The impacts of climate change are widespread, ranging from biodiversity loss to extreme weather events, rising sea levels, wildfires, and mass human migrations. Each year reveals more about our impact on the environment, with some discoveries more surprising than others.
One of the most shocking revelations to join this list is the recent discovery that our greenhouse gas emissions are altering the Earth’s rotation.
As a result, Earth days are gradually becoming longer, potentially leading to significant changes in how we experience time in the future.
“It’s fascinating how our actions as humans can have such a profound impact on the entire planet through the extensive climate change we’ve triggered over the last century,” says Professor Benedict Soja, a scientist at ETH Zurich who contributed to uncovering this concerning trend.
“This effect may surpass previous significant influences on Earth’s rotation.”
Could we see more hours in a day?
We are familiar with the greenhouse effect, where gases like carbon dioxide trap heat in the Earth’s atmosphere, leading to a rise in temperatures.
Last year, global temperatures were 1.18 degrees Celsius above the 20th-century average, approaching the 1.5 degrees Celsius target set in 2015 as a limit to avoid the worst consequences of climate change.
The primary consequence of this warming is the melting of large ice areas in the Arctic and Antarctic, with Switzerland losing 10% of its glacier mass in the last two years, Antarctica shedding 150 billion tons of ice annually, and Greenland losing 270 billion tons.
While many are concerned about the impact of this melting on coastal areas, Soja and his team posed a different question: Will this significant mass redistribution likely prevail? What will be its broad-scale impact on the planet? In a recent study published in the journal Proceedings of the National Academy of Sciences (PNAS), they provided an answer.
“As the ice melts, the Earth’s mass shifts from the polar regions to the oceans,” Soja explained. “This results in the Earth becoming flatter and more oblate, with its mass moving further from the rotation axis.”
Understanding the Mechanism
Similar to any rotating object, the Earth adheres to the law of momentum conservation. Simply put, momentum must be preserved, and it depends on the moment of inertia and rotational speed. As mass moves away from the rotation axis due to melting ice, the moment of inertia increases.
Therefore, to uphold its momentum despite ice melting, the Earth’s rotation slows down, elongating our days.
Soja likens this concept to a figure skater performing a spin, where extending the arms slows down the rotation, while pulling them in speeds it up.
The study indicated that from 1900 to 2000, the climate’s impact on the length of Earth’s day ranged from 0.3 to 1.0 milliseconds per century. Since 2000, accelerated melting has raised this rate to 1.3 milliseconds per century, with a potential increase to 2.6 milliseconds per century by 2100 if emissions remain unchecked.
While these changes may seem small in our daily lives, they could have significant effects on a globally synchronized technological network.
Considerations on Time Management
Three main timescales play crucial roles in timekeeping: International Atomic Time (TAI), Universal Time (UT1), and Coordinated Universal Time (UTC). TAI relies on atomic clocks, UT1 is determined by Earth’s rotation, and UTC synchronizes the two.
Leap seconds were introduced in 1972 to align UTC with UT1 within 0.9 seconds.
Unlike predictable leap years, leap seconds are added irregularly as needed. Since 1972, 27 leap seconds have been added, with the most recent in 2016. Disruptions from leap seconds have caused issues in the digital age, impacting technology companies striving for synchronization.
The recent discovery of Earth’s core slowing down further complicates matters. If the planet’s rotation continues to accelerate, a negative leap second may need to be introduced to UTC. This unprecedented situation poses substantial challenges as systems are unprepared for negative adjustments.
“This has never occurred before, and frankly, I don’t think anyone anticipated it,” Agnew remarked. He compares this scenario to the Y2K scare when concerns about potential computer errors surfaced at the end of the 20th century.
“The critical aspect is that we don’t know the consequences of introducing a negative leap second,” he cautioned. “The negative impacts could be unforeseen.”
According to Agnew, if the effects of climate change had not slowed down, a negative leap second would have been necessary in 2026. “Global warming might postpone negative leap seconds and eliminate their need entirely,” he noted.
While this discovery regarding climate change may offer a positive effect, considering less necessity for negative leap seconds, the implications of further greenhouse gas emissions outweigh any potential benefits. As the situation stands, negative leap seconds may still be required in 2029.
Perhaps it’s time to reconsider the current system?
Agnew proposed a solution to reduce the required precision between timescales, eliminating the need for negative leap seconds and allowing for more predictable positive adjustments.
“It could resemble a leap year. You add a fixed number of seconds at a specific time and accept that it may not be exact but is tolerable,” suggested Agnew.
This proposition aligns with the dominance of slowing over longer timescales, rather than the complex interactions involving Earth’s core or ice melting.
Efforts are reportedly underway to implement this system, with a target to eliminate the need for leap seconds by 2035. However, international agreement hurdles must be overcome. Failure to adapt before requiring a negative leap second could lead to unprecedented chaos, highlighting the urgency of the situation.
Meet the Experts
Benedict Soja: Assistant Professor in the Department of Civil, Environmental, and Geoengineering at ETH Zurich.
Duncan Agnew: Professor Emeritus at Scripps Institution of Oceanography, specializing in crustal deformation measurement and geophysical data analysis.
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Source: www.sciencefocus.com
