The climate change is having a surprising effect: lengthening Earth’s days. Melting polar ice is reshaping the planet, with consequences for our technology.
Scientists say this phenomenon highlights how human actions are fundamentally altering Earth, surpassing natural processes that have existed for billions of years. While the change in day length is measured in milliseconds, it’s enough to disrupt internet traffic, financial transactions, and GPS navigation – all reliant on precise timekeeping.
Earth’s day has naturally lengthened due to the moon’s gravitational pull on our oceans and landmasses. However, human-caused global warming is accelerating this process. The melting of Greenland and Antarctic ice sheets redistributes water towards the equator, causing Earth to bulge slightly. This “fatter” Earth rotates slower, further lengthening the day.
This isn’t the only evidence of humanity’s planetary impact. Recent research shows water redistribution has shifted Earth’s axis of rotation. Additionally, our carbon emissions are shrinking the stratosphere.
A study published in the Proceedings of the National Academy of Sciences analyzed the impact of melting ice on day length. Between 1900 and 2000, the slowing rate ranged from 0.3 to 1.0 milliseconds per century (ms/cy). Since 2000, with faster melting, the rate has jumped to 1.3ms/cy.
“This is likely the fastest rate in thousands of years,” the researchers say. Even with aggressive emissions cuts, the slowing rate is expected to stay around 1.0ms/cy for decades. If emissions continue unchecked, the rate could reach 2.6ms/cy by 2100, surpassing lunar tides as the biggest factor in day length variations.
“We can see our impact as humans on the whole Earth system, not just locally, like the rise in temperature, but really fundamentally, altering how it moves in space and rotates.”
Reference- Proceedings of the National Academy of Sciences, The Guardian, BBC, Wired, Popular Science, Nature