Earth Spinning Faster? A Curious and Concerning Intersection of Time and Climate

 

Earth Spinning Faster? A Curious and Concerning Intersection of Time and Climate

Is Earth genuinely spinning faster or is this simply scientific noise? What are the consequences if it is and could climate change be the hidden lever? These are the questions nagging at researchers and technologists alike—and they weave together physics, environmental science and humanity’s high-precision digital infrastructure.

For millennia, Earth’s rotation has been gradually slowing—thanks largely to tidal friction from the Moon, adding roughly 2 ms to the day each century. explorersweb.com But ironically, since around 2020, a subtle reversal has emerged. Short-term measurements reveal that several consecutive days have been slightly shorter than the standard 86,400 seconds, indicating a modest yet measurable spin-up. sciencefocus.com

The shortest day on record occurred on July 5, 2024, when Earth completed its rotation 1.66 milliseconds ahead of schedule. livescience.com Fast-forward to the summer of 2025: July 9, July 22 and August 5 were each recorded—or predicted—to be between 1.3 and 1.5 ms shorter, with July 10 emerging as the shortest day of 2025 so far at about 1.36 ms shorter. Space.com. Though imperceptible in daily life, these shifts matter deeply for timekeeping.

What explains these remarkable variations? A leading factor is the Moon’s orbital position. On those key dates, the Moon reaches its furthest alignment from Earth’s equator, reducing tidal drag and allowing Earth’s crust and mantle to rotate slightly faster—like a spinning skater drawing limbs closer to the body. This cyclical gravitational effect is complemented by seismic events, such as the 2011 Japan earthquake, which shortened the day by a few microseconds.

Yet climate change is now irreversibly part of the mix. As the polar ice sheets melt, vast amounts of water shift toward the equator, redistributing mass and changing Earth’s moment of inertia. ETH Zurich’s 2024 studies—supported by NASA—demonstrated that this process already rivals the Moon’s long-term influence. Indeed, since 2000, climate-driven mass redistribution has lengthened days by about 1.33 ms per century and could surpass tidal braking by mid-century if warming trends persist. Jet Propulsion Laboratory.

But here’s the twist: climate effects can both slow and stabilize depending on the interplay of factors. According to geophysicist Duncan Agnew at Scripps Institution of Oceanography, melting ice now slows rotation—counteracting the speed-up—but ironically this delay may be preventing a negative leap second from being required until 2029 instead of as early as 2026 San Francisco Chronicle.

So what might this mean beyond the realm of pure curiosity? For most of us, these millisecond tweaks are imperceptible. But modern systems like GPS, telecommunications networks, satellite navigation and financial trading platforms depend on atomic clocks synchronized to Earth’s rotation. Usually, we add a leap second to UTC when days lengthen, but removing a second would be unprecedented and risky, given that many systems are not built to lose time. Live Science

As Agnew and colleagues warn, such an event could trigger Y2K-style disruptions. In 2012, Reddit and Qantas suffered outages when a positive leap second was added. Now, a negative leap second—if ever applied—might catch technology systems unprepared. For this reason, metrology bodies worldwide are actively considering phasing out leap seconds by 2035, transitioning to timekeeping that tolerates divergence between atomic and astronomical time and corrects only when offsets become substantial. sfchronicle.com 

The question naturally arises: who bears the burden when Earth's slow transformations intersect with human systems? Vulnerable populations—low-income communities, remote regions and disaster-prone coastal zones—face the worst outcomes not because of the millisecond gain or loss, but because the same melting ice, rising seas and extreme weather that alter Earth’s rotation also directly threaten their lives and livelihoods. abc7ny.com

In essence, the high-tech crisis is a symptom of a broader climate crisis. Only by reducing greenhouse gas emissions, limiting ice melt and responsibly managing groundwater and land use can we slow mass redistribution and thereby temper its influence on planetary rotation. Geophysical feedback loops remain beyond our control—but climate action is within it.

Leading institutions—ETH Zurich, Scripps and IERS—continue to monitor rotational changes, model future scenarios and advise international bodies like BIPM, metrology agencies and satellite operators. They inform timekeeping reforms and shape contingency planning for systems reliant on ultra-precise timing.

Still unsettled is whether a negative leap second will ever be necessary—and if so, whether it can be safely implemented. The technology sector, regulators and global timekeeping bodies must prepare, ideally before such an event occurs unexpectedly.

---

In closing, Earth spinning in milliseconds faster may sound arcane and to most it is. But beneath the surface lies a profound truth: even time is being reshaped by climate change. Our increasing ability to count seconds—and our dependence on doing so precisely—links our fate to planetary dynamics more than ever before.

The question isn’t merely “Is Earth spinning faster?” It's: Can humanity adapt its systems—and its actions—to a planet that is literally in motion? And the answer begins with both climate action and institutional foresight.