Cold How We Got to Now with Steven Johnson

Imagine what life was like before we could make anything cold.

Just a few generations ago, we had no idea how to keep food fresh,

and hot places like Arizona or Dubai

were basically uninhabitable.

And forget about ice cream.

So, how did we get to today's refrigerated world?

200 years ago, there would have been no way to escape the heat.

'Well, it took people like the college dropout,

'who first decided to ship ice around the world...'

Everywhere he goes,

the ice melts,

but he doesn't give up.

'..and a guy trying to feed his family in the Arctic...'

Imagine trying to live the entire winter on, like, moose jerky(!)

'..who winds up changing the way we eat

'for ever.'

Ice fisherman!

These are classic examples of the kind of people who actually

made the modern world,

people you've probably never heard of.

'They are the hobbyists,

'garage inventors

'and obsessive tinkerers,

'ordinary people doing extraordinary things.'

The thing about these pioneers is

that they didn't just make our world a cooler place,

but they also set in motion

an amazing chain reaction of ideas.

'From the places we live,

'to the food on our plates.

'From politics to Hollywood,

'to mass migrations,

'I want to show how these seemingly unconnected worlds

'are linked by the unsung heroes of cold.'

In all my career,

I've been fascinated by ideas and innovation,

from writing books about the great British innovators

of the Enlightenment or the Industrial Revolution,

to my work with Silicon Valley start-ups.

And what I've learned about innovation

is that the experiences of the past

are still the best road map for our future,

and that's why I want to tell you the story

of How We Got To Now.

Fire,

man's original innovation.

We've been tinkering with that for over 100,000 years.

But what about the opposite of fire?

What about our relationship with cold?

I don't actually normally sleep like this in my ski gear,

but I'm actually in one of the most extraordinary rooms

I've ever been in. I'm in Quebec,

in a hotel made entirely out of ice.

I mean, not just the structure, but look around me,

everything - this bed is made of ice, that table is made of ice,

this object, I don't even know what that is, but it's made of ice.

I mean, normally when you check in to your room

and it's ten below freezing,

you're, like, calling the front desk to complain,

but people come from all over the world to stay at this hotel.

Apart from an average temperature below freezing

and the fact that it all melts every spring,

this is just like a normal hotel -

dozens of rooms,

a front desk,

a grand lobby.

It's even got a chapel.

And, of course, a bar.

The refrigerators are there actually to keep the drinks warm,

because it's actually warmer in the fridge than it is in the ambient

temperature of the hotel. Otherwise, all the drinks would freeze.

The really cool thing about this place, though,

is how its 15,000-tonne snow structure is put together.

Remember when you were a kid and you had like a competition with

the neighbours over who could build the biggest snow fort?

These guys are going to win that competition.

I mean, look at all this gear, they're blowing all this

snow on top of these metal moulds that form

the shape of the roof of the new hotel rooms that they're building.

And then they basically... All of that snow,

they let it compact and then they just pull the mould out.

It's like, physically like making a cake,

only the cake is a 40-room hotel.

For Jacques Desbois, the man who created this palace of ice,

it is a symbol of how far the French-Canadian settlers

of Quebec have come in their relationship with cold.

Snow and ice, it's just kind of like an inconvenience, you know,

it's getting your car stuck in it or something like that,

but there's so much creativity and innovation here,

in this space.

You know, we...

Well, in a way, this is an igloo.

-Mm-hm.

-It's a huge igloo.

-Right, right.

And we're at a point that,

that snow shelter,

which was used for survival

centuries and centuries ago,

now exists for our own pleasure,

for our own amazement.

And in Quebec Province, here,

our ancestors were Mediterranean people

that have lost their way.

-Right.

-They were thinking...

They were looking for tropical places in Asia,

but more and more, we are becoming real Northern people.

Right, embracing winter...

Yeah, sure, and it's a way

to make people realise that snow,

it's not only an inconvenience, but we can take advantage of it.

People have been doing imaginative things with ice

in frozen parts of the world for ever.

But just 200 years ago,

eons after we first mastered fire,

something profound changed.

We began to realise that we could use ice and cold as tools

to make life better in warmer climates.

And that revolution began with a simple idea,

one of those little pleasures of modern life

that we take for granted -

an ice cold drink on a hot summer's day.

Meet Frederic Tudor,

a wealthy young Bostonian.

In 1805,

aged just 21,

Tudor visits the fine state of South Carolina...

..the perfect environment for the fashionable elite.

Or at least, it would be the perfect environment

if it weren't so insanely hot!

I mean, it is really humid, and look at me,

I've got like seven layers on.

I mean, it looks good, but, you know,

until you die of heat stroke in the middle of the afternoon.

But 200 years ago, there would have been no way to escape

the heat of these long summer months in the South,

and Frederic Tudor found it unbearable.

'Back then, living in a hot place,

'you would never experience anything cold.

'I mean, warm lemonade, anyone?'

And this gets him thinking about home,

about the cold of the North.

And it inspires him to start taking notes in a journal.

He calls it the Ice House Diary.

In New England, there's a resource that's free

and abundant during winter...

..ice.

Upper class families store it for the summer

and use it to make ice cream,

chill drinks and preserve food.

Tudor thinks, "What if I could cut ice from frozen lakes

"and ship it to people in hot places?"

He writes about,

"The transporting of ice to popular climes."

Tudor thinks that ice is going to make him rich.

But the reality is,

in 1805,

moving ice long distances is impossible.

And even if you could get it to some far away, hot location,

there's no way it would last.

'In one of his first attempts,

'Tudor sends a ship full of ice 3,200 kilometres

'from Boston to the Caribbean island of Martinique.

'It almost all melts

'and his attempts to transport ice

'lose Tudor the modern equivalent of nearly 1 million.'

Tudor's attempts to bring ice to the South

end up landing him in a debtors' prison.

He loses his friends and his family fortune.

He ultimately has a nervous breakdown.

'His basic problem is simple -

'back then, no-one knows how to keep frozen water frozen.

'And everyone thinks his idea is nuts.'

OK, so, the way I see it is... Tudor's problem is

that his idea is really only half-baked,

and if you think about it, it's just a fragment of an idea, really,

and it's going to take him decades to get all the pieces together.

It's what I call the "slow hunch".

'If you want to understand how big ideas truly change the world,

'you need to get rid of the myth of the eureka moment.

'The truth is, there's no such thing as

'a light-bulb going off in the mind of a lone genius.'

Our best ideas start as something else,

a vague sense of possibility,

a hint of something bigger...

'Trying to turn his hunch into a viable business,

'Tudor endures more than a decade of disaster.

'At one point, he even writes to himself...'

'All the signs suggest that Tudor's dream

'is going to come to nothing.'

So, what does he do next?

He packs up a ship filled with ice and heads south.

Tudor's perseverance might seem crazy to us now,

but the thing is, he's sensing that his slow hunch

is finally going to pay off.

Let me show you why.

Tudor's problem is, how do you move ice around without it melting?

But now he has his light-bulb moment,

except that it's not really a light-bulb moment,

because it takes him ten years.

But he realises that, thanks to the lumber trade,

New England is filled with another abundant

and free resource that will solve his problem...

..sawdust.

So, let me show you how he would do it.

I feel like I'm actually doing a cooking show here,

but basically he would take these ships

and line them entirely with sawdust,

and he would fill the space

between all the blocks of ice.

And then he would put another layer of ice on top of the sawdust.

And when he did this, he found that sawdust

was the perfect insulator.

The ice wouldn't melt.

It was beautifully simple.

'Tudor's bigger challenge, though,

'is how to store ice once it arrives in sunnier climes.

'But he has a plan.'

I'm in the low country of South Carolina.

It's late July

and it's pretty humid.

But imagine what it would have been like 150 years ago.

It's sweltering like this for months on end

and there's literally no way to escape the heat.

There's no air conditioning, there's no refrigeration,

and then you walk into a space like this.

This may look like an ordinary 19th century barn,

but if I open up this hatch,

you find something miraculous.

It's a giant frozen chunk of Massachusetts.

It may seem like I'm just in a hole in the bottom of a barn here,

but actually, this was state-of-the-art technology

in the middle of the 19th century.

In fact, you can really feel how effective it is.

I mean, my upper body is still really quite warm and humid,

but my pants are starting to freeze.

And the key thing here is...

is this cavity on the side of the structure,

this is double-shelled insulation,

and this was the major breakthrough that helped him

take these giant blocks of ice that you see

and keep them cold for long periods of time.

And it was so efficient,

that a large block of ice like this

would actually last for four to six months

through the hottest time of the year.

'Tudor can now move and store ice.

'But next, he has to sell it.

'The thing is, in the early 19th century,

'most people in hot places

'have never seen or thought about ice.

'They have no idea what to do with it,

'and Tudor might as well be selling smartphones.

'So, to generate demand,

'he gives away free samples...

'..and a huge new industry is born.'

POLAR BEAR GROWLS

Ice cream,

cocktails,

chilled food...

America gets hooked.

Soon, hundreds of thousands of people work the Ice Harvest.

In New York, the iceman cometh...

Nearly half the city's population keeps ice at home.

Reports of mild winters create panic

and something extraordinary happens.

Previously, Americans had only eaten fresh food

produced on their doorstep.

Now, trains chilled with ice

create a food network.

Produce from the South and West

become staples of Northern meals.

'When you realise that about 1,000 food trains bring perishable food

'to New York every week, you'll understand that ice for refrigeration

'is something of the first water.'

We become much healthier and better nourished...

..while our cities,

freed from the limits of their surrounding resources,

experience rapid growth

and a rise in new businesses.

Cold is shaping a new America.

In 1912 in New York City,

the Armato family set up their own ice delivery company

to meet the demands of the ice craze.

It was founded by Salvatore Armato,

passed on to Anthony,

and on to Joe,

and today it belongs to Salvatore's great-grandchildren,

Bennie, Tony and Chris.

Let's go deliver some ice.

Put it right across your shoulder, Steven.

OK, let's see if I can lift it. Oh, my God!

This routine of delivering ice hasn't changed much

since the days thousands of icemen worked the streets

of New York to keep on top of restaurants' daily demands.

So, you guys now have like a fork-lift

to move these giant blocks of ice around,

but back in the day, you know,

your grandfather's time, what...

How would they move these huge blocks around?

These are the ice tongs, these are the tools that the icemen

used in the older days.

Basically, they would manoeuvre the blocks,

take it, drop it,

spin it, put it up and down,

they would be able to put it on their shoulder...

Oh, that's... Yes.

You know, go up a flight of stairs, which I'm not going to do.

-Oh, come on! Can I try?

-Of course.

Cos I'm thinking that this may be a backup career for me

if this television stuff doesn't work out.

Here we go, ready?

Oh, my God, it's really heavy,

but I got it... Over an inch above the ground,

did you see that?

All right, this is not my profession, I think,

but incredibly cool.

'It's amazing to think that the New York City ice trade

'can be traced back to Frederic Tudor's insane idea

'of transporting ice across land and oceans.

'Back in the 19th century,

'ice had become America's second biggest export, after cotton.

'India, the Caribbean,

'even Queen Victoria has New England ice served with dinner.'

But what I find incredible is how primitive our ideas

about cold are at this point.

I mean, this is the middle of the 19th century, right,

it's an era of coal-powered factories and railroads,

and telegraph wires connecting cities.

And yet, the state-of-the-art in cold technology

is cutting chunks of frozen water out of a lake!

'But Tudor hasn't just created a global appetite for ice...

'..he's also created a platform for ideas about cold...

'..which will soon trigger a chain of events

'not even Tudor could have imagined.'

I read this article the other week about scientists who

discovered this primitive ski in a Swedish bog,

and when they dated it, it turned out that it was 4,000 years old.

And I thought,

skiing is really a microcosm of our whole

relationship to cold.

We've literally spent eons taking the natural cold of snow and ice

and figuring out fun ways to do things with it.

But then cold got so fun

that everybody wanted a piece of the action,

and so we started tinkering with making artificial cold.

And that's when things started to get really weird.

'OK, enough television trickery.

'I'm not really in the mountains.

'This is one of the world's biggest indoor ski resorts.'

But it gets even crazier.

Come on, you got to check this out.

The modern world of cold does not get any weirder than this.

I'm standing above the city of Dubai.

We're in the middle of the Arabian Desert,

it's about 100 degrees out, it's 8am in the morning,

which means I have to take my ski gear off,

cos it's insane to be out here wearing this. Er...

and here we are in this vast city in the desert

and yet, beneath me...

'..are skiers, ski lifts, real snow,

'a toboggan run

'and, get this, penguins.'

Now, Ski Dubai might look like some sort of futuristic spacecraft

that has crashed into a parking garage.

'But in fact, some of the technology keeping this place cold

'is 200 years old.'

I'm here in the space between the ceiling of the indoor ski slope

and the roof of the overall structure and it's really strange,

a little bit creepy space, they call it the void.

And it's an extraordinary space because basically,

this is the primary means of insulation they're using here,

it's just the gas or the air that's keeping the temperature

28 degrees Fahrenheit below me and 110 right above me

and what I love about this is that the principle

of using the air in this void

to keep the ski slope cool is something Frederic Tudor would've recognised in a heartbeat,

it's basically the same design that he used in his ice house.

'And down below, on the slopes,

'there's another 19th century innovation

'making the snow and maintaining a temperature just below freezing.'

Artificial cold.

So there's an entire winter wonderland on the other side of that wall,

and yet we are in the middle of the desert,

it's 110 degrees outside, how do you pull this off?

There what you need is a really, really big fridge.

It's the same principle as a fridge that I've got in my house?

Absolutely, the refrigeration is very much the same

as the fridge in your house

and even the way the building is constructed and designed

-is very similar to a fridge.

-Do you worry

about the cold escaping when people are coming in and out?

I mean, is that a big concern?

Yeah, think of your fridge at home, right?

Every time you get an orange juice out, you open the door

and all the cold air rushes out.

If you look at your fridge again and you mimic Ski Dubai, your fridge,

your big American fridge would have a door the size of my thumb.

-Really?

-We only have three doors leading into ski Dubai from outside,

so we can control that air flow in and out very, very well.

'This place and the fact that I'm hanging out in the middle

'of the Arabian desert with a bunch of penguins

'is proof of just how sophisticated

'the modern use of artificial cold has become.'

'But the beginnings of man-made refrigeration

'were far from being fun.'

It's an innovation born of suffering and war.

MOSQUITOES BUZZING

Like much of the South,

Florida has a sub-tropical climate.

That means mosquitoes.

And in the 1840s,

mosquitoes mean diseases like malaria are rife.

In 1841, an outbreak of yellow fever

decimates the population of northern Florida.

In the middle of all this death and misery

there's this guy, Dr John Gorrie,

who is about to start working on an idea

that is so big it will ultimately transform all of our lives.

But the thing about it is, today he's completely unknown

and what I find fascinating about Gorrie's life

is it's a great reminder of one the most important things about innovation,

which is that timing is everything.

MOSQUITOES BUZZING

Gorrie's hospital is filled with patients burning up with fever.

I mean, just imagine what a hospital would've been like

in the American South in 1842.

You take all the advanced technology of a modern hospital out

and you're left basically just with beds

and patients dying in the sweltering heat.

But Gorrie thinks that if he can cool the air

around his feverish patients, he can both ease their suffering

and stop the spread of disease.

So he sets out to build a contraption to do just that.

This is how Gorrie's design would've worked.

He's got a chimney bringing in air from above the hospital

that flows down over this giant basin

and he would take these huge blocks of ice and put them in the basin

and the result would be...

perfectly chilled air flows over the patients in their beds,

reducing their fevers, potentially saving their lives.

It's a brilliant idea

and it's all in the service of Gorrie being a better physician.

THUNDERCLAP

But Florida isn't done with Gorrie yet.

Shipwrecks along Hurricane Alley

mean delayed ice shipments from Frederic Tudor's New England.

So one day, Gorrie's supply runs dry.

Now, Gorrie has the crazy idea to make his own ice.

But how?

Luckily, Gorrie is living at the perfect time to have this idea.

For all of human history

you couldn't even conceive of making artificial cold,

but then, somehow,

in the middle of the 19th century,

the idea becomes imaginable.

So how do we explain this kind of breakthrough?

I mean, it's not like there's some kind of solitary genius

who's so much more brilliant than everybody else,

they come up with the idea on their own.

And that's because ideas are fundamentally networks

of other ideas.

'We take the tools,

'concepts and scientific understanding of our time

'and then remix them into something new.

'But if you don't have the right building blocks,

'you can't make the breakthrough,

'however brilliant you might be.

'The smartest mind in the world

'couldn't invent a refrigerator in the middle of the 17th century.

'But by 1850, the pieces had come together.'

The first thing that had to happen seems almost comical to us now,

we had to discover that air was actually made of something,

that it wasn't just empty space between objects.

That happened in the 1600s,

when scientists used a pump to suck air from a jar

and discovered the vacuum...

proving that air was made from some mysterious, invisible elements.

We then found that when air, or other gases,

are squashed together, they heat up

and when they are stretched out, they cool down.

The thermometer comes along,

followed by a universal scale or two,

allowing us to measure temperature.

Now, amazing machines can be built

that convert the heat from gases into a usable energy.

Gorrie brings all these ideas together and builds

America's first mechanical refrigerator.

A machine that makes ice.

And then Gorrie applies for a patent for his invention,

and listen to the language he uses to describe this thing.

"Artificial cold might better serve mankind.

"Fruits and vegetables, and meat

"will be preserved in transit by my refrigeration system

"and thereby enjoyed by all."

He completely nails the modern world of artificial cold.

The rural doctor has created a technology

that's now as ubiquitous as the light bulb.

So why isn't John Gorrie as famous as Thomas Edison?

So he's got a magical, artificial ice-making machine in the South

and one would think that would be a huge financial success.

There's a proven market for ice,

there's a machine that will do it artificially...

That's true, but the problem is that there was a lot

that had to be done to perfect the equipment.

John Gorrie had a basic idea, he had a vision,

he had a machine that rudimentally did it but it had to be perfected

and it had to be brought into a point

where you could afford to use the machine to make ice.

Like any new technological innovation,

Gorrie's working prototype needs development.

The problem is, his man-made ice invention hasn't exactly

come along at a great time,

because this is an era dominated by the now very powerful

and ruthless natural ice baron, Frederic Tudor.

People who were in the business of harvesting so-called natural ice

from rivers and lakes,

they saw a threat to their business by a machine that could actually

make the ice and of course they were the ones who came up with

the term "artificial ice" - in other words, fake ice. It's not real ice.

And the thing that's interesting about it was that

the natural ice people said that,

"Well, this artificial ice could make you sick

"or it could cause disease," and things like that.

And on the other hand, their natural ice was becoming progressively

more from polluted sources and that was causing people to get sick.

I would... Drinking pond water from, like, a swampy pond in New England,

that's not something...

I would much rather have a nice, you know, artificial ice!

Unable to find backers,

John Gorrie dies penniless without selling a single machine.

But his vision of man-made refrigeration is about to inspire

a new generation of inventors.

It was an idea whose time had come.

It just needed a trigger to launch it on to the public consciousness.

That comes in the shape of the Civil War.

The Union blockades the South to cripple the Confederate economy.

Suddenly, the Southern States have no ice.

Vital supplies were smuggled

past the blockade into the Southern States.

Blockade-runners used to hide out in creeks like this one,

slipping out into the open ocean at night.

But they weren't just smuggling weapons or gunpowder.

Sometimes they had an equally precious cargo...

..ice making machines.

Check this out.

This is one of the first ice making machines ever built.

It's designed by the Frenchman Ferdinand Carre.

It can output about 400lbs of ice in an hour.

This thing is one of the world's first refrigerators

and it was smuggled all the way to the American South from France.

In the decades after the Civil War,

artificial refrigeration patents explode,

as a network of innovators adapt and improve on Gorrie's ideas.

In the 20 years following Gorrie's invention,

there are 54 separate refrigeration patents filed.

From now on, the slow decline of the ice trade is inevitable.

Refrigeration becomes a huge industry, and I do mean huge,

with steam-powered monster machines soon changing

the urban landscape of America,

turning areas like New York's Tribeca neighbourhood

into a hub of artificial cold.

This building, for instance, behind me...

Today it's a fancy condo,

it's filled with your Robert De Niros and your supermodels.

But 100 years ago, it was filled with eggs and milk and produce,

feeding a growing city.

It was a giant high-rise refrigerator.

But as with much new technology,

the machinery of man-made cold is destined to get smaller,

as the idea of a once-ridiculed amateur inventor

becomes an essential part of the modern home.

'Here she comes,

'the lucky woman who owns a new refrigerator!'

Between 1945 and 1949,

Americans purchase 20 million of these revolutionary machines.

Now, ideas about how to fill these new refrigerators

will have an even greater impact on our lives.

Clarence Birdseye...

Yes, he was a real person.

..grew up in Brooklyn, New York.

But the story of his big idea doesn't start here.

In fact, he couldn't wait to get away from this place.

Birdseye had displayed an insatiable scientific curiosity,

a streak of eccentricity and a longing for adventure.

At 21 years old,

he becomes a naturalist with the US Biological Survey,

studying animal populations on the American frontier.

He keeps a journal during this period

and it's clear if you read it now that he's not just interested

in scientifically assessing these critters,

he's also obsessed with eating them, as well.

And the weirder, the better.

I mean, listen to this passage.

"For Sunday dinner, we had horned owl.

"Does that sound good?

"Well, it was good, no matter how it sounds!"

And he goes on to eat, over the course of his adventures,

a beaver, a hawk, mice, gopher,

rattlesnake, porcupine,

chipmunk, even skunk...

although apparently only the front half.

And it all leads up to what he calls, "The piece de resistance,

"one of the most scrumptious meals I ever ate."

Which was a dish of sherry marinated lynx.

Birdseye's diet may sound crazy,

but this is common sense eating

and valuable training for the ultimate survival challenge to come.

In 1916, Birdseye brings his wife and newborn son to Labrador,

a remote, frozen wilderness in Canada's sub-arctic north.

It must have been quite a shock.

I mean, besides having to be dragged through the snow

by, like, a pack of maniacal dogs, Birdseye had moved his family

to one of the most extreme environments on the planet.

But this is an adventure that will change Birdseye's life,

and ours, for ever.

We have this cliche about innovation,

that it just happens in Silicon Valley garages

and corporate research development labs,

not in an environment like this.

I mean, I've got, like, 30mph winds blowing,

ice pellets hitting me in the face.

It's hard enough just to stand upright and talk,

much less, like, have a brilliant idea.

But in a way, it's the severity of this landscape that's kind of the point,

because it's here in the frozen Canadian winter

that Clarence Birdseye will have the beginning of an idea

that will turn out to be one of the most transformative ones

of the 20th century.

And as always with Birdseye, this new idea will revolve around food.

Birdseye is among a handful of settlers

in a region the size of Britain that has no modern food network,

no stores, no livestock and which, during the winter,

is effectively cut off from the rest of the world.

Everything people ate during the winter was preserved

and cured and stockpiled.

There was nothing fresh.

I mean, imagine trying to live the entire winter on, like, moose jerky.

Right? But like Dr John Gorrie before him, Birdseye is motivated

by basic human concerns.

He's just trying to feed good, healthy, fresh food to his family.

But Birdseye is about to get some culinary inspiration

from Labrador's indigenous Inuit.

I'm standing out here on top of a frozen fjord.

I've got 600ft of water beneath me.

We've got white-out conditions, I can't feel my toes any more.

Apparently the water beneath this layer of ice

is actually shark-infested, I'm told.

So all in all, it's a perfect day for fishing.

And Jerri Thresher, an Inuit from Canada's Northwest Territories,

is going to show me how...

..once we've dug a hole through the ice.

-Would you like to try?

-Yeah, give me a chance at this.

-OK, so I just kind of hack around the side?

-Yeah.

You want to hit the ice a little hard so,

the harder you hit, the bigger the chunks

and the less time it will take to make your fishing hole.

So if this ice is three feet thick, I think it will probably take us

-about three days to cut through this.

-It would take YOU three days!

-HE LAUGHS

-It would take me three days, really?

Spending time fishing with the Inuit,

Birdseye notices that they use the extreme weather to their advantage.

They freeze their fish in the open air so they can store it.

So how important is ice fishing to Inuit culture?

Fresh meats and fresh fish are very important.

Right.

Fish coming out of the water in -20 or -30,

you can lay the fish on the side and within the hour,

it'll be completely frozen.

They would dig, like, caches under the ground,

in the permafrost where it would stay cold during the entire winter,

and there they would...

they would store their winter supply of fish and meat.

That's amazing. So, basically, for thousands of years

there's frozen food

that the Inuit culture has kind of figured out how to do.

For Birdseye, this is a revelation.

Freshly caught fish frozen in the arctic air

could be kept for weeks or even months,

and once thawed and eaten it would still taste delicious.

He wonders if freezing can help other types of food

stay fresh for longer, so he experiments with vegetables.

He began to notice a pattern.

Food frozen in the coldest depths of mid-winter

tastes better when it's thawed

than food frozen earlier or later in the season.

And that's because slower freezing creates larger ice crystals,

which damage the cellular structure of the food.

Birdseye realised something that

the Inuits had almost instinctively understood for thousands of years -

that if you wanted to have really fresh frozen food,

you had to have the smallest possible ice crystals,

and for that you needed the fastest possible freezing time.

This is the point where you might expect me to say,

"And now Birdseye has an idea that changes the world,

"and introduces the universe of frozen convenience

"that all of us enjoy today."

But actually, that's not what happened at all.

Because, you see, like Frederic Tudor,

Birdseye's hunch will take decades to finally pay off,

but, unlike Tudor,

Birdseye basically just forgets about his hunch.

In 1917, Birdseye moves his family back to the United States

and basically stops thinking about frozen food altogether.

Back in the city he's got all the fresh produce he could possibly eat.

For the next few years, Birdseye searches for a new career direction,

and he ends up at the US Fisheries Association.

Here he studies the fishing industry.

He watches how produce makes its way from the docks to the consumer

and notices that too many fish get spoiled

and lose their value on the way to market.

So Birdseye wonders, "What's the best way to get fish

"to the kitchen in the freshest way possible?"

And this is where, finally, his slow hunch resurfaces,

and Birdseye decides that flash freezing is the key.

Birdseye develops a practical process for fast-freezing food

quickly on a commercial scale.

It's called multi-plate flash freezing,

an idea upon which an entire industry will be founded.

But, of course, no matter how brilliant Birdseye's idea,

he can't change the world all on his own.

Ideas don't really work that way.

For frozen food to reach today's ubiquity,

it will take a convergence of other ideas about cold.

And that is where we meet Frederick McKinley Jones.

Jones was born in 1893,

and he was orphaned at the age of nine.

By the time he was 11, he had his first full-time job,

and by the time he was 16 he was working in an auto repair shop.

He didn't come from the world of privilege like Frederic Tudor

and he didn't have the advanced degrees of Dr John Gorrie,

but he was destined to change the world every bit as much

as those other pioneers in the story of cold.

Jones was a natural tinkerer with a gift for innovative ideas.

This ability would lead him

to tackle the thorny problem of food transportation.

Back in the 1930s, despite the Depression,

America is changing.

It's a convergence of ideas and technologies.

Electricity has reached our homes and our stores,

airplanes are becoming a common sight overhead,

cars and trucks are beginning to populate our roads.

But the way we deliver food long distances,

that hasn't changed for 50 years.

Ice-chilled food delivery had changed the world,

but it was far from perfect.

It was always a race against time.

Freight trains had to stop at regular intervals

to replace ice from track-side ice houses.

It wasn't a perfect system, and it was even tougher in a truck,

because any delays meant melted ice and a spoiled cargo.

So, like Birdseye before him, Jones began to wonder

if there was a better way.

Jones designed a small, durable refrigerated unit

that mounted on a truck to keep its contents chilled.

Although he lived at a time when African-American inventors

were rarely recognised or given opportunities,

he managed to convince his white boss to pay for its development.

It was a success.

After World War II, he developed refrigerated containers

that could be moved from train to ship to truck,

perfecting America's food distribution network.

For nearly a century, our food networks had relied

on these two parallel systems -

the older system of natural ice,

and the new technology of artificial refrigeration.

But Fred Jones's mobile refrigerated truck marked a turning point.

It was the end of Frederic Tudor's ice trade.

New ideas and inventions for making things cold come together

and begin to transform the way we eat.

Freezer trucks, refrigerated warehouses,

supermarkets with freezer units,

an electrical grid powering new suburban homes,

with electric refrigerators in every kitchen.

By 1944, 300,000 tonnes of frozen food are being sold

in America in a single year.

By the time of his death,

the company founded by Jones - Thermo King -

is worth the modern equivalent of a quarter of a billion dollars.

His maverick invention not only makes him

one of the richest black men in the country,

it also enables frozen foods to become a part of all our lives.

Now, flash freezing is just the beginning of the story...

..because once they get into circulation,

good ideas like this have a way of opening up new doors of possibility.

And today, fast and flash freezing is shaping our world

in profound ways that even a visionary like Birdseye

could never have expected.

We freeze sperm, eggs and embryos,

creating millions of new human lives.

So this is Eamon. Tell me the story of how this guy

came into the world.

Sure, well, we were lucky enough to use IVF.

-Uh-huh.

-We have a five-year-old at home

who was conceived that day and was never frozen,

and then we were lucky enough to freeze the extra embryos.

Um, hopefully we'll come back and...

So, to store them, you have to freeze them?

Freeze them... Two days later they froze them and, you know,

then they thawed them out and said,

"All right, they're still good." And, like, "Great."

And we were able to have him implanted,

and here he is, 18 months old!

Cos it's extraordinary to think...

I mean, there's so many different scientific breakthroughs,

technological breakthroughs that make IVF possible,

but if you think about it, Eamon, without artificial cold,

without the ability to kind of flash-freeze something,

he wouldn't be here!

-He wouldn't exist.

-It's an extraordinary...extraordinary thing.

We'd be a smaller family.

We're so glad it worked out.

-We're blessed.

-We are very lucky.

From the idea that ice could cool a drink on a summer's day

to Clarence Birdseye's innovation,

the journey of cold helps shape how we live now.

But perhaps the biggest impact of all would come

as ideas about cold start to define not just HOW we live,

but WHERE.

In the summer of 1925,

a man with a big idea takes his seat in a packed New York movie theatre.

It's the first golden age of Hollywood,

but the crowds that are there that day are not there

for the usual movie escapism.

The man with a big idea has just invented something that will

revolutionise the movies.

The roots of this story go back to 1902

when, on a roasting hot summer's day, the same man,

a young engineer called Willis Carrier,

is called out to a Brooklyn printworks with a big problem.

The humid air inside the building

is causing the ink to smear on their prints.

So they need, somehow, a way to make the air consistently dry.

Carrier starts trying to solve the humidity problem

by taking notes in this actual journal.

Check this out. It's filled with all these physics equations,

so I literally have no idea what it means,

but, I mean, it's just amazingly detailed.

He's doing this before computers. This is a guy who clearly needed a spreadsheet.

But out of all this amazing work,

he comes up with a new invention,

and he calls it, "An apparatus for treating air."

It's basically a giant dehumidifier.

Air goes into a refrigerated chamber,

moisture condenses over metal coils,

and dry cool air comes out the other end,

which is then pumped into the print rooms.

It stops the ink from smearing.

But Carrier notices something interesting -

people enjoy the cool air-conditioned air, too.

And that's how, a few years later,

Willis Carrier came to be sitting nervously

in a movie theatre in New York City.

You see, Hollywood had a problem.

Nobody in their right mind would go see a movie in the summer.

It was just too hot.

But Carrier hoped that was about to change,

thanks to a prototype AC system he'd installed in the theatre's basement -

a monster machine similar to the one sitting in the basement

of this Jersey City cinema, built in 1929,

to bring a new world of "comfort cooling" to the audience sitting above.

So, now we are in front of this massive structure.

What is this part?

Well, this is the big blower that pulls air in off the street

to be conditioned and then ventilates it out the building.

And that huge fan over there is kind of powering the whole thing?

-That's it, yeah.

-It's amazing. Well, what do you think,

shall we try and actually turn it on?

There's a little switch here.

If you want... I'm just going to hide behind this pillar over here

-cos it seems very scary.

-You ready?

-OK, duck and cover, here we go.

-MACHINE WHIRS

-Oh, my God!

WHOOSHING

-Wow.

-It works.

-That's extraordinary.

I feel like a jet is about to take off.

This is from 1929. This is the original.

And it's still working.

But right now, upstairs in that giant auditorium,

people are beginning to feel cool.

I'M beginning to feel a little cool.

It's kind of incredible when you have a machine that's, you know,

almost 100 years old and it's still working.

Once the AC unit starts up, cool air is transported around the building

via a series of enormous ducts...

..reaching the customers via these beautifully camouflaged grilles...

You can really... I mean, the air is really circulating here.

It's just pouring in through this doorway.

I think this is why they call it a house fan.

It really ventilates the entire house.

It's amazing. I've got dust in my eye from, like,

the Roosevelt administration!

Carrier's idea - AC in a cinema - is revolutionary,

but what would the cinema-goers think?

Carrier takes a massive risk on this one demonstration,

even inviting Paramount Pictures' chief Adolph Zukor,

one of Hollywood's most powerful men.

Carrier stayed up all the night before

trying to get the equipment ready.

Now it was time to crank up the AC.

He wrote later about what happened...

"Final adjustments delayed us

"in starting up the air conditioning system.

"From the wings we watched in dismay as 2,000 fans fluttered."

"But, gradually, the fans dropped into laps

"as the effects of the air conditioning became evident."

'We had stopped them cold

"and breathed a great sigh of relief."

"Afterwards, when Mr Zukor saw us, he said tersely,

"'Yes, the people are going to like it.'"

And that was the understatement of the century.

Basically, you start air-conditioning theatres

and what happens to the kind of American love of cinema?

If you had stopped the average person in the street in, say,

1900 or 1910 and said,

"I have a system where if you push a button you'll get cool air,"

they would have thought you were joking - it would have been science fiction.

So for people to actually enter a movie theatre in the 1920s

and experience "comfort cool" for the first time,

changed the way they thought about their environment.

All of a sudden now, with modern air conditioning,

on the hottest days of the year people are starting to come to the movies.

In 1930, 80 million Americans go to the movies every week.

That's 65% of the entire population.

So you would say every 12 days on average

the entire country goes to the movies.

You can't pick a better venue

to expose a great new innovation like this than the movies.

So air conditioning actually ends up inventing the summer blockbuster?

Air conditioning and movies go hand in hand throughout their entire history.

Willis Carrier's invention -

a machine for cooling air in a print shop -

has changed Hollywood.

But the idea of air conditioning proves irresistible,

and soon it will trigger chain reactions more dramatic

than any other innovation in the story of cold.

AC is about to re-draw the map of the world.

OK, so take a look at a map of the United States

at the beginning of the 20th century.

Everyone lives in the growing and prosperous cities

of the North.

The South and West, meanwhile,

are economic backwaters.

Towns like Phoenix and Miami are tiny.

Las Vegas in 1910 has just 937 inhabitants.

Why?

Because this is the sunbelt.

It's too hot and no-one wants to live here.

In 1951,

Carrier's company introduces an air conditioning unit

that is miniaturised and affordable for a mass market,

and that's when AC starts to go crazy.

Between the 1950s and the 1980s,

AC becomes ubiquitous in people's homes and cars across America.

And just see what that does to where people are living.

Tucson, Arizona, grows 400%

in ten years.

Phoenix - 300%.

Tampa, Dallas, Houston and Atlanta -

populations double, triple.

And it's the same story everywhere you look.

ARCHIVE: 'By 1960, 30,000 people will live in Broomfield Heights,

'making it the fifth largest city...'

Carrier's invention is circulating people as well as air,

changing lives, changing America.

But then something even more interesting happens.

You see, people moving to the hot states are older

and tend to vote Republican,

and the growing population in the conservative South

means more electoral college votes there.

So check out what happens to the political map of America.

Between 1940 and 1980,

northern states lose an incredible 31 electoral college votes,

while the southern states gain 29,

doubling the number in California, Arizona and Florida -

the vast majority voting Republican.

This is long-zoom history.

Less than a century after Willis Carrier started to tinker with

stopping the ink from smearing on a page in Brooklyn,

our mastery of molecules of air and moisture

have helped put Ronald Reagan into the White House.

Today, many of the world's fastest-growing cities, like Dubai,

are in hot countries.

It's the first mass migration in human history

to be made possible by a home appliance.

And all this started with a half-baked idea,

a hunch in the mind of a maverick dreamer.

When you think about inventions,

we tend to be constrained by the scale of the original idea.

So, we assume that if we invent artificial cold,

our rooms will be cooler

and we'll have ice cubes in our drinks on a hot summer day.

But if you tell the story of cold that way,

you miss the majesty of it.

We make our ideas, and they make us in return.

And when you look at the story from that angle,

you can't help feel that cold isn't done with us yet.