A common perspective is that one rotation of Earth on its axis is equal to 24 hours that make up to 86400 seconds. Did you know that the Earth’s revolution in the year 2020 was a millisecond faster than average? Not even the Earth’s rotation was left unscathed in the dreadful year of 2020. The year 2020 holds the record for 28 fastest days in the year, which means that the world experienced 28 shortest days after decades—and no, that’s not just a figure of speech.
The accelerating rotation varies all the time because of variations in the atmospheric pressure, winds, ocean currents and movement in the Earth’s core. However, these variations can be troublesome for the timekeepers who are responsible for setting the Coordinated Universal Time (UTC). The UTC is used to set clocks and whenever the astronomical time differs by 0.4 seconds from UTC; UTC is adjusted.
Before the year 2020, scientists would add a leap second after every year and a half to keep the Earth’s spin and global time in line. However, the accelerating spin and shortening rotational time might result in the addition of a negative leap second. In other words, the scientist and timekeepers might have to subtract a complete second from the year to cater for the spinning speed. To elaborate, an average astronomical day is about 86400 seconds long, but the year 2021 would begin 0.05 second earlier than average day-length. Summing the entire time lag for 2021, the New Year would be 19 milliseconds shorter than an average year.
Even though it is a tiny margin, the lag indicates the increasing spin speed of Earth, making the scientists worry about the time in future. Scientists blame rapidly increasing global warming which has led to quicker melting of the glaciers. The speedy meltdown of glaciers leads to inappropriate and non-uniform distribution of mass.
There’s no doubt that global warming has disturbed most natural habitats, processes and ecology, but it could not be the only cause of the increase in spin speed. No matter what the factors and reasons are, the addition of a negative leap second could have catastrophic impacts on modern technologies. To avoid any disastrous consequence, some scientist suggests to let the difference between astronomical and atomic times expand until the addition of leap hour is required.
The International Earth Rotation and Reference System Service (IERS) in Paris will make the final decision regarding adjusting time. Currently, the organization has not issued any report that would state the highly anticipated addition or subtraction of a new leap second.