Rapid ice melt in Greenland & Antarctica is flattening Earth's shape—as mass moves from the poles to the Equator—enough to slow its rotation. Duncan Agnew explains the ramifications in the 27 March 2024 issue of Nature: "A global timekeeping problem postponed by global warming." See https://www.nature.com/articles/s41586-024-07170-0
Further discussion about Agnew's article is presented in the Nature article "Climate change has slowed Earth’s rotation — and could affect how we keep time" here: https://www.nature.com/articles/d41586-024-00932-w#ref-CR1