by Staff Writers
Copenhagen, Denmark (SPX) Jul 26, 2012
The research, which was carried out in collaboration with researchers from the University of Tasmania in Australia, is based on measurements of ice cores from five boreholes through the ice sheet in Antarctica.
The global temperature changed naturally because of the changing solar radiation caused by variations in the Earth's orbit around the Sun, the Earth's tilt and the orientation of the Earth's axis. These are called the Milankowitch cycles and occur in periods of approximately 100,000, 42,000, and 22,000 years.