The melting of the polar ice caps is shifting the Earth’s weight towards the Equator and slowing down our planet’s rotation, according to a report in the Nature scientific journal. The report warned that this slowdown could wreak havoc on global timekeeping.
Humanity depends on a network of 450 atomic clocks to keep Coordinated Universal Time (UTC). Network computing, global positioning, and financial markets all require this precise measurement of time to function. However, the Earth’s rotation doesn’t always sync up with this official standard: gravitational drag from the sun and moon, changes to the rotational speed of the planet’s core, and earthquakes can all speed up or slow down the passage of time.
The latest threat to UTC comes from melting ice caps in Greenland and Antarctica, geophysicist Duncan Agnew explained in Nature on Wednesday. Using satellite-based gravitational measurements, Agnew and his team at the University of California discovered that melting ice settles as water around the Earth’s midsection, with this change of mass slowing the planet’s rotational speed.
Since UTC was adopted in 1963, a global consortium of scientists have added 27 ‘leap seconds’ to account for the Earth’s slowing rotation. However, the Earth has spun faster in recent years, and the scientists have considered subtracting a second by 2026. According to Agnew’s research, the planet’s slowdown means that this decision will now be unnecessary until 2029.
“If polar ice melting had not recently accelerated, this problem would occur three years earlier,” Agnew wrote. “Global warming is already affecting global timekeeping.”
Regardless of when this second is subtracted, scientists are unsure how the move will affect computer and network systems.
“Different web services currently handle leap seconds differently,” Agnew wrote. “Many systems now have software that can accept an additional second, but few if any allow for removing a second, so that a negative leap second is expected to create many difficulties.”
Aside from its impact on timekeeping, the melting of the ice caps is expected to cause a range of problems and opportunities around the world. According to worst-case estimates by the World Bank, a rise in sea levels by 10-100 centimeters by the year 2100 could submerge the entire Maldives archipelago. On the other hand, melting Arctic ice along Russia’s northern coastline could open up the Northern Sea Route to year-round marine traffic, cutting journey times from China to Europe by nearly half and placing Moscow in control of a lucrative shipping lane.