Scientists Report Unprecedented Changes in Earth’s Rotation

Every day, the Earth takes a little longer to complete its rotation. Although the change is only measured in fractions of a millisecond, the forces behind it are enormous. A recent study indicates that the current rate at which our days are lengthening is unprecedented in 3.6 million years of geological history.

Researchers found that the melting of polar ice sheets and glaciers due to climate change is causing water, previously stored at high latitudes, to flow into the oceans and spread towards the equator. This movement shifts mass away from the poles, slowing the planet’s rotation, much like a figure skater slows when extending their arms.

Previous studies had already noted unusual effects of climate change on Earth’s spin. The team from the University of Vienna and ETH Zurich revisited geological data and determined that today’s rate of change has not been matched in the past. To analyse millions of years, they examined fossilised remains of marine organisms, which record ancient sea levels. This helped them calculate changes in the Earth’s rotation.

Currently, the rate of climate-driven day lengthening is 1.33 milliseconds per century. While this may seem small, it signifies a massive redistribution of mass: about 1,000 gigatonnes moving from the poles to the oceans. The energy involved in this shift is comparable to a magnitude 9.0 earthquake.

Looking ahead, if high emissions continue, climate change will likely become the primary force affecting day length by the end of the century, surpassing even the Moon’s gravitational influence. The consequences, though subtle, could impact technologies like GPS navigation and reflect broader changes in the Earth’s ecosystem. The team plans to explore other factors influencing the planet’s mass distribution, such as groundwater depletion.

How much do you know?

How long does it currently take for the Earth to complete its rotation?

24 hours

23 hours 59 minutes

Fraction of a millisecond

23 hours 56 minutes

What is causing the increase in the length of days on Earth?

Volcanic activity

Melting of polar ice sheets

Tectonic shifts

Solar flares

What is the current rate of climate-driven day lengthening?

1 millisecond per century

1.33 milliseconds per century

0.5 milliseconds per century

2 milliseconds per century

Which institutions conducted the research on Earth's rotation?

NASA and NOAA

University of Vienna and ETH Zurich

MIT and Stanford

Harvard and Yale

What is the approximate amount of mass moving from the poles to the oceans?

500 gigatonnes

1,000 gigatonnes

2,000 gigatonnes

750 gigatonnes

By the end of the century, what will likely surpass the Moon's gravitational influence?

Solar radiation

Climate change

Tidal patterns

Atmospheric pressure

The change in Earth's rotation is measured in seconds.

True False

Melting glaciers are contributing to the slowdown of Earth's rotation.

True False

The current rate of day lengthening has occurred multiple times in the last 3.6 million years.

True False

Fossilised remains of marine organisms helped researchers study ancient sea levels.

True False

High emissions are expected to decrease the influence of climate change on day length.

True False

The energy shift from polar ice to oceans is equivalent to a magnitude 9.0 earthquake.

True False

The Earth takes a little longer to complete its rotation each day, with changes measured in milliseconds.

The current rate at which our days are lengthening has not been matched in million years.

The movement of water to the oceans slows the planet's rotation like a figure skater who their arms.

The team plans to explore other factors influencing the planet's mass distribution, such as groundwater .

The consequences of changing day length could impact technologies like navigation.

Climate change is likely to become the primary force affecting day length by the end of the .

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