Earth is spinning faster this summer, making days marginally shorter. Scientists attribute this change to climate change, which is slowing down the planet’s rotation by melting ice caps in Antarctica and Greenland. The International Earth Rotation and Reference Systems Service reports that July 10 was the shortest day of the year so far, with a duration of 1.36 milliseconds less than 24 hours.
The length of a day varies slightly due to factors like the gravitational pull of the moon, seasonal changes, and the influence of Earth’s liquid core. However, these variations are measured using atomic clocks, which track oscillations of atoms in a vacuum chamber to calculate time with precision. The resulting time is UTC (Coordinated Universal Time), the global standard for timekeeping.
Researchers predict that if Earth continues to speed up, they may need to remove seconds from the UTC system rather than adding them. This concept is similar to the Y2K problem, which led to concerns about computer failures when transitioning to the year 2000.
While short-term changes in Earth’s rotation are influenced by the moon and tides, climate change plays a significant role in slowing down the planet’s spin. A study found that melting ice caps contribute to this effect, spreading over oceans like a skater spinning with their arms tucked in. Researchers acknowledge that long-term predictions on Earth’s spinning behavior remain uncertain.
The situation highlights the importance of timekeeping and its impact on global systems. As climate change continues to shape the planet’s rotation, scientists must adapt their understanding and prepare for potential changes to the UTC system.
Source: https://edition.cnn.com/2025/07/21/science/earth-spinning-faster-shorter-days