Earth's Spin Slowing: Melting Ice Accelerates Day Length

Earth's rotation is slowing down, causing days to lengthen at an unprecedented rate, according to a new study. Climate change, through the melting of polar ice sheets and glaciers, is identified as the primary driver. This process moves water from the poles towards the equator, slowing the planet's spin, much like a figure skater extending their arms.

The current rate of day lengthening is approximately 1.33 milliseconds per century. Scientists note this change is massive in scale, requiring the movement of around 1,000 gigatonnes of mass. Researchers examined geological records, including the shells of ancient sea-floor organisms, to study changes in Earth's rotation over millions of years.

This climate-driven acceleration in day lengthening is now competing with and surpassing natural influences on Earth's rotation. A similar period of accelerated change was observed around two million years ago. Projections suggest that without significant reductions in greenhouse gas emissions, climate change could be the dominant factor influencing Earth's day length by the end of the century.