The Earth's Day is Getting Longer: Climate Change is Beginning to Affect Even the "Rotation"

"Recently, the days feel shorter." Anyone living in today's busy world might have said this at least once. However, in the scientific world, the opposite is happening. Although it's so slight that we don't notice, the Earth's day is gradually getting longer.

Of course, this doesn't mean that the clock will go haywire tomorrow morning. The unit of change is milliseconds, or one-thousandth of a second. But behind that tiny number lies a massive global redistribution of mass. Polar ice is melting, flowing into the sea, and spreading towards the equator. As a result, the Earth's rotation speed slightly decreases.

According to the latest research introduced by BBC Science Focus, the current rate of increase in "day length" due to climate change has reached an unprecedented level in the geological record of the past 3.6 million years. The research team explains that the current Earth's day is lengthening at a pace of about 1.33 milliseconds per century. While the number may seem insignificant, considering it as a change that alters the rotation of the entire planet gives it a much different meaning.

Why does melting ice slow down the Earth's rotation?

The mechanism is easy to understand when compared to a figure skater's spin. When a skater pulls their arms close to their body, they spin faster, and when they spread their arms, the spin slows down. This is because the speed of rotation changes depending on whether the mass is close to or far from the axis of rotation.

Something similar happens on Earth. Ice stored in the Arctic, Antarctic, and mountain glaciers exists in high-latitude regions, relatively close to the Earth's axis of rotation. When that ice melts due to warming, the water flows into the sea and eventually spreads throughout the Earth's oceans. Some of it moves towards the equator, which is the farthest point from the axis of rotation.

As the mass moves away from the axis of rotation, the Earth becomes like a "skater with outstretched arms." As a result, the rotation slows slightly, and the length of the day increases just a bit.

Researchers treat this change not merely as a metaphor but as a geophysical issue. Sea level rise, ice sheet melting, Earth's mass distribution, and rotation speed are not separate phenomena but are interconnected. Warming affects not only temperatures and sea levels but also the very movement of the planet.

Is "1.33 milliseconds per century" small or large?

1.33 milliseconds per century. In the context of everyday life, this number seems almost meaningless. A human blink occurs in units of several hundred milliseconds. Compared to the response speed of a smartphone or communication delays, a change of just over a millisecond per century is exceedingly small.

However, the important thing is not whether it is "noticeable." It is the fact that it produces an observable change in the massive motion of Earth's rotation.

The Earth has an enormous mass of approximately 5.97×10^24 kilograms. To change its rotation speed even slightly requires a massive redistribution of mass. According to the Science Focus article, researchers explain that a mass movement of about 1,000 gigatons is necessary. This is equivalent to placing a gigantic ice cube over New York City, reaching a height of 10 kilometers.

Thus, the issue is not "small because it's 1 millisecond." It's about "how significant the global changes are that are progressing to cause a phenomenon that seems to change only by 1 millisecond."

An Unusual Pace Seen Going Back 3.6 Million Years

The attention to this research lies not only in modern observations but also in the comparison over a long timeline of 3.6 million years.

The research team focused on the fossils of benthic foraminifera, single-celled marine organisms that lived on the seabed. The shells of foraminifera contain clues about past seawater conditions and sea level changes. By estimating ancient sea level changes and mathematically tracing the relationship between Earth's mass distribution and rotation, they reconstructed past variations in the length of the day.

Of course, there is significant uncertainty in data from millions of years ago. Therefore, the research team used a probabilistic deep learning model incorporating physical laws to estimate long-term variations while handling the uncertainties of paleoclimate data.

As a result, it was shown that the current rate of change is exceptionally unusual for at least the last 3.6 million years since the late Pliocene. In the past, the growth and melting of ice sheets also changed the length of the day. Earth's rotation has never been constant. Various factors, such as the moon's gravity, internal movements of the Earth, atmospheric and oceanic circulation, and glacial-interglacial transitions, have influenced it.

Nevertheless, the climate change-induced changes observed in the early 21st century stand out even in a geological context.

Potentially Greater Impact Than the Moon

The moon's gravity is well known as a major natural factor causing the Earth's day to lengthen. The moon causes tides on Earth, and that tidal friction acts as a brake on Earth's rotation. Therefore, the Earth's day has gradually lengthened over the long term.

However, the study suggests that in future scenarios where greenhouse gas emissions remain high, the impact of climate change on the length of the day could surpass the influence of the moon by the end of this century.

This is symbolic. The moon has slowly changed Earth's rotation for billions of years. Now, climate change caused by human activities might rival or even surpass that influence. The fact that humanity is affecting the planet's rotation by altering the atmospheric chemical composition, melting ice sheets, and raising sea levels highlights the scale of global warming.

Will It Immediately Affect Our Lives?

So, will this have a significant immediate impact on our lives? The answer is, for general daily life, "hardly at all." It won't change the time we wake up in the morning, nor will the day become noticeably longer. In the world of calendars and wristwatches, the change is too small.

On the other hand, the story changes in fields requiring ultra-precise time management. In GPS, spacecraft navigation, satellite positioning, financial transactions, communication networks, and astronomical observations, even slight fluctuations in Earth's rotation cannot be ignored. Especially for accurately determining the position and orbit of spacecraft, it's crucial to know precisely when, in what direction, and how much the Earth is rotating.

In other words, this phenomenon is not the kind of crisis where "life will be difficult from tomorrow." However, considering how modern society is built on precise timing, even millisecond-level changes have scientific and technical significance.

Mixed Reactions of Surprise, Irony, and Calm on Social Media

 

Reactions on social media to this news are broadly divided into three categories.

The first is pure surprise. On X and Instagram, posts with sentiments like "Is climate change affecting even the Earth's rotation?" and "Has the impact of global warming reached this far?" can be seen. Compared to sea level rise or extreme weather, changes in rotation speed are not intuitively easy to imagine. Therefore, the news has a strong element of surprise, with many people reacting with "Is this really happening?"

The second is ironic or skeptical reactions. Some comments on Reddit question, "Isn't it an overreaction to a number like milliseconds?" or "Weren't there times in the past when there was almost no ice?" Some comments even express distrust towards climate change reporting itself.

The third is a calm reception, acknowledging the scientific interest but suggesting there are other issues to prioritize worrying about. On Reddit, comments like "Among the adverse effects of climate change, the change in the length of the day itself is not the biggest concern" can be found. Instead, attention should be focused on issues that directly impact life and society, such as ocean changes, coral reef crises, and the expansion of oxygen-poor marine areas.

This reaction is important. The study does not present the lengthening of the day itself as an object of fear. Rather, it illustrates the broad impact of global warming on the entire Earth system. The confusion and skepticism on social media can be seen as arising from the gap between the small unit of "milliseconds" and the vast scale of "planetary rotation."

The "Earth's Brake" as an Invisible Indicator of Climate Change

When considering the impacts of climate change, we first think of temperature rise, sea level rise, heatwaves, heavy rains, droughts, and wildfires. These directly affect human society, making them easy to understand as news.

On the other hand, changes in Earth's rotation are less visible. Looking up at the sky, we can't tell that the Earth is rotating slower. It doesn't affect our internal clocks. However, this invisibility itself speaks to the complexity of the Earth system.

The melting of ice sheets does more than just raise sea levels. It changes the distribution of seawater, alters the gravitational field, relates to the wobble of the Earth's axis, and affects rotation speed. Earth is a single system connected by the atmosphere, oceans, ice, lithosphere, and biosphere, where changes in one place ripple to another.

This study visualizes one of those ripples. Global warming is not just about "getting hotter." The position of water changes, the distribution of mass changes, and the movement of the planet changes. Our society is also embedded within this chain of events.

Milliseconds Speak to the Scale of the Anthropocene

There is a term "Anthropocene," which refers to an era where human activities have a geological-scale impact on the Earth's environment. The rise in atmospheric carbon dioxide levels, traces of plastics and radioactive materials, and rapid changes in biodiversity are cited as evidence.

Changes in Earth's rotation can also be seen as a symbolic phenomenon indicating that human influence has reached a planetary scale. The number 1.33 milliseconds per century is small in everyday terms. However, in terms of the significant mass redistribution that appears in Earth's rotation, it is extremely large.

We measure time with clocks. However, the movement of the Earth, which these clocks assume, is not entirely fixed. A day exists on the balance of the universe, Earth's interior, and climate systems. And now, human activities are having an undeniable impact on that balance.

The Real Fear is Not "The Day Getting Longer"

There is no need to take this news too sensationally. The lengthening of the day does not mean that human life will suddenly collapse. The change is extremely small and imperceptible to most people.

However, it is not a story to be taken lightly. This phenomenon is not a "result" of warming but an "indicator" of the broadening impact of warming on the entire Earth.

What truly matters is not the number of milliseconds the Earth rotates slower. It is the series of processes where polar ice melts, flows into the sea, raises sea levels, and even changes Earth's mass distribution. Beyond that, there are risks of coastal flooding, changes in ecosystems, intensification of extreme weather, and impacts on food and water resources.

In other words, the news of Earth's rotation slowing is not a "strange side effect" of climate change but a precise alarm indicating that the Earth system is already being significantly shaken.

Summary

The Earth's day is not as fixed as we might think. The moon's gravity, Earth's internal movements, atmospheric and oceanic changes, and now even human-induced climate change influence its length.

As polar ice melts and seawater spreads towards the equator, the Earth slightly slows its rotation. The current rate of change is about 1.33 milliseconds per century. While not perceptible, it is an unprecedented speed when viewed over a long timeline of 3.6 million years.

On social media, reactions are mixed with surprise, anxiety, irony, and calm analysis. Indeed, what we should worry about tomorrow is not the "day getting slightly longer" itself. However, the fact that human activities are affecting even the Earth's rotation quietly tells us how broadly, deeply, and globally climate change is impacting.

Source URL

BBC Science Focus Magazine: Introduces research content that shows climate change-induced melting of ice sheets and glaciers is slowing Earth's rotation and lengthening the day.
https://www.sciencefocus.com/news/unprecedented-earths-rotation

ETH Zurich: Research presentation. Explains that the length of the day is increasing by about 1.33 milliseconds per century, unprecedented in the past 3.6 million years, and may surpass the influence of the moon in the future.
https://baug.ethz.ch/en/news-and-events/news/2026/03/climate-change-slows-earths-spin-day-lengthening-unprecedented-in-3-point-6-million-years.html

University of Vienna: Research presentation. Provides analysis methods using fossils of benthic foraminifera, sea level changes, and deep learning models incorporating physical information, along with research paper information.
https://www.univie.ac.at/en/news/detail/climate-change-slows-earths-spin-day-lengthening-unprecedented-in-36-million-years

Journal of Geophysical Research: Solid Earth: Main paper of 2026 "Climate-Induced Length of Day Variations Since the Late Pliocene."
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JB032161

PNAS: Related research in 2024 "The increasingly dominant role of climate change on length of day variations." Addresses the impact of climate change on day length variations.
https://doi.org/10.1073/pnas.2406930121

Reddit r/HotScienceNews: Reference for SNS reactions. Skeptical and ironic comments about millisecond-level changes can be seen.
https://www.reddit.com/r/HotScienceNews/comments/1rshh5o/humandriven_climate_change_is_slowing_earths/

Reddit r/climatechange: Reference for SNS reactions. Calm reactions suggesting that other climate impacts, such as ocean changes, should be prioritized over the "length of the day" itself.
https://www.reddit.com/r/climatechange/comments/1rtebgq/climate_change_is_making_our_days_longer_should/

X / Astronomy Magazine: Example of news sharing on SNS. Posts about sea level rise and glacier melting slowing Earth's rotation.
https://x.com/AstronomyMag/status/203906754505594