Melting ice caps affect the rotation of the Earth and time measurement | Tech and Science

The melting of the polar ice caps creates extra water in the oceans. This mass of water moves over the Earth and has a small influence on the rotation of the Earth. This in turn affects timekeeping on Earth, as one turn equals one day.

You might think that this process presents a problem that needs to be solved. But the delay could actually solve another problem with our world clock.

There are more factors that influence the rotation speed of the Earth. For example, the Earth has rotated faster on its axis in recent years due to changes in the liquid Earth’s core.

Because the Earth has started spinning faster, a revolution on its axis now takes milliseconds shorter than a day on our clock. For example, in 2022 the fastest rotation of the Earth ever measured.

That’s why scientists are considering introducing a negative leap second. This means that a second is skipped. According to the scientists, this should happen in 2026.

But as melting ice caps slow the Earth down again, geophysicist Duncan Agnew has discovered that a negative leap second would not be necessary until 2029. A decision about such a negative leap second has not yet been made.

But Agnew would rather not use the negative leap second at all. It would pose a major challenge for computer systems.

A negative leap second has never been used. Between 1972 and 2016, 27 positive leap seconds were added to the world clock, because in those years the Earth rotated milliseconds longer than 24 hours. To make up for that difference, some years took a second longer. Now that the Earth is spinning faster again, the positive leap seconds are no longer necessary.

Leap seconds are controversial because computers cannot handle them well. That is why it was decided at an international conference on units of measurement in 2022 not to use the leap second for the time being. Scientists are looking for a better solution.