Climate Change Lengthens Earth's Days at Unprecedented Rates

Recent research from the University of Vienna and ETH Zurich has revealed that climate change is causing Earth's days to lengthen at a rate of approximately 1.5 milliseconds per century, a phenomenon not observed in the last 3.6 million years. This increase in day length is primarily attributed to rising sea levels, which slow Earth's rotation. The findings were published in the *Journal of Geophysical Research: Solid Earth*.

Rising sea levels are lengthening Earth’s days

Mostafa Kiani Shahvandi, a researcher at the University of Vienna, explained that the accelerated melting of polar ice sheets and mountain glaciers is raising sea levels, akin to a figure skater who spins more slowly when extending their arms. The study builds upon earlier work that identified a 1.33 milliseconds per century increase in day length from 2000 to 2018, marking it as the fastest rate in the past century.

Climate Change Slows Earth's Spin, Lengthens Days

To analyze day-length fluctuations over geological time, the research team utilized fossil evidence from benthic foraminifera, single-celled marine organisms. By examining the chemical composition of these fossils, researchers could infer historical sea-level changes and mathematically derive corresponding variations in day length.

Rising sea levels are lengthening Earth’s days

The team employed a novel Physics-Informed Diffusion Model (PIDM), which integrates deep learning techniques with physical constraints to produce highly accurate reconstructions of Earth's rotational history. This model achieved a prediction error of 1.5% to 2.1%, significantly better than traditional methods.

Rising sea levels are lengthening Earth’s days

The current rate of day-length increase is unparalleled in Earth's climate history, suggesting that modern climate change is exerting unprecedented effects. Benedikt Soja, a professor at ETH Zurich, noted that the rapid rise in day length can be primarily attributed to human influences. Although the changes in day length are measured in milliseconds, they could have significant implications for technologies reliant on precise measurements of Earth's rotation, such as GPS, satellite navigation systems, and atomic clock synchronization.

Rising sea levels are lengthening Earth’s daysClimate Change Slows Earth's Spin, Lengthens Days

While the study presents compelling evidence linking climate change to changes in day length, some critics argue that the long-term implications of these findings are not fully understood. Concerns have been raised regarding the potential impacts on ecosystems and human activities that depend on accurate timekeeping.

Rising sea levels are lengthening Earth’s days

• “This rapid increase in day length implies that the rate of modern climate change has been unprecedented at least since the late Pliocene, 3.6 million years ago. The current rapid rise in day length can thus be attributed primarily to human influences,” — Benedikt Soja, Professor of Space Geodesy at ETH Zurich.

Rising sea levels are lengthening Earth’s days

• “From the chemical composition of the foraminifera fossils, we can infer sea-level fluctuations and then mathematically derive the corresponding changes in day length,” — Mostafa Kiani Shahvandi, University of Vienna.

Rising sea levels are lengthening Earth’s days

The research underscores the significant impact of climate change on Earth's rotational dynamics, highlighting a critical area of study as humanity grapples with the broader consequences of environmental shifts. As day lengths continue to change, understanding these effects will be essential for both scientific inquiry and practical applications in technology and navigation.

Rising sea levels are lengthening Earth’s days