Slowing the Clock: How Melted Ice is Changing Earth’s Rotation Rate and Impacting Global Timekeeping

A study published Wednesday has revealed that melting ice in Greenland and Antarctica is changing the Earth’s rotation rate faster than previously thought. This change will affect the calculation of Coordinated Universal Time (UCT), which is used by computer networks to adjust the time around the world. UCT has been in place since 1967 with ultra-sensitive atomic clocks to ensure the accuracy of the digital and communications infrastructure.

Historically, there has been a synchronization between UCT and astronomical time based on the rotation rate of the Earth, which is not constant. Leap seconds were introduced in 1972 to compensate for these irregularities, ensuring that atomic time aligned with astronomical time. The last leap second adjustment was made in 2016.

As the speed of the Earth’s rotation changes, it causes an inverse problem where astronomical time advances ahead of atomic time. This may require the introduction of a negative leap second, which could present unprecedented challenges in an increasingly connected world. Metrology experts are concerned about the impact of a negative leap second because of possible complications.

The global community of metrologists has agreed to stop using leap seconds by 2035, and from that year there may be a transition so that the difference between atomic time and the Earth’s rotation reaches one minute. However, global warming, which is accelerating the melting of ice in Greenland and Antarctica, poses a challenge to this plan.

Melting ice is slowing Earth’s rotation and may delay the introduction of a negative leap second until 2029. This unprecedented impact on Earth’s rotation requires careful consideration by metrologists to determine the best approach to eliminating the leap second. It provides more time to make decisions about