Climate change slowing Earth’s rotation, lengthening days
10:23 AM EDT, July 21, 2024
Increasing temperatures accelerate the melting of glaciers and ice caps, directly leading to rising sea levels. As Earth's ice cover thins, the planet heats up faster. However, this is not the only consequence of climate change. Our days are also getting longer.
The problem has been examined by scientists from the Swiss Federal Institute of Technology in Zurich and NASA's Jet Propulsion Laboratory. According to them, as ice masses melt, more mass moves from the poles to the equator, slowing down Earth's rotation around its axis.
It’s like when a figure skater does a pirouette, first holding her arms close to her body and then stretching them out. The initially fast rotation becomes slower because the masses move away from the axis of rotation, increasing physical inertia. In physics, we speak of the law of conservation of angular momentum, and this same law also governs the Earth’s rotation – explains Dr. Benedikt Soja from ETH Zurich, co-author of the study, as quoted by "National Geographic".
Earth's shape also changes over the years. This is influenced by ocean tides, the drift of tectonic plates, and sudden earthquakes and volcanic eruptions.
To accurately assess the rate at which Earth rotates around its axis, scientists have turned to GPS data, cosmic radio signals, and ancient solar and lunar eclipses records.
The result? From 1900 to today, climate change has lengthened days by about 0.8 milliseconds. If greenhouse gas emissions remain unchanged, by 2100, days could be extended by 2.2 milliseconds compared to the baseline level.
Lengthening of Earth's day: Milliseconds make a big difference
Contrary to appearances, every millisecond has enormous significance – especially from the perspective of space. It affects GPS systems, is significant for rocket launches, and impacts the determination of trajectories for probes.
It is also crucial for us on Earth to know that the slower our planet rotates, the greater the likelihood of major earthquakes.