Dams Are Changing Earth's Axis!

New research has unveiled a startling truth about the thousands of dams constructed since 1835: they are actually causing the Earth's poles to wobble! These colossal structures hold such massive amounts of water that they are redistributing Earth's mass, leading to a shift of our planet's crust relative to the mantle beneath it.

The Science Behind the Shift

The Earth's mantle, a semi-solid layer underneath the solid crust, can allow the crust to slide and shift. When we add significant weight—like that from water stored behind dams—it changes the orientation of the Earth's rotation axis, a phenomenon known as "true polar wander." This was highlighted in a study published in the journal Geophysical Research Letters.

Polar Wandering: The Ice Melt Connection

Scientists have previously established that human activities, such as massive ice melting from climate change, can trigger polar wander. For instance, a study released earlier this year predicted that by the century's end, polar locations could shift by 90 feet due to accelerated ice loss.

Examining the Impact of Thousands of Dams

In this groundbreaking study, researchers investigated the effects of 6,862 dams constructed worldwide from 1835 to 2011. They used existing data, revealing that the water held back could fill the Grand Canyon twice, contributing to a significant global sea level drop of approximately 0.9 inches.

A Measurable Shift in Our Planet

The study found that as we have trapped water behind these massive barriers, the poles have shifted a total of 3.7 feet over the span of the research period. Natasha Valencic, lead author and geology graduate student at Harvard University, emphasized this dual effect of damming: not only do these structures remove water from the oceans, lowering sea levels, but they also redistribute mass worldwide.

Tracing Two Phases of Polar Wander

The study identified two distinct phases of polar wander: the first from 1835 to 1954, marked by extensive dam building in North America and Europe, which caused the North Pole to edge 8 inches closer to the 103rd meridian in eastern Russia. The second phase, from 1954 to 2011, saw dam expansion in East Africa and Asia, resulting in a more significant 22-inch shift toward the 117th meridian, traversing western North America and the South Pacific.

Implications for Sea Level Projections

Although the shift of the poles may seem insignificant to everyday life, it does have considerable ramifications for sea level projections. Valencic noted that we cannot expect an ice age simply because the pole has shifted by about a meter. However, dams are blocking a significant quantity of water from reaching the oceans, affecting global sea levels which rose between 4.7 to 6.7 inches during the 20th century.

Dams: A Hidden Player in Sea Level Rise

Approximately 25% of the water contributing to this rise is currently stored behind dams, indicating their influential role varied across locations worldwide. "We must consider these substantial changes because they can have far-reaching effects," Valencic concluded.