Study: Rising sea levels causing longer days

The melting of polar ice due to climate change is lengthening days on Earth milliseconds at a time, according to research published Monday in the journal Proceedings of the National Academy of Sciences.

The research indicated that while the pull of the moon’s gravity has caused the gradual, steady lengthening of days every century, the melting of polar ice is slowing the planet’s revolution more by redistributing mass at the equator.

Co-author Surendra Adhikari, who works as a geophysicist at NASA’s Jet Propulsion Laboratory, specifically compared the revolution of the earth to “a figure skater,” who will spread out their arms to skate faster, but pull their arms inward when slowing down. Similarly, he said, the earth will spin slightly slower when more mass is concentrated at its center.

Adhikari told The Hill in an interview that the moon's gravitational pull already extends the day slightly more every century. The research, he said, indicates that rising sea levels are already compounding that and could add more time than the moon—up to 2.6 milliseconds—by the end of the century.

The study’s authors found that during the 20^th century, the rate of slowing fell between 0.3 and 1 milliseconds per century but has increased to 1.3 milliseconds since 2000 as the melting of polar ice accelerated. Researchers estimated that the current rate of slowing is already likely the highest in thousands of years.

“Under high emission scenarios, the climate-induced LOD [length of day] rate will continue to increase and may reach a rate that is twice as large as at present, surpassing the impact of lunar tidal friction,” the researchers wrote. “These findings signify the unprecedented effect of climate change on planet Earth and have implications for precise timekeeping and space navigation, among others.”