The Tibetan Plateau acts as a giant 'speed bump' that slows down Earth's rotation.

The Tibetan Plateau, often called the 'Roof of the World,' covers approximately 2.5 million square kilometers and has an average elevation exceeding 4,500 meters. Its formation began roughly 50 million years ago during the Cenozoic Era when the Indo-Australian and Eurasian tectonic plates collided. This massive geographical feature serves as a physical barrier that significantly alters global atmospheric circulation patterns.The plateau's height places it directly in the path of the subtropical jet stream. As these high-speed winds hit the plateau, they are forced to split or rise, creating mountain waves and atmospheric torque. This interaction generates a 'drag' force known as mountain torque, which transfers angular momentum between the solid Earth and its atmosphere. Research published in journals like 'Nature' and 'Journal of Geophysical Research' highlights how these surface features influence the length of day (LOD) variations.While the slowing effect is roughly 0.2 milliseconds per day, the cumulative impact over geological timescales is profound. This process is part of a broader phenomenon where mass distribution on the Earth's surface affects its moment of inertia. Similar to how a figure skater slows down by extending their arms, the high-altitude mass of the plateau increases the planet's rotational inertia. This constant friction between the lithosphere and the moving atmosphere ensures that the Tibetan Plateau remains one of the most significant terrestrial influences on our planet's rotation.