Dams Shift Earth’s Magnetic North Pole, Study Reveals

Massive Water Storage Reorients Planetary Axis

Human engineering has subtly but measurably altered Earth’s magnetic north pole. Researchers have discovered that the sheer volume of water impounded behind the world’s largest dams has shifted the planet’s rotational axis, influencing the magnetic field’s orientation.

Axis Tilt Linked to Water Redistribution

A groundbreaking study by Harvard University geophysicist Natasha Valencic and her colleagues reveals that the immense weight of water stored in nearly 7,000 major dams has nudged Earth’s crustal axis of rotation by approximately one meter (three feet). This mass redistribution is also responsible for a 21-millimeter drop in global sea levels.

Natasha Valencic explained the phenomenon, stating, As we trap water behind dams, not only does it remove water from the oceans, thus leading to a global sea level fall, it also distributes mass in a different way around the world.

Understanding True Polar Wander

The shift affects the planet’s outer crust, causing what scientists term “true polar wander.” This occurs as additional weight on a rotating sphere pulls that mass toward the equator, altering the axis around which it spins. This effect can be triggered by various human activities, including damming water, melting glaciers, and groundwater extraction.

The research charted the North Pole’s movement in two distinct phases. Between 1835 and 1954, it drifted eastward toward Russia by about 20 centimeters (8 inches), coinciding with dam construction in Europe and North America. Subsequently, from 1954 to 2011, it moved 57 centimeters westward toward North America, linked to increased dam building in Asia and East Africa.

Implications for Sea Level Rise Projections

While the meter-scale shift in the pole does not portend an ice age, it carries significant implications for understanding sea level rise. Valencic noted, We’re not going to drop into a new ice age, because the pole moved by about a meter in total, but it does have implications for sea level.

The study estimates that human activities have sequestered a quarter of the sea level rise observed this century, roughly 1.2 millimeters annually, behind dams. This action, while mitigating some effects of human-induced climate change, requires careful consideration in future sea level projections. The placement of dams, Valencic warns, can alter the geometry of sea level rise, leading to potentially significant variations geographically.

These findings add to a growing list of global environmental changes influenced by human actions. These include alterations to atmospheric layers, shifts in ocean circulation patterns, and the increased activation of volcanoes due to melting glaciers.

New data from the National Oceanic and Atmospheric Administration (NOAA) shows that global average sea level in 2023 was 3.3 inches above the 1993 average and continues to rise at an accelerating rate (NOAA, 2024). Understanding the impact of mass redistribution, such as that caused by reservoirs, is crucial for accurate forecasting.

The research was published in the journal Geophysical Research Letters.