Climate Change Is Slowing Earth’s Rotation at an Unprecedented Rate
Our days are getting subtly longer due to the effects of climate change, with the current rate of increase in day length being unparalleled in the last 3.6 million years. This phenomenon is primarily driven by rising sea levels caused by the melting of polar ice sheets and mountain glaciers, which alters the distribution of mass on Earth and consequently slows its rotation.
How Climate Change Affects Earth’s Rotation
The length of a day isn’t fixed; it fluctuates due to gravitational forces from the Moon and various geophysical processes within the Earth. However, climate change is now playing a significant role. From 2000 to 2020, days lengthened by 1.33 milliseconds per century due to climate-related factors, particularly the redistribution of mass from land to ocean as ice melts University of Vienna.
The Role of Melting Ice and Sea Level Rise
As polar ice caps and glaciers melt, sea levels rise, shifting mass towards the Earth’s equator. This redistribution of mass is analogous to a figure skater extending their arms – it slows down the rotation. Mostafa Kiani Shahvandi of the University of Vienna’s Department of Meteorology and Geophysics explains this effect, stating, “Similar to ice skaters turning slower when they extend their arms and faster when they keep their arms close to their body.” EurekAlert
Reconstructing Earth’s Rotational History
Researchers from the University of Vienna and ETH Zurich reconstructed ancient day-length fluctuations using fossil remains of single-celled marine organisms called benthic foraminifera. By analyzing the chemical composition of these fossils, they could infer past sea-level changes and, subsequently, calculate corresponding changes in day length R&D World.
Unprecedented Rate of Change
The study, published in the Journal of Geophysical Research: Solid Earth, demonstrates that the current increase in day length is unprecedented over the past 3.6 million years. Even as changes in day length have occurred in the past due to the growth and melting of continental ice sheets during the Quaternary period, the rate of change observed today is significantly faster. “But before that, or after that, there has not been a moment when Earth’s sea level rose as rapid as during the period (climate change in 2000-2020),” noted Shahvandi IFL Science.
Implications and Future Research
This research highlights the profound and far-reaching consequences of climate change, extending beyond temperature increases and sea-level rise to even affect the fundamental rhythm of Earth’s rotation. Continued monitoring of ice melt, sea levels, and Earth’s rotation will be crucial to understanding the long-term implications of these changes.