbelievably.
4-4 days…

She'll bloody survive now. Job
well done boys. Job well done.

You've got to think. She's been
cocooned in there for four days.

You think about it.

It's being buried alive, isn't
it, it's a tomb, isn't it.

That's what, that's what
people don't understand.

The sheep
is still pregnant,

and shortly gives birth
to a healthy lamb.

But thousands of other sheep and
lambs across the Welsh valleys

are not so lucky.

GARETH
It is a crisis,

and we just have to cope
with the situation, because,

one thing I tell you,
these mountains

will have a lot less
sheep on them,

and maybe
a lot less farmers as well.

Over
the last few years,

Britain has endured some
surprisingly cold winters.

BRIAN The
expectation a few years ago was,

"oh everything's going to warm up
so we'd forgotten those cold winters."

And then it was a bit of a shock

when we actually got
a really cold winter.

We got a really cold winter in
2009-10 and then a very cold

December 2010, sort of record
levels, really intense.

As temperatures
plummet in the UK,

much of Europe shivers through
some of its coldest winters.

MAN First time
in history of Split.

Snow like you cannot believe.

In Ukraine this
house, like many others,

is buried in a snow drift.

They finally dig their way out.

An ice storm turns Switzerland
into a glistening fairy tale kingdom.

Snow even reaches as far
south as the Sahara desert.

And Israel.

MAN Shit…he's
done.

Across the Atlantic,
it's a similar story.

Frozen roads cause chaos.

MAN This is so
bad. What the hell?

The winter of
2013 seems to go on forever.

WOMAN Oh no, it's
pushing forward. This is crazy.

In May, strong winds
push a weird creeping tide of

ice crystals off a frozen lake
toward houses in Minnesota.

WOMAN Oh my god,
Nicky, look!

This freak cold
weather leads many to question

whether the world is
really warming up.

If the world's getting warmer,
why are these winters getting

colder and longer?

The answer may lie
in an unlikely place.

The rapidly warming Arctic.

Paradoxically, as
the Arctic heats up,

it could be cooling
other places down.

As it warms, it appears to
be disrupting the jet stream,

a band of fast-flowing air
high in the atmosphere,

which blows weather
systems around the planet.

That could be keeping cold air
masses in place for weeks on end.

Climatologist Heidi
Cullen explains.

HEIDI The weather
is a lot like traffic in Manhattan.

When traffic is moving,
everybody is happy.

Same thing with weather systems.

It's basically the equivalent of
the jet stream zooming along

and the weather systems moving
along right with it.

The jet stream is actually
steering our weather systems

around the world.

Like cars
passing an intersection,

you never have one kind
of weather in one place

for too long.

Cold weather quickly moves on,
giving way to warmer weather,

and then colder weather again.

HEIDI But if
that Jetstream slows down

the weather systems
slow down with it.

We're basically seeing the
equivalent of a traffic jam

in the atmosphere.

This is known
as a blocking system.

And it causes one type
of weather to get stuck

in one place for a long time.

That's exactly
what we saw in Europe

and the US this past winter -

we had you know blocking
pressure systems

and you just had cold weather
essentially locked in place

for months on end.

When the weather is moving
people can deal with it,

but just like with
traffic in Manhattan,

you know when you're in
gridlock, it's miserable.

Blocking systems,
like traffic lights,

stop anything from moving on.

Instead of a brief icy blast
followed by a warmer spell,

the freezing air
is fixed in place.

In the future as the Arctic
warms up even faster,

the jet stream could
get even slower,

locking in the colder weather.

Snowstorms could reach places
we'd never expect to turn white.

Ironically
in a warmer world

we could actually
see colder winters

and, and it really
comes down to the fact

that our climate system
is incredibly complex.

But these freak cold
winters won't last forever.

In the long term,
you can think of it as

the heat wins out over the cold.

So we're gonna see more,
more heat extremes

and fewer cold extremes.

As sea ice in
the Arctic continues to melt,

the traffic jam in the sky may
have far-reaching repercussions.

As well as big freezes,
the same blocking systems

could make all kinds
of weather even worse.

When hot weather gets
stuck in one place,

it triggers even hotter heat
waves, and more wildfires.

When dry weather gets stuck,
droughts get drier and dustier still.

And when heavy rain gets
stuck, it can cause catastrophic floods.

Climate change is already making
some kinds of extreme weather worse.

More blocking systems would
be a brutal double whammy.

And the knock on effects
of a warmer Arctic

may even be changing the course
of dangerous hurricanes,

like Hurricane Sandy.

Storms that move up
America's east coast,

normally drift out
harmlessly into the Atlantic,

but not this time.

So Sandy took
this very unusual course

back towards land.

There's emerging research exploring
whether loss of sea ice in the Arctic

may make storms taking that path
more frequent in the future.

Many scientists
already expect climate change

to cause more powerful
hurricanes and higher storm surges.

So a damaging shift in
hurricane paths, if confirmed,

would be a devastating
triple whammy.

Colder winters, hotter summers,
droughts, floods,

thunderstorms, wildfires and
hurricanes spiraling out of control.

The weather is already changing.
And this is only the beginning.

Just how bad will
the weather get?

The answer depends on
the amount of carbon dioxide

and other greenhouse gases,
we release into the air.

The carbon dioxide
has risen in my lifetime

from about 330 parts per million
to about 400 parts per million.

In my children's lifetime,
it's likely to hit 800 parts per million.

We ain't seen nothin' yet.

If levels continue
to increase at this rate,

by the end of the century,
temperatures could rise by

as much as seven
degrees on average

and trigger extreme weather
like we've never seen before.

What we now consider
a severe heat wave

could be a normal summer.

Sparking more wildfires on
every populated continent.

Powerful hurricanes could
stray far from their current territory.

And their higher storm surges
could inundate the homes

of 150 million more people.

SCOTT If we keep
burning fossil fuels, coal, oil,

natural gas like
there's no tomorrow,

we're on our way to a situation
where these freak weather events

we talk about now are going
to be the weather normals

by the end of the century.

For storm chasers,
pursuing freak weather is now

an exhilarating way of life.

Whoa, man alive!

They witness
nature at its most extreme.

MAN Wow!
Are we gonna be ok?

MAN
Yeah, yeah, fine.

But even for them,
as the weather changes,

the future looks frightening.

GEORGE I
can see what's coming.

I know our weather is getting
worse. I've seen it.

I'm anticipating it to
get even worse still.

And as a storm chaser, someone
who actively pursues these

things passionately, I want to
be there for the worst of the worst.

But at the same time, I don't
want to see the death

and destruction that
goes along with it!

But many experts
believe it's not yet too late

to prevent this
climate catastrophe.

If we switch soon to sources
of power that don't release

greenhouse gases, we may only
heat the world by two degrees.

SCOTT So it's
really on us. We have choices.

We decide the weather of
the future. We decide today.

Scientists are
confident the weather will get worse.

How much worse is up to us.