Climate change could affect timekeeping

LONDON, Mar 28 (BBC): Climate change is affecting the speed of the Earth's rotation and could impact how we keep time, a study says. Accelerating melt from Greenland and Antarctica is adding extra water to the world's seas, redistributing mass.

That is very slightly slowing the Earth's rotation. But the planet is still spinning faster than it used to. The effect is that global timekeepers may need to subtract a second from our clocks later than would otherwise have been the case.

"Global warming is already affecting global timekeeping," says the study, published in the journal Nature. Coordinated Universal Time (UTC) - which is used by most of the world to regulate clocks and time - is calculated by the Earth's rotation.

But the Earth's rotation rate is not constant and can therefore have an effect on how long our days and nights are. As a result, since the 1970s around 27 sec1onds - known as leap seconds - have been added on to keep our time accurate.

The study finds that a "negative leap second" - subtracting a second from world clocks - would have been needed in 2026 without accelerating polar ice melt.

But now, with ice sheets losing mass five times faster than they were 30 years ago, this change is needed in 2029, the study suggests.

"It's kind of impressive, even to me, we've done something that measurably changes how fast the Earth rotates," Duncan Agnew, the author of the study, told NBC News.