After Humans (Science Illustrated Australia - 24_2013)

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ISSUE #24ScIEncEIllUStratEd.com.aU

QUANTUM SPYCRAFTCreating a truly uncrackable code

ZOONAUTSThe amazing history of animal astronauts

lIcE: oUr conStant companIonS + amazIng StonE agE toolS + nExt gEnEratIon aIrcraft carrIErS + and mUcH morE!

How our cities will decay, and how nature will bounce back - fast!

What happens to the Earth

MEDICAL NANOBOTSSoon you’ll be fixed from the inside

DEEP SUITArchaeology’s latest toy

GIANT BLACK HOLESCracking a cosmic mystery

In the film ”After Earth”, Will Smith and his son make an emergency landing on Earth 1,000 years after a mass evacuation from the planet. But what would a world without people be like? According to scientists, nature will bounce back fast. Predators will spread, human artefacts will break down, and after 1,000 years, all that will remain of us are our quarries and waste.

Nature restores itselfEcOLOgIcAL SUccESSION For nature, the

disappearance of humans will not be a loss. On the

contrary. Nature will return to the ecological

balance, which humans have disrupted. Biologists

call it “ecological succession”, by which plants and

animals will produce tougher original forms through

natural selection.

Why our world will decay ENTROPy When houses decay, it is due to the

thermodynamic law of entropy. The degree of

entropy or disorder increases over time. A shapeless

pile of sand has high entropy, while a sandcastle has

low entropy. A structure with low entropy will move

towards a state of still higher entropy, disorder, and

disintegration over time.

THe cURe FOR HUMAnITY? Humans have made drastic changes to the Earth, but to restore a pristine

wilderness, all we need to do is leave... and wait. Fundamental laws of

physics will cause our structures to decay, and life will surge into the

spaces we leave behind...

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THEORy

26 | SCIENCE ILLUSTRATED

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By Antje Gerd Poulsen

the “life after people” tV series

created this cgI image of what Hollywood

might look like after 175 years.

scienceillustrated.com.au | 27

FEATURE | after humans


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DAY 7 (After the sudden disappearance of

all humans) in houses and flats, on farms and

in zoos throughout the world, animals starve

to death. The majority of the world’s 1 billion

pigs die, as do many of our 400 million dogs.

YeAR 1 Wild animals enter our cities

and farmlands – particularly adaptive

species like bears and wild hogs, which eat

many types of food. On the other hand, the

population of vermin like cockroaches and

rats will initially fall dramatically as their

current numbers are supported by us.

YeAR 5 Despite our pampering,

domestic cats never lost their desire to

hunt. In Australia, where there are few

small predators, cats thrive and might

even drive native predators extinct.

YeAR 7 By now, most fish species

have recovered from decades of overfishing.

YeAR 8 A new equilibrium has

emerged. Predators and prey have

populations that can be sustained. The real

winners are the big predators - bears,

wolves, tigers, sharks: every animal

humans saw as a threat is back on top.

In Europe and northern

america, the wolf

population would explode.

In australia, cats and

dingos may dominate

WIlDlIFe Predators reclaim their hunting grounds

Day 7

year 1

year 7

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C a r s T e n r a h b e k President of the International Biogeography Society.Biogeography is the study of the geographic distribution of plants and animals.

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nature is drawn toward a dynamic balance“[In the abscence of

humans] The animals,

that benefited from a

man-made environment

will be under severe

pressure, and the

majority of our

domesticated animals

will die quite fast. But a

few of them will adapt.

In a few generations,

natural selection will see

to this. We have

observed it before. The

Australian dingo was

originally a tame dog

turned wild. Nature will

not be drawn to an

original state, it will

always be drawn

towards a

dynamic balance.”



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The first years after the loss of humanity will mean fires, flooding, and decay. But within

days, nature will begin to conquer cities, and millions of pets and domestic animals will starve to death or be

eaten by predators.

cITIeS · SIlenT, DARk, cHAOTIc

DAY 14 As many as 50,000 power

plants worldwide have shut down.

At night, the globe is almost

completely dark. Electric pumps

normally keep cities like London,

Amsterdam, and New York clear of

water, but now, tunnels are

flooded, and canals overflow, filling

basements with water.

YeAR 1 Plant seeds find

nourishment in gutters and

cracks between pavements and

high-rise facades.

YeAR 3 Windows break in

storms and temperature

fluctuations. Once wind and

water get inside, the structures

will decay quickly.

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DAY 20 The world’s 441 nuclear

power plants are close to disaster.

Cooling systems collapse, and a

few weeks later, the coolant

water has evaporated. Then,

reactors melt down or catch fire.

The air, land, and water around

the plants become radioactively

contaminated, and many animals

and plants die.

lAnDScAPeS · FIReS AnD FlOODIng

MOnTH 6 Forest fires run wild

without humans to fight them. In

nature, the fires serve

a purpose, and new plants

emerge from the ash after their

seeds are cracked in the heat. In

other places, dykes collapse, and

vast areas are flooded. Reclaimed

land (such as some airports) slips

back beneat the waves.

YeAR 5 Farm fields are now

overgrown. In 1882, British

scientists demonstrated how fast

other plants will take over an

abandoned wheat field. After

four years, only a few wheat

spikes remained, and the next

year, they were gone. Without

humans, aggressive species like

trees and hedges can dominate.



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YeAR 10 Grass grows

between paving stones, cracking them.

Trees already grow into houses.

YeAR 25 Skyscraper

windows are broken, letting wind and

rain in. The steel inside reinforced

concrete rusts. Bolts and screws corrode,

and panels fall out.

YeAR 50 The world’s one

billion cars have corroded beyond

recognition. In the humid coastal

climate, after 20-30 years a car is

barely recognisable.

YeAR 100 The steel wires of

suspension bridges have corroded. Their

flexibility is gone, and one single gust of

wind will make the bridge collapse.

YeAR 200 The joints of

the Eiffel Tower have corroded, and it

collapses. Most skyscrapers and many

older structures follow suit – particularly

those with submerged foundations.

cITIeS · Air, water and rust undoes our mightiest creations

Frost + rust break

down concrete

From high-rises to bridges – concrete is the most common building material of modern times and has been used since Antiquity. Concrete is highly weather resistant, and reinforced concrete even more so. Nevertheless, nature makes concrete crumble over time.

PlAnTSIf plants are allowed to climb a concrete structure, the roots will find even the tiniest cracks and draw water. The concrete continues to crumble.

cORROSIOnOnce the concrete is cracked, moisture gets to the reinforcement, and the steel rods corrode. They expand, making the concrete burst even more.

FROSTFrost damage occurs when water in concrete pores expands in frosty weather, first cracking and then bursting the concrete, and flaing off the surface.s

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the city of

pripyat near

chernobyl

25 years after

the nuclear

disaster.a. skelly/getty IMages

year 25

year 50

year 200



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J o h n s T u b b sProfessor of Preservation Practice (historical buildings) and Director of Preservation Studies at the Tulane School of Architecture in New Orleans.

After 200 years without maintenance, most houses have become overgrown

ruins. Structures which have not already collapsed continue to come down.

Cities are as quiet as deep forests.

YeAR 10 Static electricity or

lightning strikes cause fires on

oil rigs throughout the

world, and unmanned

supertankers, container

vessels, and cruise liners

drifting with the current

plough into the rigs, which col-

lapse. Result: millions of litres

of oil gushing into the ocean.

YeAR 200 Corrosion makes

time bombs explode

all over the world. Silos, tanks,

and other containers with

encapsulated nuclear waste,

fuel, and chemicals begin to

leak or even explode. Animals

and plants die, but over time,

bacteria will break down

most oil and toxic residue.

YeAR 200 New ecosystems have been

established. Australia’s vast eucalypt forests have

returned, and native birds thrive. Horses are well-

established in some niches where rainfall is

constant - other less-hardy European animals are

driven out by our variable climate.

YeAR 50 Almost no

nitrate and phosphorous

remain in fresh water, but cor-

roded tanks filled with chlorine

for swimming pools leak. Toxic

chlorine gas clouds spread in

the environment, and when

chlorine encounters water

vapour, acid is produced.

Tankers with chemicals leak.

YeAR 100

Domestic animals

and pets have

reverted to their

original forms.

Racehorses have

become brumbies, ,

and the descendants

of domestic cats

resemble forest cats.

lAnDScAPeS · TOXIc TIMe BOMB

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year 100

year 50

After 200 years, most buildings will be gone

“the temperature of buildings

is key to their lifespan. With

no people around, they would

be subjected to disrupting

temperature fluctuations.

the materials will expand and

contract, until the structures

fall apart. New, mass-

produced buildings will not

last as long as carefully

constructed historical

buildings, which are often

huge and made of more

durable materials than

modern buildings.”


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More than ever, Earth is a blue planet. Even several hundred years after the last gram of coal is burned, ocean water levels are still rising, swallowing cities and landscapes.

YeAR 300 The Statue of Liber-

ty in New York collapses, and

parts fall into the harbour.

YeAR 500 The Sydney Harbour

Bridge, which contains iron, has

crumbled. Now concrete buil-

dings collapse: the twin towers

of Kuala Lumpur and St. Peter’s

Basilica in Rome.

YeAR 1000 The world’s metro-

polises have lost their famous

skylines. Instead, the cities are

hilly landscapes with rivers and

lakes. Everything is overgrown.

An archaeologist could find the

ruins, if they looked closely.

Huge trees have

overgrown angkor

Wat in cambodia -

but it’s a well-built

monument. modern

buildings would

collapse under a

tree this size.

cITIeS · A HIllY lAnDScAPe

YeAR 500 Lack of habitats and

the intense search for tusks kept

down the elephant population,

when humans lived on

the planet. But now, they migrate

with rhinos from Africa and Asia

to Europe. Those venturing far

north develop fur in cold weather.

Predators also move north. The

Romans were the last to hunt wild

lions in Greece, but now the big

cats are back to take advantage of

booming prey populations.

WIlDlIFe · RHInOS AnD

lIOnS MOve nORTH

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YeAR 400 Most cities have

been totally taken over by plants.

In 1860, French explorer Henri

Mouhot discovered what an

overgrown city looks like,

when he found the great temple

complex of Angkor Wat in

Cambodia. In 400 years, the city

had been almost devoured by

the big roots of silk cotton trees.year 500


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aniMaLs in The european virGin foresT

BisonWild hogBearWolfLynxEagleBlack storkBeaver

central Europe would be like the

Bialowieza national park in 500 years.

The virgin forest is self-sustaining

The Bialowieza National Park in Poland and

Belarus is an example of what Europe may look like after 500

years without humans. The virgin forest remains the way it

was after the ice age, and rare animals like bison, lynx, and

beaver thrive. Nature has its own ways, and when a forest is

left alone, old trees collapse, leaving room for new ones.

Thus, the forest becomes varied with trees of different ages,

swamps, and clearings: habitats for many animals.

after 300 years, the Statue of

liberty’s internal iron structures

collapse, and she falls into the ocean.

lAnDScAPeS · Oceans swallow countries. new habitats appear

Water will break free, providing new habitats

Humans and nature compete for water. Everywhere,

humans built cities near large waterways and

redirected rivers by means of dams and canals. The

course of waterways and different water levels are key

factors determining which plants thrive. Different

plant species have adapted to different moist levels,

and when the water once breaks free of its man-made

barriers, there will be habitats for more animals and

plant species.

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steve Mcghee

YeAR 400

Low-lying cities throughout the

world are underwater. Large

parts of the Netherlands have

disappeared due to collapsed

dykes, but the ocean water levels

are also still rising. Even if we

stopped emitting greenhouse

gasses tomorrow, water levels

could still rise by 1.8 m until 2500

due to the long response times

of oceans and ice.

YeAR 300

Restored fresh water wetlands are

efficient water purification plants,

which absorb chemicals.

YeAR 500

The wildwood is back in Europe,

and the African jungle and Australia’s

eucalypt forests have regrown.

YeAR 1000

Flooded cities and sunken ships

have become new homes

for marine animals. The oceans

are filled with whales, tuna,

and sea turtles, and destroyed

coral reefs recover.


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Few traces of humans will remain after 1,000 years. But humans have managed to create a few things that will endure for a millennium or more - not all of them good.

Diamonds are forever

The Mona Lisa and other paintings have long

crumbled, but works of art made of gold and

precious stones will remain for more than 1,000

years – such as “The Love of God”, a human skull

made of titanium and studded with 8,601 dia-

monds. The jewels of royal treasuries and national

banks’ gold bars will also remain intact, as will

works of art made of ceramics, glass, marble, gra-

nite, and bronze, like the presidential faces of

Mount Rushmore, which are carved into granite.

the mount rushmore granite will

remain for 1,000+ years.

ART

We should build like the RomansIn Antiquity, the Romans used granite, sandstone, and marble, which can all last for more than 1,000 years. Plus a highly durable type of concrete consisting ofcalcium, crushed tiles, and volcanic ash.

The cupola of the Pantheon in Rome is made of this material and has nowremained for almost 1,900 years. Only a

few modern buildings are constructed to similar levels of toughness.

The Channel Tunnel will still link England and France

A millennium from now, only the ruins of very few

buildings will remain. Paradoxically, some of the

most ancient ones such as the Sphinx and the Gre-

at Pyramid of Giza are still around, protected by

the warm, dry climate. Sandblasted, they are

about to be swallowed by the desert, however.

The Great Wall of China has crumbled, but still

marks the landscape. Of modern structures, only

protected concrete buildings like military facilities

will remain, and the tunnel between France and

England still exists, as it was made in an intact

chalk layer and is unlikely to collapse.

GreaT survivors

of The aGe

of huMans

The Lascaux cave paintings, Southern France

The Sphinx of Egypt

The Great Pyramid of Giza

Bronze church bells, statues, and propellers

Mount Rushmore’s presidential faces

Venus de Milo – a marble statue

The tunnel between France and England

Military concrete facilities

Gold, silver, and other precious metals

Diamonds

STRUcTUReS

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dolls can remain for

1,000+ years in a dry,

oxygen-free

environment.

environmental toxins will remain on Earth long after

humans. Heavy metals like mer-

cury, lead, chromium, and cadmi-

um. Plus radioactive waste and

plastic like the polyethylene of

carrier bags.

Plastic will remain in the sea.

Humans left more than 100 milli-

on tonnes of plastic in the oce-

ansÐ including some of the 500

million straws used in the US

every day. Plastic leaves toxic

chemicals in the food chain.

The landscape still

features traces of humans after

1,000 years in the form of mines

and quarries. But the dams of the

Panama Canal and elsewhere

have long collapsed, and the

water has blazed its own trails.

TOxiNS ARe FOReveR

Cadmium compounds: 7,500 years

Lead compounds: 35,000 years

highly radioactive nuclear waste:

100,000 years

polyethylene, pCb, and pbDe: Unknown

WASTe · RUBBISH WIll Be OUR legAcY

SOMe ARTeFAcTS WIll

SURvIve In lAnDFIll

Mobile phones, computers, TVs, and other electronics

Wine bottles and glasses

Kitchen aids and tools made of plastic and stainless steel

Car/bike tyres + other rubber objects

Newspapers, magazines, and books

Shoes and bags

Dolls, Lego, and other plastic toys

Landfill will be the pyramids of our time Ironically, our waste will survive for at least a millennium or perhaps even longer.

Huge landfills dot the landscape in the form of hills containing objects, which reveal details about

human life on Earth. Deep inside a large landfill, which is dry like a pyramid and low in oxygen like a

bog, even newspapers and books can survive, along with millions of tonnes of domestic waste.

Today, itÕs a problem - in a distant future, our junk might be a boon to visiting aliens who want to

study the long-disappeared human race.

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toxic life cycle


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After Humans (Science Illustrated Australia - 24_2013)

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