''The results show that the temperature rise and the CO2 increase were much closer than what was believed before,'' said the study's lead author, Joel Pedro, a researcher at the Antarctic Climate and Ecosystems Cooperative Research Centre in Hobart. ''It shows that the process of warming and CO2 rises in the past were actually very fast - though what's happening now is much faster.''
The study, published in the journal Climate of the Past, narrows the window of uncertainty around how long it took for slight natural changes in the Earth's temperature to be propelled by rising levels of greenhouse gases. Instead of an estimate of thousands of years, the results show a period of about 400 years in which the world switched from a frozen place to one which was decisively warming up.
A US ice core expert from the University of Washington, Eric Steig, said the paper represented a significant advance. ''I cannot emphasise enough how important this result is,'' Professor Steig said in a statement, after reviewing the findings.