A team of U.S. ice-coring scientists and engineers in Antarctica, funded by the National Science Foundation (NSF), have recovered from the ice sheet a record of past climate and greenhouse gases in the atmosphere that extends back 68,000 years.
Retrieved from the West Antarctic Ice Sheet (WAIS), the ice containing the record is known as the WAIS Divide ice core. The cylinders of ice that make up the core contain uniquely detailed information on past environmental conditions such as the atmospheric concentration of greenhouse gases, surface air temperature, wind patterns, the extent of sea ice around Antarctica, and the average temperature of the ocean.
Successfully retrieving the core is the culmination of an eight-year project to obtain a paleoclimate record from one of the remotest parts of the continent.
The ice containing the record was recovered at a field camp in the center of West Antarctica, 1,040 kilometers (650 miles) from the geographic South Pole, where the ice is more than 3,460 meters (two miles) thick. In the new WAIS Divide core each of the past 30,000 years of snowfall can be identified in individual layers of ice. By allowing an examination of past climate at an annual resolution, the record will help scientists understand why climate can change abruptly--in less than 10 years--and how climate could unfold in the coming century.
Other ice-coring projects have produced cores of lower temporal resolution, showing that the current level of atmospheric greenhouse gases, which is due to the burning of fossil fuels, is the highest in at least 800,000 years.The ice that is between 30,000 and 68,000 years old--while not containing records with annual resolution--contains a higher time resolution record than previous projects.
When snow falls at WAIS Divide, it rarely melts, but builds up in thick annual layers, which are compressed into ice by subsequent snowfall. Chemicals and gases in the atmosphere that
|Contact: Peter West|
National Science Foundation