Days on Earth are slowly getting longer, and scientists say the reason is not cosmic forces but climate change driven largely by human activity.

Researchers have found that the planet’s rotation is slowing down as global temperatures rise and ice masses melt. The resulting redistribution of water across the planet is subtly altering how Earth spins, lengthening the duration of a day by tiny fractions of a second.

Why Earth’s rotation is slowing down

Normally, several natural forces influence how fast Earth spins. The gravitational pull of the Moon, along with movements inside Earth’s atmosphere and core, can slightly speed up or slow down the planet’s rotation.

For example, in July and August 2025, changes in the Moon’s proximity caused Earth to spin slightly faster, shortening days by about 1.25 milliseconds.

However, scientists say another factor is now becoming increasingly important: global warming.

As temperatures rise, glaciers and permafrost melt, releasing large amounts of water into the oceans. This water spreads across the planet, redistributing Earth’s mass and slightly altering its rotation.

Melting ice is changing the planet’s balance

When polar ice sheets melt, the water moves from concentrated masses of ice to a broader distribution across the oceans.

This process acts a bit like a spinning ice skater extending their arms. When the mass spreads outward, the rotation slows.

Scientists say the same principle is affecting Earth’s spin. As the water from melting glaciers and ice sheets spreads across the globe, it exerts a small but measurable effect on the planet’s rotation speed.

What scientists discovered

Researchers from the University of Vienna and ETH Zurich studied changes in Earth’s rotation to understand whether similar events occurred in the past.

They examined geological records going back to the Late Pliocene period to see if climate-driven changes had ever altered the length of a day so quickly.

Their findings revealed that Earth’s day length is currently increasing by about 1.33 milliseconds every 100 years.

More strikingly, scientists say such a rapid climate-driven change has not occurred in roughly 3.6 million years.

Why the change matters

The difference is extremely small and impossible for humans to feel in daily life. But even tiny changes in Earth’s rotation can affect modern technology.

A slowing spin can influence systems that rely on precise timing, including:

• satellite navigation such as the Global Positioning System
• spacecraft navigation
• telecommunications networks
• high-speed financial trading systems

Because these systems depend on extremely accurate timekeeping, even millisecond-level changes must be carefully monitored.

What it says about climate change

Scientists say the findings highlight how rapidly Earth’s climate is changing.

According to researchers, the accelerated melting of polar ice sheets and mountain glaciers in the 21st century is raising sea levels and redistributing mass across the planet.

This shift is now strong enough to measurably slow Earth’s rotation, something researchers say has not happened at this pace since the Late Pliocene period.

The bottom line

• Earth’s rotation is gradually slowing down, making days slightly longer.
• The main reason is climate-driven melting of glaciers and polar ice sheets.
• Scientists estimate days are increasing by about 1.33 milliseconds per century.
• The speed of this change has not been observed in around 3.6 million years.
• While humans cannot feel the difference, it can affect satellites, navigation systems, and precise global technologies.