2021 will be the shortest year in decades. Here's why
TORONTO -- Scientists say 2021 is expected to be a shorter year than normal with the Earth spinning at a faster rate than it has in the last 50 years.
York University astronomy and physics professor Paul Delaney explained to CTV's Your Morning that as the Earth’s rotation speeds up, the shift means that time is slowing on the planet’s surface, making each day a "fraction of a second" shorter than 24 hours.
He said in an interview on Tuesday that this phenomenon is likely being caused by climate change.
"There is such [sic] a lot of ice that is becoming liquid and… as a consequence of that you're changing the way the mass on the surface of the Earth is situated," Delaney said. "When you bring the amount of material, the amount of mass, closer to our rotation axis that actually spins up our rotation rate a little bit faster."
Delaney compared this shift in the Earth’s mass to that of figure skaters pulling their arms in closer to their body in order to spin faster.
However, he says this change does not mean the timing of one's day-to-day activities will change.
"We're talking about a fraction of a second here. People shouldn't think they're about to get an hour's extra sleep as a result of this, but it really is associated with the melting of the polar ice caps," he said.
While the planet's rotational speed often drifts around slightly, Delaney said the melting of the ice caps with climate change can alter the global time frame as well as the marking of days.
Due to this increase in rotation speed, scientists report that the average day in 2021 is expected to be 0.05 milliseconds shorter than the 86,400 seconds that normally make up the 24-hour period.
Delaney says adding an extra second to clocks in what is called a leap second can help with this.
"The fraction of a second per day is not going to make much of a difference to you and me, but things like leap seconds have been introduced over the last sort of 40 to 50 years to compensate for this change in the Earth's rotation rate compared to what we call our fixed frame," Delaney said.
Delaney explained that leap seconds are irregular, with one second added to the last minute of a given calendar year. Since 1972, scientists have added leap seconds about every year-and-a-half, on average, according to the National Institute of Standards and Technology (NIST).
But with the Earth rotating faster over recent years, the International Earth Rotation and Reference Systems Service (IERS) says no leap seconds have been necessary since 2016.
IERS announced in July that no leap second would be added to the world’s official timekeeping in December 2020. However, a second may actually have to be subtracted in the future in what is known as a negative leap second, which would be a first for the IERS.
While the change in time may not affect every day activities, Delaney says atomic clocks used in GPS satellites do not consider the planet's evolving motion, which can cause potentially confusing implications for smartphones, computers, and communications systems that synchronize with Network Time Protocol (NTP) servers.
"Most computer systems are expecting 60 seconds in a minute and when you get 61 seconds in a minute, then you can cause computer crashes, so it's a little bit like having Y2K thrown around in a way that you just don't expect," Delaney said.
Because leap seconds are irregular, he says there may be only a "few weeks or a few months notice" that time will be added or subtracted. This can lead to computer glitches and crashes, which Delaney said is a "big problem in our very computerized society."
Delaney added that this can also be a problem for stock markets. For example, he noted that the New York Stock Exchange went down for over an hour on June 30, 2015 because of a leap second.
"If you're the person who is on the selling floor trying to transact millions if not billions of dollars, and the stock market disappears on you, you're not going to be a very happy camper. So there is financial issues that are driving this whole question of leap seconds, and that brings into sharper focus the changing of the day," Delaney said.
So, what can be done to help adjust the Earth’s rotation? Delaney said there isn't much people can do.
"The Earth is doing what it wants to do. As we move around the sun, as we rotate on our axis, the rate at which we are rotating is completely independent of what you and I are wanting to do," he said.
With ice caps melting as a result of climate change, Delaney said the "easy answer" would be to stop the global warming of the planet.
"Let's keep the ice where it should be so that the rate of rotation is retained in the way that we're expecting it to be," he said.