Climate change is causing polar ice to melt, shifting water from the poles to the equator, altering the shape of the Earth, and slowing the planet’s rotation.
The melting of polar ice due to global warming is changing the speed of Earth’s rotation and increasing the length of each day, according to CNN. This trend is expected to continue to rise in the 21st century as human activities continue to emit pollutants that warm the planet, according to a study published on July 15 in the Proceedings of the National Academy of Sciences.
Icebergs drifting along Scoresby Sound in East Greenland. (Photo: Olivier Marin/AFP).
The changes are minimal, only a few milliseconds per day, but in today’s highly connected technological world, they significantly impact the computer systems we rely on, including GPS. This also indicates the profound impact humans have on the planet, according to Surendra Adhikari, a geophysicist at NASA’s Jet Propulsion Laboratory and a member of the research team.
The hours, minutes, and seconds that make up each day on Earth are determined by the planet’s rotational speed, influenced by many complex factors. These factors include processes in Earth’s liquid core, the ongoing impact of the recession of major glaciers since the last Ice Age, as well as the melting of polar ice due to climate change. However, over millennia, the Moon’s influence has remained dominant, causing the length of a day to increase by milliseconds each century. The Moon’s gravitational pull causes the oceans to bulge toward it, slowing down Earth’s rotation.
Previously, scientists had discovered a correlation between melting polar ice and longer days, but the new research indicates that global warming has a much greater impact. In the past, the influence of climate change on time was negligible, according to Benedikt Soja, an assistant professor of space geodesy at ETH Zurich in Switzerland and a co-author of the study.
However, this could change. If pollution continues, climate change will become the new dominating factor, surpassing the Moon’s role. As humans warm the Earth, glaciers and ice sheets melt, and meltwater moves from the poles to the equator. This alters the shape of the planet, making it flatter at the poles and bulging at the equator, which slows down rotation.
The international team of scientists examined a 200-year period from 1900 to 2100, using observational data and climate models to understand how climate change has affected the length of a day in the past and to predict its role in the future. They found that the impact of climate change on day length is significantly increasing.
Sea level rise due to climate change has caused the length of a day to change by 0.3 to 1 millisecond in the 20th century. However, in the past two decades, scientists have calculated an increase in day length of 1.33 milliseconds per century, much higher than at any point in the 20th century.
If pollution continues to rise, warming the oceans and accelerating ice melt in Greenland and Antarctica, the rate of change will soar. If the world fails to reduce emissions, climate change could extend the length of a day by an additional 2.62 milliseconds by the end of the century. “In just 200 years, we will alter the Earth’s climate system so much that we could witness its impact on how the Earth rotates,” Adhikari emphasized.
The added time of a few milliseconds each day may be difficult for humans to perceive, but it still affects technology. Precise timing is essential for GPS, which relies on the frequency of several atoms. Since the late 1960s, the world has begun using Coordinated Universal Time (UTC) to set time zones. UTC is based on atomic clocks but is still adjusted according to Earth’s rotation. This means that at certain times, it is necessary to add or subtract leap seconds to synchronize with the planet’s rotation.
