Copenhagen - By the end of the century, sea levels may rise twice as much as was predicted two years ago in the fourth assessment report by the U.N. Intergovernmental Panel on Climate Change (IPCC).

This means that the lives of some 600 million people living on low-lying islands, as well as those living in Southeast Asia's populous delta areas, will be put at serious risk if climate change is not quickly and radically mitigated.

These conclusions, presented yesterday by a group of scientists hailing from several countries, dominated day one of the International Scientific Congress on Climate Change, organized by the University of Copenhagen and other members of the International Alliance of Research Universities. An estimated 2,000 people are attending the event.

"The seas are undergoing much greater changes than those described in the IPCC report," explained Eric Rignot, one of the study's authors, in a discussion with reporters. Rignot is professor of earth system science at the University of California, Irvine. "This is the crux of the problem. Two or three years ago, those making this type of statement were seen as extremists," he added.

According to the new research, the upper range in the rise of sea levels could be approximately 1 meter (3.28 feet), "possibly more," by 2100. At the lower end of the spectrum, it appears increasingly unlikely, say the study's authors, that sea level rise will be much less than a half-meter by 2100. They conclude that low-lying coastal areas, which house one in 10 humans, will be hit hard -- even in a best-case scenario -- if emissions of greenhouse gases are not reduced quickly and substantially.

'There's no good news here'

The most recent satellite and ground-based observations show that sea levels have been continuing to rise since 1993, at a rate well above average for the 20th century, explained another of the researchers, John Church of the Centre for Australian Weather and Climate Research. "The oceans are continuing to warm and expand; the melting of mountain glaciers has increased, and the ice sheets of Greenland and Antarctica are also contributing to rising sea levels."

Several years ago, says Rignot, the science community believed that the Antarctic did not affect sea levels substantially; today, "we have results demonstrating that what is happening down there is as significant as is Greenland's ongoing ice loss."

The previous IPCC assessment report, published in 2007, projected a sea level rise of "only" 18 to 59 centimeters by 2100. Copenhagen's speakers stated today that the 2007 numerical models did not fully represent either outlet glaciers or their interactions with the ocean.

"Even the IPCC said that they didn't take some factors into consideration because they lacked the data," Katherine Richardson, vice dean of the University of Copenhagen's faculty of science, noted in an interview.

"Now we have the data, and it seems very clear that sea level rise by 2100 will be greater than the IPCC's prediction, and also that the rate of increase after 2100 will be faster than it will be before 2100. We are at the very least in the worst-case scenario of the IPCC. There's no good news there."

Richardson added that climate researchers now have enough data to understand what is happening to sea temperatures and are able to say that these are rising 50 percent more rapidly than they had thought at the time of the IPCC report. "The climate system is changing," she said. "That's crucial, because it means that ice will melt more quickly, and that means a lot of things as to how much carbon the ocean can take up."

Previous computer models missed ice slipping into the ocean

According to Rignot, the scientific community is now more fully aware that ice sliding into the ocean -- as opposed to ice melting -- plays a preponderant role in ice-cap evolution. "Ice is slipping into the ocean at a rapid rate, a phenomenon that was not correctly incorporated into previous models," said Ringot.

"In Greenland, we estimate that two-thirds of the cause of the glaciers' disappearance is accelerated ice slide, while the remaining third of the cause is ice melting. In the Antarctic, the cause is 100 percent ice slide, and the speed-up there is exponential."

Nongovernmental organizations have seized on the publication of this new research to urge the international community to move faster in cutting emissions of greenhouses gases. "These startling new predictions on sea level rise spell disaster for millions of the world's poorest people," said Oxfam International yesterday. "This must be a wake-up call for rich countries."

Scientists, academics and politicians speaking at the conference's opening session also tried to ring the alarm bell in the debate on climate change. "Unless we undertake urgent and significant mitigation action, the climate could cross a threshold during the 21st century, committing the world to a sea level rise of meters," said Church.

The speakers often decried the poor communication between the scientific community on the one hand and politicians and the media on the other.

The U.S. 'needs to listen to science'

"For some reason, scientists have not been able to communicate to politicians through the media that there is a 90 percent chance that climate change is due to human activity," said Richardson.

"We need a better sense of the urgency of the problem in our society," added John Ashton, climate adviser to the British government. Noting that the world is facing the worst economic crisis in several generations, Ashton predicted that politicians would be focusing on "one big thing" until the December U.N. conference, at which a new global climate agreement will be negotiated, takes place in Copenhagen. That one thing will be "jobs, jobs, jobs."

Ashton went on to argue that the international community thus needs to frame the climate change equation in economic terms, making it part of the solution by facilitating the creation of green jobs. And once again, a European politician has urged the United States to adopt tighter deadlines in the fight against global warming.

Danish Minister for Climate and Energy Connie Hedegaard commented that although the Obama administration's greenhouse gas reduction plan is "a start," the United States needs to "listen to science" and define medium-term targets. "This is key to making other countries, like China, move from their own position," she added.

The scientists attending this week's conference in Copenhagen hope that their work will influence the agenda of the U.N. conference that will convene later this year in the very same congress center where they are now meeting. "We all want something to happen," said Ian Chubb, vice-chancellor of Australian National University, a member of the International Alliance of Research Universities.

The congress's outcome will be summed up in recommendations that will go to political negotiators as they prepare for the December meetings.