<p>Yes, it is not just possible, but highly probable.</p>

<p>Detailed palaeomagnetic data have revealed how the Earth's magnetic field changes in a polarity shift. In relative terms (time scale inaccurately known) there is a slow decrease to &lt;10% of the normal field intensity. After an uncertain interval the field intensity picks up to some 20 or 30% of the normal field intensity during a relatively brief spike. Then another low field intensity interval, and finally it picks up to full field intensity - of either normal or reversed polarity.</p>

<p>This has never happened in real-time during the scientific era, so the effects are necessarily speculative. Amongst the expected effects would be:</p>

<ol>
<li><p>Vulnerability of satellites, power lines and communications to the effects of solar storms.</p></li>
<li><p>Increased UV, and hence increased incidence of skin cancer.</p></li>
<li><p>All sorts of changing physico-chemical processes in the upper atmosphere, of which the weakening ozone layer would be the most alarming.</p></li>
</ol>

<p>On average these magnetic flips occur about every 11,000 to 12,000 years - although there is a great deal of variation. On this basis the next one is about due.</p>

<p>It won't be lethal. Neanderthals, Denisovans and Hom.sap's prehistoric forebears survived the last magnetic flip, but it will be inconvenient, and probably not without a serious health impact.</p>

CC BY-SA 3.0
2015-10-28T11:03:50.350Z
It might not be _directly_ lethal to organisms on the planet but given the fragility of the current global politico-economic system, I suspect it might be a tad more than _inconvenient_. Knockout of GPS, satcoms and mobile telephony would be enough to trigger an economic recession at the very least. If electricity production and distribution was affected (cf. _Carrington Event_ https://en.wikipedia.org/wiki/Solar_storm_of_1859), we could expect severe civil disruption. Wars and governmental collapse in some regions could not be excluded. So yes, _a serious health impact_.
Oscar Bravo
CC BY-SA 3.0
2015-10-28T11:46:15.507Z
@OwenBoyle Wars?  Why?  Soldiers cannot read maps and will accidentally stray into enemy territory?
gerrit
CC BY-SA 3.0
2015-10-28T15:09:17.533Z
@gerrit No electricity means discomfort and hardship. No communications means general unrest, lower productivity, and slower response times of things like police and emergency services, as well as making it harder to clear up the inevitable disagreements before things turn nasty. So you've got the populace enduring hardship, getting angry, and feeling they aren't being listened to who, and a government who's slow to respond and lacking their usual level of situational awareness and technological advantage. In short, the playing field is more level and the civilians are angry. Tinderbox.
anaximander
CC BY-SA 3.0
2015-10-28T15:14:04.760Z
@gerrit Wars *between nations* (as opposed to civil wars) are less likely. Still, recent history shows that supposedly internal matters like that rarely stay internal (Ukraine, Syria, etc) - neighbours often get involved. It's possible that in some of the more volatile parts of the world, a nation might take offence to this interference and oppose it, and with reduced intel and comms down, force may be the only way available (or at least, a more attractive option). There's also a few places where one side might see it as an opportunity to settle a grudge while their opponent is crippled.
anaximander
CC BY-SA 3.0
2015-10-28T19:52:02.840Z
@OwenBoyle: to my knowledge, GPS, satcoms and mobile telephony are not at all dependant on the Earth's magnetic field polarity. Unless the field's *intensity* rises enough and fast enough to fry electronics, I don't see how they would be affected. Or did I miss something? I think the only tecnology to break just by polarity would be compass-based navigation (very important for ships and airplanes)
Emilio M Bumachar
CC BY-SA 3.0
2015-10-28T20:06:48.030Z
Why would UV doses increase? As it's comprised of (uncharged) photons, it is unaffected by the magnetic field, but is blocked by ozone. Would the geomagnetic reversal affect the ozone layer somehow?
Nick T
CC BY-SA 3.0
2015-10-29T01:22:20.553Z
Although the rate of change of magnetic intensity is not clear, it is probably in the order of decades. In principle, therefore we could adapt fast enough to cope. One example: by accelerating the current trend to local renewable electricity generation and storage, which would not be greatly influenced by a change in the Earth's magnetic field. On the other hand, the world's painfully slow response to climate change doesn't fill one with optimism!
Gordon Stanger
CC BY-SA 3.0
2015-10-29T01:36:32.230Z
Regarding ozone, it isn't the magnetic reversal as such that is the problem; it is the weakening of the Earth's magnetic field during the transition that allows more cosmic rays and solar wind (charged particles) to disrupt the normal equilibrium between ozone synthesis and decay. Such disruption occurs all the time due to solar storms, atmospheric pollutants and seasonal daylight hours. The extent to which this would be exacerbated by a weakening magnetic field is debatable, but the consensus is that the ozone depletion would be 'huge'.
Gordon Stanger
CC BY-SA 3.0
2015-10-29T04:28:28.963Z
@EmilioMBumachar the *reduction* of the field during the reversal greatly decreases Earth's protection from the solar proton flux, which means satellites would be much more likely to be killed by solar storms. And although I'm not sure, the interaction of the proton flux with the remnant magnetic field could also cause larger geomagnetic storms than we have today, interfering with power grids and ground-based communications.
hobbs
CC BY-SA 3.0
2015-10-30T07:36:52.157Z
As pointed out above, the magnetic field isn't just a handy help for navigators. It is an essential element in protecting us from solar storms. A _Carrington Event_ hitting us when the shields are down would blow us back to the 1850s. Then we'd get 1850s-style politics and war-mongering again.
Oscar Bravo
CC BY-SA 3.0
2015-10-28T07:30:54.653Z
2015-10-28T12:49:51.093Z
2015-10-28T12:49:51.093Z
Gordon Stanger
<p>Please consider that the strength of the magnetic field determines atmospheric density and pressure. Planets with strong magnetic fields have thick oceans and atmosphere, while planets with very weak magnetic fields have no oceans and very thin atmosphere. That's because hydrogen atoms from solar winds are attracted and condensed around magnetic fields and the strength of the MF dictates the atmospheric density, and atmospheric pressure dictates the ocean levels.
Mars for example shows signs of erosion as it had oceans and atmosphere but when the dynamo inside went through a hard double flip (most probably) and slowed down so much, cooled down so much that it could never recover, the atmosphere was blown away by solar winds, oceans boiled away, etc. Mars's gravity field doesn't explain how it lost its oceans and atmosphere when Earth still has them. Mars's gravity field didn't change, it lost its magnetic field. 
Jupiter's bigger moons have thick ocean frozen at the surface (frozen because of distance from the Sun) but they are smaller than Mars and have strong magnetic fields.. So size and amount of pressure inside doesn't necessarily mean a stronger magnetic field,, what all planets and terrestrial moons with strong MF have in common is an inner core that makes a small orbit around the center of the planet/moon, because of tidal effect (gravitational pull) from a big body nearby. For example, Earth's inner core is attracted by our big and heavy Moon, and it's not spinning in the dead center of Earth but has a small orbit around the center, planar to the Moon's orbit, and it stirs the soup inside as Earth spins on itself. It keeps the soup warm and generates friction thus electric currents, thus electromagnetism.
Jupiter's moons have their inner core drawing a larger orbit inside as they (moons) spin on themselves, their core is off-centered toward Jupiter.
Our Moon is actually the big core of an ancient planet that collided with our former (smaller) planet about 4.5 Billion years ago. Their liquid matter blobbed together and the smaller core bounced from the explosion as just the right speed and angle to stabilize on orbit, and the little bit of liquid matter on it cooled fast with a tide towards Earth, witch is the heavier side of the Moon that always point to Earth. With time it gathered the splash from the collision. It's a big metal core with a thin crust and this is why it rings like a bell and the craters are all shallow.
So anyway.. we're very lucky to have the Moon because otherwise Earth would be like Mars right now. Mars doesn't have a big moon so its core just spins in the center and doesn't generate enough friction. Maybe it had a moon before, with an unstable orbit destined to swing away..
Now, why does our MF tend to flip every 12-13000 years, or twice every Great Year (Precession of the Equinoxes, a 26000-year Milankovitch Cycle when the Earth's spin tilt axis wobbles 360*)?
I think it's because there are 2 critical tilt angles, during the Precession,, where the spin inertia of the iron currents, plus the angle of the inner core's orbit (planar to the Moon's orbit, not the same angle as the Earth's rotation axis),, plus the difference in speed (earth spins on itself in one day while the Moon takes 27.3 days to go around Earth),,, produce electric currents that don't agree with the magnetic field orientation and forces it to either reverse or migrate..
(to visualize this, have a pot of sauce that represents Earth, a wooden spoon that represents the inner core and an imaginary moon that goes around the pot in 27 days. Turn the pot of sauce continually to simulate earth's rotation and imagine it's tilted 23.4*,, and place the spoon (core) off-centered in the pot and tilt the spoon to simulate the difference in angles of the Earth's spin and of the moon's orbit plane. As you spin the pot, continuously, slowly orbit the spoon in the same time as your imaginary moon,, and see the currents you're generating in the sauce.. Then slowly change the tilt of the spoon to simulate Earth's precession.. It sounds fun? Do this to really get a visual)..
Now during the reversal or excursion process, the convection currents need to reorient and mix and slow down, producing less friction thus less electromagnetism, so the atmosphere gets thinner and filters out less solar and cosmic radiation. Less friction also means less heat produced inside the planet, so the volume of the planet has to shrink a little bit, and that explains the spike in seismic and volcanic activity around the Peak.
What explains how ocean levels can drop 400ft? Well if the atmosphere is thin during the day, then raw solar radiation evaporates tons and tons of ocean surface and during the night it gets very cold so all the moisture in the air has to precipitate within hours. Most of it falls back in the oceans and on land, and some of it becomes atmosphere and is eventually blown away by solar winds. That explains the biblical amounts of precipitations and erosion (Grand Canyon fills up and deserts turn into seas and the northern atmosphere is covered with very thick glaciers, big mammals flash frozen, etc).. Flash frost is also explained by rapid atmospheric density drop when a CME impacts the already thin atmosphere and temporarily blows some of it away: pressure drops fast and flash-freezes everything at the surface.
A thin atmosphere also explains the number of meteorite impacts because meteors rain down every day but usually burn with friction, blow up into small bits and only tiny bits of metal reach the ground,, but when the atmosphere is thin, meteors have much less friction so better chances to hit the ground in bigger chunks.
Those 2 critical tilt angles during the Precession are:
one as we enter Leo (the stronger magnetic Excursions (double flips) like the Gothenburg Magnetic Excursion 13000 years ago and the Leschamp Magnetic Excursion 40000 years ago, etc)
and the other one as we enter Aquarius (the mild semi-reversals (also calles Excursions) like now, or like the Lake Mungo Magnetic Excursion 26000 years ago,, etc).
This is all over ancient civilizations calendars, like the Mayan calendar, etc. For Example, the Sphinx was pointing Leo 13000 years ago, but was probably built 11000 years ago after the Younger Dryas warming, as a big immortal monument to commemorate this strong event that almost got us extinct.
Also, one important principal, heat generated inside the planet goes up slowly through the crust, then slowly raises up in the oceans, then joins the heat on the surface from solar radiations, and that heat has to go up in the atmosphere to reach the space vacuum.. The stronger the magnetic field and the thicker the oceans and the atmosphere,,, and the slower heat can reach up into space. Vice-versa, the thinner the oceans and atmosphere and the faster heat can reach up into space..
We could say that at Peak, a typical day would be like: super windy as almost unfiltered solar radiation expands the air very rapidly,, then all day would feel like a super hot sauna with tons of melting and floods, and evaporation would look like a steam engine.. Then, as the Sun starts to set the sky veils with thick condensation. Shortly after, deluges and super flash floods, turning into super ice storm breafly, then meters of snow until the air is dry and very cold, like -50C (moisture can stay in the air up to -20C but lower than that, all humidity is already deposited, so all moisture in the air has to deposit within a few hours)... Then, in the morning it starts all over again. Sometimes when there is a CME impact, it gets worse.
OK, I'll stop here, will elaborate more if there is interest.. Please give me feedback,, wherever I'm wrong and how I should rethink.. Thanks</p>

CC BY-SA 4.0
2019-01-11T20:46:58.973Z
This is wrong on so many accounts, I wouldn't even know where to begin, but your final sentence in which you ask what's wrong and where you should rethink, obviously means that this all is how you think things should be and not what you've learned through acquired knowledge.
BillDOe
CC BY-SA 4.0
2019-01-11T20:50:39.893Z
Please do begin :)
daniel brastaviceanu
CC BY-SA 4.0
2019-01-11T22:36:41.873Z
Please guys,, if you down vote my comment, I would like to know why.. That's what I would do anyways. I would like to have at least a short constructive feedback. Thanks!
daniel brastaviceanu
CC BY-SA 4.0
2019-01-11T22:41:37.683Z
And if you up vote a comment that says my comment ''is wrong on so many accounts'' but then doesn't elaborate and doesn't justify,, then what kind of ''community'' is this? I was expecting constructive criticism and a decent argument. This is kind of disappointing.
daniel brastaviceanu
CC BY-SA 4.0
2019-01-11T23:37:47.067Z
I'm downvoting because it's unreadable. Have you ever heard of paragraphs? Proper punctuation? This is a wall of text.
Gimelist
CC BY-SA 4.0
2019-01-11T23:48:52.033Z
A.) I didn't downvote; B.) There's not enough space in comments to itemize everything you've gotten wrong; C.) Stack Exchange is a question and answer forum, not discussion, nor is it a place to air your hypotheses.
BillDOe
CC BY-SA 4.0
2019-01-12T00:31:03.667Z
In this case here, my answer is as good as anyone's answer. I've read many papers on this subject for the past 10 years and all have different views.. I've gathered the pieces of puzzle that matched together and build my own view of the forest. Anyone's answer here is the result of more or less the same process, +/- interdisciplinary knowledge and judgement.
daniel brastaviceanu
CC BY-SA 4.0
2019-01-12T00:37:55.137Z
This is a very important subject because it is happening and we need to prepare. This kind of event is catastrophic. Evidence of this is overwhelming and any ''answer'' that says ''it's nothing to be worried about'' is misleading readers who come here for good answers.
daniel brastaviceanu
CC BY-SA 4.0
2019-01-12T01:10:56.230Z
I edited my comment some time ago and saved, but the changes didn't appear and now the comment is light gray. Why is this?
daniel brastaviceanu
CC BY-SA 4.0
2019-01-12T07:42:38.460Z
you did only expand the wall of text with the edit,you made the wall of text less readable.
trond hansen
CC BY-SA 4.0
2019-01-12T14:14:17.757Z
Is this all that is wrong with my answer? That it's "unreadable"? Please expand on the content of my answer. Is the information useful for anyone seeking to understand the phenomenon?
daniel brastaviceanu
CC BY-SA 4.0
2019-02-18T04:06:35.580Z
It is hard to expand on the content of your answer if it is hard to digest the information presented in it due to formatting. If you make the information easier to read, then it will be easier to determine if the information presented is useful.
Jon P
CC BY-SA 4.0
2019-01-11T19:45:33.833Z
2019-01-12T00:14:51.647Z
2019-01-12T00:14:51.647Z
daniel brastaviceanu
<blockquote>
  <p>Is it possible for Earth to experience Polar Shift?</p>
</blockquote>

<p>Yes, and it has happened before.</p>

<p>In the past 80 million years it happened over 150 times. The last time this happened was around 800 thousand years ago. A quick note about what a polar shift is, more properly termed a <em>geomagnetic reversal</em>. Earth's magnetic is such that a compass points to a certain direction. For example, a modern compass would point north. In a reversal, it would point south instead because the poles are reversed. Without going too much into detail, this occurs not by spinning of the poles but rather by decreasing in intensity until it becomes negative, thus reversing the poles.</p>

<p>Another important thing is the intensity. A strong magnetic field shields Earth's from some kinds of radiation, for example the stuff you can see in Gordon's answer. However, a reversed but strong magnetic field is just as fine. What you should be worried about is the change in the intensity of the field, and this is going up and down all the time, quite rapidly as you can see in the following figure:</p>

<p><a href="https://i.sstatic.net/3zS9I.png" rel="noreferrer"><img src="https://i.sstatic.net/3zS9I.png" alt="enter image description here"></a></p>

<p>The black bit (called Brunhes) is now - when the magnetic field is "normal". The white field in the bottom is more than ~780 thousand years ago, when it was reversed (called Matuyama). As you can see, even though the magnetic field has been normal though this entire time, the intensity went up and down. So yes, a reversal would mean that at one point the intensity would be very low, but this can happen even without a reversal.</p>

<blockquote>
  <p>What would be the possible effect to human beings if this happens?</p>
</blockquote>

<p>In contrast to what some people on the Internet claim, there would be no earthquake or volcanoes or other scary stuff related to it. This is simply not how this works. Also, mass extinctions from the geological history are not correlated with geomagnetic reversals, so you can take that worry off your mind. What can happen is detailed in a good way in Gordon's answer. Nothing too scary.</p>

<blockquote>
  <p>Magnetic Field of the earth is seriously degrading for the past centuries and we are currently in the process of the so called Polar Shift</p>
</blockquote>

<p>Not necessarily. It seriously degraded many times before without associated geomagnetic reversals.</p>

CC BY-SA 3.0
2015-10-28T18:19:57.610Z
Didn't see it mentioned, but we can observe the history of polar reversals by examining magnetized iron particles in basalt sea floor rock (rock created by magma at tectonic plate boundaries). When the magma first reaches the water, it starts to rapidly cool. In this process, the magnetic particles align in the liquid magma pointing towards whatever happens to be the current N and S. We can see layers where the N and S ends are seemingly pointed in the opposite direction of present day. There are many of these layers, which, along with dating techniques, give us a timeline of polar reversals.
SnakeDoc
CC BY-SA 3.0
2015-10-29T03:13:38.823Z
@SnakeDoc Yes, magnetized iron particles created by magma is good reference to tell the magnetism history of the earth, other scientist even used ancient clay pots.
stack
CC BY-SA 3.0
2015-11-16T13:02:36.433Z
This answer would be improved by a reference or two, at least for the figure (a basic requirement), or links. The cross-references to @gordon's answer don't help — he doesn't give any links or references either.
Matt Hall
CC BY-SA 3.0
2015-10-28T07:43:26.197Z
2015-10-28T07:56:44.773Z
2015-10-28T07:56:44.773Z
Gimelist
<p>Many accounts claim that the <a href="https://en.wikipedia.org/wiki/Earth%27s_magnetic_field">Magnetic Field</a> of the Earth has been seriously degrading for the past centuries and we are currently in the process of the so called Polar Shift. How likely would it be for Earth to experience this phenomenon. Is it really possible? </p>

<p>What would be the possible effect to human beings if this happens?</p>

CC BY-SA 3.0
2015-10-28T12:21:56.083Z
Polar or Pole shift can suggest more than one meaning.   Probably better to say magnetic pole shift or geomagnetic polar shift or reversal.  You said earth, so Geo is redundant I realize, but you mean this:  https://en.wikipedia.org/wiki/Geomagnetic_reversal  not this:  https://en.wikipedia.org/wiki/Pole_shift_hypothesis
userLTK
CC BY-SA 4.0
2022-01-20T00:20:10.537Z
"wall of text" not withstanding, I found it all very interesting and a lot of it makes sense. Too many academics try to put the thought down by picking on the format. Whatever.
I've been looking around for explanations for what is happening, (and it is happening by the way) and this seemed to be a very good explanation. Keep it up.
Chris Nordling
<earthquakes><geomagnetism><electromagnetism>
Is it possible for Earth to experience Polar Shift?
stack
# Is it possible for Earth to experience Polar Shift?

(Asked by: username_0 on 2015-10-28)

Many accounts claim that the [Magnetic Field](https://en.wikipedia.org/wiki/Earth%27s_magnetic_field) of the Earth has been seriously degrading for the past centuries and we are currently in the process of the so called Polar Shift. How likely would it be for Earth to experience this phenomenon. Is it really possible?

What would be the possible effect to human beings if this happens?

**Tags:** earthquakes, geomagnetism, electromagnetism

> **Comments:**
> **username_1**: Polar or Pole shift can suggest more than one meaning.   Probably better to say magnetic pole shift or geomagnetic polar shift or reversal.  You said earth, so Geo is redundant I realize, but you mean this:  https://en.wikipedia.org/wiki/Geomagnetic_reversal  not this:  https://en.wikipedia.org/wiki/Pole_shift_hypothesis  
> **username_2**: "wall of text" not withstanding, I found it all very interesting and a lot of it makes sense. Too many academics try to put the thought down by picking on the format. Whatever. I've been looking around for explanations for what is happening, (and it is happening by the way) and this seemed to be a very good explanation. Keep it up.  

---

## 3 answers

### Answer by username_12 on 2015-10-28. Score: 15 | Accepted answer

> Is it possible for Earth to experience Polar Shift?

Yes, and it has happened before.

In the past 80 million years it happened over 150 times. The last time this happened was around 800 thousand years ago. A quick note about what a polar shift is, more properly termed a *geomagnetic reversal*. Earth's magnetic is such that a compass points to a certain direction. For example, a modern compass would point north. In a reversal, it would point south instead because the poles are reversed. Without going too much into detail, this occurs not by spinning of the poles but rather by decreasing in intensity until it becomes negative, thus reversing the poles.

Another important thing is the intensity. A strong magnetic field shields Earth's from some kinds of radiation, for example the stuff you can see in username_3's answer. However, a reversed but strong magnetic field is just as fine. What you should be worried about is the change in the intensity of the field, and this is going up and down all the time, quite rapidly as you can see in the following figure:

[![enter image description here](https://i.sstatic.net/3zS9I.png)](https://i.sstatic.net/3zS9I.png)

The black bit (called Brunhes) is now - when the magnetic field is "normal". The white field in the bottom is more than ~780 thousand years ago, when it was reversed (called Matuyama). As you can see, even though the magnetic field has been normal though this entire time, the intensity went up and down. So yes, a reversal would mean that at one point the intensity would be very low, but this can happen even without a reversal.

> What would be the possible effect to human beings if this happens?

In contrast to what some people on the Internet claim, there would be no earthquake or volcanoes or other scary stuff related to it. This is simply not how this works. Also, mass extinctions from the geological history are not correlated with geomagnetic reversals, so you can take that worry off your mind. What can happen is detailed in a good way in username_3's answer. Nothing too scary.

> Magnetic Field of the earth is seriously degrading for the past centuries and we are currently in the process of the so called Polar Shift

Not necessarily. It seriously degraded many times before without associated geomagnetic reversals.

> **Comments:**
> **username_15**: Didn't see it mentioned, but we can observe the history of polar reversals by examining magnetized iron particles in basalt sea floor rock (rock created by magma at tectonic plate boundaries). When the magma first reaches the water, it starts to rapidly cool. In this process, the magnetic particles align in the liquid magma pointing towards whatever happens to be the current N and S. We can see layers where the N and S ends are seemingly pointed in the opposite direction of present day. There are many of these layers, which, along with dating techniques, give us a timeline of polar reversals.  
> **username_0**: @username_15 Yes, magnetized iron particles created by magma is good reference to tell the magnetism history of the earth, other scientist even used ancient clay pots.  
> **username_16**: This answer would be improved by a reference or two, at least for the figure (a basic requirement), or links. The cross-references to @username_3's answer don't help — he doesn't give any links or references either.  

---

### Answer by username_3 on 2015-10-28. Score: 10

Yes, it is not just possible, but highly probable.

Detailed palaeomagnetic data have revealed how the Earth's magnetic field changes in a polarity shift. In relative terms (time scale inaccurately known) there is a slow decrease to <10% of the normal field intensity. After an uncertain interval the field intensity picks up to some 20 or 30% of the normal field intensity during a relatively brief spike. Then another low field intensity interval, and finally it picks up to full field intensity - of either normal or reversed polarity.

This has never happened in real-time during the scientific era, so the effects are necessarily speculative. Amongst the expected effects would be:

1. Vulnerability of satellites, power lines and communications to the effects of solar storms.
2. Increased UV, and hence increased incidence of skin cancer.
3. All sorts of changing physico-chemical processes in the upper atmosphere, of which the weakening ozone layer would be the most alarming.

On average these magnetic flips occur about every 11,000 to 12,000 years - although there is a great deal of variation. On this basis the next one is about due.

It won't be lethal. Neanderthals, Denisovans and Hom.sap's prehistoric forebears survived the last magnetic flip, but it will be inconvenient, and probably not without a serious health impact.

> **Comments:**
> **username_4**: It might not be _directly_ lethal to organisms on the planet but given the fragility of the current global politico-economic system, I suspect it might be a tad more than _inconvenient_. Knockout of GPS, satcoms and mobile telephony would be enough to trigger an economic recession at the very least. If electricity production and distribution was affected (cf. _Carrington Event_ https://en.wikipedia.org/wiki/Solar_storm_of_1859), we could expect severe civil disruption. Wars and governmental collapse in some regions could not be excluded. So yes, _a serious health impact_.  
> **username_5**: @OwenBoyle Wars?  Why?  Soldiers cannot read maps and will accidentally stray into enemy territory?  
> **username_6**: @username_5 No electricity means discomfort and hardship. No communications means general unrest, lower productivity, and slower response times of things like police and emergency services, as well as making it harder to clear up the inevitable disagreements before things turn nasty. So you've got the populace enduring hardship, getting angry, and feeling they aren't being listened to who, and a government who's slow to respond and lacking their usual level of situational awareness and technological advantage. In short, the playing field is more level and the civilians are angry. Tinderbox.  
> **username_6**: @username_5 Wars *between nations* (as opposed to civil wars) are less likely. Still, recent history shows that supposedly internal matters like that rarely stay internal (Ukraine, Syria, etc) - neighbours often get involved. It's possible that in some of the more volatile parts of the world, a nation might take offence to this interference and oppose it, and with reduced intel and comms down, force may be the only way available (or at least, a more attractive option). There's also a few places where one side might see it as an opportunity to settle a grudge while their opponent is crippled.  
> **username_7**: @OwenBoyle: to my knowledge, GPS, satcoms and mobile telephony are not at all dependant on the Earth's magnetic field polarity. Unless the field's *intensity* rises enough and fast enough to fry electronics, I don't see how they would be affected. Or did I miss something? I think the only tecnology to break just by polarity would be compass-based navigation (very important for ships and airplanes)  
> **username_8**: Why would UV doses increase? As it's comprised of (uncharged) photons, it is unaffected by the magnetic field, but is blocked by ozone. Would the geomagnetic reversal affect the ozone layer somehow?  
> **username_3**: Although the rate of change of magnetic intensity is not clear, it is probably in the order of decades. In principle, therefore we could adapt fast enough to cope. One example: by accelerating the current trend to local renewable electricity generation and storage, which would not be greatly influenced by a change in the Earth's magnetic field. On the other hand, the world's painfully slow response to climate change doesn't fill one with optimism!  
> **username_3**: Regarding ozone, it isn't the magnetic reversal as such that is the problem; it is the weakening of the Earth's magnetic field during the transition that allows more cosmic rays and solar wind (charged particles) to disrupt the normal equilibrium between ozone synthesis and decay. Such disruption occurs all the time due to solar storms, atmospheric pollutants and seasonal daylight hours. The extent to which this would be exacerbated by a weakening magnetic field is debatable, but the consensus is that the ozone depletion would be 'huge'.  
> **username_9**: @username_7 the *reduction* of the field during the reversal greatly decreases Earth's protection from the solar proton flux, which means satellites would be much more likely to be killed by solar storms. And although I'm not sure, the interaction of the proton flux with the remnant magnetic field could also cause larger geomagnetic storms than we have today, interfering with power grids and ground-based communications.  
> **username_4**: As pointed out above, the magnetic field isn't just a handy help for navigators. It is an essential element in protecting us from solar storms. A _Carrington Event_ hitting us when the shields are down would blow us back to the 1850s. Then we'd get 1850s-style politics and war-mongering again.  

---

### Answer by username_10 on 2019-01-11. Score: -10

Please consider that the strength of the magnetic field determines atmospheric density and pressure. Planets with strong magnetic fields have thick oceans and atmosphere, while planets with very weak magnetic fields have no oceans and very thin atmosphere. That's because hydrogen atoms from solar winds are attracted and condensed around magnetic fields and the strength of the MF dictates the atmospheric density, and atmospheric pressure dictates the ocean levels.
Mars for example shows signs of erosion as it had oceans and atmosphere but when the dynamo inside went through a hard double flip (most probably) and slowed down so much, cooled down so much that it could never recover, the atmosphere was blown away by solar winds, oceans boiled away, etc. Mars's gravity field doesn't explain how it lost its oceans and atmosphere when Earth still has them. Mars's gravity field didn't change, it lost its magnetic field.
Jupiter's bigger moons have thick ocean frozen at the surface (frozen because of distance from the Sun) but they are smaller than Mars and have strong magnetic fields.. So size and amount of pressure inside doesn't necessarily mean a stronger magnetic field,, what all planets and terrestrial moons with strong MF have in common is an inner core that makes a small orbit around the center of the planet/moon, because of tidal effect (gravitational pull) from a big body nearby. For example, Earth's inner core is attracted by our big and heavy Moon, and it's not spinning in the dead center of Earth but has a small orbit around the center, planar to the Moon's orbit, and it stirs the soup inside as Earth spins on itself. It keeps the soup warm and generates friction thus electric currents, thus electromagnetism.
Jupiter's moons have their inner core drawing a larger orbit inside as they (moons) spin on themselves, their core is off-centered toward Jupiter.
Our Moon is actually the big core of an ancient planet that collided with our former (smaller) planet about 4.5 Billion years ago. Their liquid matter blobbed together and the smaller core bounced from the explosion as just the right speed and angle to stabilize on orbit, and the little bit of liquid matter on it cooled fast with a tide towards Earth, witch is the heavier side of the Moon that always point to Earth. With time it gathered the splash from the collision. It's a big metal core with a thin crust and this is why it rings like a bell and the craters are all shallow.
So anyway.. we're very lucky to have the Moon because otherwise Earth would be like Mars right now. Mars doesn't have a big moon so its core just spins in the center and doesn't generate enough friction. Maybe it had a moon before, with an unstable orbit destined to swing away..
Now, why does our MF tend to flip every 12-13000 years, or twice every Great Year (Precession of the Equinoxes, a 26000-year Milankovitch Cycle when the Earth's spin tilt axis wobbles 360\*)?
I think it's because there are 2 critical tilt angles, during the Precession,, where the spin inertia of the iron currents, plus the angle of the inner core's orbit (planar to the Moon's orbit, not the same angle as the Earth's rotation axis),, plus the difference in speed (earth spins on itself in one day while the Moon takes 27.3 days to go around Earth),,, produce electric currents that don't agree with the magnetic field orientation and forces it to either reverse or migrate..
(to visualize this, have a pot of sauce that represents Earth, a wooden spoon that represents the inner core and an imaginary moon that goes around the pot in 27 days. Turn the pot of sauce continually to simulate earth's rotation and imagine it's tilted 23.4\*,, and place the spoon (core) off-centered in the pot and tilt the spoon to simulate the difference in angles of the Earth's spin and of the moon's orbit plane. As you spin the pot, continuously, slowly orbit the spoon in the same time as your imaginary moon,, and see the currents you're generating in the sauce.. Then slowly change the tilt of the spoon to simulate Earth's precession.. It sounds fun? Do this to really get a visual)..
Now during the reversal or excursion process, the convection currents need to reorient and mix and slow down, producing less friction thus less electromagnetism, so the atmosphere gets thinner and filters out less solar and cosmic radiation. Less friction also means less heat produced inside the planet, so the volume of the planet has to shrink a little bit, and that explains the spike in seismic and volcanic activity around the Peak.
What explains how ocean levels can drop 400ft? Well if the atmosphere is thin during the day, then raw solar radiation evaporates tons and tons of ocean surface and during the night it gets very cold so all the moisture in the air has to precipitate within hours. Most of it falls back in the oceans and on land, and some of it becomes atmosphere and is eventually blown away by solar winds. That explains the biblical amounts of precipitations and erosion (Grand Canyon fills up and deserts turn into seas and the northern atmosphere is covered with very thick glaciers, big mammals flash frozen, etc).. Flash frost is also explained by rapid atmospheric density drop when a CME impacts the already thin atmosphere and temporarily blows some of it away: pressure drops fast and flash-freezes everything at the surface.
A thin atmosphere also explains the number of meteorite impacts because meteors rain down every day but usually burn with friction, blow up into small bits and only tiny bits of metal reach the ground,, but when the atmosphere is thin, meteors have much less friction so better chances to hit the ground in bigger chunks.
Those 2 critical tilt angles during the Precession are:
one as we enter Leo (the stronger magnetic Excursions (double flips) like the Gothenburg Magnetic Excursion 13000 years ago and the Leschamp Magnetic Excursion 40000 years ago, etc)
and the other one as we enter Aquarius (the mild semi-reversals (also calles Excursions) like now, or like the Lake Mungo Magnetic Excursion 26000 years ago,, etc).
This is all over ancient civilizations calendars, like the Mayan calendar, etc. For Example, the Sphinx was pointing Leo 13000 years ago, but was probably built 11000 years ago after the Younger Dryas warming, as a big immortal monument to commemorate this strong event that almost got us extinct.
Also, one important principal, heat generated inside the planet goes up slowly through the crust, then slowly raises up in the oceans, then joins the heat on the surface from solar radiations, and that heat has to go up in the atmosphere to reach the space vacuum.. The stronger the magnetic field and the thicker the oceans and the atmosphere,,, and the slower heat can reach up into space. Vice-versa, the thinner the oceans and atmosphere and the faster heat can reach up into space..
We could say that at Peak, a typical day would be like: super windy as almost unfiltered solar radiation expands the air very rapidly,, then all day would feel like a super hot sauna with tons of melting and floods, and evaporation would look like a steam engine.. Then, as the Sun starts to set the sky veils with thick condensation. Shortly after, deluges and super flash floods, turning into super ice storm breafly, then meters of snow until the air is dry and very cold, like -50C (moisture can stay in the air up to -20C but lower than that, all humidity is already deposited, so all moisture in the air has to deposit within a few hours)... Then, in the morning it starts all over again. Sometimes when there is a CME impact, it gets worse.
OK, I'll stop here, will elaborate more if there is interest.. Please give me feedback,, wherever I'm wrong and how I should rethink.. Thanks

> **Comments:**
> **username_11**: This is wrong on so many accounts, I wouldn't even know where to begin, but your final sentence in which you ask what's wrong and where you should rethink, obviously means that this all is how you think things should be and not what you've learned through acquired knowledge.  
> **username_10**: Please do begin :)  
> **username_10**: Please guys,, if you down vote my comment, I would like to know why.. That's what I would do anyways. I would like to have at least a short constructive feedback. Thanks!  
> **username_10**: And if you up vote a comment that says my comment ''is wrong on so many accounts'' but then doesn't elaborate and doesn't justify,, then what kind of ''community'' is this? I was expecting constructive criticism and a decent argument. This is kind of disappointing.  
> **username_12**: I'm downvoting because it's unreadable. Have you ever heard of paragraphs? Proper punctuation? This is a wall of text.  
> **username_11**: A.) I didn't downvote; B.) There's not enough space in comments to itemize everything you've gotten wrong; C.) Stack Exchange is a question and answer forum, not discussion, nor is it a place to air your hypotheses.  
> **username_10**: In this case here, my answer is as good as anyone's answer. I've read many papers on this subject for the past 10 years and all have different views.. I've gathered the pieces of puzzle that matched together and build my own view of the forest. Anyone's answer here is the result of more or less the same process, +/- interdisciplinary knowledge and judgement.  
> **username_10**: This is a very important subject because it is happening and we need to prepare. This kind of event is catastrophic. Evidence of this is overwhelming and any ''answer'' that says ''it's nothing to be worried about'' is misleading readers who come here for good answers.  
> **username_10**: I edited my comment some time ago and saved, but the changes didn't appear and now the comment is light gray. Why is this?  
> **username_13**: you did only expand the wall of text with the edit,you made the wall of text less readable.  
> **username_10**: Is this all that is wrong with my answer? That it's "unreadable"? Please expand on the content of my answer. Is the information useful for anyone seeking to understand the phenomenon?  
> **username_14**: It is hard to expand on the content of your answer if it is hard to digest the information presented in it due to formatting. If you make the information easier to read, then it will be easier to determine if the information presented is useful.  

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