Life After People (2008) - full transcript

what would happen

if every human being on earth disappeared?

[music]

at some point in the future,

this could be the fate of our planet

this isn't the story of how we might vanish

it is the story of what happens

to the world we leave behind.

life after people

the disappearance of humans

may seem like science fiction,



but eventually,

there will come a day like this;

a day when people no longer walk the earth

it's no great stretch

to imagine humans disappearing

from the face of the earth.

every generation has its tales

of armageddon or apocalypse.

we're the first generation

that could,

by deliberate actions,

cause its own doom.

>> what will life be like after people?

>> we're tantalized by our myths



about our own destruction,

but also tantalized

by the notion,

"hey,maybe it's the turn of someone else."

what will they do

if we're gone?

what will the earth do

when i'm gone?

it's the most natural question in the world

[alarm buzzing]

>> time has run out for man.

our hold on the planet is over.

welcome to earth,

population zero.

within hours after we're gone,

lights start going out

around the world.

more than 70 percent of power

in the united states

is generated by the burning

of fossil fuels.

>> the plant will only continue

to produce electricity

as long as the fuel

takes to be consumed.

if there's no one around

to provide the new fuel

into the generating plant,

then it'll be quite quick

before the lights

start going out in cities

all over the world.

>> nuclear power plants

are unlikely to melt down.

the average reactor

holds enough fuel

to keep running for two years.

but without humans

consuming the power

generated by the plant,

the reactors will automatically

shut down into a safe mode

in as little as two days.

>> even wind generation

can't last forever.

the turbines require bearings

and lubrication of those bearings

in order to keep operating.

if there's no one around

to maintain the turbines,

the electricity doesn't get produced

>> as generating plants go down,

outages on the power grid

contribute to a cascade of failure worldwide

after a few weeks,

the planet is plunged

into a deep darkness.

it has not experienced

since humans first huddled around campfires

perhaps,the last glow of artificial lights on earth

will be seen in the american southwest

here,the mighty hoover dam

hydropower plant

takes little notice

of the absence of humans.

its source of fuel

is virtually limitless.

>> at hoover dam,

our fuel supply

is actually the water

in the reservoir in lake mead

behind hoover dam,

so as long as there's water

in the reservoir,

this power plant

can keep running.

there's water in the reservoir

keeps supplying the water

to the hydro turbine generators.

these generators

are operating automatically

and that would continue

as long as all of the systems

are functioning normally.

if i and my staff

were to leave tonight

and not come back to hoover dam,

say just in the condition

of the plant is in right now,

this would continue operating

without us here.

that would still be true

after about a week,

several weeks,several months,

maybe even a couple of years,

everything would still be

running normally.

in a life after people,

it is possible that hoover dam

would be one

of the last power plants

still running.

>> as the power goes out

around the world,

other systems

are quickly beginning to fail.

>> beneath all the major cities,

there's a complex network

of underground tunnels,

and these are there

for drainage purposes

or for cabling purposes,

and in the case

of the big cities,

for transportation as well.

there are many of those

sit below the level

of the water table,

and in order to keep them dry,

we have to have

a system of pumps

that are switched on

when necessary

to drain the tunnels.

>> deep within new york

city subways,

more than 700 pumps

constantly struggle to keep out

a flood of ground water,

an average of 13 million gallons

a day.

>> now,if all these people

were not around,

there will be nobody

to switch the pumps on.

it's estimated,

that the tunnels will fill

with water in about 36 hours.

[music]

>> back above ground,

food is rotting

on supermarket shelves.

home refrigerators

become nothing more

than cabinets for decaying food,

but melt water

from defrosting freezers

may provide a temporary lifeline

for some of the creatures

we've left behind.

what will be the fate

of our family pets

once there are no humans left

to care for them?

>> right from the get-go,

there's gonna be a massive

die off of dogs.

the instance that humans

are gone,

they're not creating the debris

or producing the food

that the dogs are living on.

he can't open cans,

he can't get

in the refrigerator.

they gotta get

out of the house.

the family dog

has gotta get out of the house

or he's gonna die there.

and once he gets out,

he's got to go

to some source of food.

the first thing that happens

is that they all jump out

of the windows

and they are now out there

in a new landscape.

and the first to whack at it

it is that they go back

to scavenging a whole bunch

of dead things out there

in the world.

>> there are estimated to be

four hundred million dogs

in the world

and 300 different breeds.

but very few of them are suited

to surviving in a life

after humans.

the smallest dogs

probably won't last a week

without us.

>> there's probably no niche

for the smaller dogs.

dogs are very competitive

and when you have wolves,

they displace coyotes,

coyotes displace foxes,

and we would assume

that hierarchy would prevail

among domestic dogs.

>> in fact,

many of the unique features

that have been bred into dogs

over the years

will now become major handicaps

in the fight for survival.

>> there are dog

for the really short legs,

i think,the dogs

with the really short faces

or long faces,i think,

that they're all doomed.

you know,they're not

gonna move well,

they're not gonna be able

to search and explore.

i think that the kind of

the middle of the spectrum,

the kind of average dog,

has the best chances in this.

i think that they will survive

in the long haul,

but it's not gonna be pretty.

>> as the surviving dogs

struggle to find

their new niche,

household pests

are slowly beginning to notice

our absence.

little creatures,

rats and house mice,

they would seem to be able

to exist without us

are surprisingly quite dependent

on our food supplies.

>> rats and mice

are usually termed

"commensal rodents," which means

that term means literally

sharing the table.

they're very dependent

on people.

and the little house mouse

and norway rat

are great examples of animals

that would do less well

in the absence of people.

>> in the initial weeks

after people are gone,

they will raid pantries

in homes,in grocery shelves

in stores.

after eating through

these food supplies,

they will struggle to survive

on things like cardboard,cloth,

or glue.

>> i think that if a city

was abandoned,

the rats would have to go back

to earning an honest living.

an honest living

means to go back to the wild

and compete for resources there.

>> eventually,these rodents

will abandon homes

and buildings,

which will make them

easy pickings for predators.

although,rats and mice

will mostly likely survive

in the future,

their numbers

will be greatly diminished.

after six months

into a life after people,

urban areas

are already taking a turn

for the wild.

>> the predators would return

very quickly in the absence

of humans

because we suppress them,

we create conditions

that either work against them,

or we deliberately go out,

and remove and destroy them.

they would come back

very quickly.

>> smaller predators

like coyotes and bobcats

always survive on the fringe

of human populations.

they are the first to colonize

our abandoned neighborhoods.

larger carnivores

will have to wait longer

for the habitat

to recover enough

to support their appetites.

but soon enough,they,too,

will hunt in what

were once our backyards.

1 year after people

one year into a life

after people,

towns and cities

are still recognizable.

but nature

is beginning to reclaim

her old turf.

>> one of the first

great physical effects

in the absence of people

would be the transition

of the impervious surfaces:

the parking lots,the roads

into places that supported

and then had an abundance

of plant life.

>> any place

where you have sunlight

that's hitting,

you're probably gonna get

some plant growth.

little seeds

are gonna get stuck

in the cracks and so forth,

and these things

are all gonna start to creep.

plants are wonderful that way.

they can destroy things

in matters of,you know,

a few years.

>> without humans

to remove them,

weeds like dandelions

infiltrate every crack

in the pavement.

as these weeds die,

their remnants combine

with ever-spreading moss

and lichen

to create a layer of topsoil.

this sandy soil

is poor in nutrients,

so only plants like clover

that can pull nitrogen

from the air

flourish at first.

formerly manicured yards

morph into fields

for a white-tailed deer

forage for food.

wild animals have also begun

to find their way

into abandoned cities.

man's supposed domination

over nature

has proven to be quite tenuous.

the signs of our vulnerability

have always been there.

>> this is an ailanthus tree.

it seems to enjoy rooting itself

in very inhospitable locations.

and it likes to attach itself

to crevices in buildings.

and when it does so,

it causes damage.

the roots expand,

and the expansive forces of that

force out mortar

and stone and cause crumbling

of a facade.

if you get a lot of this

on an entire building facade,

it could cause

major,major damage.

>> as nature battles back,

even manmade goliaths

like hoover dam

aren't invincible.

to harness the power

of this river

took 21,000 men and five years

of hard labor.

but one year after people,

its 17 massive and seemingly

indestructible generators

are about to be brought down

by an organism

the size of a human thumbnail.

the lake above the dam

is infested

with an invasive species

of mollusk

called the "quagga mussel."

this stealthy invader

from eastern europe

had no natural predators

in north america

other than the humans tasked

with scraping it from the grates

and pipes it colonizes.

>> the mussels attach themselves

to the inside wall of pipes

and they're very prolific.

they colonize

and rapidly build up

and can grow

on top of each other,

and eventually completely block

the diameter of a pipe.

>> the small pipes

that bring cooling water

to hoover dam's generators

make perfect homes

for these creatures.

and with no people around

to remove them,

they spread like a cancer.

>> and in fact,

those mussels could clog up

the cooling water pipes,

to the point

where we couldn't keep

these generators cool anymore.

and it would cause

the high temperature alarm

in the automatic control system.

and that automatic

control system

would then start

the shutdown sequence

of that generator.

well,that would happen

one by one

for all of the generators

of hoover dam,

and eventually

the entire power plant

would be shut down.

>> in las vegas,

the last glimmers

of manmade light on earth

relinquish the night

to its primeval blackness.

with the generators

no longer running,

no water at all

is passing through hoover dam.

and the colorado river

downstream begins to run dry.

on the other side of the dam,

the water has nowhere to go

and lake mead starts to rise.

>> it would just keep

building up in lake mead.

and it would eventually

gets to the point

of spilling over

through the spillways

on either side of the dam.

>> unchecked,

nature's most powerful elements

reclaim their supremacy

on earth.

triggered by lightning strikes,

the wildfires

that humans once battled

so valiantly

now rage unchecked.

cities and neighborhoods

full of abandoned buildings,

wild grasses,and debris

are prime fuel for the flames.

chicago burns.

san francisco's

stately wooden victorians

are now only useful as kindling.

and just as it did

in the time of the ancients,

rome is burning again.

as structures

burn to the ground,

charred timbers

release nutrients into the soil,

providing the next wave

of plant life,

with the nitrogen

it needs to grow

and thrive.

five years after people,

the roads of the world

are disappearing

beneath a green map

that spreads

like some relentless monster.

the advance of nature

knows no boundaries.

the gates

of london's buckingham palace

are easily breached by vines

and moss.

in moscow,red square

is becoming very green.

>> in reality,

nature will reclaim earth

very quickly.

these stairs were cleared

18 months ago.

if we came back

in another 18 months,

we'd have a hard time

finding them.

if we came back in five years,

it would be almost impossible

to find.

>> man's mastery over nature

has always been

just an illusion.

when the cambodian city

of angkor

and its temple complexes

were abandoned in 15th century,

jungle trees grew

indiscriminately

over its stone structures.

entangling them in their roots.

now,without armies of gardeners

and repairmen,

modern cities are laid bare

to nature's revenge.

in new york's central park,

the great lawns,now untended,

sprout with saplings.

five years without humans

leaves the park

looking more like a forest.

>> central park will go bananas.

so all of a sudden

you'll get trees,

you'll get growth.

all the animals and plants

that are there now will go up

in population levels

and they'll start to spread out

into the city.

>> the story is the same

in washington d.c.

the great monuments

have been swallowed by greenery.

and on what used to be

the national mall,

the sounds of the jungle

are echoing.

>> zoo animals

are really the great unknown.

depending on whether or not

they could escape

from their confinement,

then things change dramatically

because you might have lions,

you might have tigers;

both of which

would be perfectly capable

of surviving

in a post-human period.

they'd do better further south

than they would do

in washington d.c.

but these are animals

that are perfectly capable

of figuring out how to do it

and how to survive.

>> zoo animals

may be the great unknown

but there are things

we can know for sure

about life 20 years

after people are gone

because there's one spot

on the globe

where it's already happened.

[music]

>> it's 20 years

into a life after people.

without humans

to apply fresh paint

and fill in cracks,

even concrete buildings

have already begun to crumble.

lack of maintenance turns cities

into eerie ghost towns.

animals that have long avoided

human population centers

now return to make new homes

among the decaying walls.

how do we know this?

because there's one place

in the world

where it's already happened.

>> we're standing

in the central square

of pripyat,ukraine,

the city that was once

the most modern city

in the former soviet union.

for 20 years now,

this city

has been sitting abandoned,

and it really gives you

a picture of what would happen

if people are removed

from a place

of normal civilization.

>> evacuated after

the chernobyl nuclear disaster,

pripyat went

from a city of 50,000

to ghost town overnight.

dust-covered school rooms remain

as students left them

just over 20 years ago.

vegetation pries apart masonry

as it crawls over buildings.

an amusement park

scheduled to open

four days after the date

of the accident

remains never used.

the park's ferris wheel

accumulates rust

rather than riders.

the bumper cars sit in a state

of motionless decay.

pripyat has provided an amazing

and rare opportunity

to see what happens

to a manmade city

when humans disappear.

>> i can see

from my geiger counter

that it's really quite safe

to be here,

radiation levels

were not very high.

but you can see

that we've really hit

a point of no return

in recapturing these facilities.

we're in what was

the cultural center

of the city of pripyat.

and indeed,this was a place

where friends gathered,

where there would be

celebrations,

there would be balls,

there would be music,

there would be dancing,

there would be performing

on the stage here behind me.

but after 20 years,

the forces of nature

have started to decay

this facility.

>> this concrete soviet facade

may look imposing

but it's no match

for the frigid ukranian winters.

as the temperature drops

below freezing,

water that has accumulated

in cracks,expands,

exerting bursting pressure

that pulls apart

the masonry.

as vegetation grows unchecked,

the roots spread

through foundations and stairs.

these roots suck in moisture

that makes them expand and grow.

like miniature hydraulic jacks,

over time,

they slowly push apart

the concrete.

>> this is only 20 years.

can you imagine

what this facility

will look like after 200 years?

>> after the accident,

scientists expected the worst

for the wildlife in the region.

most of the trees

in a 1 1/2 square mile area

around the nuclear plant

were killed off by radiation.

many animals died.

but incredibly,the effect

of the absence of humans

for 20 years has outweighed

the initial damage

caused by the nuclear nightmare.

>> this is the red forest,

an area

that was horribly impacted

by radioactivity

due to the chernobyl explosion.

and the trees that you see

around me were killed

by the radioactivity.

the original amounts

of radioactivity were sufficient

to kill all of the wildlife

in the region as well.

but now we see a resurgence

of the wildlife.

as an example of how wildlife

has prospered here,

we see,here,we have an antler

from a red deer and,obviously,

a fairly large

and healthy red deer.

red deer are hardly found

in any other areas

in this region

and the chernobyl zone

is the only place

that you'll find populations

of red deer.

we also find russian wild boars

that the populations in the zone

are 10 to 15 times higher

than they are outside

of the zone.

[speaking russian]

>> we're now at the kindergarten

of karpachi village,not far

from the chernobyl station.

children were living here

while their parents worked.

but after that night

in april 1986,

they never returned.

we are in what was formerly

a bedroom in this kindergarten

where children used to sleep

and rest.

now,there's

a certain emptiness here.

all these windows are broken.

but the room continues

to live on.

birds fly in here

and sit on these bars.

we even found evidence

that an owl comes here.

an owl,it regurgitates food,

fur,bones,and feathers.

evidently,it likes to sit here

on this window pane.

so this room continues

to maintain life.

even trees which had proven

especially vulnerable

to radioactive fallout.

are finding new homes

in the evacuation zone.

>> i'm sitting

in the pripiat soccer stadium

where,20 years ago,

hundreds of people would come

and cheer

on their favorite team.

you can imagine the laughter

of the sounds

of the crowds here.

the activity on the field

which,20 years later,

is barely discernable.

the soccer field now is going

through succession

as you would expect in returning

to what it was originally

hundreds of years ago

which was a mixed

deciduous forest.

>> i grew up in a town

about like this

and i used to enjoy

riding bumper cars like these

about a half a world away.

and it seems pretty sad

when you look now

and you see what's become

of this beautiful city

of pripiat and that people

will never live here again.

but there's another side

to this story,

a very encouraging side;

one that says that life

is much more resilient

than what we thought possible.

that in the absence of man,

that life will continue

and that life will thrive

and that the legacy of life

will always be here,

because we are a part of life.

even if we disappear,

our legacy of life

will continue.

[music]

it's 25 years into a life after people

out in the country

nature is beginning to erase all evidence of man

in the suburb

packs of fellow dogs roam through decaying neighborhoods

in search of their next meal.

in some of the great cities

of the world,

solid ground is getting harder

to find.

in the time of humans,

london was protected

from tidal surges

by 10 retractable steel gates

that could be raised

during storms to seal off

the thames river

from the north sea.

without humans

to operate the barrier,

london is defenseless.

another low-lying city,

amsterdam,

meets the same watery fate.

in a new york city high rise,

some windows have already

cracked and slipped loose

from their frames and many more

are on the verge of destruction.

after a quarter century

of exposure to moisture

and heat without maintenance,

the normally flexible window

sealant has become rigid,

locking this window

to its frame.

as the metal frame expands

and contracts with changes

in temperature,

it induces stresses

on the glass.

it cracks and plummets

to the sidewalk below.

>> after a few of the windows

fall out of a building

like this,

then the wind pressure effect

changes dramatically.

as well as external pressure

coming on to the building,

you also get suction.

and that aggravates the problem

so more of the panels

are likely to fall out.

>> through these gaping holes,

the building fills

with windswept debris.

a summer storm rolls in.

on top of the structure,

the copper-lightning deterrent

system that once protected

thousands of office workers

is now corroded and useless.

a lightning bolt turns the tower

into a raging inferno.

the gutted building makes

the perfect home

for a surprising survivor.

although pigeons once relied

on the handouts of humans,

they have done just fine

in 25 years without us.

>> pigeons are survivors.

they can live in the wild;

they do live in the wild still.

and in a period

where there were no people

but there still were edifices

and artifacts,our buildings,

they would do very well

because they would adopt these

as kind of

artificial cliff faces,

which is what they really are

adapted to.

>> like the pigeon,

the disappearance of humans

forced a change in the habits

of the lowly cockroach.

>> think of the poor cockroach

after they gorge

upon our surplus

when we're gone,

they'll mourn us.

they'll be sorry.

>> but the morning won't last

for long.

while cockroaches thrived

on our scraps,

they can also eat bookbindings,

and cardboard,

and any rotting organic matter

including dead leaves and roots.

while food isn't a problem,

roaches also need warmth;

the kind that humans

had always supplied

through artificial heat.

cockroaches started

as a tropical species

and some experts say

they couldn't survive the winter

in colder cities.

but it's hard to bet

against a creature that has seen

the dinosaurs come and go.

>> cockroaches are

extremely adaptable.

they've been around

for 300 million years.

if i have to bet,

i'd put my money on them

being able to survive

in one form or another.

>> the first winter

after humans did witness

the die-off of some cockroaches,

but many more moved underground

to find warmth until

milder temperatures returned.

in an abandoned downtown

devoid of insecticides,

overrun by vegetation

and with a rising water table,

this former pest is now enjoying

a golden age.

cockroaches were only a nuisance

to humans,

but wolves were a terror.

so man hunted them mercilessly.

when the first european settlers

arrived in what is now

the united states,

it's believed nearly half

a million wolves roamed

the country side.

by the 20th century,

these predators

were nearly extinct

in the lower 48 states.

now,with no humans left

to battle them,

wolf populations multiply

by as much six times each year.

within 25 years

of our disappearance,

there could easily be half

a million of them roaming

the united states again.

this amazing comeback

has been seen

on a small scale before.

in 1995,biologists released

a few dozen wolves

within the boundaries

of yellow stone national park;

a place

where they would be protected

from persecution by humans.

within a decade,

a few dozen had multiplied

into 1,500

and the wolves

quickly spread out

from their release point

to occupy territory

throughout the states

of wyoming,montana,and idaho.

>> it would be fast

if you can start

with just a few dozen wolves

and in the course of one decade,

have a population of 1,500

and you could have

a geographic expansion

where they filled up a big chunk

of a three-state area.

and these are

big western states.

yeah,when the conditions

are right,

they can re-colonize

pretty rapidly.

could we see them in manhattan

or chicago?

as soon as the deer get there,

the wolves will be right

behind them.

>> animals haven't

just been hunted by humans;

they've also been hemmed in.

there are roughly three million

miles of paved road

in the united states alone.

and it's no coincidence

that many of them cut

right through the paths

animals use to get from place

to place.

>> the things that make

a landscape good

for animal movement

also make it easy to engineer

a road in that location.

so,we've cut off pretty much

all major migrations

in north america.

>> asphalt and automobiles

wreaked particular havoc

on the grizzly bear.

their habitat

was so carved up by roads

that they're confined

to isolated pockets,

cutting them off

from food sources

and potential mates.

in a life after humans,

roads are no longer barriers

for the grizzly.

instead they are pathways;

trails that lead them back

into the heart

of their former range.

>> forty years after people.

while cities of steel

and concrete

are still standing tall,

the suburbs are under attack.

roughly 90 percent of all homes

in the united states

have wood frames.

while some have burned,

others are now being devoured.

without paint and preservatives,

the lumber of homes

is defenseless against termites.

termites feast on cellulose,

the basic building block

of wood.

and their appetites

are relentless.

some colonies can eat

as much as 1,000 pounds of wood

per year.

in this destructive advance,

the termites

aren't working alone.

>> the process we know

as rotting will occur

when the wood gets exposed

to the elements.

and this rotting,actually,

is a more complicated process.

it's a process by which microbes

attack the wood

and release carbon dioxide

and methane to the atmosphere.

if humans were to leave,

it'd be a matter of decades

before most structures

that had significant

wood components

would start to decay.

>> faced with

a two pronged attack

from termites and rot,

the beams that hold up the roof

give way.

and the boundary

between inside and out,

that had once been so important

to the humans

who called this building home,

is forever erased.

>> other substances

like this mortar and rock

are gonna last longer

than several decades,

but they'll still crumble

after natural,chemical,

and physical weathering

processes,

and eventually these walls

will fall down as well,

and there'll be no remnants.

>> now,nature will act quickly

to swallow up these ruins.

this crumbling house

in baltimore's druid hill park

was once home to the caretaker

of the city zoo.

>> it looks like this building

has been abandoned

for more than a hundred years.

but in reality,

people have been living here

up till 40 years ago.

it's amazing how quickly

the vegetation has reclaimed

the area.

the vines have started to climb

up the walls.

the trees are growing

into the structure,

and they're both physically

pulling the structure apart,

and chemically dissolving it.

>> structures built entirely

of stone or masonry

will far outlive

anything made of wood.

exactly how fast

they will crumble depends

on their environment.

>> the coast of maine,really,

isn't very kind to buildings.

structures out here

don't so much decay

when you live them alone;

they melt.

>> these structures

on black island,maine

used to be part

of a granite quarry whose stone

was used to build and decorate

cities like boston,new york,

and philadelphia.

it was abandoned around 1920.

>> here,the buildings

have all vanished

within the space

of 80 and 90 years.

there's almost nothing left.

>> in the right conditions

and with human maintenance,

stone construction can last

for thousands of years.

in some places in europe,

ancient roman aqueducts

are still in use.

but without maintenance,

stone can fall victim

to a very stealthy enemy.

>> one of the great enemies

of stone is actually salts

and salt crystals.

even thousands of years ago,

people notice the effect

that salts had on deteriorating

the ancient pyramids.

>> there are many ways

salts infiltrate stone buildings

and monuments:

polluted air,seawater,

and even bird droppings.

>> soluble salts dissolve

in water,

and as the water evaporates,

it will rise up inside

of porous building materials;

things like brick and stone

and even concrete.

and what happens is the salts

will continue to grow

inside the pores of the stone

until they come up

against the side of the wall,

and they'll actually push

the stone apart.

>> what we're seeing

in this time-lapse video

really shows the rapid decay

of the stone in response

to this deterioration by salts.

in this experiment,

it took about three weeks to go

from this piece of stone

to this piece of stone,

which is completely deteriorated

by sodium sulfate

crystallization.

>> three weeks in this

accelerated aging chamber

are equivalent to a few years

in the harshest of environments,

or a few decades in a more

benign desert climate.

>> if we could see

microscopically what's going on

inside the pyramids,

this is what

would be taking place.

you can actually see the salts

deteriorate the stone.

>> although not immune to decay,

the pyramids have survived

for nearly 5,000 years

because of their sheer volume

and their hot,

dry desert environment.

too massive to be destroyed

by either man or nature,

the pyramids of giza

were the only one

of the seven wonders

of the ancient world to survive

into the modern era.

many ancient monuments

have survived only

because of human maintenance

throughout the centuries.

the sphinx was uncovered

and restored for the first time

back in 1400 b.c.

modern experts who have studied

the sphinx,predict

that without human intervention,

deterioration from salts

and wind erosion could render it

a pile of dust

within 500 to 1,000 years.

the largest concrete structures

like hoover dam,will last

even longer than that.

hoover is so thick

that over 70 years

after it was constructed

the concrete deep inside

was still curing.

but of the 15 tallest dams

in the united states,

only 10 are concrete.

the others are made of compacted

rock or earth,

like northern california's

trinity dam.

if there were humans around,

this leak in the dam would get

an emergency fix.

but those days are long gone.

>> some of these dams

are absolutely enormous.

and if they fail,

as they will in time,

then the surge of water

that falls in behind them

and cascades

down a valley below

would have a huge force,

big enough to sweep away

everything on its path.

>> fifty years after humans,

the strain of neglect

is beginning to show

on even the best design

of manmade structures.

>> everything that man designs

carries within it,the seeds

of its own destruction;

that includes bridges

and buildings.

the brooklyn bridge,

one of the most famous bridges

in the world for over 125 years.

the reason

that bridges last so long

is because engineers

look after them.

they inspect them regularly,

they maintain them,

they paint them,

they replace pieces that need

to be replaced.

without people,

without engineers,

the deterioration process

will accelerate dramatically.

>> the most vulnerable parts

of a suspension bridge

are the steel vertical hanger

cables.

>> these have been tested

in the laboratory,

unfortunately not on the bridge,

but what you see

is a classic kind of a failure

that occurs in these wires.

these are the individual wires,

all right?

that's an individual wire.

that probably has

a tensile strength

that's maybe 200,000 pounds

per square inch.

that's a very high strength

steel.

>> as strong as they are,

these cables have a fatal flaw:

it's the stuff they're made of.

>> steel is a mineral

that comes from the earth

that's mostly iron,

so it's probably

95,98 percent iron.

>> exposed to moisture

in the environment,

iron will start to revert

back to the minerals

it came from.

ashes to ashes,dust to dust.

>> it's gonna go back home.

it came from the earth

as iron oxide of some form,

and it's gonna go back.

>> this is the process we know

as corrosion,

and you see it wherever steel

is exposed to moisture.

>> the enemy of steel

is corrosion.

the problem

is keeping the water out.

part of that is maintenance.

if you don't maintain them,

you will get corrosion.

>> completed in 1883,

the brooklyn bridge cost

$15 million to build.

over the last two decades,

$3 billion have been spent

maintaining it

and the other bridges

over the east river.

in the time of humans,

the brooklyn bridge

was continually maintained

and fully repainted,

roughly,every dozen years.

while across the country

in san francisco,

the golden gate bridge

was protected at all times

by a vigilant brigade

of 17 iron workers

and 38 painters.

>> what do they do all the time?

they will tell you,"we paint

this bridge continuously."

what happens when that stops?

i can tell you what happens

when that stops.

the cables begin to rust,

the paint peels off,

the wires begin to break,

and they'll come to a point

when the bridge

is gonna come down.

>> seventy-five years

after people.

most of the 600 million cars

that once traveled the roads

of the world

are now just rusted remnants

of the human past.

>> abandoned cars will behave

differently depending

on the environment

that they're in.

a car left in the mojave desert,

for example,

is gonna last a long time.

a car abandoned

in my native scotland

is gonna have

a very different fate.

any cars

in a coastal environment

with salt in the atmosphere,

they might not last

more than 20,30 years.

>> tires deflate

within a few years,

although the rubber

and synthetics they're made of

will remain intact

for centuries.

paint deteriorates quickly.

and once it flakes away,

rust corrodes the car's body

at a rate of 5,000ths

of an inch per year.

seventy-five years after humans,

most cars,

even in the most forgiving

of environments,

will be reduced to skeletons.

after a century,the family car

is a barely recognizable heap

of metal.

it's now 100 years into a life

after people.

the brooklyn bridge,

which had stood

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 gonna be gone.

two hundred years?

i doubt it will last 200 years.

the bridge is gonna 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 cds 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 cd,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 hold 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 gotta 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 colosseum--

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 use 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.

[music]

>> i think our dogs,

as placid as they may seem

when they're in our homes

lying on the living room floor,

still posses the instinct

to survive,

enough that they would be able

to do whatever it took

in bringing down prey

in order to live.

[music]

>> 150 years after people,

the oceans are teeming

with life.

the creatures of the sea

have welcomed

the disappearance of mankind.

>> historically,

we've treated the oceans

in two strange ways

at the same time:

a pantry and a toilet.

and over time,

our ability to damage the ocean

has grown and grown and grown.

>> with humans no longer fishing

and polluting the sea,

the path was cleared

for this astonishing recovery.

it has happened before.

during world war ii,

allied fishing trawlers

avoided the north atlantic,

and populations of fish there

skyrocketed.

>> in here,the basic biology

of these kinds of animals

is working in our favor

because animals

like this sunfish

can produce millions

of offspring in a year,

much more

than an equivalent-sized

terrestrial animal like a cow.

and because of that

prodigious potential

to reproduce,

the oceans could come back

pretty quickly

if the human population

were suddenly to disappear.

>> research has shown

that in the 18th century,

before the havoc

caused by humans,

the oceans were capable

of sustaining

massive amounts of life.

>> so many whales

that they stink up the air;

so many tunas

that they froth the ocean;

so many turtles

that you could walk

across the sea on their backs.

so,if people were to vanish

off the face of the earth,

then that's the kind of ocean

it could be.

[music]

>> seagulls are also

flourishing,but it has been

a treacherous flight.

the abundance of food

from humans

had allowed gull populations

to explode beyond what nature

could normally support.

>> we humans

are pretty messy species.

and for a very long time,

we had open landfill dumps

where,as far

as we were concerned,

all the stuff

that wasn't fit to eat

was just thrown out.

but from the gulls'

point of view,

this was an amazing

free lunch counter.

so,you had a lot of birds

that probably

wouldn't have made it through

their first winter

if they've had to feed

for themselves.

suddenly,they had

all these free food

available to them.

an immediate consequence

of a world without people

would be some very hungry gulls

who would be very voraciously

looking for other things to eat.

>> after an initial die-off,

the remaining gulls

took advantage

of the recovering oceans,

where plentiful schools of fish

erased any memories

of the human-manufactured feasts

they used to enjoy.

two hundred years after people,

from new york to chicago,

seattle and paris,

our iron and steel icons

are on the verge of collapse.

while it has outlived

our great suspension bridges,

the eiffel tower

is not invincible.

in the time of humans,

its iron superstructure

was painted

once every seven years

to protect it from corrosion.

in both age and structure,

the eiffel tower

has a lot in common

with the 300-foot high

kinzua railroad viaduct

in pennsylvania.

>> was a bridge

that was wrought iron

originally.

it was reconstructed

about the turn of the century

in steel.

and what happens here of course

is that unless it's maintained,

corrosion occurs.

and what happens

with the corrosion?

the connection points freeze up.

they are not allowed to move.

and here are some pieces

from that viaduct.

you can see

that there's corrosion

all over the place.

that's no longer steel.

>> a structure

with frozen connection points

can't absorb the stress

of high winds.

>> eventually,

in this strong wind storm,

it literally fell over.

section by section,

piece by piece,

it fell over into the valley

where it had spanned the valley

for over a hundred years.

just not maintained.

you can think of many structures

that are coming

from that same era

like the eiffel tower,

its iconic structure.

that doesn't shield it

from the fact that's it

in a corrosive environment.

and so in time

if you do not do anything

for that structure,

it will fail.

and it will come down.

>> the time between one

and 300 years after people

will likely be the era

of the great collapses

worldwide.

in seattle,

the iconic space needle

was designed to sway

one inch for every 10 miles

per hour of wind,

but with its steel

weakened by corrosion,

it takes little more

than a strong breeze

for the symbol

of the 1962 world's fair

to crash down from the skyline.

when humans disappeared,

sea levels were already

on the rise.

in manhattan,

over the centuries,

saturated soil

around the empire state

building's foundation pilings

have allowed the building

to lean.

>> once a building strays

from the vertical,

then gravity forces

are also acting

against the structure,

increasing the stresses

at the base of the building,

now we're unlikely to see

a skyscraper fall

like a tree in the forest.

once it does start to incline,

gravitational force will cause

the top of the building

to collapse downward

on top of itself.

>> decay has also overtaken

the city of chicago,

the birthplace

of the skyscraper.

the sears tower,

the tallest man-made structure

in north america,

has reached

the end of its reign.

the first 500 years

after people has been an era

of decay and destruction.

our concrete structures

have lasted the longest.

the ancient romans

invented the first form

of concrete.

and some of their structures

remained intact

for over 2,000 years.

but modern concrete

isn't nearly as durable.

it has a higher water content

and is more loosely packed,

which leads to more

air pockets and cracks.

modern concrete structures

have another fatal flaw.

>> below the surface

of reinforced

concrete structures,

there is a mesh

of steel reinforcing bars

and they don't corrode

because the concrete maintains

an alkaline environment

around them.

now,when that alkalinity

breaks down,

as it will in time,

then the steel

will start to corrode.

>> as the steel rebar rusts,

it expands to three times

its original volume

creating an outward pressure

that causes the concrete

to crumble.

>> in very broad terms,

after 50 years

we'd start to see

surface cracking on concrete.

after a hundred years,

flaking of the concrete surface.

after maybe 500 years,

most reinforced

concrete structures

will be gone.

>> we look at these images

of our fallen civilization,

it helps us to identify

with the past,

with the greeks and the romans,

with the crumbled

mud brick cities of ur.

each of us knows

that our bodies

are going to fall apart;

why not our cities too?

>> a thousand years ago,

6 1/2 billion people

called this planet home.

at the early 21st century,

more than half of them

lived in cities.

now those cities

are unrecognizable.

>> after maybe a thousand years

or so,the scene behind me

would be very,very different.

there'll be very little evidence

of buildings,

very little evidence

of the activities of man.

what we would see

would be a jungle of vegetation.

>> the future of cities

in a life after people

can be best imagined

by looking to the past.

>> this is minetta street

in greenwich village.

most new yorkers might come here

and wonder why it curves

like this.

it curves

because once upon a time

there was a stream here,

and then a brook.

there were more than 40 streams

on manhattan island.

all flowing down

and carrying the rainwater

down to the sea.

so what happens today,

the rain falls,the snow melts,

but it flows

right along the street

and down into that storm drain

there.

if there weren't people here

anymore,there'll be no one here

to maintain the sidewalks

and maintain the streets.

they'd start to crumble up.

they'd start to break apart.

trees would come back,

vegetation would come back,

and eventually

the hydrological cycle

would reestablish itself.

and who knows,

maybe minetta street

might once again

become minetta brook.

>> using historic maps

and computer modeling,

scientists

with the manahatta project

are rediscovering

what manhattan island

looked like when explorer

henry hudson first sailed

around its shores in 1609.

>> here we are in foley square,

the administrative center

of new york city

and location to the famous

courthouses you see on tv.

this place hasn't always had

such colossal buildings

and stony streets.

once upon a time,400 years ago,

the collect pond was here,

the freshwater source

for new york city.

right behind me,

there was a stream that drained

down to the hudson river shore,

another stream

to the east river.

and there was

this beautiful pond

that was nestled

in an amphitheater of hills.

so what would happen

if all the people

were to disappear?

the buildings,

they would tumble down.

the soil would start to reform.

trees would start to grow

out of them.

they would become the new hills,

the new amphitheater

around this place.

nature would reestablish itself

and slowly bring this place

back into the green heart

of what it means to be here

on planet earth.

>> new york city,

like the rest of the planet,

has changed radically.

the transformation

is most shocking in times square

as the once beating

heart of the city is silenced

by nature's onslaught.

it's 10,000 years after people.

could it be possible

after only 10 millennia

that humanity has vanished

without a trace?

human scientists once predicted

that our history and culture

would live on through our radio

and television broadcasts,

which carry on

through the universe

toward the infinite,

perhaps to be tuned in

by an intelligent species

on a distant planet.

>> some people think

that there's an expanding shell

of radio and television

from earth,expanding outward

alerting the universe,

"here we are

and this is our culture."

unfortunately,

recent calculations

by of all people,the seti,

search for extraterrestrial

intelligence group,

has shown that all

of this dissipates

within one and two light-years

into noise.

>> if this is true,

our signals won't even make it

out to the newest star

beyond the sun.

so what will remain 10,000 years

after people to tell the story

of the once great civilizations

that walked the earth?

iron corrodes,

concrete crumbles,

wood and paper decay.

still,some of what man

built on earth remains.

the most colossal

of our stone structures

like the great wall of china

have aged like mountains,

subject to erosion,

but at such slow time scales,

they will still be recognizable

in some form for eons.

the great pyramid at giza

is so massive that it lasts

long enough to be swallowed up

by the desert sands.

the hoover dam

built to be as tough

as the canyon walls around it

is one of the last

man-made structures

still standing.

but now thousands of years

in the future,

earth is about to be visited

by the last

of the great collapses.

>> it's the environment

that eventually wins.

earthquakes,sandstorms,rain.

but there are a few exceptions.

i would have to say

that mount rushmore,

carved out of solid granite

in an ecologically stable place,

the only enemy it has

is wind-driven pellets of rain.

i think that mount rushmore

may be around

a hundred thousand years,

possibly 200.

possibly even in time

to be looked at in awe

by the earliest

of our replacements.

>> and who or what might

those replacements be?

perhaps chimpanzees

might somehow make the leap.

>> but we have to consider this:

some scientists believe

that it's easy for nature

to bring animals

up to a clever level

where they might use tools,

they might become masters

of their environment.

but the leap to being able

to stare at the sky

and imagine a cosmos,

to be able

to contemplate yourself,

to be able to contemplate

your own role in the earth,

this may be a leap

that was a sheer accident

for humanity.

in which case,

you're not talking

about a complete recovery.

you're talking about a planet

that may continue,

but nobody to talk about it,

nobody to think about it.

>> if earth's 4.5 billion years of existence

were condensed into 24 hours,

the passage of 10,000 years

would be a fraction of a second.

man's time on the planet so far

would be about half a minute long

so,like an abandoned village on a global scale

the earth will move on without us

there was life before people.

there will be life after people.

resync by
Santa aka Snt, 2009