Chris studies how life and climate interact of through Earth’s history by analyzing the chemistry of ancient sediments. He is particularly interested in how the concentrations of oxygen have changed in the atmosphere and ocean over time, and how life responds to transitions in Earth’s climate state. His research spans the last 2.5 billion years of Earth’s history, and his research has taken him as far away as the Arctic Circle and as close as Green Lakes State Park. Recently, he spent two months as a scientist aboard the research vessel JOIDES Resolution to recover sediment cores from the Atlantic Ocean in an effort to better understand the causes of extremely warm climate 50 million years ago.