Earth’s magnetic poles "overdue" for reversal, study says

The Earth’s magnetic field plays a very significant role in everyday life on the planet. In many ways, the field serves as an invisible shield that protects us from harmful solar radiation. But Earth’s magnetic field is also ever changing, and several times each millennium, the north and south magnetic poles switch places. According to new research from a team of scientists from the University of Leeds, Earth is “overdue” for such a reversal.

During such a reversal, the magnetic field becomes weaker and could drop to as low as 10% of its current strength. When the transition occurs, both magnetic poles could end up at the equator or even simultaneously exist as double north or south magnetic poles.

When the magnetic field weakens, increased levels of solar radiation make their way to the Earth’s surface. This can cause chaos for satellites, air travel, and all electrical infrastructure, leading to blackouts that could cost billions of dollars per day in economic disruption.

The last full reversal occurred roughly 780,000 years ago and was known as the Brunhes-Matuyama reversal. 41,000 years ago, a temporary reversal occurred known as the Laschamp event. Temporary reversals happen when the magnetic poles drift away from the geographic poles but then return back to their original location. The Laschamp event lasted less than 1,000 years.

But because modern humans did not exist at the time of the last full reversal, it is difficult to accurately predict the full impact on life during the transition. However, animals who possess a sense of magnetoreception that allow them to use the Earth’s magnetic field to navigate during migration would be especially affected.

The Earth’s magnetic field is currently decreasing at a rate of 5% per century, which according to scientists, means that the next reversal could occur within the next 2,000 years.

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By Rory Arnold, Earth.com Staff Writer

Images: NASA Goddard Space Flight Center