What would happen if every human suddenly disappeared Dan Kwartler
Human beings are everywhere.
With settlements on every continent,
we can be found in the most isolated
corners of Earth’s jungles,
oceans,
and tundras.
Our impact is so profound,
most scientists believe
humanity has left a permanent mark
on Earth’s geological record.
So what would happen if suddenly,
every human on Earth disappeared?
With no one maintaining them, some
of our creations backfire immediately.
Hours after we disappear,
oil refineries malfunction,
producing month-long blazes at
plants like the ones in western India,
the southern United States,
and South Korea.
In underground rail systems
like those in London,
Moscow,
and New York City,
hundreds of drainage pumps are abandoned,
flooding the tunnels in just three days.
By the end of the first week,
most emergency generators have shut down,
and once the fires have gone out,
the earth goes dark
for the first time in centuries.
After the first catastrophic month,
changes come more gradually.
Within 20 years, sidewalks have been
torn apart by weeds and tree roots.
Around this time,
flooded tunnels erode
the streets above into urban rivers.
In temperate climates,
the cycle of seasons freezes
and thaws these waterways,
cracking pavement
and concrete foundations.
Leaking pipes cause the same reaction
in concrete buildings,
and within 200 winters, most skyscrapers
buckle and tumble down.
In cities built in river deltas
like Houston,
these buildings
eventually wash away completely -
filling nearby tributaries
with crushed concrete.
Rural and suburban areas
decay more slowly,
but in largely unsurprising ways.
Leaks, mold, bug
and rodent infestations -
all the usual enemies of the homeowner-
now go uncontested.
Within 75 years, most houses'
supporting beams have rotted and sagged,
and the resulting collapsed heap
is now home to local rodents and lizards.
But in this post-human world,
“local” has a new meaning.
Our cities are full of imported plants,
which now run wild across
their adopted homes.
Water hyacinth coat the waterways
of Shanghai in a thick green carpet.
Poisonous giant hogweeds overgrow
the banks of London’s Thames River.
Chinese Ailanthus trees burst
through New York City streets.
And as sunken skyscrapers add
crumbled concrete to the new forest floor,
the soil acidity plummets,
potentially allowing
new plant life to thrive.
This post-human biodiversity
extends into the animal kingdom, as well.
Animals follow the unchecked
spread of native and non-native plants,
venturing into new habitats
with the help of our leftover bridges.
In general, our infrastructure
saves some animals and dooms others.
Cockroaches continue to thrive
in their native tropical habitats,
but without our heating systems,
their urban cousins likely freeze
and die out in just two winters.
And most domesticated animals
are unable to survive without us –
save for a handful of resourceful pigs,
dogs, and feral housecats.
Conversely, the reduced light pollution
saves over a billion birds each year
whose migrations were disrupted
by blinking communication tower lights
and high-tension wires.
And mosquitos multiply endlessly in one
of their favorite manmade nurseries –
rubber tires, which last
for almost a thousand years.
As fauna and flora flourish,
Earth’s climate slowly recovers
from millennia of human impact.
Within 35,000 years,
the plant cycle removes
the last traces of lead
left by the Industrial Revolution
from Earth’s soil,
and it may take
up to 65,000 years beyond that
for CO2 to return pre-human levels.
But even after several million years,
humanity’s legacy lives on.
Carved in unyielding granite,
America’s Mt. Rushmore
survives for 7.2 million years.
The chemical composition
of our bronze sculptures
keeps them recognizable
for over 10 million.
And buried deep underground,
the remnants of cities
built on floodplains
have been preserved in time
as a kind of technofossil.
Eventually, these traces, too,
will be wiped from the planet’s surface.
Humanity hasn’t always been here,
and we won’t be here forever.
But by investigating the world without us,
perhaps we can learn more
about the world we live in now.