Worst Weather Ever (2013) - full transcript
Scientists find out what impact climate change has on our world.
Oh my God, oh my God.
The world's weather is going wild.
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.
Yeah. He's
not looking too well really.
The largest Atlantic hurricane on record...
and the widest tornado ever known.
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.
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.
Yep, there goes the roof off the house.
Is tornado alley becoming
an even more dangerous place to live?
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.
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.
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.
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.
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.
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.
Calm
down. We're in a brick building, it's ok.
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.
Keep your heads down.
And then it finished,
and then when it was
over it started raining.
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.
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.
Oh, it's a tornado.
It's a tornado, power flashes.
Again, storm chaser
George Kourounis is close by.
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.
Strong tornado.
And even more surprising is its size.
The tornado is rapidly getting bigger.
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.
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.
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?
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.
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.
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.
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.
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.
Check it out.
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.
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.
...very large
hail... Holly...
It can even be deadly.
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.
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.
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.
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...
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.
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.
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.
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.
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.
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.
Oh my God, I gotta get out of here.
All the way down
the hill, dude, look at this. We gotta go!
Experts are investigating whether
extreme heat is linked to more wildfires.
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.
Really we didn't
think it was going to be that big,
we were just going up
this road and filming the smoke.
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.
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.
That's where those people lived.
Aw, jeeze.
The ones that died.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Think it just exploded.
As the power fails,
explosions continue to light up the sky.
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.
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.
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.
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.
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.
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.
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.
Several years ago, a hurricane formed
in the South Atlantic, much
to our surprise, and hit Brazil.
Fortunately no densely
populated cities are hit,
so the death toll is just four.
Next time, Brazil might not be so lucky.
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.
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.
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.
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.
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.
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
Oh my God.
Oh that's destroyed the back of his car.
To Mauritius.
Hey, be careful!
To Australia.
Here the most destructive floods
in the country's history cause
over 20 billion dollars' worth of damage.
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.
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.
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.
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.
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.
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.
Seriously Wendy, get out of the pool.
The biggest in a generation.
What the hell is that?
Mom I'm
scared! Daddy! Oh my God!
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.
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.
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.
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.
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.
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.
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
Give it a try then boys.
BOY Ok daddy, here we go!
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.
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.
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.
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.
Shit... he's done.
Across the Atlantic, it's a similar story.
Frozen roads cause chaos.
This is so
bad. What the hell?
The winter of 2013 seems to go on forever.
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.
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.
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.
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.
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.
Wow!
Are we gonna be ok?
Yeah, yeah, fine.
But even for them, as the weather changes,
the future looks frightening.
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.
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.
The world's weather is going wild.
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.
Yeah. He's
not looking too well really.
The largest Atlantic hurricane on record...
and the widest tornado ever known.
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.
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.
Yep, there goes the roof off the house.
Is tornado alley becoming
an even more dangerous place to live?
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.
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.
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.
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.
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.
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.
Calm
down. We're in a brick building, it's ok.
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.
Keep your heads down.
And then it finished,
and then when it was
over it started raining.
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.
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.
Oh, it's a tornado.
It's a tornado, power flashes.
Again, storm chaser
George Kourounis is close by.
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.
Strong tornado.
And even more surprising is its size.
The tornado is rapidly getting bigger.
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.
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.
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?
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.
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.
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.
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.
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.
Check it out.
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.
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.
...very large
hail... Holly...
It can even be deadly.
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.
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.
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.
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...
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.
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.
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.
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.
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.
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.
Oh my God, I gotta get out of here.
All the way down
the hill, dude, look at this. We gotta go!
Experts are investigating whether
extreme heat is linked to more wildfires.
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.
Really we didn't
think it was going to be that big,
we were just going up
this road and filming the smoke.
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.
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.
That's where those people lived.
Aw, jeeze.
The ones that died.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Think it just exploded.
As the power fails,
explosions continue to light up the sky.
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.
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.
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.
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.
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.
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.
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.
Several years ago, a hurricane formed
in the South Atlantic, much
to our surprise, and hit Brazil.
Fortunately no densely
populated cities are hit,
so the death toll is just four.
Next time, Brazil might not be so lucky.
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.
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.
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.
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.
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.
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
Oh my God.
Oh that's destroyed the back of his car.
To Mauritius.
Hey, be careful!
To Australia.
Here the most destructive floods
in the country's history cause
over 20 billion dollars' worth of damage.
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.
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.
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.
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.
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.
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.
Seriously Wendy, get out of the pool.
The biggest in a generation.
What the hell is that?
Mom I'm
scared! Daddy! Oh my God!
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.
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.
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.
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.
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.
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.
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
Give it a try then boys.
BOY Ok daddy, here we go!
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.
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.
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.
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.
Shit... he's done.
Across the Atlantic, it's a similar story.
Frozen roads cause chaos.
This is so
bad. What the hell?
The winter of 2013 seems to go on forever.
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.
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.
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.
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.
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.
Wow!
Are we gonna be ok?
Yeah, yeah, fine.
But even for them, as the weather changes,
the future looks frightening.
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.
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.