Magnetism and Electromagnetism — The World, with the Evidence

A long airport runway at sunrise, with a large number painted in white on the ground and, in the distance, a worker on the ladder of a truck; in the foreground, an old compass and a curved red arrow showing that the needle deviates. — At dawn, the number on an airport runway is being repainted; the compass is a reminder that magnetic north moves. Erosophia illustration, réalisée avec l'aide d'une IA

North is moving, and airports have had to repaint the numbers on their runways.

This is not a figure of speech. It happened, and here is why.

Magnets and fields

A magnet always has two poles, a north and a south. Opposite poles attract, like poles repel — and there is no way of isolating just one. A magnet cut in two gives two complete magnets, each with its own two poles. The operation can be repeated indefinitely: the result does not change.

Around the magnet lies a region in which its influence is felt: the magnetic field. It is invisible, but its shape can be revealed by sprinkling iron filings on a sheet of paper: the grains line up in loops that leave one pole and join the other. The field is stronger near the poles, and it weakens very quickly with distance.

Very few materials are attracted by a magnet. Iron, nickel, cobalt and their alloys are; aluminium, copper, gold, glass and plastic are not, despite what is often assumed about metals in general. The former are called ferromagnetic.

The Earth is a magnet

Our planet produces its own magnetic field, generated by the movements of the liquid iron in its outer core. It is this field that aligns the needle of a compass, and it is this field that deflects a large share of the particles emitted by the Sun — without which the atmosphere would long since have dissipated.¹

This field is neither regular, nor fixed, nor symmetrical. It becomes distorted, it weakens in places, its poles move, and it has already reversed hundreds of times over the course of the Earth’s history. That is precisely the subject of the rest of this page.²

Magnet and current are the same thing

The most important point fits in a single sentence: magnetism and electricity are not two separate phenomena. An electric current always creates a magnetic field around it — this is what makes it possible to build an electromagnet, a simple coil of wire that can be switched on and off. Conversely, moving a magnet near a wire gives rise to a current in it: this is induction, and it is how almost all the world’s electricity is produced.³

This reciprocity has a name, electromagnetism, and its discovery in the nineteenth century brought together two fields once thought to be unrelated.

Two norths, and they are not the same

Geographic north is the point around which the Earth rotates. On the scale that concerns us, it does not move.

Magnetic north is the place where the Earth’s magnetic field points vertically downwards. This one moves.⁴

An important clarification: a compass does not “aim” at this point. It aligns itself with the magnetic field where it happens to be, and this field does not point exactly towards the pole. In many places, the needle points noticeably to one side. The compass shows the local field, not a distant point.⁵

How fast

The position of the pole was measured on site for the first time in 1831, in the Canadian Arctic. Since then, it has been drifting inexorably towards Siberia — that is the term the researchers use.⁶

0 to 15 km/year: the historical speed, observed for more than a century.
50 to 60 km/year: after a marked acceleration between 1990 and 2005.
Late October 2017: the pole crosses the date line, passing within 390 km of the geographic pole. It is now heading south.
~35 km/year: speed forecast for the five years after 2025, slowly decelerating.⁷

The researchers also made a prediction that can be checked in a few years: within the decade following their article, the pole should travel between 390 and 660 kilometres further towards Siberia.⁸

Why this becomes a problem

A global model of the magnetic field is drawn up and updated every five years. It is used for air and underwater navigation, for maps, and for phone apps.⁹

But the model goes out of date between updates, because the field keeps changing.

The drift was so fast that an out-of-cycle update had to be published in 2019, because the model in use had become too inaccurate.

The numbers painted on airport runways indicate their orientation relative to magnetic north as seen from that airport. When that direction shifts far enough, the number no longer matches.¹⁰

The runway then has to be repainted and the charts updated. This happened at Tampa (Florida) in 2011, for example, as well as at several airports in Alaska and the United Kingdom.

Where it comes from

The cause is not at the surface. It lies 3,000 km beneath our feet.¹¹

The Earth’s magnetic field is produced by the movements of the liquid iron and nickel of the outer core. When these flows change, the field changes.

A team of researchers proposes an explanation that is more elegant than one might expect.

For twenty years, the position of the north magnetic pole has been determined by two large patches of field located at the very bottom, at the boundary between the core and the mantle: one under Canada, the other under Siberia. The surface pole sits where the influences of the two balance out.¹²

But the Canadian patch has stretched, probably because of a change in the circulation of the liquid metal between 1970 and 1999. As it lengthened, it lost some of its strength at the surface. The Siberian patch won out, and the pole raced towards it.¹³

Two patches each pulling their own way, and one of them weakening. That is why airport runways have had to be repainted.

One could speak of magnetic weather: fluid movements, very deep down, whose effects can be seen at the surface.

What links the magnet and the current

A word about the “electro” in the title, because it sheds light on the previous section.

A magnet produces a magnetic field: the compass responds to it. But an electric current produces one too — this is what the Danish physicist Hans Christian Ørsted discovered in 1820 when he saw a needle deflect near a live wire. Conversely, a magnet moved near a wire gives rise to a current in it — this is induction, discovered by Michael Faraday in 1831.

This is how motors and alternators work. This is how the Earth makes its field: liquid conducting metal in motion creates a current, and this current generates the field. No giant magnet at the centre of the Earth — a fluid in motion.¹⁴

A word of caution about the figures

The speed went from 15 to 60 km/year, then came back down towards 35. Each figure carries its date.

Stopping at “the pole is speeding up” would give only part of the picture: the speed has varied in the past, and it has just slowed down. When this page was first written, we anticipated a possible slowdown. A year later, the measurements confirmed it.

That is why the figures on this page carry their date and are re-examined every year.

Note 1

The Earth's magnetic field is generated in the fluid outer core by a self-exciting dynamo process. […] Electrical currents flowing in the slowly moving molten iron generate the magnetic field.

British Geological Survey, “An Overview of the Earth’s Magnetic Field”, Geomagnetism

See the full note ↓

Note 2

Over the past 250 Ma, there have been a few hundred magnetic field reversals, and their timing has been anything but regular.

Earle, Steven, Physical Geology, 2e éd., BCcampus, 2019, section 9.3 “Earth’s Magnetic Field”

See the full note ↓

Note 3

His ita comparatis, acus magnetica movebitur, et quidem sub ea fili conjungentis parte, quae electricitatem proxime a termino negativo apparatus galvanici accipit, occidentem versus declinabit. […] Similiter ex observatis colligere licet, hunc conflictum gyros peragere

With things thus arranged, the magnetic needle will move, and indeed, under that part of the connecting wire which receives electricity most directly from the negative end of the galvanic apparatus, it will decline towards the west. […] Similarly, it may be gathered from the observations that this conflict performs circles

Ørsted, Hans Christian, Experimenta circa effectum conflictus electrici in acum magneticam, Copenhague, 1820

the galvanometer-needle being stationary, the magnet was suddenly thrust in; immediately the needle was deflected in the same direction as if the magnet had been formed […] and then the magnet being withdrawn the needle was deflected in the opposite direction.

Faraday, Michael, “Experimental Researches in Electricity”, Philosophical Transactions of the Royal Society, vol. 122, 1832, p. 125-162

See the full note ↓

Note 4

the north magnetic pole, the location where the magnetic field points vertically downwards

Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391

See the full note ↓

Note 5

Magnetic declination, sometimes called magnetic variation, is the angle between magnetic north and true north. […] Magnetic declination changes over time and with location. As the compass points with local magnetic fields, declination value is needed to obtain true north.

NOAA NCEI, “Wandering of the Geomagnetic Poles” et “Magnetic Declination”

See the full note ↓

Note 6

Since the first in situ measurements in 1831 of its location in the Canadian arctic

We accordingly commenced our journey in the middle of May 1831 […] Having gained the calculated position on the 1st of June […] the resultant mean dip in each of the three directions in which they were obtained placed us as near to the magnetic pole as, with our limited means, we were able to determine.

Ross, James Clark, “On the Position of the North Magnetic Pole”, Philosophical Transactions of the Royal Society, vol. 124, 1834, p. 47-52

the pole has drifted inexorably towards Siberia

In 1831, James Clark Ross located the north dip pole position in northern Canada.

NOAA NCEI, “Wandering of the Geomagnetic Poles” et “Magnetic Declination”

See the full note ↓

Note 7

accelerating between 1990 and 2005 from its historic speed of 0–15 km yr⁻¹ to its present speed of 50–60 km yr⁻¹

In late October 2017 the north magnetic pole crossed the international date line, passing within 390 km of the geographic pole, and is now moving southwards.

Over the next five years, the WMM2025 predicts a very slow drift of the south dip pole, at about 9 km/year on average, and a faster (yet gradually decelerating) drift of the north dip pole, at about 35 km/year.

NOAA National Centers for Environmental Information and British Geological Survey, World Magnetic Model

See the full note ↓

Note 8

over the next decade the north magnetic pole will continue on its current trajectory, travelling a further 390–660 km towards Siberia

See the full note ↓

Note 9

A new version of the model is updated every five years to address changes in Earth’s magnetic field. […] An out-of-cycle update of the WMM2015 was developed and released in early 2019 (WMM2015v2) to address this performance degradation.

NOAA National Centers for Environmental Information and British Geological Survey, World Magnetic Model

See the full note ↓

Note 10

Runway numbers and letters are determined from the approach direction. The runway number is the whole number nearest one‐tenth the magnetic azimuth of the centerline of the runway, measured clockwise from the magnetic north.

Federal Aviation Administration, Aeronautical Information Manual, chapitre 2, section 3, “Airport Marking Aids and Signs”, § 2-3-3 “Runway Markings”, b. “Runway Designators”, open access

Tampa International Airport on Florida's west coast just finished renaming its three runways, a laborious project that interrupted airport traffic for a month while runways were shut down for repainting.

NBC News, “Compass Direction, True North Parting Ways”, no author or date shown

See the full note ↓

Note 11

Beginning at a depth of 2900 kilometers, we encounter the dense metallic core of Earth. In addition to iron, the core probably also contains substantial quantities of nickel and sulfur, all compressed to a very high density. The outer core is liquid, but […] This magnetic field is generated by moving material in Earth’s liquid metallic core.

Fraknoi, Andrew, Morrison, David and Wolff, Sidney C., Astronomy 2e, OpenStax, 2022, § 8.1 “The Global Perspective”

See the full note ↓

Note 12

over the last two decades the position of the north magnetic pole has been largely determined by two large-scale lobes of negative magnetic flux on the core–mantle boundary under Canada and Siberia

See the full note ↓

Note 13

elongation of the Canadian lobe, probably caused by an alteration in the pattern of core flow between 1970 and 1999, substantially weakened its signature on Earth's surface, causing the pole to accelerate towards Siberia

See the full note ↓

Note 14

This magnetic field is generated by moving material in Earth’s liquid metallic core. As the liquid metal inside Earth circulates, it sets up a circulating electric current. When many charged particles are moving together like that—in the laboratory or on the scale of an entire planet—they produce a magnetic field. […] Although the Earth's magnetic field resembles that of a bar magnet we must find another explanation for the field's origin. Permanent magnets cannot exist at the temperatures found in the Earth's core.

Fraknoi, Andrew, Morrison, David and Wolff, Sidney C., Astronomy 2e, OpenStax, 2022, § 8.1 “The Global Perspective”; and Natural Resources Canada, “Generation of the Earth’s magnetic field”, Geomagnetism, 2019

See the full note ↓

Key terms

Magnetic field: Region of space in which a magnetised needle experiences a force.
Declination: Angle, at a given place, between the direction of the compass and geographic north.
Drift: Slow, continuous movement.
Electromagnet: Coil of wire carrying a current, which produces a magnetic field that can be switched on and off.
Ferromagnetic: Describes a material attracted by a magnet: iron, nickel, cobalt. Neither aluminium nor copper is.
Induction: Appearance of a current in a wire when a magnet is moved close to it. This is how almost all the world’s electricity is produced.
Model: Calculated representation, regularly updated to forecast changes in the field.
Outer core: Liquid layer of iron and nickel located beneath the Earth’s mantle.

Notes and sources

↑
Passage Our planet produces its own magnetic field, generated by the movements of the liquid iron in its outer core.
The Earth's magnetic field is generated in the fluid outer core by a self-exciting dynamo process. […] Electrical currents flowing in the slowly moving molten iron generate the magnetic field.
Source British Geological Survey, “An Overview of the Earth’s Magnetic Field”, Geomagnetism, § 1 (“Introduction”), 1st paragraph.
Open access open the source · checked on 27 October 2026
↑
Passage it has already reversed hundreds of times over the course of the Earth’s history
Over the past 250 Ma, there have been a few hundred magnetic field reversals, and their timing has been anything but regular.
Source Earle, Steven, Physical Geology, 2e éd., BCcampus, 2019, section 9.3 “Earth’s Magnetic Field”, section 9.3 (“Earth’s Magnetic Field”), 3rd paragraph (beginning “Earth’s magnetic field is generated within the outer core”).
Open access open the source · checked on 27 October 2026
↑
Passage An electric current always creates a magnetic field around it
His ita comparatis, acus magnetica movebitur, et quidem sub ea fili conjungentis parte, quae electricitatem proxime a termino negativo apparatus galvanici accipit, occidentem versus declinabit. […] Similiter ex observatis colligere licet, hunc conflictum gyros peragere
Editors’ translation With things thus arranged, the magnetic needle will move, and indeed, under that part of the connecting wire which receives electricity most directly from the negative end of the galvanic apparatus, it will decline towards the west. […] Similarly, it may be gathered from the observations that this conflict performs circles
Source Ørsted, Hans Christian, Experimenta circa effectum conflictus electrici in acum magneticam, Copenhague, 1820, 1820 memoir (4 pages), beginning of the account of the experiments, then the paragraph of conclusions on the “electric conflict”.
Public domain open the source · checked on 24 October 2026
Passage moving a magnet near a wire gives rise to a current in it: this is induction
the galvanometer-needle being stationary, the magnet was suddenly thrust in; immediately the needle was deflected in the same direction as if the magnet had been formed […] and then the magnet being withdrawn the needle was deflected in the opposite direction.
Source Faraday, Michael, “Experimental Researches in Electricity”, Philosophical Transactions of the Royal Society, vol. 122, 1832, p. 125-162, § 39 (eleventh page of the paper).
Public domain open the source · checked on 24 October 2026
↑
Passage Magnetic north is the place where the Earth’s magnetic field points vertically downwards.
the north magnetic pole, the location where the magnetic field points vertically downwards
Source Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, abstract of the article.
Open access open the source · checked on 9 September 2026
↑
Passage It aligns itself with the magnetic field where it happens to be […] In many places, the needle points noticeably to one side.
Magnetic declination, sometimes called magnetic variation, is the angle between magnetic north and true north. […] Magnetic declination changes over time and with location. As the compass points with local magnetic fields, declination value is needed to obtain true north.
Source NOAA NCEI, “Wandering of the Geomagnetic Poles” et “Magnetic Declination”, NCEI page “Magnetic Declination (Variation)”, introductory paragraph (https://www.ngdc.noaa.gov/geomag/declination.shtml).
Open access open the source · checked on 24 October 2026
↑
Passage The position of the pole was measured on site for the first time in 1831, in the Canadian Arctic.
Since the first in situ measurements in 1831 of its location in the Canadian arctic
Source Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, abstract of the article.
Open access open the source · checked on 9 September 2026
Passage measured on site for the first time in 1831
We accordingly commenced our journey in the middle of May 1831 […] Having gained the calculated position on the 1st of June […] the resultant mean dip in each of the three directions in which they were obtained placed us as near to the magnetic pole as, with our limited means, we were able to determine.
Source Ross, James Clark, “On the Position of the North Magnetic Pole”, Philosophical Transactions of the Royal Society, vol. 124, 1834, p. 47-52, p. 49-51.
Public domain open the source · checked on 24 October 2026
Passage it has been drifting inexorably towards Siberia
the pole has drifted inexorably towards Siberia
Source Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, abstract of the article.
Open access open the source · checked on 9 September 2026
Passage The position of the pole was measured on site for the first time in 1831
In 1831, James Clark Ross located the north dip pole position in northern Canada.
Source NOAA NCEI, “Wandering of the Geomagnetic Poles” et “Magnetic Declination”, page “Wandering of the Geomagnetic Poles”, section “Experimental Observations of Dip Poles”.
Open access open the source · checked on 24 October 2026
↑
Passage 0 to 15 km/year: the historical speed […] 50 to 60 km/year: after a marked acceleration between 1990 and 2005
accelerating between 1990 and 2005 from its historic speed of 0–15 km yr⁻¹ to its present speed of 50–60 km yr⁻¹
Source Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, abstract of the article.
Open access open the source · checked on 9 September 2026
Passage Late October 2017: the pole crosses the date line, passing within 390 km of the geographic pole. It is now heading south.
In late October 2017 the north magnetic pole crossed the international date line, passing within 390 km of the geographic pole, and is now moving southwards.
Source Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, abstract of the article.
Open access open the source · checked on 9 September 2026
Passage ~35 km/year: speed forecast for the five years after 2025, slowly decelerating
Over the next five years, the WMM2025 predicts a very slow drift of the south dip pole, at about 9 km/year on average, and a faster (yet gradually decelerating) drift of the north dip pole, at about 35 km/year.
Source NOAA National Centers for Environmental Information and British Geological Survey, World Magnetic Model, WMM 2025 Report (WWM_Report_2025.pdf, linked from the WMM page), section 1.6, p. 21.
Open access open the source · checked on 24 October 2026
↑
Passage within the decade following their article, the pole should travel between 390 and 660 kilometres further towards Siberia
over the next decade the north magnetic pole will continue on its current trajectory, travelling a further 390–660 km towards Siberia
Source Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, abstract of the article.
Open access open the source · checked on 9 September 2026
↑
Passage A global model of the magnetic field is drawn up and updated every five years […] an out-of-cycle update had to be published in 2019
A new version of the model is updated every five years to address changes in Earth’s magnetic field. […] An out-of-cycle update of the WMM2015 was developed and released in early 2019 (WMM2015v2) to address this performance degradation.
Source NOAA National Centers for Environmental Information and British Geological Survey, World Magnetic Model, NOAA WMM page (presentation of the model); then WMM2015v2 Technical Note, Abstract, p. 2.
Open access open the source · checked on 24 October 2026
↑
Passage The numbers painted on airport runways indicate their orientation relative to magnetic north […] The runway then has to be repainted
Runway numbers and letters are determined from the approach direction. The runway number is the whole number nearest one‐tenth the magnetic azimuth of the centerline of the runway, measured clockwise from the magnetic north.
Source Federal Aviation Administration, Aeronautical Information Manual, chapitre 2, section 3, “Airport Marking Aids and Signs”, § 2-3-3 “Runway Markings”, b. “Runway Designators”, open access.
Open access open the source · checked on 24 October 2026
Passage The numbers painted on airport runways indicate their orientation relative to magnetic north […] The runway then has to be repainted
Tampa International Airport on Florida's west coast just finished renaming its three runways, a laborious project that interrupted airport traffic for a month while runways were shut down for repainting.
Source NBC News, “Compass Direction, True North Parting Ways”, no author or date shown, beginning of the article.
Open access open the source · checked on 24 October 2026
↑
Passage The cause is not at the surface. It lies 3,000 km beneath our feet.
Beginning at a depth of 2900 kilometers, we encounter the dense metallic core of Earth. In addition to iron, the core probably also contains substantial quantities of nickel and sulfur, all compressed to a very high density. The outer core is liquid, but […] This magnetic field is generated by moving material in Earth’s liquid metallic core.
Source Fraknoi, Andrew, Morrison, David and Wolff, Sidney C., Astronomy 2e, OpenStax, 2022, § 8.1 “The Global Perspective”, § 8.1, subsections “Earth’s Interior” and “Magnetic Field and Magnetosphere”.
Open access open the source · checked on 27 October 2026
↑
Passage the position of the north magnetic pole has been determined by two large patches of field located […] at the boundary between the core and the mantle: one under Canada, the other under Siberia
over the last two decades the position of the north magnetic pole has been largely determined by two large-scale lobes of negative magnetic flux on the core–mantle boundary under Canada and Siberia
Source Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, abstract of the article.
Open access open the source · checked on 9 September 2026
↑
Passage the Canadian patch has stretched, probably because of a change in the circulation of the liquid metal between 1970 and 1999. As it lengthened, it lost some of its strength at the surface.
elongation of the Canadian lobe, probably caused by an alteration in the pattern of core flow between 1970 and 1999, substantially weakened its signature on Earth's surface, causing the pole to accelerate towards Siberia
Source Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, abstract of the article.
Open access open the source · checked on 9 September 2026
↑
Passage liquid conducting metal in motion creates a current, and this current generates the field. No giant magnet at the centre of the Earth
This magnetic field is generated by moving material in Earth’s liquid metallic core. As the liquid metal inside Earth circulates, it sets up a circulating electric current. When many charged particles are moving together like that—in the laboratory or on the scale of an entire planet—they produce a magnetic field. […] Although the Earth's magnetic field resembles that of a bar magnet we must find another explanation for the field's origin. Permanent magnets cannot exist at the temperatures found in the Earth's core.
Source Fraknoi, Andrew, Morrison, David and Wolff, Sidney C., Astronomy 2e, OpenStax, 2022, § 8.1 “The Global Perspective”; and Natural Resources Canada, “Generation of the Earth’s magnetic field”, Geomagnetism, 2019, Fraknoi et al., § 8.1, subsection “Magnetic Field and Magnetosphere”; Natural Resources Canada, 1st paragraph.
Open access open the source 1 open the source 2 · checked on 27 October 2026

Bibliography

British Geological Survey, “An Overview of the Earth’s Magnetic Field”, Geomagnetism, open access (the field generated in the fluid outer core by currents flowing in the moving molten iron). https://geomag.bgs.ac.uk/education/earthmag.html
Earle, Steven, Physical Geology, 2e éd., BCcampus, 2019, section 9.3 “Earth’s Magnetic Field”, open access (a few hundred reversals of the magnetic field in 250 million years, at irregular intervals). https://opentextbc.ca/physicalgeology2ed/chapter/9-3-earths-magnetic-field/
Faraday, Michael, “Experimental Researches in Electricity”, Philosophical Transactions of the Royal Society, vol. 122, 1832, p. 125-162, public domain (the discovery of induction).
Federal Aviation Administration, Aeronautical Information Manual, chapitre 2, section 3, “Airport Marking Aids and Signs”, § 2-3-3 “Runway Markings”, b. “Runway Designators”, open access (the runway number is derived from the magnetic azimuth of its centreline, measured from magnetic north). https://www.faa.gov/air_traffic/publications/ATpubs/AIM_html/chap2_section_3.html
Fraknoi, Andrew, Morrison, David and Wolff, Sidney C., Astronomy 2e, OpenStax, 2022, § 8.1 “The Global Perspective”, open access (Earth’s internal structure: core at 2,900 km, iron and nickel, liquid outer core; the field generated by moving liquid metal and the current it creates). https://openstax.org/books/astronomy-2e/pages/8-1-the-global-perspective
Livermore, Philip W., Finlay, Christopher C. and Bayliff, Matthew, “Recent North Magnetic Pole Acceleration towards Siberia Caused by Flux Lobe Elongation”, Nature Geoscience, vol. 13, 2020, p. 387-391, open access (the first measurement in 1831; the successive speeds; the crossing of the date line within 390 km of the geographic pole; the two flux lobes under Canada and Siberia; the elongation of the Canadian lobe; the forecast of a further 390 to 660 km). https://arxiv.org/abs/2010.11033
Merrill, Ronald T., McElhinny, Michael W. and McFadden, Phillip L., The Magnetic Field of the Earth, Academic Press, 1996, in libraries (the geodynamo: liquid metal in motion, not a central magnet; reversals of the field).
Natural Resources Canada, “Generation of the Earth’s magnetic field”, Geomagnetism, 2019, open access (no permanent magnet can exist at core temperatures). https://www.geomag.nrcan.gc.ca/mag_fld/fld-en.php
NBC News, “Compass Direction, True North Parting Ways”, no author or date shown (remarks gathered by Discovery News), open access (Tampa airport closed its runways for a month to repaint their numbers, which had become wrong because of the movement of the magnetic pole). https://www.nbcnews.com/news/amp/wbna41904110
NOAA National Centers for Environmental Information and British Geological Survey, World Magnetic Model, open access (the model updated every five years, the out-of-cycle update of 2019, and the recent slowdown). https://www.ncei.noaa.gov/products/world-magnetic-model
NOAA NCEI, “Wandering of the Geomagnetic Poles” et “Magnetic Declination”, open access (the historical positions of the pole and the notion of declination). https://www.ncei.noaa.gov/products/wandering-geomagnetic-poles
Ross, James Clark, “On the Position of the North Magnetic Pole”, Philosophical Transactions of the Royal Society, vol. 124, 1834, p. 47-52, public domain (the 1831 measurement).
Ørsted, Hans Christian, Experimenta circa effectum conflictus electrici in acum magneticam, Copenhague, 1820, public domain (a current deflects a magnetised needle).

Figures re-examined every year.

Spotted an error or have a doubt? Write to us.