A study by researchers at the University of Vienna and ETH Zurich has found that Earth's days are getting longer at an unprecedented rate of 1.33 milliseconds per century. This acceleration is driven by climate change, as melting polar ice sheets and glaciers shift water from the poles toward the equator, slowing the planet's rotation. According to the study, the current rate of change in day length is faster than any other period in the last 3.6 million years, though a comparable rate occurred around 2 million years ago.
Professor Benedikt Soja, a co-author of the study, told Daily Mail - Science & Tech that while natural cycles have caused variations in the past, the current rate due to human impact is so rapid that it stands out in climate history. He noted that only around 2 million years ago was the rate of change nearly comparable, but never before or after has the planetary 'figure skater' raised her arms and sea levels so quickly as between 2000 and 2020.
While natural cycles caused variations in the past, the current rate of change, due to human impact, is so rapid that it stands out in climate history.
The study projects that by the end of the 21st century, climate change could affect day length more strongly than the moon's gravitational pull. Starting from the 2080s, days could lengthen by 2.62 milliseconds every century due to climate change alone. This would surpass the moon's tidal influence, which has been gradually slowing Earth's rotation over billions of years.
Although the changes are only milliseconds and not noticeable to humans, they can disrupt precise timekeeping systems. According to Daily Mail - Science & Tech, Professor Soja explained that even millisecond changes can affect space navigation, GPS and satellite navigation systems, and the synchronization of atomic clocks. This makes it important to precisely monitor Earth's rotation.
Only one time – around 2 million years ago – the rate of change in length of day was nearly comparable, but never before or after that has the planetary 'figure skater' raised her arms and sea-levels so quickly as in 2000 to 2020.
The study, published in the Journal of Geophysical Research: Solid Earth, was led by Mostafa Kiani Shahvandi and included contributions from NASA researcher Surendra Adhikari. The researchers used a combination of observational data and climate models to reconstruct day length changes over millions of years.
Even though the changes are only milliseconds, they can disrupt systems that require extremely precise time keeping.
This includes space navigation, GPS and satellite navigation systems, and synchronisation of atomic clocks, which makes it so important to precisely monitor the Earth's rotation.