Over the past 3,000 years, the core of the Earth has been speeding up a little, and the mantle-crust on which we stand is slowing down. As a consequence of Earth rotating more slowly, the length of our days is slowly increasing. In fact, a century from now, the length of a day will have increased by 1.7 milliseconds. This may not seem like much, but Dumberry notes that this is a cumulative effect that adds up over time.
Based on their work reconciling these discrepancies, the scientists involved in the study are confident in predicting sea levels to the end of the 21st century. "This can help to better prepare coastal towns, for example, to cope with climate change," says Dumberry. "We're talking billions of dollars of infrastructure here," Dumberry notes that this study serves as a stimulus for more work to continue investigating the deep interior of our planet.
The findings, "Reconciling past changes in Earth's rotation with 20th-century global sea-level rise: Resolving Munk's enigma," were published in the Dec. 11 issue of the journal Science Advances.