Earth’s magnetic field: still not reversing

A post by Chris RowanSome rather apocalyptically minded people – a couple of whom have actually contacted me – have seen a connection between two recent odd occurrences. First came all those birds falling from the sky over the Christmas period. Then, there was this rather odd report of runways in Florida having to be repainted due to ‘the shift in the location of the Earth’s magnetic north pole’. Perhaps fuelled by fuzzy memories of The Core, my worried correspondents – and others around the internet – are musing whether this is a sign of an imminent magnetic field reversal (or ‘pole flip’ as it is often called), with all of the nebulously dire consequences that would ensue.

Well…no.

In fact, neither the bird deaths, nor the runway realignment, are heralds of anything particularly unusual. On the avian mortality front, some digging by the Christian Science Monitor reveals that on average, mainland North America seems one mass wildlife die-off every two days. According to this report from the USGS, there were eight events that involved more than 1000 bird deaths in 2010, and if anything it was a quiet year. Furthermore, although birds do have the ability to sense magnetic fields, it seems unlikely that some disruption of that ability would cause them to fall from the sky. It might make them a little lost and confused, perhaps.

But crucially, there is no sign of any unusual disruption of the Earth’s magnetic field – the reported runway re-alignment is certainly not one. Here’s what the article from the Tampa Bay Online site linked to above says:

Scientists say the magnetic north pole is moving toward Russia and the fallout has reached — of all places — Tampa International Airport…

…The busiest runway will be re-designated 19R/1L on aviation charts. It’s been 18R/36L, indicating its alignment along the 180-degree approach from the north and the 360-degree approach from the south.

To check what is going on, I plugged the co-ordinates of Tampa Airport (around 28°N, 82.5°W) into NOAA’s handy online magnetic field calculator, which allows you not only to calculate the magnetic field direction and strength at any point on the Earth, but also track how it has changed over time. Below is the declination – the deviation of magnetic north from true, geographic north – at Tampa airport for the last 20 years.

January 1991: - 2° 37′
January 1992: - 2° 45′ (-8 minutes)
January 1993: - 2° 54′ (-9 minutes)
January 1994: - 3° 2′ (-8 minutes)
January 1995: - 3°11′ (- 9 minutes)
January 1996: - 3° 18′ (- 7 minutes)
January 1997: - 3° 25′ (- 7 minutes)
January 1998: - 3° 33′ (- 8 minutes)
January 1999: - 3° 40′ (- 7 minutes)
January 2000: - 3° 47′ (- 7 minutes)
January 2001: - 3° 53′ (- 6 minutes)
January 2002: - 3° 59′ (- 6 minutes)
January 2003: - 4° 5′ (- 6 minutes)
January 2004: - 4° 11′ (- 6 minutes)
January 2005: - 4° 17′ (- 6 minutes)
January 2006: - 4° 23′ (- 6 minutes)
January 2007: - 4° 29′ (- 6 minutes)
January 2008: - 4° 35′ (- 6 minutes)
January 2009: - 4° 42′ (- 7 minutes)
January 2010: - 4° 48′ (- 6 minutes)
January 2011: - 4° 54′ (- 6 minutes)

What this shows is that the ‘shift in the location of the pole’ that has necessitated the Tampa runway realignment is not a big, recent jerk – instead, it’s the result of the gradual – and entirely unremarkable – motion of the magnetic pole relative to the geographic pole over the past few decades (what people who study the Earth’s magnetic field call secular variation). In the figure below, I’ve included a British Geological Survey plot of the magnetic pole’s motion from a location in the northern reaches of Canada into the Arctic ocean in the past century. This motion has produced a steadily more negative declination in the vicinity of Tampa Airport over the past couple of decades. A look at Google Maps indicates that the main runways at Tampa have an absolute (geographic) orientation close to due north. Many aircraft (particularly smaller, non-commercial aircraft) still use a compass to direct their course, and pilots need to know what direction the runway is oriented, particularly at night or in bad weather, when visibility is limited. With a negative magnetic declination, you would have to fly at a magnetic bearing a few degrees east of north to parallel the runway.

Pilots must compensate for magnetic declination when lining up with a runway. In Florida, declination is now closer to -10° than 0° due to gradual drift of magnetic north.

The numbers on runway numbers are their bearing relative to magnetic north to the nearest 10 degrees, divided by 10 (e.g., 5=50°, 22=220°). For the past few decades the small declination at Tampa has effectively rounded to 0, and the runway numbers reflected this. Now however, the declination is on the verge of being more than -5 degrees*, which rounds to 10; this means that the runway markings must be updated to tell pilots that they should set their landing course to a bearing of 10° rather than 0, or 190° rather than 180 if you’re flying in the opposite direction.

So move along, nothing to see here. For those who are interested in what the real prospects for a future reversal of the Earth’s magnetic field are, I’ve already written an opus on this subject. Basically, the magnetic field will not be reversing any time soon, unless you are talking about ‘soon’ in the sense of ‘in the next few tens of thousands of years at the earliest’. When it does begin to reverse, it will take several thousand years – probably longer than currently recorded human history – to do so. And given that there is absolutely no correlation between extinction events and magnetic field reversals in the geological record – rather fortunate as there’s a reversal every half a million years on average – I don’t think we have much to worry about when it does happen. Except, perhaps, we might need to repaint our runways more often.

Still, I do have my own premonition. Somehow I can’t help thinking that, as we get closer to some arbitrary milestone in the Mayan’s cyclical calendar, I may have to revisit this subject again.

Update 24th January 2010: Apparently, Stanstead airport in the UK, close to where I grew up, is also having to repaint it’s runway markings for the same reason. Given that this has to be a semi-regular occurence in the aviation world, I wonder why such things are getting more play in the media world right now. Are they deliberately trolling people who are worried about 2012?

*given that the Tampa runways appear to run a little east of true north, their magnetic bearing may already be more than 5°. Also, the numbers above are from a global field model, so are probably not completely accurate at such a local scale. I’d suspect that Tampa airport has performed it’s own direct measurements before deciding to change their markings.

Categories: antiscience, palaeomagic
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Comments (16)

  1. Bob O'H says:

    Still, I do have my own premonition. Somehow I can’t help thinking that, as we get closer to some arbitrary milestone in the Mayan’s cyclical calendar, I may have to revisit this subject again.

    As I have already shown, 2012 will start with a sudden die-off of Mayas.

  2. Les Francis says:

    Haven’t we always used the “variation” to navigate with?
    Depending on the known current deviation from magnetic North at your known location guides your traversing across country with the aid of a compass and a grid map.

  3. Kristin says:

    What are your view points on the new zodiac changes, due to the gravitational pull of the moon? Just curious since this is all happening together. The zodiac hasnt changed in some 2000 years. A lot of people again are having suspicions that this is an early indication of 2012.

    • Chris Rowan says:

      I assume you’re talking about this. If so, you’re talking about the effects of the precession of the equinoxes: another gradual, continuous occurring process. Humans are the ones pressing the arbitrary reset buttons, not nature.

      Regardless: I predict that 2012 will occur in roughly eleven and a half months.

  4. Curt the Viking says:

    How did the Mayans know about this galactic alignment anyways? I have always given it heed and wonder, what would happen if the Earth’s polarity was suddenly switched, like a light switch. If our planted gets caught between the sun and the zenith point of a black hole, I believe this could do it.

    So then what? The core is dense, the mantle is thin. Does the planet reverse it’s rotation? HOw many hours, days months would that take? And what happens to the atmosphere if the earth’s rotation slows?? Would the mantle slip like the skin on a grape? could we get the amazon river up at the north pole after it all shakes out?

    Love to hear your comments. I know I’m crazy, so don’t go there. Just tell me “hypothetically” and I won’t tell your friends….

    • Bob O'H says:

      Does the planet reverse it’s rotation?

      No it doesn’t. The magnetic pole is not the same as the pole that the earth rotates around.

  5. Ok, you say you don’t think the magnetic field has anything to do with the recent happenings concerning the birds dropping to the ground or the 1000″s of fish dying and the airport changes, do you have a theory of your own as to why this would be happening, we have certainly been destroying our planet since god knows when, also, with holes in our ozone layer would gases in our atmosphere have something to do with these animals, I also had another question, with as much oil as we pull from the earth, it is heavier than water, yet they say they put the water elements back in the earth after taking the oil, doesn’t this do anything to our planet, what purpose does oil have in our planet to begin with, by sucking all these elements from our planet doesn’t that throw something off balance and affect something, I’m not going to consider these dumb questions because no question is dumb if you don’t know the answer, I would just like to get information from someone that may actually have an answer that isn’t just talk, thank you

  6. Curt the Viking says:

    Well Tawny(sexy name) there is this thing called the carbon cycle and it affects how much O2 is in the atmosphere…..by releasing carbon that the earth has stored for billions of years, it does change things….Global warming is the result.

    Back to my pole reversing question….so the Earth’s rotation just keeps on going, even if the poles flip? Why wouldn’t it be like a motor reversing it’s elec. field? It changes direction? Are they two different forces entirely? please explain to this nimrod….

    • Bob O'H says:

      You’re right: the forces are different. The rotation of the earth isn’t caused by its magnetic field. I don’t know how it got started, but by now it’s just going under its own momentum. It would take a huge amount of energy to reverse the earth’s rotation.

  7. Chris Rowan says:

    Wow – you spend a weekend at a conference, and look what happens. Thanks to Bob for keeping an eye on things.

    Curt – the earth’s magnetic field is generated by convection in the outer core. That would happen regardless of whether the Earth is rotating or not (although the earth’s rotation does affect the shape of the field, because it affects the pattern of convection). But the Earth keeps right on rotating when the magnetic field goes through one of it’s more random phases – that’s the primary reason why it eventually becomes dipolar (like a bar magnet) again, although sometimes with the opposite polarity. Basically, reversals are all about processes that are going on in the core – not the rest of the Earth, which really doesn’t care what the magnetic field looks like.

    Tawny – as I say in my post, my ‘theory’ is that nothing particularly out of the ordinary is happening, with the die-offs or the magnetic field, whatever the buzz around these events. And whilst our extraction of oil is obviously having significant effects on the earth’s atmosphere and oceans – they are but a thin veneer on a very very big planet. Our drilling barely scratches the surface.

  8. Curt the Viking says:

    Chris,

    I’m not thinking that the magnetic field is caused by the spinning of the Earth, but just the opposite. Nobody has told me what generates the spin of the Earth. Bob says it just “is”. That’s no good. perpetual motion? I’m not asking for an explanation for the expanding universe. Just want to know what keeps this earth spinning….?

    • Chris Rowan says:

      The Earth’s rotation is a leftover from the time of its formation – as it collapsed and coalesced out of the planetary nebula at the time the solar system formed, conservation of angular momentum imparted a rotation on the resulting clump (see here). It has nothing to do with the magnetic field (I suppose the phrase ‘geodynamo’ might be misleading here?)

      The only thing that affects the Earth’s rotation is gravitational interactions with other planets – the interactions with the moon (tidal friction) are gradually slowing slowing it down, for example. But it’s a very slow process.

  9. Curt the Viking says:

    Oh my Gosh, you mean the Earth has been slowing it’s spin for billions of years? With nothing to keep a constant rate? No power source? NO way! I’m not buying it. There is no such thing as perpetual motion. Even if the magnetic field put a very slight influence on the earths rotational axis, it would keep us spinning. I think you guys have it all wrong. How sure are you? Nothing I hate more than an ego with no brains, so I need facts. It just “is” doesn’t cut it. sorry to turn up the volume on the rhetoric, but sometimes even smart global people need a little push in the right direction.

  10. Curt the Viking says:

    Well I hear some people are recanting on the Resurrection and Darwinism has expanded it’s views…we’ll see what happens in a couple years..but if this big ol’ world just keeps on spinning, that would be great. NOw all I have to worry about is Cosmic Rays and planet-killer volcanoes. I live downstream from Yellowstone Lake…

    Our spinning earth is our blessing. Accept it. Peace!