Researchers examining the Younger Dryas (YD) paleoclimatic oscillation were brought together at an international, interdisciplinary workshop sponsored by PAGES (Past Global Climate Changes) and the Lamont‐ GISS (Goddard Institute for Space Studies) Climate Center and organized by D. Peteet. The workshop was held April 29–30 at Lamont‐Doherty Earth Observatory in Palisades, N.Y.The YD event was a major return to cold conditions that occurred approximately 11‐10,000 radiocarbon years B.P., after the warming trend following the last ice age. This pronounced and rapid cooling, identified almost a century ago in terrestrial records, continues to challenge our thinking about how various components of the biosphere, ocean, atmosphere, and cryosphere interact on short time scales. Because it is clearly evident in terrestrial, marine, and ice core repositories, the evidence provides an intriguing example of past climate fluctuation that is relevant for future climate change.