“This has never happened before, and it's a huge challenge to ensure that all parts of the global time infrastructure show the same time,” said Duncan Agnew, a researcher at the University of California, San Diego.
“Many computer programs assume for leap seconds that they are all positive, so these have to be rewritten,” he told AFP.
Using partly satellite data, Agnew looked at Earth's rotation rate and the impact of its slow core for the new study published in the journal Nature.
They determined that if climate change did not occur, a negative leap second might need to be added to UTC by 2026.
But the study said that since 1990, melting ice in Greenland and Antarctica has slowed the Earth's rotation. It says this delays the need for negative leap seconds until at least 2029.
“When ice melts, water spreads throughout the ocean; this increases the moment of inertia, which slows the Earth down,” Agnew said.
If the “unprecedented” negative leap second requirement were delayed, it “would be welcome news indeed,” Patrizia Tavella, head of the International Bureau of Weights and Measures, responsible for UTC, commented in Nature.
