An international team of geologists led by Peter Davies of the University of Sydney feel that Australia's Great Barrier Reef is a lot younger than what it is believed to be. It may have been part of the driving force behind a mysteriously hot period on Earth around 4,00,000 years ago. For years most researchers assumed that because the reef lies close to the reefs of Papua New Guinea, which have been dated to be three to four million years old, it must be similar in age. Last year, Davies's team drilled two holes into the reef and dated the corals at the bottom of the reef as well as the material below. The results indicate that the reef began growing 3,00,000 to 4,00,000 years ago. At that time, the sea level was up to 20 m higher than today