Earth’s rotation is changing speed. It's actually slowing down.

Question

This means that, on average, the length of a day increases by around 1.8 seconds per century. 600 million years ago a day lasted just 21 hours. The mysteries of Earth’s core – the deeper scientists look into the heart of our planet, the more puzzling it becomes.

Answer 1

Yes this is true that Earths speed is changing slightly. The source you used is a trustworthy source, and other trustworthy sources such as CBS news also reported on this topic. In Cbs article I found it very interesting that they wrote "For the first time in history, world timekeepers may have to consider subtracting a second from our clocks in a few years because the planet is rotating a tad faster than it used to." via https://www.cbsnews.com/news/earth-spinning-time-second-removed-world-clocks/. In this article from cbs they also include a quote from a trusted geophysicist where he had this to say. "This is an unprecedented situation and a big deal," said study lead author Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography at the University of California, San Diego. So yes this is a true statement that the earth is spinning slightly faster, and we may have to adjust our clocks by a second.