The Late Paleozoic Ice Age extended across a vast span of geological time, when large ice sheets covered parts of the supercontinent Gondwana. The geological timescale of the ancient warming is also central to the study’s relevance. In scientific usage, Earth remains in an ice age because substantial permanent ice sheets still exist in Greenland and Antarctica. The ancient warming episode matters precisely because it demonstrates that an ice age does not guarantee a permanently cold or stable climate. Subject of Research: Ancient global warming, permafrost methane feedbacks, and climate tipping points during the Late Paleozoic Ice AgeArticle Title: A transient global warming event during Earth’s penultimate icehouseWeb References: https://doi.org/10.1073/pnas.2601643123References: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.2601643123Image Credits: Andrew Higley, University of CincinnatiKeywords: climate change, global warming, ice age, Late Paleozoic Ice Age, permafrost, methane, climate feedback, tipping point, paleoclimate, geology, volcanic activity, Earth’s climate history