The climate crisis is causing each day to become longer, as massive melting of polar ice reshapes the planet, the analysis shows.
Scientists say the phenomenon is striking evidence of how human actions are changing the planet, comparable to natural processes that have existed for billions of years.
The change in the length of a day is measured in milliseconds, but it’s enough to potentially disrupt web traffic, financial transactions and GPS navigation, all of which rely on precise timing.
The length of Earth’s day has been steadily increasing over geological time due to the Moon’s gravitational pull on Earth’s oceans and land. However, due to human-caused global warming, the Greenland and Antarctic ice sheets are melting, redistributing water stored at high latitudes into the world’s oceans, resulting in more water in the oceans near the equator. This makes the Earth flatter—or fatter—slowing its rotation and further lengthening the day.
Human impact on the Earth is also supported by recent research, which shows that the redistribution of water has led to shifts in the Earth’s axis of rotation (North and South Poles). Other studies show that human carbon emissions are shrinking the stratosphere.
Professor Benedikt Soja of the Swiss Federal Institute of Technology in Zurich said: “We can see the impact of humans on the entire Earth system, not just local effects, such as rising temperatures, but fundamentally changing the way the Earth moves and rotates in space. ” “Because of our carbon emissions, it only took us 100 or 200 years to do this. Previous governance processes had lasted billions of years, which is astounding.
Human timekeeping is based on extremely accurate atomic clocks. However, the exact length of a day (one rotation of the Earth) varies depending on lunar tides, climate effects and a number of other factors, such as the slow rebound of the Earth’s crust as ice sheets formed during the last ice age retreat.
Soja says these differences must be taken into account: “All data centers running the Internet, communications and financial transactions are based on precise timing. We also need precise knowledge of time for navigation, especially satellites and spacecraft.
The study, published in the Proceedings of the National Academy of Sciences, used observations and computer reconstructions to assess the impact of ice melt on day length. Between 1900 and 2000, the slowing rate varied between 0.3 and 1.0 milliseconds per century (ms/cy).
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“The current rate is likely higher than at any time in the past several thousand years,” the researchers said. “Even if greenhouse gas emissions are tightly controlled, they are expected to remain around 1.0 ms/cy for decades to come.” They said, If emissions are not reduced, the slowing rate will increase to 2.6 ms/w by 2100, surpassing lunar tides as the largest single factor in long-term changes in day length.
Dr Santiago Verda of the University of Alicante in Spain, who was not involved in the research team, said: “This study is a huge advance as it confirms that the worrying ice loss that Greenland and Antarctica are suffering has an impact on daytime This change in day length has had a major impact not only on how we measure time, but also on GPS and other technologies that govern our modern lives.
