John Williams


College of Letters & Science | Department of Geography and Center for Climatic Research

John (Jack) Williams is Professor in Geography and affiliated with the Center for Climatic Research at UW-Madison.  Much of his work focuses on the large ecological and climate changes accompanying the end of the last ice age, with many instructive parallels to current climate changes.  His work ranges from site-based fieldwork to helping lead and build global-scale community data resources for studying ecosystem responses to past environmental change at global scales.  Awards include election as a Fellow of the Ecological Society of America, the Phil Certain Distinguished Faculty Award and a Romnes Fellowship from UW-Madison, a Bullard Fellowship from Harvard University, an Aldo Leopold Leadership Fellowship from Stanford, and a Institute for Advanced Study Fellowship from Durham University.  He and his wife Sarah have lived in Wisconsin since 2004 and have raised their kids here; they enjoy kayaking, dog-walking, and board-gaming.  More information can be found at or via Twitter @IceAgeEcologist


  • How do species adapt to changing climates and how can we help them? Some of our best examples come from the end of the last ice age, when the world warmed by 5-10F. Here I’ll review how we study past climates and ecosystems, what we’ve learned, and insights for today. 

  • Here I’ll review how we study past climates and ecosystems, what we’ve learned and insights for today.

  • Climate Science and Solutions: An Overview
  • Life and Death of the Mammoths on St. Paul Island, Alaska