A new study finds Earth's rotation is slowing due to climate-change–induced sea-level rise, lengthening the average day by about 1.33 milliseconds per century, in a rate unseen for 3.6 million years.

The slowing is explained through angular momentum: melting ice redistributes mass away from the rotation axis, causing a slower spin and longer days, with the effect potentially intensifying toward the century's end.

Scientists compare the process to a figure skater extending or drawing in their arms to alter spin, illustrating how mass distribution affects rotation.

While biological effects on humans are unlikely, the biggest concern is for technologies that require extremely precise timekeeping.

The study appears in the Journal of Geophysical Research: Solid Earth, with quotes from Mostafa Kiani Shahvandi and Benedikt Soja about its significance and future implications.

Researchers emphasize this rapid change signals a broader shift in the climate system and its deeper physical processes, with relevance to daily life and future tech.

The current rapid change in day length is mainly driven by human greenhouse gas emissions, and this impact is expected to grow by the end of the century.

Natural factors also influence day length, but emissions from greenhouse gases are accelerating changes more quickly, especially since 2000–2020.

The study uses fossil records and a probabilistic deep-learning model to reconstruct past sea levels and infer historical day-length changes, showing current rates are anomalously high.

Researchers Soja and Shahvandi used benthic foraminifera fossil data and a Physics-Informed Diffusion Model to translate sea-level fluctuations into changes in day length.

Findings published in the Journal of Geophysical Research: Solid Earth reinforce the link between anthropogenic climate change and measurable shifts in Earth's rotation.

The reporting underscores the importance of science journalism to understand and communicate these complex climate-related changes.