Forget global warming, worry about the MAGNETOSPHERE: Earth's magnetic field is collapsing and it could affect the climate and wipe out power grids
- Earth's magnetic field has weakened by 15 per cent over the last 200 years
- Could be a sign that the planet's north and south poles are about to flip
- If this happens, solar winds could punch holes into the Earth's ozone layer
- This could damage power grids, affect weather and increase cancer rates
- Evidence of flip happening in the past has been uncovered in pottery
- As the magnetic shield weakens, the spectacle of an aurora would be visible every night all over the Earth
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Deep within the Earth, a
fierce molten core is generating a magnetic field capable of defending
our planet against devastating solar winds.
The
protective field extends thousands of miles into space and its
magnetism affects everything from global communication to animal
migration and weather patterns.
But this magnetic field, so important to life on Earth, has weakened by 15 per cent over the last 200 years. And this, scientists claim, could be a sign that the Earth’s poles are about to flip.
Experts believe we're currently overdue a flip, but they're unsure when this could occur.
If a switch happens, we would be exposed to solar winds capable of punching holes into the ozone layer.
The
impact could be devastating for mankind, knocking out power grids,
radically changing Earth’s climate and driving up rates of cancer.
‘This
is serious business’, Richard Holme, Professor of Earth, Ocean and
Ecological Sciences at Liverpool University told MailOnline. ‘Imagine
for a moment your electrical power supply was knocked out for a few
months – very little works without electricity these days.’
The Earth's climate would
change drastically. In fact, a recent Danish study believes global
warming is directly related to the magnetic field rather than CO2
emissions.
The
study claimed that the planet is experiencing a natural period of low
cloud cover due to fewer cosmic rays entering the atmosphere.
Radiation at ground level would
also increase, with some estimates suggesting overall exposure to cosmic
radiation would double causing more deaths from cancer.
Researchers predict that in the event of a flip, every year a hundred thousand
people would die from the increased levels of space radiation.
'Radiation
could be 3-5 times greater than that from the man-made ozone holes.
Furthermore, the ozone holes would be larger and longer-lived,' said Dr Colin Forsyth from the Mullard Space Science Laboratory at UCL.
The magnetosphere is a large area around the
Earth produced by the planet's magnetic field. It presence means that
charged particles of the solar wind are unable to cross the magnetic
field lines and are deflected around the Earth
The
magnetosphere is a large area around the Earth produced by the planet’s
magnetic field. It presence means that charged particles of the solar
wind are unable to cross the magnetic field lines and are deflected
around the Earth.
Space
agencies are now taking the threat seriously. In November, three
spacecraft were launched as part of the SWARM mission to uncover how the
Earth’s magnetic field is changing.
The
mission plans to provide better maps of our planet's magnetic field and
help scientists understand the impact of space weather on satellite
communication and GPS.
‘Whilst we have a basic understanding of the interior of the Earth, there is much we still don’t know,’ said Dr Forsyth.
‘We
do not fully understand how the Earth’s magnetic field is generated,
why it is variable and the timescales of these variations.’
The
mission will provide a current map of Earth’s magnetic field. But
historic evidence of its decline has already been found in a surprising
source – ancient pottery.
Scientists
have discovered that ancient pots can act as a magnetic time capsule.
This is because they contain an iron-based mineral called magnetite.
When pots form, the magnetite minerals align with the Earth’s magnetic
field, just like compass needles.
WHAT IS GEOMAGNETIC REVERSAL?
The Earth’s magnetic field is
in a permanent state of change. Magnetic north drifts around and every
few hundred thousand years the polarity flips so a compass would point
south instead of north. The strength of the magnetic field also
constantly changes and currently it is showing signs of significant
weakening.
The Earth
magnetic field is mainly generated in the very hot molten core of the
planet. The magnetic field is basically a dipole (it has a North and a
South Pole). Magnetic reversal or flip is the process by which the North
Pole is transformed into the South and vice versa, typically following a
considerable reduction in the strength of the magnetic field. However,
weakening of the magnetic field does not always result in a reversal.
During
a reversal, scientists expect to see more complicated field pattern at
the Earth's surface, with perhaps more than one North and South Pole at
any given time. The overall strength of the field, anywhere on the
Earth, may be no more than a tenth of its strength now.
The Earth's magnetic field is generated in the
very hot molten core of the planet. Scientists believe Mars used to have
a magnetic field similar to that on Earth which protected its
atmosphere
By examining pottery
from prehistory to modern times, scientists have discovered just how
dramatically the field has changed in the last few centuries.
They’ve
found that Earth’s magnetic field is in a permanent state of flux.
Magnetic north drifts and every few hundred thousand years the polarity
flips so a compass would point south instead of north.
If
the magnetic field continues to decline, over billions of years, Earth
could end up like Mars - a once oceanic world that has become a dry,
barren planet incapable of supporting life.
WHAT ARE THE DANGERS OF A MAGNETIC FLIP?
Life has existed on the Earth for billions of years, during which there have been many reversals.
There
is no obvious correlation between animal extinctions and those
reversals. Likewise, reversal patterns do not have any correlation with
human development and evolution.
It
appears that some animals, such as whales and some birds use Earth's
magnetic field for migration and direction finding.
Since geomagnetic
reversal takes a number of thousands of years, they could well adapt to
the changing magnetic environment or develop different methods of
navigation.
Radiation
at ground level would increase, however, with some estimates suggesting that overall
exposure to cosmic radiation would double causing more deaths from
cancer. ‘But only slightly,’ said Professor Richard Holme.
‘And
much less than lying on the beach in Florida for a day. So if it
happened, the protection method would probably be to wear a big floppy
hat.’
Electric grid
collapse from severe solar storms is a major risk. As the magnetic field
continues to weaken, scientists are highlighting the importance off-the
grid energy systems using renewable energy sources to protect the Earth
against a black out.
'The very highly charged particles can
have a deleterious effect on the satellites and astronauts,' added Dr
Mona Kessel, a Magnetosphere discipline scientist at Nasa.
In one area, there is evidence
that a flip is already occurring. ‘The increasing strength of the South
Atlantic anomaly, an area of weak field over Brazil, is already a
problem,’ said Professor Richard Holme.
The
Earth's climate could also change. A recent Danish study has found that
the earth's weather has been significantly affected by the planet's
magnetic field.
They
claimed that fluctuations in the number of cosmic rays hitting the
atmosphere directly alter the amount of cloud covering the planet.
Henrik
Svensmark, a weather scientist at the Danish National Space Centre who
led the team behind the research, believes that the planet is
experiencing a natural period of low cloud cover due to fewer cosmic
rays entering the atmosphere.
But
scientists claim the rate of decline is too fast for the Earth’s core
to simply burn out. Instead, the story told by ancient pottery suggests
the Earth's poles could be about to undergo another flip.
According
to the British Geological Survey, the Earth's magnetic field has on
average four or five reversals in polarity every million years and we’re
now overdue a similar event.
‘At
the moment, we cannot accurately determine whether or not the Earth’s
field is about to flip,’ said Dr Forsyth. ‘We have only been recording
the Earth’s field for around 170 years; about 1-15 per cent of the time a
flip is expected to take.’
If
a flip occurs, it would cause the Earth’s magnetic shield to be
weakened for thousands of years, opening up our defences and causing
cosmic radiation to get through.
'We have a double layer defence shield,' said Jim Wild a space scientists at Lancaster University.
'Space is full of
stuff that’s not great for biological tissue. If we didn’t have an atmosphere,
that stuff would be hitting us. It’s the magnetic field protects atmosphere
from the solar wind.'
‘Some speculative
studies have suggested that as the Earth’s magnetic field weakens we
could see an increase in cloud coverage in the troposphere and an
increase in the polar ozone holes,’ added Dr Forsyth.
‘This
would be particularly evident in the northern hemisphere where up to 40
per cent of the ozone within the hole region could be lost, far greater
than the current losses.’
In
fact, in one area, there is evidence that a flip is already occurring.
‘The increasing strength of the South Atlantic anomaly, an area of weak
field over Brazil, is already a problem,’ said Professor Holme.
Not all of the effects of a weak magnetic field
will be bad. The much sought-after spectacle of an aurora would be
visible every night all over the Earth as solar winds hit the atmosphere
‘Satellites flying over
have far more problems than in other locations. Astrophysical satellite
are just switched off in this location, but from my perspective, this
isn’t much good if you want to study the Brazilian rainforest.’
'The
very highly charged particles can have a deleterious effect on the
satellites and astronauts,' added Dr Mona Kessel, a Magnetosphere
discipline scientist at Nasa.
Scientists
however, are quick to point out that while a magnetic flip could cause
problems for mankind, the event won’t be a catastrophic.
‘We’ve
had many reversals in the past, and haven’t been able to show that they
had anything to do with, for example, mass extinctions,’ said Professor
Holme.
And not all of the
effects will be bad. The much sought-after spectacle of an aurora would
be visible every night all over the Earth as solar winds hit the
atmosphere.
There remains, however, much work yet to be done in understanding the properties of the deep Earth.
The
Earth’s core is a hostile world where the crushing forces and
temperatures, similar to that of the surface of the sun, take our
scientific understanding and abilities to the limit.
'This
isn't some crazy theory that might happen,' said Professor Wild. 'There
is evidence, but we still need to do more science to understand the
impact...I'm confident we can come up with a solution.'
WHAT IS THE SWARM MISSION?
The
mission consists of three identical satellites which will precisely
measure the strength and direction of Earth's magnetic field. The new
data will be processed by British Geological Survey to produce an
accurate map of this field.
In
order to best measure the field, the satellites will orbit in a unique
configuration. Two satellites will fly side-by-side at height of 450 km,
while the third satellite will fly at an altitude of 530 km.
The
lower two satellites will allow very fine measurements of the magnetic
field generated by the rocks in the Earth's crust, which are difficult
to detect otherwise. The upper satellite will give a simultaneous
measurement at a different location.
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