Two more scientific studies show a large part of the Antarctic ice cap melting at a much faster rate than previously predicted.
The studies, published Thursday in the London-based science journal Nature, said global sea levels could rise up to seven meters if the ice sheet in western Antarctica collapses centuries from now, as some researchers predict.
Scientists from New Zealand, Italy, the United States and Germany conducted the studies, which involved extensive drilling into the sea floor under the Ross ice shelf - a glacier several hundred meters thick and the size of France.
Research links much of the current meltdown to warming under-sea currents.
It remains unclear whether warming sea temperatures are being driven by climate change as scientists working for the United Nations Climate Panel on emissions of hydrocarbons (greenhouse gases) theorize.
Last month, scientists contributing to the U.N. Polar Year survey said ice caps on both poles are melting at a much faster pace than expected. A Polar Year statement said researchers found Arctic ice levels at their lowest point since satellites began measuring the northern ice mass three decades ago.
The report also said Antarctic researchers have found large pools of carbon, stored as methane gas, in the melting polar permafrost. Scientists have identified the large-scale release of methane into the atmosphere as one of the chief causes of global warming.
Some information for this report was provided by AP and Reuters.