What's an Ice Core?
An ice core model in the exhibition is based on a real core from Greenland that is over 3 kilometers (1.9 miles) long. Cores drilled from Greenland's thick ice cap faithfully record the local climate over the past 108,000 years. The ice cap on Antarctica offers a climate record that stretches back even further, to 800,000 years.
Snow falls year-round over the ice sheets in Greenland and Antarctica, but summer snow and winter snow differ enough to be visible as distinct ice layers.
Ice cores provide a timeline of climate, with each year represented by a new layer formed on top of the ones from the year before. One way to date the layers is simply to start at the surface and count back the years.
The thickness of a layer—when compared to adjacent layers—gives a sense of how much snow fell at that spot in any one year.
Climate, On Ice
Ice cores can tell us a lot about ancient climates, including local temperature, CO2 concentration and, based on dust trapped in the ice, global and local wind patterns. These data, in turn, help us understand why and how the climate system changed in the past, how it works today, and how we might expect it to change in the future.
More About This Resource...
Our innovative Science Bulletins are an online and exhibition program that offers the public a window into the excitement of scientific discovery. This interactive was published in March 2005 as part of Archived in Ice: Rescuing the Climate Record Earth Feature.
- It begins with an introduction that explains how glaciers trap air, chemical, dust, and pollen from the atmosphere; over time creating a time capsule of past climatic conditions.
- Students then "take the ice core to the lab," where they can explore its Ice Layers, Pollen, Oxygen Isotopes, Dust, Ice Crystals, and Other Chemistry.
Supplement a study of geology with a classroom activity drawn from this Science Bulletin interactive.
- Working individually or in small groups, have students explore the What Is an Ice Core? interactive.
- If necessary, have them further research glaciers and what they have revealed about climate change. A good place to start is the NSIDC All About Glaciers site.
- Using what they've learned, have students create a poster that illustrates how glacial ice cores are time machines into the past.