CNN
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Effects Human-caused climate change According to new research, they actually mess with time.
The pace is changing as the polar ice melts due to global warming According to a study published Monday in the Proceedings of the National Academy of Sciences, Earth’s rotation and the increasing length of each day will accelerate this century as humans continue to emit planet-warming pollutants.
The changes are small – milliseconds per day – but have a critical impact on the computing systems we rely on, including GPS, in our high-tech, hyper-connected world.
This is another sign of the enormous impact humans are having on Earth. “This is a testament to the gravity of current climate change,” said report author Surendra Adhikari, a geophysicist at NASA’s Jet Propulsion Laboratory.
The number of hours, minutes, and seconds that make up each day on Earth is dictated by the speed of Earth’s rotation, which is influenced by a complex knot of factors. This includes Processes in the liquid core of the planetThe continued impact of the melting of the largest glaciers since the last ice age, as well as the melting of polar ice caused by climate change.
However, over thousands of years, the influence of the Moon dominates, increasing the length of a day by a few milliseconds per century. The Moon exerts a pull on the Earth, causing the oceans to swell toward it, gradually slowing the Earth’s rotation.
Scientists have Previously made connections Longer days between polar ice melt, but new research suggests global warming has a bigger impact on timing than recent studies have shown.
In the past, the impact of climate change was “not so dramatic,” said Benedict Soja, assistant professor of space geography at the Swiss university ETH Zurich and study author.
But that could change. If the world continues to emit planet-warming pollutants, “climate change could become the new dominant factor,” more than the moon’s share. he told CNN.
It works like this: As humans warm the world, glaciers and ice caps melt, and meltwater flows. From the poles towards the equator. This changes the shape of the planet – flattening it at the poles and bulging more in the middle – slowing its rotation.
This process is often compared to a skier turning. As the skater pulls their arms toward their body, they spin faster. But if they move their arms out, away from their body, their spin slows down.
Olivier Marin/AFP/Getty Images
Glaciers are moving in Scoresby Sound Fjord, East Greenland.
An international team of scientists is looking at the 200-year period between 1900 and 2100, using observational data and climate models to understand how climate change has affected day length in the past and calculate its role in the future.
They found that the impact of climate change on day length has increased significantly.
Sea level rise was caused by climate change in which the length of a day varied between 0.3 and 1 millisecond during the 20th century. However, over the past two decades, scientists have calculated an increase in day length of 1.33 milliseconds per century, which is “more significant than at any time in the 20th century,” the report said.
The report found that the rate of change would rise if planetary thermal pollution increased in Greenland and Antarctica, warming oceans and accelerating ice loss. If the world can’t curb emissions, climate change could increase the length of a day by 2.62 milliseconds by the end of this century — overtaking the natural effects of the moon.
“In another 200 years, we’ll be changing the Earth’s climate system so much that we’re seeing an impact on the way the Earth rotates,” the official told CNN.
A few milliseconds of extra time per day may be incomprehensible to humans but it has an impact on technology.
Accurate timekeeping is essential to GPS, which everyone with a smartphone has, as well as other communication and navigation systems. These use more precise atomic timing based on the frequency of certain atoms.
From the late 1960s, the world began using Coordinated Universal Time (UTC) to set time zones. UTC depends on atomic clocks, but still keeps the speed of the planet’s rotation. This means that “leap seconds” must be added or subtracted to align with the Earth’s rotation at some point.
Some studies have also suggested a link to increasing day length Earthquakes are increasing, said study author and geoscientist Mostafa Giani Shawanti of ETH Zurich. But the link remains speculative, and more research needs to be done to establish a clear link, he told CNN.
An article published in March on the same topic concluded That As climate change increasingly slows Earth’s rotation, processes at Earth’s core may become more important and actually speed it up, shortening day length.
“What we’ve done is go a little further and reevaluate these trends,” Shawanti said. They found that any influence from the molten core was outweighed by climate change.
Duncan Agnew, professor of geophysics at the University of California San Diego and author of the March study, said the new The study still ties in with his research, and is valuable because it expands the conclusion further in the future and looks at more than one climate scenario.”
Jacqueline McCleary, an assistant professor of physics at Northeastern University who was not involved in the study, said the new research helps inform “a decades-long debate about what role climate change might play in the changing length of the day.”
Although there is now general agreement that climate change will have a “net lengthening effect on days,” there is still uncertainty about which time-affecting processes will dominate this century. Climate change is now the second most important factor in the study, he said.
It was a sobering decision, said Soja of ETH Zurich. “We have to consider that we are now influencing the Earth’s orientation in space so much that we are dominating effects that have been going on for billions of years.”
