Copenhagen - Fast rising sea levels that pose a future threat to populations living in coastal regions was one of the topics debated Tuesday when hundreds of international researchers gathered to a three-day meeting in Denmark.

The opening of the meeting was attended by among others Rajendra K Pachauri, chairman of the United Nations climate body the Intergovernmental Panel on Climate Change (IPCC), that shared the 2007 Nobel Peace Prize for work on climate change.

Research presented Tuesday included forecasts based on satellite imagery on rising sea levels. By the year 2100 sea levels could rise up to one metre - but could also be less than 0.50 metres.

Some 600 million people are estimated to live in low-lying regions at risk during flooding.

The meeting was part of the run-up to the UN Climate Change Conference that Denmark is to host in December. The conference aims to seek an agreement on a new international treaty to succeed the Kyoto Protocol on curbing greenhouse gas emissions.

"The oceans are continuing to warm and expand, the melting of mountain glacier has increased and the ice sheets of Greenland and Antarctica are also contributing to sea level rise," Dr John Church, lead speaker in the session on sea levels, said.

Church is with the Centre for Australian Weather and Climate Research based on Tasmania, and called for "urgent and significant mitigation actions."

The IPCC in 2007 forecast sea levels rising some 18 to 59 centimetres, but at the time said "there was a lot of uncertainty about ice sheets," Professor Eric Rignot at the University of California Irvine said. (dpa)