These days, it sometimes feels like the world is spinning uncontrollably fast. However, new research reveals that Earth’s rotation is actually slowing down significantly. Scientists from Vienna and Zurich have studied ancient climate data, particularly sea level changes, to show this trend. Between 2000 and 2020, our days grew longer by about 1.33 milliseconds each century. This is the quickest slowdown since the Late Pliocene, around 3.6 million years ago.
Benedikt Soja, a geophysicist from ETH Zurich, explains that this increase in day length is linked to human activities. In a press statement, he highlighted that climate change is the main driver of this phenomenon. As ice sheets melt, more water accumulates in the oceans, especially at lower latitudes near the equator. This added mass slows down Earth’s spin, similar to how a figure skater slows down when they stretch their arms out.
Soja’s colleague, Mostafa Kiani Shahvandi, elaborated on this comparison. He noted that the current rate of change in day length is unmatched by any previous period in the last 2 million years.
The research relies on a wealth of data from tiny marine fossils called benthic foraminifera. By analyzing these fossils, scientists can infer historical sea levels and calculate corresponding changes in day length. This study employed a new deep-learning method combining machine learning with physical constraints to enhance the accuracy of their findings.
While small shifts in Earth’s rotation may seem trivial, they hold importance in fields like navigation and satellite technology. For instance, on July 4, 2024, Earth spun faster than usual by 1.66 milliseconds. Factors like the movement of molten rock, atmospheric pressure, and lunar influences all play a role in daily rotation variations.
In contrast, this research focuses on long-term trends that span decades, contrasting them with patterns observed over millions of years. Soja warns that as climate change progresses, the growing weight of water at the equator will significantly impact Earth’s rotation speed. “By the end of the century, climate change may affect day length more than the moon does,” he said. Although these changes are minute, they can disrupt systems relying on precise timing.
This research sheds light not only on Earth’s changing rotation but also on the broader implications of climate change. As we continue to alter our planet, understanding these subtle shifts will be crucial for many areas of science and technology.
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earth science,machine learning,sea level rise
