Doomsday: 9 Real Ways the Earth Could End
Tia Ghose, LiveScience Staff Writer
From catastrophic climate change to hostile aliens, Hollywood routinely
envisions apocalyptic endings to humanity's stint on planet Earth.
For instance, in the movie "After Earth," opening in theaters Friday
(May 31), a series of earthquakes, floods, tsunamis and other natural
disasters makes the planet inhospitable to humans, who resettle on a new
world called Nova Prime.
But although the movie may be pure fantasy, many scientists are worried
about other perilous scenarios — some of which are even scarier than
anything that's been depicted on the silver screen.
From pandemic fungus to robot insurrection, here are 9 apocalyptic visions that scientists foresee.
1. Global warming
The mother of all apocalyptic fears, climate change is the biggest
threat facing the planet, many scientists say. Climate change could make
extreme weather more severe, increase droughts in some areas, change
the distribution of animals and diseases across the globe, and cause
low-lying areas of the planet to be submerged in the wake of rising sea
levels. The cascade of changes could lead to political instability,
severe drought, famine, ecosystem collapse and other changes that make
Earth a decidedly inhospitable place to live.
It's the mainstay of disaster movies, but scientists are legitimately
worried that a space rock could wipe out Earth. A meteor impact probably
doomed the dinosaurs, and in the Tunguska event, a massive meteoroid
damaged about 770 square miles (2,000 square kilometers) of the Siberian
forest in 1908. Even more frightening, perhaps, is that astronomers
only know about a fraction of the space rocks lurking in the solar system.
3. Pandemic threat
New deadly pathogens crop up every year: Recent pandemics have included outbreaks of SARS (severe acute respiratory syndrome), bird flu, and, most recently, a coronavirus called MERS
that originated in Saudi Arabia. And because of our highly
interconnected, global economy, a deadly disease could spread like
"The threat of a global pandemic is very real," said Joseph Miller,
co-author (along with Ken Miller) of the textbook "Biology" (Prentice
4. Fungus among us
Though bacterial threats are dangerous, fungal threats are even
scarier, said David Wake, curator at the Museum of Vertebrate Zoology at
the University of California, Berkeley.
"We've had a new amphibian fungal disease that has just had devastating
effects," Wake said of the chytrid fungus that is wiping out frogs
across the United States.
An equally fatal fungus in humans would be catastrophic. And though
bacteria are deadly, antibiotics are plentiful. By comparison, we know
much less about treating fungal infections, Wake told LiveScience.
5. Engineered disease
Natural diseases aren't the only ones to fear.
In 2011, the scientific community was outraged that researchers had engineered a mutant version of the bird flu
H5N1 that was transmissible in ferrets and transmitted via the air. The
results sparked fears that engineered deadly diseases could
inadvertently escape from the lab or be intentionally released, leading
to a global pandemic.
6. Nuclear war
Many scientists are still worried about the classic end-of-the-world
threat: global nuclear war. Beyond North Korean leader Kim Jong Un's
saber rattling and Iran's secretive nuclear efforts, massive stockpiles
of nuclear weapons around the globe could wreak destruction if they were
to get into the wrong hands. Last year, the Bulletin of the Atomic
Scientists, a nontechnical magazine on global security founded in 1945
by former Manhattan project physicists, moved the Doomsday Clock,
at five minutes to midnight. The Doomsday Clock shows how close
humanity is to destruction via nuclear or biological weapons or global
climate change. [7 Strange Cultural Facts About North Korea]
7. Robot ascension
"The Terminator" may be science fiction, but killing machines are not
far from reality. The United Nations recently called for a ban on killer
robots — presumably because experts worried that several countries were
Many computer scientists think the singularity,
the point at which artificial intelligence overtakes human
intelligence, is near. Whether those robots will be benevolent helpers
or the scourge of humanity is still up for debate. But a lot can go
wrong when there are hyperintelligent robots armed with lethal weapons
The fear of an overpopulated globe has been around since the 18th
century, when Thomas Malthus predicted that population growth would
cause mass starvation and overtax the planet. With the global population
at 7 billion and counting, many conservationists think population growth
is one of the key threats to the planet. Of course, not everyone
agrees: Many think population growth will stabilize in the next 50
years, and that humanity will innovate its way out of the negative
consequences of the overcrowding that does occur.
9. Snowball effect
Though each of these scenarios could happen, most scientists think a
snowball effect of multiple events is more likely, Miller said. For
instance, global warming
could increase the prevalence of pathogens while also causing
widespread shifts in climate. Meanwhile, ecosystem collapse could make
it slightly harder to produce food, with no bees to pollinate crops or
trees to filter agricultural water. So, instead of an epic catastrophe,
several relatively small factors would slightly worsen life on Earth
until it gradually degraded, Miller said.
In that scenario, the downfall of Earth is not dramatic, "like being
attacked by a saber-toothed tiger," Miller told LiveScience. "It's more
like being nibbled to death by ducks."http://www.livescience.com/36999-top-scientists-world-enders.html