W Washington, May 15 : The newest analysis of trace gases trapped in Antarctic ice cores has confirmed that current levels of concentrations of carbon dioxide and methane are the highest in 800,000 years.
  Carried out by members of the European Project for Ice Coring in Antarctica, the research also confirms that greenhouse gas concentrations go back as much as 800,000 years into the past. According to Edward Brook, an associate professor of geosciences at Oregon State University, it extends the data on trace gases back another 150,000 years beyond any studies done prior to this. Ultimately, researchers would like to achieve data going back as much as 1.5 million years. According to the data, the current levels of primary greenhouse gases - those that are expected to cause global warming - are off the charts. The concentration of carbon dioxide is now a bit more than 380 parts per million, compared to a range of about 200-300 parts per million during the past 800,000 years. The current concentration of methane is 1,800 parts per billion, compared to a range of about 400-700 parts per billion during that time. In every case during that extended period, warm periods coincide with high levels of greenhouse gases. "The fundamental conclusion that today's concentrations of these greenhouse gases have no past analogue in the ice-core record remains firm," said Brook. "The remarkably strong correlations of methane and carbon dioxide with temperature reconstructions also stand," he added. Of some interest, the latest studies are showing that the temperature increases have been even more pronounced during the most recent 450,000 years, compared to several hundred thousand years prior to that. "It appears there may even be very long term natural cycles that have operated on much longer periods of 400,000 years or more," Brook said. The tiny bubbles of ancient air trapped in polar ice cores have been used to provide records of trace gases in the atmosphere at distant points in the past, and better understand the natural fluctuations that have occurred, largely as a result of cyclical changes in Earth's orbit around the sun. "These natural cycles that occur on the order of tens or hundreds of thousands of years can help us understand both the forces that have controlled and influenced Earth's climate in the past, and the implications of current changes on future climate," said Brook. (ANI) © 2007 ANI TAGS: Science 
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