Earth's climate has undergone dramatic changes throughout its history, but new research suggests those changes may not have been as random as previously thought. A study led by an international team of researchers, including University of New Mexico paleobiologist Corinne "Cori" Myers, found that Earth's climate over the past 539 million years tended to remain within a small number of recurring climate states. The research also found that periods of elevated extinction, including the five major mass extinction events in Earth's history, frequently occurred as the planet transitioned between those states.