CNN
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Impact of Man-made climate change According to a new study, they’re so overwhelming that they actually ruin your time.
The melting of polar ice due to global warming As humans continue to emit global-warming pollutants, trends in the Earth’s rotation and the length of its day will accelerate over the course of this century, says a study published Monday in the Proceedings of the National Academy of Sciences.
The changes are small — a matter of milliseconds per day — but in today’s high-tech, hyper-connected world, they have important implications for the computing systems we rely on, such as GPS.
It’s another sign of the outsized impact humans are having on the planet. “This is a testament to the magnitude of ongoing climate change,” said Surendra Adhikari, a geophysicist at NASA’s Jet Propulsion Laboratory and author of the report.
The number of hours, minutes and seconds that make up a day on Earth is determined by the speed at which the Earth rotates on its axis, which is affected by a complex set of factors. Processes in the fluid cores of planetsthe ongoing effects of the melting of large glaciers after the last ice age, and melting of polar ice due to climate change.
But for thousands of years, the influence of the Moon has dominated, lengthening the length of the day by a few milliseconds every century. The Moon exerts a gravitational pull on the Earth, causing the oceans to bulge towards the Moon and gradually slowing the Earth’s rotation.
The scientists Previously connected Melting polar ice has long been thought to be correlated with longer hours of daylight, but new research suggests that global warming’s impact on time may be greater than recent studies have suggested.
In the past, the effects of climate change over time “were not as dramatic,” said study author Benedict Soya, an assistant professor of space geodesy at the Swiss Federal Institute of Technology in Zurich.
But that’s changing: If the world continues to emit global-warming pollutants, “climate change will become the new dominant factor,” potentially outweighing the moon’s role. he told CNN.
Here’s how it works: As humans warm the planet, glaciers and ice sheets melt, and the meltwater runs off. It moves from the poles towards the equator, which changes the shape of the planet, making it flatter at the poles and bulging in the center, slowing down its rotation.
This process is often compared to an ice skater spinning: When the skater pulls their arms in towards their body, they spin faster, but when they move their arms to the outside, or away from their body, they spin slower.
Olivier Marin/AFP/Getty Images
An iceberg drifts along the Scoresby Bay fjord in East Greenland.
An international team of scientists used observational data and climate models to look at a 200-year period between 1900 and 2100 to understand how climate change has affected day length in the past and predict its role in the future.
The researchers found that the impact of climate change on day length is increasing dramatically.
Sea-level rise due to climate change caused the length of the day to vary between 0.3 and 1 millisecond during the 20th century, but over the past two decades scientists have calculated that day length has increased by 1.33 milliseconds per century, “significantly higher than at any time during the 20th century,” the report said.
The rate of change is set to accelerate if global-warming pollutants continue to rise, oceans warm, and ice loss in Greenland and Antarctica accelerates, the report said. If the world cannot curb emissions, climate change could add 2.62 milliseconds to the length of each day by the end of the century, surpassing the natural effect of the moon.
“In just 200 years, we could see significant changes to Earth’s climate system that could affect the very rotation of the Earth on its axis,” Adhikari told CNN.
A few extra milliseconds a day may be imperceptible to humans, but it has an impact on technology.
Accurate timekeeping is essential for GPS and other communication and navigation systems that everyone with a smartphone has. These systems use highly accurate atomic time, which is based on the frequencies of specific atoms.
Starting in the late 1960s, the world began using Coordinated Universal Time (UTC) to set time zones. UTC relies on atomic clocks, but is timed to the rotation of the Earth, which means that at some point “leap seconds” must be added or removed to accommodate the rotation of the Earth.
Some studies have shown that increasing day length Study author Mostafa Kiani Shavandi, a geologist at ETH Zurich, said an increase in earthquakes was to blame, but the link is still speculative and more research is needed to prove a definitive link, he told CNN.
A paper on the same topic published in March concluded: that Climate change is causing the Earth to rotate more slowly on its axis, but processes occurring in the Earth’s core are more important and may actually be speeding up the rotation and shortening the length of the day.
“What we’ve done is go a little further and reassess these trends,” Shahvandi said. They found that the effects of climate change are greater than those of a melting core.
Duncan Agnew, a professor of geophysics at the University of California, San Diego and author of the March study, said the new He said the study remains consistent with his work and is “valuable in extending the results into the future and considering multiple climate scenarios.”
Jacqueline McCleary, an assistant professor of physics at Northeastern University who was not involved in the study, said the new research informs “a decades-long debate about what role climate change plays in changing the length of the day.”
While there is now general agreement that climate change has an “overall lengthening effect on the day,” there is still uncertainty about which processes will dominate in influencing time this century, she told CNN. The study concludes that climate change is now the second most dominant factor, she said.
This is a tough conclusion, says ETH Zurich’s Soya: “We have to take into account that we are now exerting a huge influence on the Earth’s orientation in space, dominating influences that have been at work for billions of years.”
