By Ravish Handoo
In an era where the impacts of climate change are becoming increasingly evident, a new dimension has been added to our understanding of its effects. Groundbreaking research from ETH Zurich reveals that climate change is not only altering our environment but is also affecting Earth’s rotation and axis. This revelation opens a new chapter in climate science, illustrating the profound influence of human activities on the fundamental mechanics of our planet.
Earth’s rotation and the length of our days have traditionally been influenced by gravitational forces, primarily from the moon. Tidal friction, caused by the gravitational pull of the moon, has been the dominant factor in gradually lengthening the day over billions of years. However, the recent studies published in Nature Geoscience and Proceedings of the National Academy of Sciences (PNAS) by the ETH Zurich team suggest that human-induced climate change could soon surpass the moon’s influence.
As polar ice caps melt due to rising global temperatures, water redistributes from the poles to the equatorial regions. This redistribution affects the mass distribution of Earth, altering its rotation. Professor Benedikt Soja of ETH Zurich explains this phenomenon using a figure skater analogy: “It’s like when a figure skater does a pirouette, first holding her arms close to her body and then stretching them out.” When the skater extends her arms, she slows down due to the increase in inertia. Similarly, as Earth’s mass moves away from its axis, the planet’s rotation slows, leading to longer days.
The melting ice does not only slow Earth’s rotation; it also causes a shift in the planet’s rotational axis. This axis is an imaginary line around which the Earth rotates, and its stability is crucial for maintaining the balance of the planet. The studies indicate that as ice melts and mass redistributes, the axis shifts, leading to polar motion. This polar motion has been occurring at a rate of about ten meters per century. The team, led by Professor Soja and doctoral student Mostafa Kiani Shahvandi, utilized advanced models combining physical laws with artificial intelligence to recreate and predict these shifts with unprecedented accuracy.
The ETH Zurich team’s research is notable for its comprehensive approach, examining the interconnected processes within Earth’s core, mantle, and surface. Their model, the most detailed to date, demonstrates that these internal and surface processes are interrelated and collectively influence polar motion. As Kiani Shahvandi states, “For the first time, we present a complete explanation for the causes of long-period polar motion.” The findings reveal that climate change not only impacts surface conditions but also reaches deep within the Earth, potentially altering the dynamics of the core.
One of the key insights from the study is the feedback mechanism between surface processes and the Earth’s interior. The melting ice and the consequent redistribution of mass affect the conservation of angular momentum, which in turn influences the dynamics within the Earth’s core. This interconnectedness underscores the far-reaching impacts of climate change, extending beyond surface-level changes to fundamental planetary processes.
While the changes in Earth’s rotation and axis might seem minimal in the context of everyday life, they have significant implications for space navigation. Precise calculations are essential for space missions, especially those involving landings on other planets. Even minor deviations in Earth’s rotation can translate into substantial errors over vast interplanetary distances. As Professor Soja emphasizes, “Even a slight deviation of just one centimetre on Earth can grow to a deviation of hundreds of metres over the huge distances involved.”
This precision is crucial for missions aiming to land in specific locations on other celestial bodies. Without accounting for these shifts, achieving targeted landings on planets like Mars would be challenging. The research thus highlights the importance of considering Earth’s rotational changes in the planning and execution of space missions.
The innovative approach of combining physical laws with artificial intelligence has been pivotal in achieving the detailed modelling presented in these studies. The team utilized physics-informed neural networks, which integrate the principles of physics into AI algorithms, enhancing their reliability and accuracy. This methodology, supported by the expertise of Professor Siddhartha Mishra from ETH Zurich, has allowed for a comprehensive recording and modelling of various effects on Earth’s surface, mantle, and core.
These advanced models have not only provided a historical perspective on polar motion since 1900 but also enable future predictions. The ability to accurately forecast these changes is invaluable for various scientific and practical applications, from understanding climate impacts to planning space missions.
The research underscores a crucial message: human activities have a more significant impact on our planet than previously understood. The study’s findings reveal that if greenhouse gas emissions continue unabated, the influence of climate change on Earth’s rotation could surpass the moon’s gravitational effects. This realization places a tremendous responsibility on humanity to mitigate climate change and safeguard the future of our planet.
Professor Soja poignantly remarks, “We humans have a greater impact on our planet than we realize, and this naturally places great responsibility on us for the future of our planet.” The research serves as a stark reminder of the interconnectedness of human actions and natural processes, highlighting the need for sustainable practices to preserve Earth’s delicate balance.
The studies conducted by ETH Zurich mark a significant advancement in our understanding of climate change’s impact on Earth’s rotation and axis. By unravelling the complex interplay of surface and internal processes, the research provides a comprehensive explanation of long-period polar motion and the role of climate change. The findings emphasize the far-reaching effects of human activities, extending beyond environmental degradation to fundamental planetary dynamics.
As we continue to grapple with the challenges of climate change, this research highlights the urgency of taking decisive action to reduce greenhouse gas emissions and protect our planet. The implications for space navigation further underscore the importance of considering these changes in future scientific and exploratory endeavours.
In the face of these revelations, it becomes imperative for policymakers, scientists, and the global community to work together in addressing climate change. The future of our planet and the accuracy of our space missions depend on our collective efforts to mitigate the impact of human activities on Earth’s rotation and axis. As we move forward, let this research serve as a reminder of the profound connection between human actions and the natural world, and the responsibility we bear in shaping the future of our planet.
