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Fossil Wood Gives Vital Clues To Ancient Climates
Hamilton ON (SPX) Feb 23, 2006 New research into a missing link in climatology shows that the Earth was not overcome by a greenhouse period when dinosaurs dominated, but experienced rapid fluctuations in temperature and sea level change that resulted in a balance of the global carbon cycle. The study is being published in the March issue of Geology. "Most people think the mid-Cretaceous period was a super-greenhouse," says Darren Grocke, assistant professor and Director of the Stable Isotope Biogeochemistry Laboratory at McMaster University. "But in fact it was not to dissimilar to the climates over the past 5 million years." By using high-resolution stable-isotope analysis from 95-million-year-old fossilized wood collected from Nebraska, Grocke and his team were able to precisely correlate the terrestrial carbon cycle with that from deep-sea records. However, when they compared the carbon curves from both records, it was evident that a chunk of about 500,000 years was missing from the terrestrial record. Other records already indicated a drop in sea level, a 2-4�C drop in oceanic temperature and a breakdown in oceanic stratification coincident with a marine extinction event. "Rapid, large falls in sea-level in the ancient record are typically only produced by a glaciation, and so the combination of all the data during the mid-Cretaceous period suggests a short-lived glaciation during a period generally considered to be a super-greenhouse," says Grocke. "Whatever hits the water causes a ripple effect on land," says Grocke. "Earth often undergoes rapid temperature fluctuations, and this new information may help us to understand how the biosphere will respond to human-generated alterations of CO2 concentration." He said the research not only challenges conventional wisdom surrounding ancient climates, it makes a case for the use of high-resolution sampling in order to reconstruct a more accurate picture of the ancient climate and its affect on the Earth. Community Email This Article Comment On This Article Related Links McMaster University Climate Science News - Modeling, Mitigation Adaptation
NASA Under Pressure To Ensure Researcher Independence
St Louis MO (AFP) Feb 22, 2006The US space agency NASA is under increasing pressure from Congress and the scientific community to make sure its researchers remain independent after the agency's top expert on climate publicly denounced attempts to censor his work. The charges, first reported by The NY Times in January, have since been confirmed by NASA public relations officials. |
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