What do fossil molecules tell us about Earth’s history and the extinction of dinosaurs? In this presentation, Dr. Julio Sepúlveda weaves together chemistry, biology, history, and paleoclimatology. Julio is an Earth scientist who studies the co-evolution of life and climate over geological timescales, all the way until today. He is particularly interested in intervals in Earth’s history when global temperatures were similar or even warmer than today, and more like what we expect for our planet to experience in the future if humankind continues to burn fossil fuels and release greenhouse gases to the atmosphere. He does this by studying fossil fat molecules (known as biomarkers) preserved in the layers of mud that accumulate at the ocean floor over centuries, millennia, or even millions of years.