Heat drives our weather.
From the rage of a tropical storm, the blinding heat of the deserts,
to the violence of a summer sky.
I'm Donal Maclntyre, and I'm about to take a journey with heat
from the equator to the poles
to see for myself the awesome power it can unleash around the world.
From its birth in the tropics, through the perfect summer,
into a hotter world -
one which could turn the weather of the future into a nightmare.
This is... "Wild Weather"!
Have you ever wondered, what's the power behind the weather?
What makes it tick?
In a few moments, we're going to see the true source of all weather.
And this is it. The sun. The fuse that lights the weather.
It's over a hundred times bigger than Earth,
and every second it releases enough energy
to power the USA for nine million years.
It takes one million years for the heat at its core to reach the surface.
Once it does, it makes its journey here in just eight and a half minutes,
a journey that ends in a blaze of glory every single day.
All that blinding heat and light is blasted out through space towards us.
As it homes in on our little planet,
it's at its most intense heading for the steaming jungles of the tropics.
The sun's rays hit the equator.
It's the start of heat's epic journey around the planet.
To find out what it does to the weather down here,
I'm heading to where the sun's energy is most intense.
Trapped beneath the jungle canopy,
all that heat creates one of the most extreme environments there is.
So to find out what all that heat does to the weather,
I'll spend the next 24 hours in the jungles of Belize.
If you're in the jungle and you don't know what you're doing, like me,
then you're already this close to death.
Sergeant Bob McCloud is an expert in jungle survival - a handy man to know.
- "Good morning. " - You're looking after me.
- "I sure am. " - That's a heavy responsibility.
One second it's torrential rain, next it's a sauna.
That's right, so you're constantly wet.
And it'll go from one extreme to another in such a short time.
Within one day, hypothermia and dehydration. That's crazy.
Follow me. I'll show you.
For most of the year, the sun lies directly overhead,
so there are no conventional seasons here as we know them.
Just hot and wet, then a little less wet.
The daily weather is delightfully predictable.
There are clear skies in the morning, showers in the afternoon,
and clear skies again in the evening.
It's a weatherman's dream.
The one wild card in all this predictability
is the vast amount of energy being built up in this heat and humidity.
It's all that energy that makes this place as cloudy as it is.
The heat warms the land,
rainwater evaporates from the vast amount of vegetation, and rises.
The water vapour condenses into tiny droplets that create huge clouds.
The droplets collide, growing larger, until gravity pulls them down again.
The weather here is in a continuous cycle, fuelled by heat.
Whether you're in the water or on the river bank,
it doesn't make a lot of difference, because everything is permanently soaked.
Everything's just wet, wet, wet.
That's the big problem in the jungle.
It doesn't matter if it's hot or actually raining,
everything ends up wet, which is a big problem.
The only way round it is having a dry set of kit and a wet set of kit,
and at night the discipline is to get into your dry kit
to give you 12 hours when your body can recuperate.
In the morning you put on your wet gear?
Y"eah. If you don't," things are going to start to rot.
Y"our boots will go and your clothes,"
and your skin will start to rot away
and you end up with crotch rot and foot rot.
Bob has spent the last five years training the British Army
how to deal with life in this kind of heat.
God, I'm knackered.
As I struggle through the jungle, my body produces more heat.
My blood carries that heat away from the muscles
and is cooled when it finally reaches the skin.
Out here, that's never enough, so we sweat.
One drop of sweat can cool a litre of blood as it evaporates off the skin.
Get going. Get up there.
It's the process of evaporation that cools you down,
but it's not working here.
The hotter I get, the faster my heart beats and the tireder I feel.
Come on. Keep moving. Get up there.
I'm soaked in sweat, but the air here is so damp that it can't evaporate.
Stop moaning and keep going.
I'm a dangerous man with a weapon like this.
Y"ou're being a cowboy. " There's a technique to using a machete.
This is crazy terrain.
But it is what every kid trained for, aged six, hacking through the jungle.
I'm just doing it a little late in life.
As the day wears on, it gets hotter and hotter.
More and more moisture fills the air until it becomes saturated with water.
Finally, it reaches a point where your sweat can't evaporate any more.
I'm pouring sweat, but it's not doing me any good.
You can't see heat or humidity,
but to appreciate it, you've got to imagine closing your bathroom door...
knocking the central heating up to full blast, turning the hot taps on,
and leaving it on for a couple of hours.
That gives you a sense of it.
- Give us a break, Bob. - "Breaks are for losers. Keep moving. "
Fortunately, this kind of weather is rare outside the jungle,
but occasionally, it reaches out beyond the tropics
and when it does, the results can be lethal.
In 1995, tropical weather descended on Chicago.
Even in a modern city like this, it brought chaos and death.
July, and the temperatures were already soaring
when heavy rains drenched the great plains outside the city.
The air mass above these fields became hot and steamy.
Days later, things took a turn for the worse.
A mass of warm moisture-laden air from the Gulf of Mexico forced its way north.
The 2.8 million inhabitants of Chicago were about to experience
the extremes of tropical weather.
That's when it really hit you.
Y"ou sat back and said, "Gosh, 600-"7"00 people" died because of this event. "
Weathermen in the midwest were the first to realise something was wrong.
We're taking a look at temperatures well over 100 degrees.
Widespread, not just one or two places.
High pressure produced hours of uninterrupted sunshine,
and as the moist air from Mexico arrived in the area,
levels of humidity shot up to 90%.
This mass of sweltering tropical air
was then blown over Chicago by south-westerly winds.
It sat over the city like a steaming wet blanket.
Day two. Heatwave. The city is an oven.
All over Chicago, an invisible enemy takes hold.
It was like hitting a brick wall. It was...
It just totally surrounded you, like walking into a blanket.
Y"ou could put a bathing suit on, be in" the water and it would still be hot.
It affected the sound too when you walked out.
For Gaby "K"uhn, this freak tropical weather made life difficult...
but for Mabel, her elderly neighbour, it was deadly.
It was about the second day of the heatwave.
Mabel had done fine. We had set up fans for her.
She sat in this seat and we put a fan here that would blow on her face.
And the next day...
Normally she called me around two in the afternoon, and she didn't call.
Day three. The story's the same all over the city.
The emergency services are in freefall.
She's not alert?
The city's emergency warnings have failed to reach those most at risk.
As the heat increases, the emergency centre is swamped
with thousands of calls for help.
Back in the suburbs, Gaby still hadn't heard from Mabel.
I said to my daughter, "I think I need to check on Mabel. "
She usually calls between two and three.
I tried to call her, but she didn't answer.
I tried a couple of times, so I thought I'd come over.
I came in, and when I walked into the house
I found her laying here in-between the dining room and the bathroom.
Apparently, she tried to get into the washroom and didn't make it
and collapsed here on the floor.
The ironic thing is this is my house right here.
It's probably three feet, a metre away.
And I didn't see her.
I often think about that.
Is the patient conscious and breathing?
By Saturday, 165 people lay dying all over Chicago.
Many would not be discovered for days. By then, it would be too late.
- "Stay home. " - "Help is on the way. "
When it hit us, we started watching television ourselves
and they were having pictures of the morgues -
they were hauling bodies into the morgues and they were piling up.
It was a shock.
Mabel was one of the first twenty to die of heat-related...
And then there were more.
Day four. Hospitals are at breaking point.
It started on a Thursday and it continued to build Friday.
By Saturday, we started having such a huge influx of patients
that where we had one cubicle, we'd now have 3A, 3B, 3C, 4A, 4B, 4C.
The death toll rose dramatically.
Most of the victims were elderly or impoverished,
who found it more difficult to cope with extreme temperature conditions,
leading to a deadly cycle of events.
First, the body's temperature rises to dangerous levels,
bringing about a state of confusion.
In this state of mind, we're less likely to seek shelter
or the aid of a cooling fan.
As the body dehydrates, we slip into coma.
In these super-heated conditions, our internal structure changes.
Our blood loses its ability to clot, leading to a cruel and bizarre fate.
Blood oozes from almost any orifice.
So out of your nose and your mouth and your bottom, from your stomach.
Anywhere in your body. People just die from that.
Day five. By the time all the victims had been discovered,
the heatwave had already left Chicago.
It's just unbelievable that so many people
can die so quickly just from the weather.
It was an awful week.
In the end, the tropical heatwave had claimed 525 victims in under a week.
The city and its people were simply not prepared
for the intense jungle weather that invaded their lives.
With only 12 hours left in the jungle,
I'm about to experience night-time weather in the tropics.
As the heat of the day subsides,
all the moisture in the air means nightfall can bring heavy rain or worse.
Bob and I are making sure we're ready for anything.
- Have you brought the duvets? - "I'm afraid not. "
We do have sleeping bags. Is that good enough?
I could do with a little Coke here and a mini-bar
and a phone here for room service.
- "The creature comforts, eh?" - Plenty of creatures, no comforts!
Y"ou're looking at 12 hours" of darkness.
We won't move during the night because of how thick the jungle is.
So you'll probably get a good 12 hours' kip.
Any Maltesers, chocolates, Pringles?
I've got some noodles.
I can't remember where I left my machete.
As night falls, a stormier kind of weather takes hold.
After 12 hours of sunshine,
when hot humid air releases massive amounts of energy,
this is the result.
A big storm can dump several inches of rain in a night.
Equal in power to an atomic bomb...
they can also reduce the jungle to matchwood.
There aren't supposed to be seasons in the jungle,
but this feels like winter to me.
It's about seven o'clock in the morning.
It's raining outside, it's cold. I've had an awful sleep.
And I'd just like to say that communing with nature in the jungle
isn't all it's set up to be.
Oh, God!
Sorry.
- Disaster, Bob. - "I did warn you. "
At least the spiders that were in them are now gone, or drowned.
I thought that the tropics, where the sun's energy is at its most intense,
would be the hottest place on Earth. But I'm wrong.
I'm getting out of the frying pan and into the fire - the hottest place on Earth.
From the tropics, all that warm air rises, dumping its rain as it goes.
At nine miles high, at the edge of the troposphere, it can rise no further.
So it begins to head both north and south of the equator.
1,500 miles later, at about 30 degrees latitude,
the air begins to sink back down to Earth, warming as it drops.
Where it falls, it creates two strips of arid land that circle the globe,
and that's where you'll find the great deserts of the world.
And the greatest of them all is the Sahara.
Having left all that wet heat in the jungle,
I'm about to find out what dry heat does to the weather.
The air above me here is so warm that water cannot condense into rain,
and so it hangs there, trapped above the very places that need it most.
Just look around me at the results.
There's more moisture in the sky above me now than over the skies of Britain,
and yet it's completely clear.
In fact, this desert only gets a measly three inches of rain a year,
and even when it does rain, the sun's rays are so intense
that it evaporates 200 times the amount that falls. So...
this is what we're left with.
The blazing sun cooks the desert rocks,
causing the minerals to expand so much that the rocks eventually shatter.
Over thousands of years, powerful desert winds grind them all to sand.
The Sahara covers an area of over three million square miles -
almost as big as the USA.
It's also record-breakingly hot.
In 1922, the highest air temperature ever recorded was taken here -
a staggering 58 degrees Celsius, 136.4 degrees Fahrenheit.
Just one of these dunes is made up of thousands of tons of sand.
Those tiny grains make up our romantic and enduring image of the world's deserts...
endlessly driven by the winds like some half-frozen ocean.
This is an amazing place.
The vast stillness is completely overwhelming.
It's timeless. There's a real sense that nothing here has ever changed.
But that's an illusion.
Beneath this ocean of sand lies an incredible secret.
In 1981, 140 miles above my head,
the space shuttle Columbia looked down upon this desert and took a snapshot.
What they saw took them completely by surprise.
Instead of a flat and barren expanse of sand,
the infra-red revealed mountains and river valleys underneath.
The picture revealed a hidden world only a few metres beneath my feet.
As they saw through the layers of sand,
they were amazed to discover that 35 million years ago
the Sahara was once a great fertile savannah with rivers and lush meadows.
Over time, small changes in the global climate
meant that life simply withered and died.
We think of the desert as timeless, but in fact it is constantly changing.
Here, in the dry heat of the desert, my journey continues,
this time to see if I can survive the highest temperatures on the planet.
Instead of sunbathing and camel treks, I have to face a tougher test,
so I'm practising for the most gruelling marathon on Earth.
I've come here to run in the toughest race in the world -
the infamous Marathon of the Sands.
Seven days in some of the hottest and most hostile environments on the planet.
If you want to experience the worst that desert weather can throw at you,
then this event hits you with everything -
cutting winds, killer dehydration, blinding dust,
and, of course, the unbelievable, unbearable searing heat.
Earlier on, it seemed like a good idea.
Unlike in the jungle, all this hot dry air sucks the water out of you,
so I've been told to carry and drink at least nine litres per day.
And when it really heats up, I'll be losing a litre an hour.
It's a really tough part. I'm hardly moving.
I haven't been running for long, but I can feel myself sweating all over.
You can't see it because the sun's evaporating it straight from my skin,
but if you do this...
you can taste the salt and the sweat.
The more I sweat, the more salt I lose.
In a full day, I can lose about three teaspoonfuls.
That can be really dangerous out here.
I can get muscle cramps and, because salt's essential for brain function,
I can become disorientated and confused.
No change there!
The desert heat can play tricks on you at the best of times,
but without water these tricks can be lethal.
The temperature on the ground gets close to boiling point.
It's nine in the morning, but the heat is vicious.
I can feel my head throbbing and tightening as the sun takes its toll.
But if I do this...
that's when the heat really hits you.
Down here, it's 50% hotter than at eye level.
This temperature difference creates strange, sometimes deadly effects.
We've all heard the stories.
You're lost, you've used your last drop of water.
And just as it looks like it's all over,
you see a lake shimmering on the horizon.
In the distance, you see the water you've been desperately searching for,
but however fast you run towards it, it never gets any closer.
Desert mirages occur because of the temperature difference between here...
and here. It cools by nearly 20 degrees in less than two metres.
That incredibly hot layer near the ground can behave just like a lens.
Like the lens in your spectacles, it can refract - actually bend the light.
So when I look towards the horizon, I can see a cool lake of water.
What I'm actually seeing is the sky refracted,
so it appears to be lying on the ground.
A cruel trick indeed.
What monster designed that race?
It's just you sink into the sand and it's blistering with the sunshine.
Dust in your ears and eyes, burning your throat...
It's a killer.
At dusk, the desert has another trick of the light up its sleeve.
There's one kind of mirage you can see out here just about every day.
The sun I'm looking at has actually already set.
It's the same effect as the lake mirage.
This illusion gives us two minutes' extra light at the end of the day.
Out here you can drive for days without seeing any signs of life.
And if that's not worrying enough,
the desert also has some special weather treats
for those foolish enough to venture into its dusty heart.
Here in the desert, there's a menace as old as the wind
that turns day to night in an instant.
The heat rising from the desert floor mixes with powerful easterly winds,
creating a turbulence that whips the sand up and blasts it into the air.
It's called a "haboob".
When the wind gets going and you're in its way,
it can be very nasty indeed.
Sometimes it can look like the whole desert is on the move,
and the sight can be truly apocalyptic.
In happened in Melbourne, Australia, in February 1983,
when a massive cold front gathered to the north of the city.
As it flowed south, a thunderstorm grew along its leading edge,
causing a downdraught that kicked up the dust beneath it
and drove it forward like a vast red wave.
As it swept into town, this huge wall of dust instantly blotted out the sun
and brought the city to a standstill.
The cloud was 320 metres thick
and dumped over 1,000 tons of sand in an hour.
From miles above the Sahara,
we can see clouds of fine sand that dwarf even Melbourne's experience.
When the wind and the sun get going, the clouds they create can be global.
Some of them can be the size of Europe.
Caught up in the winds that blow west across the Atlantic,
these fine sands are carried as far as the Caribbean,
where they help top up the perfect beach.
From the mountains of Morocco to the palm trees of the Caribbean,
these enormous dust clouds travel 4,500 miles,
bringing around 90 million tons of the Sahara to the Caribbean every year.
That's an awful lot of beach.
My journey has finally arrived in the kind of heat we all love.
A friendly sun, a cooling dip - it all makes for a holiday mood.
The sun's rays boost our levels of seratonin -
a brain chemical that makes us feel good.
But this sense of well-being can be deceptive.
It's easy to forget, as we cover ourselves in sun cream,
the price we pay to soak up those rays.
This feels great. Lying here is deeply relaxing.
I'm getting a good dose of Vitamin D from the sun's rays.
But as the hours tick by, it's a very different story.
Sunburn.
Beneath the surface of my skin,
only half the ultraviolet light from the sun is getting through.
But even so, it's destroying the skin cells nearest the surface.
My skin reddens as blood flow increases,
carrying nutrients and oxygen to repair the damage.
The longer I spend in the sun, the more permanent the damage becomes.
Like me, the planet also has a protective skin.
The atmosphere above us stops half of the sun's lethal rays,
which are absorbed or reflected back into space by clouds,
particles in the air, and atmospheric gases.
Without the atmosphere, life wouldn't be possible.
But the skies that shield us from these harmful rays
also contain their own deadly energy.
It's one of summer's biggest killers - lightning.
From space, NASA cameras captured amazing images of our electric skies.
At this moment, there are almost 1,800 individual thunderstorms
taking place around the planet.
On average, lightning strikes the earth about a hundred times a second.
When the lightning hit me, it was like nothing I could ever imagine.
I felt like someone had thrown a hand grenade in my face.
To get as close as I could to being struck by lightning,
I went to see Mike Alexander at the Theatre of Electricity in Boston.
This is your own lightning machine.
It's a Van de Graaf generator. It was invented in Boston.
It really works in a very simple way.
It stores a lot of extra negative charge on top of those two spheres
until there's enough for 1.5 million volts.
That's a lot of volts. That could do a lot of damage.
Everyone's safe out here, but inside this cage it can get a bit dangerous.
Y"our hair stands on end," you get a bluish glow off your nose,
you get a shock if you touch anything.
The scientists say that if you were hit by one of those lightning bolts,
you would probably live, but I haven't tried that yet.
They say you will feel your hair stand up on your arms or your skin tingle.
I didn't. I felt this enormous blast.
This enormous white light blinded me,
and I felt the electricity going through my body.
That's the last thing I felt because it threw me up and knocked me out.
Would you like to come in?
(DRAMATIC, THREATENING CHORDS)
While the machine is on, the safest place to be is surrounded by metal.
It seems that all this metal is the most unsafe it could possibly be.
It goes against your common sense,
but if you're surrounded by metal you're safe - lightning can't get in.
So if you're in a thunderstorm and in a car, that's a safe place to be?
It is, surprisingly enough. It's not the tyres, it's the metal surrounding you.
It protects you absolutely, but it has to be a metal car, not fibreglass.
What about rubber soles and Wellington boots?
It would keep your feet dry, but it won't stop lightning hitting you.
You've just buried another old wives' tale.
You feel a bit like God's booth up here - lightning on command.
Y"ou feel like the guy from" the Wizard of Oz behind the curtain.
Y"ou can make lightning happen" whenever you want.
And they say lightning never strikes twice. Not so for Linda Cooper.
I answered the telephone, it was my daughter, she wanted her dad.
I said, "Hello', and as she said, "Is Dad there...?"
Lightning struck the telephone.
I had the receiver up to my face.
I could feel electricity in my face. I dropped the phone and screamed.
Then I said, "It got me again. I cannot believe that it got me again. "
The pain was nothing like the first time.
The first time was like being hit by a truck, the second time like a moped.
But the fearl I had just come back from years of studying,
trying to get my health back and my strength back...
and it got me again. I thought it was going to steal all that away from me.
To the naked eye, lightning always looks like it comes from the sky,
but that's only half the story.
You can't see that the flash is actually shooting up from the ground
into the clouds in one ten-thousandth of a second.
And at 30,000 degrees Celsius, the bolt superheats the air around it,
making it literally explode.
That's the sound of thunder.
Some day somebody's going to be zapped. Let's hope it's not today.
- It's pretty safe though? - Y"eah. It's very safe. "
As long as you stay inside this metal cage,
the lightning can strike half an inch away and you're still absolutely safe.
But put your finger out, you'll get a bad zap.
I've done it a couple of times by mistake and it hurts.
What's getting 1.5 million volts like?
I feels sort of like someone hits you with a hammer or something.
All your muscles tense suddenly. It's not pleasant.
O"K".
You look a bit like the mad professor.
It feels that way sometimes.
Three, two, one...
Oh, my God!
A bolt of lightning can be 30 miles long and is the width of my thumb.
It's also six times hotter than the sun. I'm going to be very careful.
In the real world, the chances of being hit by lightning are minimal.
Even so, about a thousand people are killed by lightning every year.
That's about 1.5 million volts hitting my finger right now.
Oh, my God. Thank God for that.
The third time I was struck was totally different than the first two.
I thought the storm was gone, so I got up and made jello.
I went to wash out the cup after I'd finished making the jello.
I put it in the sink and turned on the faucets.
I didn't realise that the cold water faucet was ground to your house.
Lightning struck, came through the cold water faucet,
ran up both my arms and across my chest.
I felt like I was on fire. This was totally different to the other times.
It felt like someone had taken a torch and lit both my arms.
I put my arms up inside the freezer
and leaned into my freezer and stayed there for I don't know how long.
Lightning is nature's electricity.
It's in the air and it's going to hurt you if it hits you.
It could kill you, but if you live, you will never be the same.
Y"ou will never feel the same," you will never think the same.
I wouldn't wish that on anyone.
In the future, the violence of our summer skies may get worse.
So the next time you're caught in a storm, consider this...
it could be all your own fault.
It's Friday and time to go home.
The weather's been lovely all week
and everyone's looking forward to a sunny weekend.
But have you ever noticed how the weather messes it all up?
Not again.
You may think that rain at the weekend is just bad luck,
but scientist Randy Savini has stumbled on something really strange -
we may be the cause of it.
My research into weekend rainfall began as a fortunate accident.
I had been studying hurricanes and inadvertently ran a computer programme
that classified hurricane observations by day of the week.
When I plotted those observations, I found a bizarre, interesting pattern.
He found that the strength of hurricanes seemed to differ
depending on the day of the week.
What Randy's computer told him about hurricanes
led him to realise that the way we live and work
may be changing the weather around us.
It all comes down to the seven-day week.
Given that the seven-day cycle doesn't occur in nature -
it's something man came up with thousands of years ago -
if we see changes in weather occurring on a seven-day cycle,
the assumption is it's something we're doing to create that.
To prove we are influencing the weather on a weekly basis,
Randy needed more evidence.
We went to the archive and grabbed 20 years of data,
and looked at rainfall.
Rainfall is easily measured,
measured in many different locations, and is important to people.
And for location after location, as I was doing this,
we found that rainfall showed the same cycles that we saw with hurricanes.
It was actually a lot wetter at weekends than it was during the week.
Randy found that as pollution levels built up over the course of the week
from car exhausts and factories,
the warm air carries these particles of pollution upwards.
They rise high above the city and begin to seed the clouds.
Moisture attaches to the particles, which then turn into water droplets.
By the end of the week, it has drifted out into the suburbs,
bringing thunderstorms and showers.
So the ironic twist is that we work all week
to be able to enjoy a weekend barbecue or weekend picnic,
and the activities we did in the week are going to rain out our barbecue.
But it's not just our cities. It seems the whole planet is warming up.
The next stage of my journey is to Hawaii.
This might tell us that a big change is just around the corner.
I'm on my way to find the cleanest air on the planet.
I'm going to show you something that changed the world.
For weather, it's the most important scientific device in a hundred years.
And it's just over there.
Just a second.
It's over here.
Hang on a minute. I'll just try and find the lights.
Yes. This is it. You've guessed it.
You're looking at the Ultramat III - the machine that changed the world.
The reason the Ultramat llI is so important
is because up here, at 14,200 feet in the middle of the Pacific,
is the purest air on Earth.
So it's the best place to detect any changes in the global atmosphere.
The Ultramat llI sniffed out a big change.
The burning of fossil fuels has put more carbon dioxide gas into the air
than at any other time in the last 20 million years.
The gas acts like a greenhouse -
letting the sun's energy into the atmosphere,
but preventing it from leaking into space.
So it heats up - 0.6 degrees Celsius in the last 150 years.
A tiny amount, but we are already seeing the effects.
One of the biggest concerns is how these changes will affect the oceans.
This small rise in global temperature is warming the sea,
causing the water to expand.
Even a fraction of a degree could mean a rise in sea level of a metre.
Research by NASA's Goddard Space Institute
has produced a glimpse of the future for New York's 20 million inhabitants.
In the next 100 years, there could be as much as 42 inches of higher seas
surrounding Manhattan and New York.
In the most catastrophic case, Manhattan turns into two islands.
With higher sea levels, an ordinary storm will have drastic consequences
for cities by the sea.
This just in. City Hall has issued an urgent flood warning.
A storm surge is expected to swamp areas from the Battery to mid-town.
The Mayor's office is advising the immediate evacuation
of basements and the subway.
The subterranean basements of New York flood about once every 100 years.
The research suggests that this could start to happen once every ten years.
But it's not just New York.
Every city by the sea faces the same future.
As the world heats up and the oceans expand, the sea level will rise.
Around the world, low coastlines, like those of Bangladesh and Mozambique,
face an even more uncertain future.
In London, the Thames will rise...
and already we can see the effects on our coastline.
Further inland, the future will bring more rain and more floods.
It's wet, it's flooded and it's cold.
It's also the future.
This is Britain tomorrow - wetter, stormier, and altogether under water.
Back in the clean, clear mountain air of Hawaii,
where we first realised that big change was on the way,
the Ultramat llI is still counting the cost of our effect on the weather.
Which is why this little machine is so important.
There are many theories about the weather
over the next 50, 100 or even 200 years.
One thing's for sure - a warmer climate means wilder weather.
The question we all have to ask is, what kind of world do we want?
Because to a certain extent, each of us holds that in our own hands.
Every time you flick a switch, you affect the future.
We've already seen the changes around us.
All we can do is learn to cope - whatever those changes bring.
My journey is at an end.
I've been blasted, roasted and soaked
by the invisible forces that drive our weather.
It's been a wild ride,
and in the future it may be about to get even wilder.