<p>The term ‘polar wander’ is ambiguous. In this case it's got nothing to do with the magnetic poles, but rather with the Earth's spin axis. If you think about a desk globe mounted on an axle, the poles under consideration here are the points where the axle intersects the globe's surface.</p>

<p>The paper is essentially saying that climate changes are changing the distribution of ice and water on the surface of the planet, and this in turn is shifting the spin axis slightly. You're right that the mass of material on the Earth's surface is dwarfed by the mass under the surface; however, if you look at the paper you'll see that they're talking about miniscule shifts in the axis. The changes shown in Figure 1 are on the order of tens of mas (milliseconds of arc) over a few decades. One mas is one 3.6-millionth of a degree, or about 3.09 cm as measured on the Earth's surface. So, at least at first glance, the changes don't seem too implausible.</p>

<p>You mention isostatic response as another concern, but this is a slow process which doesn't really come into play on the decadal time scales considered in the paper. Fennoscandia and northern North America are still rebounding isostatically from the last ice age.</p>

CC BY-SA 3.0
2016-04-09T07:15:07.057Z
2016-04-09T07:15:07.057Z
Pont
<p>Further to Pont's comments, there is often confusion about polar drift, which is two entirely different processes. The magnetic north pole is created by the rotation of the Earth's core, and possible differential rotation between core and mantle. This effect has historically shifted the magnetic north pole by about 50 km.</p>

<p>The geographic north pole, which is the Earth's spin axis, has seen significant shift since the end of the last ice age, mainly due to melting of the North American ice cap. As N. America got 'lighter' the geographic north pole moved towards Hudson Bay. Now, with climate change Greenland is starting to melt so that the polar shift has changed direction - towards the UK in fact, but the total measured effect over the last few decades is only a few tens of metres. </p>

CC BY-SA 3.0
2016-04-16T06:49:03.590Z
2016-04-16T06:49:03.590Z
Gordon Stanger
<p>After coming across this article <a href="http://www.climatecentral.org/news/climate-change-polar-motion-20229#article-comments" rel="nofollow">here</a>, and reading the paper <a href="http://advances.sciencemag.org/content/2/4/e1501693.full" rel="nofollow">here</a> I came away with the impression that the authors were saying that <a href="https://en.wikipedia.org/wiki/Polar_wander" rel="nofollow">polar wander</a> is being affected by climate change due to mass rebalancing as ice caps melt. As I understand it, the magnetic field of Earth derives from the liquid outer core, and due to the sheer mass difference between the core and any surface mass losses, combined with the lost mass being rebalanced isostatically, such a theory seems on first glance improbable. Could someone with more knowledge perhaps explain how the proposed theory operates?</p>

CC BY-SA 3.0
2016-04-08T21:10:50.397Z
As far as I got the content of the article from reading the abstract (and from searching for 'magnet' in the articles text), it is not about a shift of the magnetic poles but it is about a shift in the rotation axis. In other words: the rotation axis is wandering and not the magnetic poles. The Wikipedia article, in contrast, is about wandering of the magnetic pole.
daniel.heydebreck
CC BY-SA 3.0
2016-04-09T09:19:37.130Z
Thanks for the clarification, I guess I just assumed it was the magnetic pole, rather than the rotation axis..
Siv
CC BY-SA 3.0
2016-04-11T11:43:58.817Z
See also this question: [Does the geographic north pole move?](http://earthscience.stackexchange.com/questions/7740/does-the-geographic-north-pole-move).
Matt Hall
CC BY-SA 3.0
2016-12-29T09:32:54.837Z
@Siv, The article and the paper clearly talk about polar motion, not polar wander. These are distinct concepts.
David Hammen
<climate-change>
Is this paper attributing a change in polar wander to climate change?
Siv
# Is this paper attributing a change in polar wander to climate change?

(Asked by: username_0 on 2016-04-08)

After coming across this article [here](http://www.climatecentral.org/news/climate-change-polar-motion-20229#article-comments), and reading the paper [here](http://advances.sciencemag.org/content/2/4/e1501693.full) I came away with the impression that the authors were saying that [polar wander](https://en.wikipedia.org/wiki/Polar_wander) is being affected by climate change due to mass rebalancing as ice caps melt. As I understand it, the magnetic field of Earth derives from the liquid outer core, and due to the sheer mass difference between the core and any surface mass losses, combined with the lost mass being rebalanced isostatically, such a theory seems on first glance improbable. Could someone with more knowledge perhaps explain how the proposed theory operates?

**Tags:** climate-change

> **Comments:**
> **username_1**: As far as I got the content of the article from reading the abstract (and from searching for 'magnet' in the articles text), it is not about a shift of the magnetic poles but it is about a shift in the rotation axis. In other words: the rotation axis is wandering and not the magnetic poles. The Wikipedia article, in contrast, is about wandering of the magnetic pole.  
> **username_0**: Thanks for the clarification, I guess I just assumed it was the magnetic pole, rather than the rotation axis..  
> **username_2**: See also this question: [Does the geographic north pole move?](http://earthscience.stackexchange.com/questions/7740/does-the-geographic-north-pole-move).  
> **username_3**: @username_0, The article and the paper clearly talk about polar motion, not polar wander. These are distinct concepts.  

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## 2 answers

### Answer by username_4 on 2016-04-09. Score: 6

The term ‘polar wander’ is ambiguous. In this case it's got nothing to do with the magnetic poles, but rather with the Earth's spin axis. If you think about a desk globe mounted on an axle, the poles under consideration here are the points where the axle intersects the globe's surface.

The paper is essentially saying that climate changes are changing the distribution of ice and water on the surface of the planet, and this in turn is shifting the spin axis slightly. You're right that the mass of material on the Earth's surface is dwarfed by the mass under the surface; however, if you look at the paper you'll see that they're talking about miniscule shifts in the axis. The changes shown in Figure 1 are on the order of tens of mas (milliseconds of arc) over a few decades. One mas is one 3.6-millionth of a degree, or about 3.09 cm as measured on the Earth's surface. So, at least at first glance, the changes don't seem too implausible.

You mention isostatic response as another concern, but this is a slow process which doesn't really come into play on the decadal time scales considered in the paper. Fennoscandia and northern North America are still rebounding isostatically from the last ice age.


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### Answer by username_5 on 2016-04-16. Score: 2

Further to username_4's comments, there is often confusion about polar drift, which is two entirely different processes. The magnetic north pole is created by the rotation of the Earth's core, and possible differential rotation between core and mantle. This effect has historically shifted the magnetic north pole by about 50 km.

The geographic north pole, which is the Earth's spin axis, has seen significant shift since the end of the last ice age, mainly due to melting of the North American ice cap. As N. America got 'lighter' the geographic north pole moved towards Hudson Bay. Now, with climate change Greenland is starting to melt so that the polar shift has changed direction - towards the UK in fact, but the total measured effect over the last few decades is only a few tens of metres.


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