Cornucopia of ice core results.

Examines research that studied the cores of large polar ice sheets to describe glacial-interglacial cycles. Extent of the core record; Research by Petit et al in this issue; Previous research; Details about the four transitions from glacial to warm epochs evident from Vostok drillings in Antarctica; Interplay between greenhouse gases and climate; Role of CO2 in temperature increases; Mechanisms governing global climate change. INSET: Box 1: Ice cores south and north.