Tim Newfield (Georgetown University) talks to Merle and Lee about the connected histories of climate change and diseases that become pandemics, focusing on the early medieval and late antique periods. Tim opens by discussing the global cooling events starting in 536 and how researchers know they happened through various proxy datasets, such as tree rings, along with how historians should approach using these types of natural sources. He then talks about the long-term climate cooling event, the Late Antique Little Ice Age, along with its supposed connections to the outbreak of the Justinianic Plague in 541. Tim also talks about why researchers have remained so focused on the influence of climate on plague. At the end, he discusses where he believes the field of pre-modern historical diseases is going and the influence of Covid in this trajectory.