This episode addresses how we know what temperatures and concentrations of atmospheric gases were long before humans could record it with modern instrumentation. Ice tells a story about what the environment was like tens to hundreds of thousands of years ago. Here we interview Dr. Dr. Kaden Martin, a scientists interested in major climate shifts over geologic time. Dr. Martin is currently a postdoctoral fellow at Woods Hole Oceanographic Institution. Dr. Martin graduated from Oregon State University with a Ph.D. in Ocean, Earth, and Atmospheric Sciences and has seven peer-reviewed articles that document the use of ice core data to better understand climate variability across geographic regions and time. In this episode we discuss his most recent paper titled: “Greenland Ice Cores Reveal a South-To-North Difference in Holocene Thermal Maximum Timings” published in 2024 in the peer-reviewed journal Geophysical Letters Research. To follow along you can view his paper here: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024GL111405.