With a year packed full of strong solar flares
affecting communications, future volcanic predictions and giant
asteroids passing dangerously close to Earth, what kind of cataclysmic
events are most likely to push humans to the brink of extinction? We
look at some of the most popular doomsday theories and examine whether
these five natural phenomena could end the world as we know it – or
whether they are just pure science fiction.
Meteorites and asteroids
Giant pieces of rock falling from space made exciting plots for ‘90s sci-fi movies like ‘Armageddon’ and ‘Deep Impact’.
Meteorite impact or The ‘Alvarez’ hypothesis met criticism when the
theory was first raised in 1980, but it has since been widely accepted
that a meteorite strike could have actually wiped out the whole dinosaur
population over 65 million years ago.
The last known meteorite to hit Earth,
causing significant damage, was in 1908 when a meteorite the size of a
ten-storey building exploded over Siberia, flattening 80 million trees
over 2,000 square kilometres near the Tunguska River. Luckily, the
region was so remote that the strike didn’t harm anyone. Programme
scientist for Near Earth Objects at NASA told Yahoo! News: “Such an
event releases energies on the order of a few megatons of TNT, because
of the velocity at which they impact – many kilometres per second. The
Hiroshima atomic bomb released the equivalent of about 15 kilotons of
TNT. So even relatively small asteroids could cause the damage
equivalent to a very large nuclear weapon if they were to strike the
Earth.”
Russian
scientists have issued some more apocalyptic predictions. An asteroid
dubbed ‘Apophis’, estimated to be the size of two football fields, could
collide with Earth as early as 16 April 2036 if a change in gravity
causes it to fall out of its orbit. While they admit it is theoretically
possible for the asteroid to hit Earth, they note that the chances are
remote; in fact, they put the odds at one in 233,000. Sergei Smirnov, a
spokesman at St. Petersburg's Pulkovo Observatory, said: “How much of a
threat this asteroid actually presents will be impossible to assess
until 2028, when it approaches our planet. If it does strike, our planet
will face a continental disaster and major climate change. And if the asteroid falls into an ocean, the disaster could assume global proportions.”
[Related feature: Dates the world was supposed to end]
Powerful
solar storms exactly like the ones the world witnessed at the beginning
of 2011 occur once every eleven years as the sun’s magnetic field flips
over. ‘Solar Cycle 24’ has been building gradually with the number of
sunspots and solar storms set to reach a ‘solar maximum’ by 2013. Super solar flares
send great geysers of hot gas and huge quantities of charged particles
erupting from the surface into space. These flares of charged particles,
called ‘coronal mass ejections’, slam into the Earth's magnetic shield
impairing electrical devices in their path.
In 1859, the
‘Carrington Event’, a solar flare which lasted eight days, wreaked havoc
on all of the world’s telegraphs and set buildings on fire. The
National Academy of Sciences says that in modern times the solar flares
could knock out 300 important transformers within 90 seconds and cut
power for 130 million people. They also estimated that during the first
year after a solar storm, damage could be as high as £1.2 trillion with a
recovery time of four to ten years. A spokeswoman from the Heliophysics
division at NASA told Yahoo! News: “Saying solar flares
would end the world is a little drastic. But in terms of affecting us
as humans, it is very damaging to our lifestyles; it can destroy
communications that we are very dependent on, like power lines and GPS
satellites.”
As the sun is said to become more turbulent as it
approaches the peak in its activity cycle around 2013, the UK
government’s chief scientific adviser, Professor Sir John Beddington,
warned: “We've had a relatively quiet period of space weather. We can't
expect that quiet period to continue. At the same time over that period
the potential vulnerability of our systems has increased dramatically,
whether it is the smart grid in our electricity systems or the
ubiquitous use of GPS in just about everything we use these days. The
situation has changed. We need to be thinking about the ability both to
categorise and explain and give early warning when particular types of
space weather are likely to occur.”
Pole shift
According
to some modern astronomers and an ancient Mayan prophecy, on the winter
solstice of 21 December 2012, Earth will be in exact alignment with the
sun and the centre of the Milky Way galaxy - an extraordinary event
which happens once every 25,800 years. No one knows exactly what effect
this alignment will have on Earth, but the Mayans believed that the
consequences of the inter-galactic occurrence would be catastrophic,
prompting the world’s end. It is imagined that a magnetic field effect
reversal will take place, where the entire mantle of the earth would
shift in a matter of days, changing the position of the North and the
South Pole. Such a rapid change in the Earth’s dynamics would result in
earthquakes, tsunamis, global climatic change and eventually the
ultimate planetary disaster, similar to the one depicted in the disaster
movie ‘2012’.
Despite their beliefs, polar shift has been backed
by some scientists, albeit not at the rapidity the Mayans believed.
Renowned scientist Albert Einstein is known to have been an advocator of
the theory and according to a 2006 study by Princeton University,
geologist, Adam Maloof said that the Earth’s poles have shifted before.
The study found that the North Pole could have rested in the middle of
the Pacific Ocean 800 million years ago, placing the state of Alaska as
far south as the equator.
However, NASA disagrees, predicting
that the polar shift event will not mean that Earth meets it fate.
Experts debunked the theory, saying: “Nothing bad will happen to Earth
in 2012. Our planet has been getting along just fine for more than four
billion years, and credible scientists worldwide know of no threat
associated with 2012. There are no planetary alignments in the next few
decades, Earth will not cross the galactic plane in 2012, and even if
these alignments were to occur, their effects on the Earth would be
negligible.”
Super volcano eruptions
2010’s
eruption of Eyjafjallajokull in Iceland brought air travel across
Northern Europe to a virtual standstill, but if one of the largest known
super volcanoes was to blow, it could cause a global disaster of
biblical proportions. According to volcanologists, the last super
volcano to erupt was Mount Toba in Sumatra, Indonesia, 75,000 years ago.
Thousands of cubic kilometres of ash and sulphur dioxide were thrown
into the atmosphere - so much that it blocked out light from the sun all
over the world, resulting in global temperatures plummeting by 21°c. It
is imagined that black acidic rain would have fallen due to gas
poisoning. Such an event supposedly eradicated mankind, cutting the
population to just a couple of thousand people, and three quarters of
all living plants in the northern hemisphere are thought to have been
killed.
Now international scientists speak about the possibility
of a future eruption of one of the largest known prehistoric volcanoes -
the Yellowstone caldera in Wyoming, which sits above a large magma
chamber and is showing more signs of activity. Observers say that an
eruption would result in a mega disaster coating half the US in a layer
of ash up to one metre deep, killing livestock and putting thousands of
human lives at risk. Scientists say that it typically erupts every
600,000 years, but the last eruption occurred 640,000 years ago, meaning
the next one is long overdue.
Global warming
Should
the Earth’s average temperature continue to rise at the rate it has
done over the last 50 years, the face of the Earth as we know it will
change, say climatologists. The reasons for this type of man-made climate change
have been well-documented and the Intergovernmental Panel on Climate
Change (IPCC) says it’s not too late to save our planet as leading
figures try to stop the ill-effects that the Earth’s population and
living species will experience from the so-called ‘greenhouse effect’
before the world becomes unbearable for man to live in.
The IPCC
has drafted the worst-case scenario. According to an assessment of how
global warming could progress beyond 2100 - the normal time frame of
model predictions - if temperatures rise by even 6°C rainforests will be
wiped out, fertility of many soils will be destroyed and the Arctic
will be left ice-free even in midwinter. London will be as hot as Cairo
with air quality so poor it would endanger human respiratory systems.
The world’s most populous low-lying cities like Tokyo, New York, Mumbai,
Shanghai and Dhaka will be engulfed by floods after an eleven-metre
rise in sea levels. Extreme weather events, like hurricanes and droughts
will become more common, with climate change spreading more infectious
diseases.
Doctors
warn that global warming will also create more heat-related deaths from
cardiovascular problems and strokes. Young children and the elderly
will be especially vulnerable to higher temperatures. Scientists claim
that humanity will be reduced to a few last survivors living near the
poles with it eventually going extinct over the next couple of centuries
if we don’t stop emissions.
When Yahoo! News asked The Union of
Concerned Scientists about what impact global warming is having on our
world, they maintained: “While higher temperatures and rising sea levels
resulting from climate change may make some parts of the world effectively uninhabitable, it would not be scientifically accurate to put climate change in the same world-ending category as impact by a large asteroid. Instead, we should think of climate change as presenting us challenges for which we must prepare as well as opportunities for reducing emissions and the associated climate change risks that come with them.”
credit: yahoo news
