Keyword: millennia

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  • Arctic reverses trend, is warmest in two millennia

    09/04/2009 2:44:18 PM PDT · by NormsRevenge · 27 replies · 1,186+ views
    AP on Yahoo ^ | 9/4/09 | Randolph E. Schmid - ap
    WASHINGTON – The Arctic is warmer than it's been in 2,000 years, even though it should be cooling because of changes in the Earth's orbit that cause the region to get less direct sunlight. Indeed, the Arctic had been cooling for nearly two millennia before reversing course in the last century and starting to warm as human activities added greenhouse gases to the atmosphere. "If it hadn't been for the increase in human-produced greenhouse gases, summer temperatures in the Arctic should have cooled gradually over the last century," said Bette Otto-Bliesner, a National Center for Atmospheric Research scientist and co-author...
  • Once Lush Sahara Dried Up Over Millennia, Study Says

    05/08/2008 7:08:12 PM PDT · by blam · 26 replies · 178+ views
    National Geographic News ^ | 5-8-2008 | James Owen
    Once Lush Sahara Dried Up Over Millennia, Study SaysJames Owen for National Geographic NewsMay 8, 2008 The grassy prehistoric Sahara turned into Earth's largest hot desert more slowly than previously thought, a new report says—and some say global warming may turn the desert green once again. The new research is based on deposits from a unique desert lake in remote northern Chad. Lake Yoa, sustained by prehistoric groundwater, has survived for millennia despite constant drought and searing heat. The body of water contains an unbroken climate record going back at least 6,000 years, said study lead author Stefan Kröpelin of...