9:00 AM | *Magnetic North Pole is slowly moving towards Asia as Earth’s magnetic field changes quicker than previously thought*

Measurements from April 2016 of the Earth's magnetic field where blue depicts weak regions and red shows areas where it is strong (white circles represent the north and south polar locations); map courtesy European Space Agency, Swarm satellites

Overview
The Earth’s magnetic field acts like a shield protecting us from harsh solar winds and cosmic radiation and new research has shown just how rapidly it is changing.  With more than two years of measurements by the European Space Agency (ESA) Swarm satellite trio, changes in the strength of Earth’s magnetic field are being mapped in detail.  The magnetic field has actually weakened over parts of the world in recent years, strengthened over others, and is changing quicker than previously thought.  In addition, the magnetic north pole is wandering east towards Asia. These changes have occurred over the relatively brief period between late 1999 and May 2016.

Depiction of the Earth's magnetic field; courtesy University of Rochester

Earth’s magnetic field
Although invisible, the Earth’s magnetic field and electric currents in and around Earth have immeasurable effects on our everyday lives and could determine how space events such as solar storms affect us in the future.  The magnetic field is thought to be produced largely by an ocean of molten, swirling liquid iron that makes up our planet’s outer core, 3000 km under our feet. Acting like the spinning conductor in a bicycle dynamo, it generates electrical currents and thus the continuously changing electromagnetic field.   The magnetic field protects us from cosmic radiation and electrically charged atomic particles that bombard Earth in solar winds.  Researchers have long known that the Earth’s magnetic field is in a constant state of flux. Less magnetism means more radiation can penetrate our planet's atmosphere. Indeed, high altitude balloons launched routinely detect increasing levels of cosmic rays over portions of North America. Perhaps the ebbing magnetic field is contributing to that trend.  Research studies in recent years have found that an increase in cosmic rays reaching the Earth’s atmosphere can, in turn, lead to an increase in certain types of clouds that can act to cool the Earth.
  
The latest measurements from the ESA Swarm constellation and CHAMP and Orsted satellites show clearly that the magnetic field has weakened by about 3.5% at high latitudes over North America while strengthening about 2% over Asia.  The region where the field is at its weakest – the South Atlantic Anomaly – has moved steadily westward and weakened further by about 2%.  In addition, the North Pole is wandering eastward towards the Asian continent pretty quickly. In the map (above), blue depicts where Earth's magnetic field is weak and red shows regions where it is strong:
 
While quite significant, the recent changes in Earth’s magnetic field are mild compared to some that have taken place in the past.  Sometimes the magnetic field completely flips, with north and the south poles swapping places. Such reversals - recorded in the magnetism of ancient rocks - are unpredictable. They come at irregular intervals averaging about 300,000 years; the last one was 780,000 years ago.  This pole reversal sounds a lot scarier than it really is. There's no evidence that life on Earth suffered when this happened in the past - the most likely impact is that our compasses would eventually point south instead of north. "Such a flip is not instantaneous, but would take many hundred if not a few thousand years," according to Rune Floberghagen from the European Space Agency. "They have happened many times in the past." 

ESA Swarm satellites
Swarm is a trio of satellites (Alpha, Bravo and Charlie) launched at the end of 2013 to study the Earth’s magnetic field.  The constellation of three satellites was placed in two different polar orbits with two flying side-by-side at an altitude of 450 kilometers and a third at an altitude of 530 kilometers.  Each satellites is equipped with vector magnetometers capable of sensing Earth's magnetic field all the way from orbital altitudes down to the edge of our planet's core. Swarm is measuring and untangling the different magnetic signals from Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere – an undertaking that will take several years to complete.  The constellation is expected to continue operations at least until 2017, and possibly beyond, so stay tuned for updates.

This video of the Earth’s magnetic field changes since 1999 shows clearly the gradual movement of the north and south poles (white circles) and the shifting of weak (blue) and strong (red) regions. 

Meteorologist Paul Dorian
Vencore, Inc.