How does magnetic variation change over time?

Magnetic variation, also known as magnetic declination, is influenced by various factors, including the movement of the Earth's magnetic poles and geological factors. The Earth's magnetic field is not static; it changes over time due to the dynamic nature of the Earth's core, where the magnetic field is generated. This results in gradual changes in the position of the magnetic poles and variations in strength and direction of the magnetic field.

Additionally, geological factors, such as changes in the Earth's crust and the presence of different materials, can affect local magnetic fields, contributing to the change in magnetic variation in specific areas.

The understanding of magnetic variation is crucial for navigation, as pilots and navigators rely on accurate readings to adjust their courses. Hence, knowing that magnetic variation changes over time due to these factors enables navigators to make necessary adjustments to their tools and approaches to ensure safe and accurate navigation.

Other options suggest that magnetic variation is either stable over long periods, constant across regions, or only influenced by solar events, each of which does not align with the documented, dynamic changes of the Earth's magnetic field.