Jakarta –
One day in the next few years, everyone in the world will lose their time. According to a new study, exactly when that will happen is influenced by humans, as melting polar ice changes Earth’s rotation and time.
The hours and minutes that define our days are determined by the Earth’s rotation. However, the rotation is not constant. It can change ever so slightly, depending on what happens on Earth’s surface and its molten core.
These almost imperceptible changes sometimes mean the world clock needs to be adjusted to ‘leap seconds’ which may sound trivial but can have a big impact on computing systems.
Many seconds have been added over the years. However, after a long slowing trend, the Earth’s rotation is now speeding up due to changes in its core.
“A negative leap second has never been added or tested, so the problems it could cause are unprecedented,” said Patrizia Tavella, a member of the Time Department at the International Bureau of Weights and Measures in France, quoted by CNN.
But exactly when this will happen, according to research published in the journal Nature, is influenced by global warming. Melting polar ice delays the second jump by three years, pushing it from 2026 to 2029, the report found.
“Part of figuring out what’s going to happen in global timekeeping depends on understanding what’s happening due to the effects of global warming,” said Duncan Agnew, a professor of geophysics at the University of California San Diego.
Before 1955, one second was defined as the time required for the Earth to make one rotation about the stars.
Then came the era of highly precise atomic clocks, which proved to be a much more stable way of determining the physical second.
Since the late 1960s, the world began using coordinated universal time (UTC) to establish time zones. UTC relies on atomic clocks but still compensates for planetary rotation.
However, because the rotation speed is not constant, the two time scales slowly diverge. This means, ‘leap seconds’ have to be added occasionally to bring the two back into line.
Long-term changes in the Earth’s rotation are dominated by tidal friction on the sea floor, thereby slowing down its rotation. Recently, the impact of melting polar ice caps, caused by humans burning Earth-warming fossil fuels, has become a significant factor.
“As the ice melts into the oceans, the meltwater moves from the poles toward the equator, which further slows down the Earth’s rotation speed,” Agnew said.
Ted Scambos, a glaciologist at the University of Colorado Boulder who was not involved in the research, described the process as like a skater spinning with his hands above his head. As they lower their arms toward their shoulders, their rotation slows.
“The melting of the polar ice caps is already large enough to affect the rotation of the entire Earth in an unprecedented way. To me, the fact that humans have caused changes in the Earth’s rotation is truly amazing,” said Agnew.
But while melting ice may be slowing the Earth’s rotation, the report says there is another factor at play in global timekeeping: processes in the Earth’s core.
“The planet’s liquid core rotates independently of its solid outer shell. If the core slows down, then the solid shell will speed up to maintain momentum, and that’s what’s happening right now,” explained Agnew.
Very little is known about what happens about 4.5 meters below the Earth’s surface, and it is not clear why the speed of the Earth’s core changes. “It’s basically unpredictable,” Agnew explained.
However, what is clear, according to the research, is that although the melting of polar ice has a slowing effect, overall the Earth’s rotation is speeding up. This means the world will soon need to subtract one second for the first time.
“One second doesn’t sound like much, but computing systems designed for activities like stock exchange transactions need to be accurate to the thousandth of a second,” Agnew explains.
Many computer systems have software that allows them to add a second, but few have the ability to subtract a second. Humans need to reprogram computers, creating the potential for errors.
“Nobody really anticipated that Earth’s speed would reach the point where we might have to eliminate leap seconds,” Agnew said.
Scambos, the University of Colorado Boulder glaciologist, said the “big deal” about the study is that it shows changes in the Earth’s core are now likely to be greater than trends in polar ice loss, even though ice loss has accelerated in recent decades.
“This is a ‘wow’ moment for some computer applications. But for most people, life will go on as usual,” he said.
For Agnew, these findings could be a powerful tool for connecting humans to the ways humans are changing the planet.
“To be able to say that so much ice is melting that it’s changing the Earth’s rotation by a measurable amount, I think that gives an idea: okay, this is a big problem,” he concluded.
Watch the video “Climate Activists Demonstrate at British Broadcasting Office, Protest Climate Denial”
(rns/rns)
2024-03-30 03:00:17
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