Life After People Page #6

For over 125 years with people,

Can't survive even a century

Without them.

As the cables fail,

The deck and railings begin

To warp and sway.

The deck pulls free,

And the roadway spills

Into the east river.

as an engineer,

It's very sad to contemplate

That this beautiful iconic

Structure has got an end

To its life.

But without maintenance,

An end to its life

It certainly has.

how exactly do bridges fail?

Once corrosion starts,

The wires begin to crack.

and the wire

Doesn't have to have

A very big crack

Before it breaks.

Maybe a third

Of the way through.

You may wonder what happens

When they fail.

How do they fail?

Do they just break?

And what do they do?

And the answer

Is they tend to shred and fail,

With individual strands

Starting to fail

And then, kind of, cascading,

And a whole series of wires

Then begin to break.

a suspension bridge

Like the golden gate can survive

The weakening of one

Of its vertical cables.

But once two or three

Start to go,

The whole bridge is in jeopardy.

Twisted steel crashes

Into the waters below.

it's going to be gone.

Two hundred years?

I doubt it will last 200 years.

The bridge is going to be

In the drink.

[music]

if some

Of our largest structures

Have already failed

After 100 years,

Can there be any hope

That our civilization

Will leave a permanent mark

After we're gone?

What will remain of the records?

Of our history and culture

A hundred years after people?

our vaults contain

Our most precious materials,

And their biggest enemies

Are temperature and humidity.

As long

As their long-term storage

Is kept at these

Very controlled settings,

We feel assured

That the materials

Will be lasting a long time.

stored

Under ideal conditions,

Paper and film both have

An estimated shelf life

Of 200 to 300 years.

But expose them to the rigors

Of an uncontrolled environment

And that lifespan is cut

At least in half.

if all the power went off,

Probably within a week,

We'd see very big spikes

In the temperature and humidity.

in this hostile environment,

Cellulose acetate,

The most common material

Used for films and photographs

Throughout the 20th century

Begins to bubble and warp.

All of that culture and history,

From the landings on d-day

To Hollywood films

And even your cherished

Home movies and photographs,

Won't last a century

Without the care of humans.

so, those precious images,

Given time,

Are going to end up like this.

All of these are examples

Of various stages in the decay

Of cellulose acetate-based film

Exposed to very high amounts

Of humidity.

Essentially,

These materials are finished.

in libraries,

The great repositories

Of our collective knowledge,

The damage comes

From microscopic invaders.

Although we can't see them,

Mold spores

Are on all the surfaces

Around us, lying dormant,

Biding their time

For the right conditions

To strike.

High humidity

Creates the right conditions.

and so,

The situation is set up

For the mold to really boom.

some books and documents

Will avoid this fate.

The Dead Sea scrolls

Survived 2,000 years in caves

In the Judean desert,

Owing their longevity

To the arid climate

And lack of damaging sunlight.

But these are rare exceptions.

so without

Human intervention,

A book like this might last,

At best, another hundred years.

[music]

even our digital media

Won't last forever.

Estimates for the lifespan

Of cads and DVDs range

From a few decades

To a few centuries

Under ideal conditions.

we know

About the ancient Egyptians

Because what they left behind

Was engraved in stones.

[music]

Our form of capturing knowledge,

Information, our history,

Our advancement is typically

Either in a computerized form,

In a cod, or in a printed paper

Like this.

What we have here is something

That will degrade over time.

It will not last

For thousands of years

Like what

The ancient Egyptians

Left behind.

it seems pretty ironic

That with all of our advances,

We still have not come up

With anything as durable

As clay tablets and stone tools.

[music]

150 years after humans,

The subways

That had started to flood

In the first 36 hours

Are now flowing

Subterranean streams.

The beams and archways

That holds up the roofs

Of these tunnels

Are on the verge of collapse.

now, these tunnels

Are not far below street level.

These columns are supporting

Not just the roof of the tunnel,

But the street above.

And in time that these tunnels

Are inundated,

Flooded with water,

Corrosion will start

To take hold and we'll start

To see collapses.

the tunnels echo

With the sound

Of cracking steel and cement

As the streets above

Are sucked into the underground.

[music]

Above ground, life in the city

Is once again bustling.

Vines have grown up the sides

Of abandoned skyscrapers,

Adapting to feed off rainwater

That pools in crevices

And on ledges.

these vines all start up.

And the vines

Have little branches.

It'd be nice

If they produce a fruit

Or something that was edible.

You got to have a plant

With some fruit or, you know,

Some source of energy

For animals.

And then you would get

This vertical ecosystem

Out there, and you would get

Birds nesting in there.

You get things

Hunting in through there.

You could have snakes there.

You could have

All kinds of things.

as insects

And smaller animals

Get established,

Cats move in.

and there's some

Interesting examples of that

Around the world.

If you go to the coliseum--

You just look in it--

It's just loaded with cats.

And the old tombs

And old catacombs and so on

Get loaded with cats

That uses this as a living space

From which, then,

They radiate out during the day.

these felines

Are the descendants

Of our former house cats.

Immediately after people

Were gone, they replaced

Their human-supplied diets

With field mice and small birds.

Hunting out in the open

Was hard work.

But up here,

The pickings are easy.

Now, they live

Their whole lives

High above the city,

Finding all that they need

To survive without

ever having

To touch the ground.

They are the kings

Of the new high altitude

Food chain,

With million-dollar views

Of a bizarrely

Altered cityscape.

I could picture new York city

With all the buildings

Covered with vines, you know?

Hawks sailing around.

It'd be lovely.

It would be absolutely lovely.

[music]

for cats,

Life in this new environment

Could eventually lead

To some strange adaptations.

I suppose, if you wanted

To be really imaginative

About it, you could say that,

Eventually, they could be

Like flying squirrels and so on.

They could glide from places.

The possibility is always there

For some imaginative responses

To this unusual environment.

while some cats

Have made a great leap forward,

Many dogs have reverted

To the ways of their ancestors.

Some that have interbred

With wolves now fall in packs

To bring down larger prey.

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