Climate change’s impact on weather patterns and sea levels is widely recognized. However, a recent study published in the science journal Nature suggests that it may also be influencing timekeeping.
The study highlights that the rapid melting of glaciers and ice sheets in Greenland and Antarctica, driven by increasing temperatures, is leading to the redistribution of weight across the Earth. This subtle shift in weight distribution is gradually slowing down the planet’s rotation on its axis.
Our timekeeping systems, including clocks and calendars, rely on the steady rotation rate of the Earth, which is monitored by scientists through calculations of Coordinated Universal Time (UTC). However, the Earth’s rotation has not been completely consistent. Over the past few decades, it has been observed that the Earth has been spinning slightly faster than usual.
To compensate for this acceleration, timekeepers have occasionally inserted a “leap second” into clocks worldwide – a practice that has occurred 27 times since the 1970s. The intention was to remove that leap second for the first time in 2026, a modification referred to as the “negative leap second.”
However, recent research indicates that the rapid melting of ice from Antarctica and Greenland has acted as a brake, slowing down the Earth’s rotation just sufficiently. This suggests that we may not require the negative leap second until 2029 or beyond.
Duncan Agnew, the study’s author from the University of California San Diego, highlighted to AFP, “It’s quite remarkable, even for me, that we’ve made a tangible impact on the Earth’s rotation speed. Unprecedented events are unfolding.”
Agnew cautioned that when the time comes to introduce the negative leap second adjustment, it could pose significant challenges for computer systems ill-prepared to accommodate such a subtraction of time.
However, not all experts share this perspective. Demetrios Matsakis, former chief scientist for time services at the US Naval Observatory, expressed skepticism to the publication. Matsakis argued that the Earth’s rotation is too erratic to confidently predict when or if we will require the negative leap second in the near future.
