A recent study revealed that dam construction has shifted Earth’s rotational axis by over 1 meter since 1835 i.e., they have driven True Polar Wander (TPW).
What Is True Polar Wander (TPW)?
- Definition: TPW, or planetary reorientation, is the rotation of the solid Earth (crust and mantle) about the liquid outer core.
- It helps the Earth maintain rotational balance due to mass redistribution.
- Natural Factors driving TPW: Traditionally, TPW has been linked to natural processes such as glacial melting, Ice sheet melt, tectonic plate shifts, and ocean swell.
How Dams Are Driving TPW?
- Reservoirs trap large volumes of water that would otherwise remain in oceans.
- This redistributes Earth’s mass inland, causing shifts in the planet’s rotation.
- The study also revealed that the shift was not smooth—it varied depending on the size and location of dams built over time.
Effects of Shifting Poles
- Navigation Problems: Shifting poles can affect satellites and space telescopes, which depend on Earth’s rotation for accurate positioning.
- Longer Days: The days on Earth are growing slightly longer, and this change is accelerating.
