Drilling a vertical hole through this ice involves a serious effort involving many scientists and technicians, and usually involves a static field camp for a prolonged period of time. Shallow ice cores (100-200 m long) are easier to collect and can cover up to a few hundred years of accumulation, depending on accumulation rates. 420,000 years of ice core data from Vostok, Antarctica research station. From bottom to top: * Solar variation at 65°N due to en: Milankovitch cycles (connected to 18O). They spent two nights at each site, first collecting radar data and secondly collecting a 15 m shallow ice core. This schematic cross section of an ice sheet shows an ideal drilling site at the centre of the polar plateau near the ice divide, with ice flowing away from the ice divide in all direction. The large Greenland and Antarctic ice sheets have huge, high plateaux where snow accumulates in an ordered fashion. The team were travelling across the West Antarctic Ice Sheet to study snow accumulation. Soon after moving to slash his agency's budget and staff, Scott Pruitt, the new head of the Environmental Protection Agency (EPA), said on Thursday that he doesn't believe that the human-caused buildup in atmospheric carbon dioxide concentrations is the primary contributor behind global warming.These statements go beyond his previous expressions of doubt regarding mainstream climate science findings, and indicate that the person responsible for regulating carbon dioxide does not believe that this pollutant is much of a problem after all.
Depending on the amount of extracted air, three to five successive analyses are done.In an interview with CNBC's "Squawk Box," Pruitt said: "I think that measuring with precision human activity on the climate is something very challenging to do and there's tremendous disagreement about the degree of impact, so no, I would not agree that it's a primary contributor to the global warming that we see.""But we don't know that yet, as far as...we need to continue the debate and continue the review and the analysis," he said.A correction for the half-life is incorporated into calibration curves, so even though radiocarbon ages are calculated using a half-life value that is known to be incorrect, the final reported calibrated date, in calendar years, is accurate.Libby and James Arnold proceeded to test the radiocarbon dating theory by analyzing samples with known ages.To assure proper credit is given, please follow the citation instructions in the headers of the data files and/or at the end of this page when using any of this material.