Climate Change Disrupting Earth's Timekeeping More Than Previously Understood, New Research Reveals

In a study published in the Proceedings of the National Academy of Sciences, scientists have discovered that human-caused climate change is not only reshaping the planet's ecosystems but also affecting the fundamental way we measure time. Polar ice melt driven by global warming is altering the Earth's rotation speed, thereby increasing the length of each day, a trend poised to accelerate throughout this century.

The changes, though measured in mere milliseconds per day, have profound implications for our high-tech, interconnected world. Precise timekeeping systems, including GPS and other communication and navigation technologies, rely on atomic timekeeping aligned with Earth's rotation. These minute alterations can disrupt the synchronization required for these systems to function correctly.

The Earth's rotation and the length of its days are influenced by a complex interplay of factors. Historically, the moon's gravitational pull has been the dominant force, gradually lengthening days by a few milliseconds per century. However, the new research indicates that climate change is becoming a more significant factor.

Surendra Adhikari, a geophysicist at NASA’s Jet Propulsion Laboratory and a lead author of the study, emphasized the gravity of these findings. "This is a testament to the ongoing and overwhelming impact of climate change," Adhikari stated. The study highlights how the melting of glaciers and polar ice due to human-induced warming is redistributing Earth's mass, akin to a spinning ice skater extending their arms and slowing down.

Benedikt Soja, Assistant Professor of Space Geodesy at ETH Zurich: "This research underscores how deeply we are affecting Earth's natural systems. The impact of climate change on day length is an aspect that has not been so dramatic in the past, but that could be changing. If we continue on our current path, climate change could become the new dominant factor, outpacing even the moon's influence."

The international team of scientists examined a 200-year period from 1900 to 2100, using observational data and climate models to understand past and future impacts on day length. Their findings revealed that climate change-driven sea level rise has already caused the length of a day to vary by 0.3 to 1 milliseconds over the 20th century. More recently, this rate has increased to 1.33 milliseconds per century, a significant acceleration.

If current emission trends continue, warming oceans and accelerated ice loss in Greenland and Antarctica could increase the length of a day by 2.62 milliseconds by the end of the century, surpassing the natural impact of the moon. "In barely 200 years, we will have altered the Earth's climate system so much that we are witnessing its impact on the very way Earth spins," Adhikari noted.

The study has garnered significant attention from the scientific community, with experts highlighting both its innovative approach and its alarming implications:

Jacqueline McCleary, Assistant Professor in Physics at Northeastern University: "This research helps inform a decades-long debate over what role, exactly, climate change will play in the changing length of the day. There is now a general agreement that climate change will have a net lengthening effect on the day. This study conclusively shows it as the second-most dominant factor."

The study underscores the interconnectedness of Earth's systems and the extensive reach of human activities. The implications of this disruption extend beyond scientific curiosity:

• Technological Impact: Precise timekeeping is vital for GPS and other systems that depend on highly accurate atomic time. The introduction of "leap seconds" to keep atomic time aligned with Earth's rotation could become more frequent, complicating technology synchronization.
• Geophysical Changes: The research also touches on potential correlations between increased day length and seismic activity, although this connection remains speculative and requires further investigation.
• Policy and Awareness: The findings add urgency to global climate action, highlighting an aspect of climate change that affects fundamental natural processes and human technology alike.

Duncan Agnew, Professor of Geophysics at UC San Diego: "The study provides a valuable extension of previous research by looking further into the future and considering multiple climate scenarios. It meshes well with existing studies and highlights the increasing significance of climate change in affecting Earth's rotation."

Duncan Agnew, a geophysics professor at the University of California San Diego and author of a related study, praised the new research for extending the analysis further into the future and considering multiple climate scenarios. "The study aligns with and extends my own research, providing a broader perspective on the future impacts of climate change on Earth's rotational dynamics," Agnew stated.

Jacqueline McCleary, an assistant professor in physics at Northeastern University, noted that this study adds clarity to the ongoing debate about climate change's impact on Earth's rotational dynamics. "While there is now general agreement that climate change will have a net lengthening effect on the day, this study conclusively shows it as the second-most dominant factor," McCleary said.

The discovery that climate change is altering Earth's rotation and lengthening days is a profound reminder of the extensive impact of human activities. As scientists continue to explore these changes, it becomes increasingly critical to address the root causes of climate change with urgency. This research not only highlights the immediate environmental and technological challenges but also emphasizes the need for comprehensive and sustained climate action to mitigate these far-reaching effects.