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The present interest in global climate change makes any information about Earth's climate history valuable for modeling purposes. Thick Antarctic ice sheets provide one of the best records for past climate change, so a great effort has been made to collect ice cores from some of the oldest and deepest parts of the ice sheet. The only area where an ice core capable of providing a long, annual history of Southern Hemisphere climate exists is in the interior of West Antarctica, where compressed snow layers are thick enough to allow absolute dating.
- Snow is a valuable storehouse of information to a glaciologist.
- When a snowflake falls, it brings with it important details about the atmosphere at the time it was formed.
- As it is slowly compacted and recrystallized by subsequent snowfalls, it forms a historical record.
Ice core researchers in the United States are analyzing two ice cores, one from Siple Dome, Antarctica, and one from upslope of Byrd Station in West Antarctica. The two cores, one far inland, and one near the coast, complement each other and allow scientists to discriminate between local and regional influences on the climate records recovered from the cores. The Siple Dome core comes from the Siple Coast region of Antarctica and is situated on a dome of ice that is a thousand meters in thickness and is expected to contain ice that is up to a hundred thousand years old.
Scientists expect to be able to use the results from West Antarctic Ice Core Projects to better understand the relationship between atmospheric carbon dioxide and temperature. They also expect to learn more about the influence of the West Antarctic ice sheet on sea level and the likelihood for unexpected rapid changes in sea level. Finally, they will be able to observe and record the influence of southern ocean and atmospheric circulation patterns on past climates.
- Ice cores can reveal patterns of mean air temperature, evidence of major volcanic eruptions and, by analysis of the air trapped in ice bubbles, data on the composition of the atmosphere.
- Scientists still disagree about the effects of the present increase in carbon dioxide, therefore, the historical record from ice cores is of considerable significance.
- The data so far indicate that there has been a 30% increase in the concentrations of carbon dioxide since the last Ice Age.
- Analysis of the ice core particles will show if they are volcanic in origin or come from dust storms associated with more arid conditions.
- Virtually all life native to Antarctica is supported by the food-rich sea surrounding the continent.
- All are dependent upon each other as parts of a continuing food chain, beginning with phytoplankton (algae, particularly diatoms) and zooplankton (including krill) and extending through the fishes, squid, octopus, sea birds (including penguins), and the large marine mammals (whales, porpoises, and seals).
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