 climate models to understand how climate change has affected day length in the past and to project its role in the future. Climate change fueled sea level rise caused the length of a day to vary between 0.3 and 1 milliseconds in the 20th century. Over the past two decades, however, the scientists calculated an increase in day length of 1.33 milliseconds per century, significantly higher than at any other time in the 20th century.