Several studies have already shown that climate change is slowing down the Earth’s rotation. In addition, scientists say, these changes in the climate are also shifting the axis of rotation and stirring up the planet’s molten interior.
The planet is warming... and slowing down
Humanity's increased release of greenhouse gases has caused the planet's temperature to rise, and no one expects it to stop any time soon. As the globe heats up, a study shows it is also spinning more slowly.
New research from ETH Zurich illustrates how the loss of ice cover in the polar regions could affect the Earth’s rotation. The impact of melting ice could even surpass the effects of the Moon on the Earth’s rotation.
The science is clear that global temperatures are rising, and human activity is to blame. A direct consequence of this is the increasing loss of ice in Greenland and Antarctica, which is causing sea levels to rise. However, the rise is not consistent across the globe. Earth's rotation pushes more meltwater toward the equator and away from the polar regions.
This means that a shift in mass is occurring, which affects the Earth's rotation.
Affirms Benedikt SojaETH Zurich.
The Earth's rotation speed is about 1666 km/h, or 465 m/s near the equator. The Earth's rotation speed in Portugal is approximately 1293 km/h.
The Earth is also affecting the Moon's rotation
Benedikt uses the analogy of a figure skater to explain the mechanism. When a skater spins with his arms pulled in towards his body, the speed of rotation increases. If the arms are pulled out, the rotation slows down. This is what is happening to the Earth.
Conservation of angular momentum means that Earth's days will become longer due to this effect. The change is small, just a few milliseconds per day. However, the effect can be significant over time.
A Moon also slows Earth's rotation as a result of tidal friction. ETH Zurich's studies on this phenomenon, published in the journals Nature Geoscience e Proceedings of the National Academy of Sciencespredict that continued warming could eventually cause so much water to migrate to central latitudes that it would slow Earth's rotation even more than the Moon's.
The work also goes deeper—literally, by examining how displacements in Earth's mantle and core change along with angular momentum.
The Earth's rotation speed has slowed down and, consequently, the length of the day has been lengthening. Even today, the length of a day increases by 1.7 milliseconds every 100 years. Small, but measurable! The Moon also feels this effect and also sees its rotation slow down.
The team built a 120-year model of polar motion, which allowed them to track changes in the Earth's axis over time, showing that the displacement of the mass can also change the axis of rotation. They found that changes in the axis and rate of rotation can affect how molten material is distributed across the planet.
This could affect the planet's magnetic field. However, this will be difficult to measure in real life, as we cannot directly examine the Earth's core.
Climate change: days will get longer
The full consequences of climate change are still being known, but this work suggests that the effects will be felt in unexpected ways.
The team says space exploration may need to start considering the effects of climate. A few milliseconds added to Earth’s day won’t affect its daily commute. But a spacecraft heading to another planet could be off by a kilometer when it reaches its destination.
We humans have a greater impact on our planet than we realize.
Benedikt concluded, adding that this naturally places a great responsibility on us for the future of the Earth.
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Source: pplware.sapo.pt
