The greenhouse climate on Earth of the Late Cretaceous Epoch was influenced by circulation in the deep oceans, they said, and changes in those circulation patterns 70 million years ago could help scientists understand the consequences of modern increases in greenhouse gases.
"We are examining ocean conditions from several past greenhouse climate intervals so that we can understand better the interactions among the atmosphere, the oceans, the biosphere, and climate," Kenneth MacLeod, professor of geological sciences, said in a UM release Thursday.
While high atmospheric levels of carbon dioxide caused Late Cretaceous warmth, ocean circulation influenced how that warmth was distributed around the globe, the researchers said.
"Understanding the degree to which climate influences circulation and vice versa is important today because carbon dioxide levels are rapidly approaching levels most recently seen during ancient greenhouse times," MacLeod said.
"In just a few decades, humans are causing changes in the composition of the atmosphere that are as large as the changes that took millions of years to occur during geological climate cycles."