PubTalk 12/2005 — Frozen in Time

How Ice Cores Are Revealing the Composition and Temperature of Earth's Atmosphere During the Past Million Years

by Todd Hinkley, Geologist

• Scientifically invaluable ice cores taken from Antarctic and Arctic ice are stored and safe guarded at the U.S. National Ice Core Laboratory, operated by the U.S. Geological Su rvey
• These ice cores are the only systematic record of the composition (including "greenhou se" gasses) and temperature of the Earth's atmosphere over the past million years
• The ice cores show that most of Earth's geologically recent climate history has been characterized by great instability and rapid, extreme swings of temperature, beyond anything we have experienced in historical times
• These ice cores are our only source of information about natural, pre-industrial levels of toxic trace metals and other substances deposited from the atmosphere into the world's ecosystems