http://earthobservatory.nasa.gov/Features/Paleoclimatology_IceCores/
In The Ends of the Earth: Perspectives on Modern Environmental History, Donald Worster tries to get the point across that environmental history has to form a tight alliance with science. To become more applicable and credible. Scientist are using ice cores to compose an environmental history of Earth.
Ice cores are cylindrical ice blocks removed from the Antarctic. When laid out vertically ice cores can give all type of information by the horizontal stripes formed from snow deposited. Similar to how tree trunk rings can provides on with information on the past. Throughout the years layers of snow fall upon the ice sheets. The layers of snow are each different with unique chemical make ups. During the summer months when Antarctica has 24 hours of sunlight the snow melts to form its own layer. Its these layers that scientist use to study the history of Earths climate. Ice cores have been pulled out from depths beyond 3000 m, 2 miles, and have recorded on them the history from 750,000 years ago.
Ice cores can provide many much information from their make up. With the right calculations they can find out a multitude of information from a block of ice. The thickness of each layer can be used to calculate the snow fall of any year. Chemicals found in the ice can tell of chemicals in found through out the atmosphere. If ash is found it can be concluded that their was a volcanic eruption in that time period; while the amount can conclude the magnitude of the eruption. Upon further studies ice cores can provide an annual record of temperature, precipitation, atmospheric composition, volcanic activity, and wind patterns. They are time capsules that allow us to look into the past.
Using information gather from these ice cores in Antarctica (as well as glaciers all over the world) and other means scientist are able to understand the Earth’s climate history. The ice has remain preserved and undisturbed providing a credible resource.
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