Earth’s rotation is slowing down due to melting ice, satellite measurements show

New research has implications for how we keep track of time

FILE - Icebergs float in a fjord after calving off from glaciers on the Greenland ice sheet in southeastern Greenland, Aug. 3, 2017. The Greenland ice sheet, the second largest body of ice in the world which covers roughly 80 percent of the country, has been melting and its glaciers retreating at an accelerated pace in recent years due to warmer temperatures. If all of that ice melts, sea levels will rise by several meters, though there will be regional differences. (AP Photo/David Goldman, File) (David Goldman, Copyright 2017 The Associated Press. All rights reserved.)

The Earth’s rotation isn’t always constant, leading to the need for adjustments in our clocks. Recent satellite measurements reveal that the Earth’s rotation is slowing down faster than before due to melting ice in places like Greenland and Antarctica.

This slowdown affects the Earth’s core and its overall rotation speed.

A new scientific paper highlighted how these changes complicate our timekeeping system called Coordinated Universal Time (UTC), especially in the face of climate change.

Since 1972, timekeepers have had to add “leap seconds” 27 times to keep up with the pace. However, there may be a need to reduce leap seconds in the coming years as the Earth slows from various factors, including the redistribution of mass and influences by the planet’s axial wobble.

The moon is known to slow the Earth’s rotation since it is receding from Earth about 1.49 inches per year.

But new research using satellite measurements shows melting ice, particularly from regions like the Canadian Arctic and Fennoscandia, affects the Earth’s rotation in multiple ways. When ice melts from polar regions, water is redistributed, causing shifts in the Earth’s mass distribution, and impacting its rotation.

According to Duncan Carr Agnew, the report’s author, if these trends continue, significant changes to UTC may be necessary by 2029 due to the Earth’s slowing spin. This highlights how global warming not only impacts the environment but also affects our timekeeping systems.


About the Author

After covering the weather from every corner of Florida and doing marine research in the Gulf, Mark Collins settled in Jacksonville to forecast weather for The First Coast.

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