Seas will rise faster than thought by 2100 – study

• Rise would threaten coasts, islands, wildlife
• Oceans seen up 0.9 to 1.6 metres by 2100 - AMAP
• Arctic warmer than ever, change accelerates

OSLO (Reuters) - Global sea levels will rise faster than expected this century, partly because of quickening climate change in the Arctic and a thaw of Greenland’s ice, an international report said.

The rise would add to threats to coasts from Bangladesh to Florida, low-lying Pacific islands and cities from London to Shanghai. It would also raise the cost of building tsunami barriers in Japan.

Record temperatures in the Arctic will add to factors raising world sea levels by up to 1.6 metres (5.2 feet) by 2100, according to a report by the Oslo-based Arctic Monitoring and Assessment Programme (AMAP), which is backed by the eight-nation Arctic Council.

“The past six years (until 2010) have been the warmest period ever recorded in the Arctic,” said the report.

“In the future, global sea level is projected to rise by 0.9 metres to 1.6 metres by 2100 and the loss of ice from Arctic glaciers, ice caps and the Greenland ice sheet will make a substantial contribution,” it added.

The rises were projected from 1990 levels. The United Nations’ Intergovernmental Panel on Climate Change (IPCC) said in its last major study in 2007 that world sea levels were likely to rise by between 18 and 59 cms by 2100. Those numbers did not include a possible acceleration of a thaw in polar regions.

Foreign ministers from Arctic Council nations -- the United States, Russia, Canada, Sweden, Finland, Denmark, Norway and Iceland -- are due to meet in Greenland on May 12.

“The increase in annual average temperature since 1980 has been twice as high over the Arctic as it has been over the rest of the world,” the report said. Temperatures were higher than at any time in the past 2,000 years, it added.

The IPCC also said it was at least 90 percent probable that human emissions of greenhouse gases, led by burning fossil fuels, were to blame for most warming in recent decades.

“It is worrying that the most recent science points to much higher sea level rise than we have been expecting until now,” European Climate Commissioner Connie Hedegaard told Reuters.

“The study is yet another reminder of how pressing it has become to tackle climate change, although this urgency is not always evident neither in the public debate nor from the pace in the international negotiations,” she said.

U.N. talks on a global pact to combat climate change are making sluggish progress. The United Nations says national promises to limit greenhouse gas emissions are insufficient to avoid dangerous change such as floods or heatwaves.

The AMAP study, drawing on work by hundreds of experts, said there were signs that Arctic warming was accelerating. It said the Arctic Ocean could be nearly ice free in summers within 30 to 40 years, earlier than projected by the IPCC. The thaw would disrupt the hunting livelihoods of indigenous peoples and threaten creatures such as polar bears. But it could also make the Arctic more accessible for oil exploration, mining or shipping.

The Arctic is warming as shrinking ice and snow exposes ever bigger areas of darker-coloured water or soil. Those regions soak up ever more heat from the sun, accellerating the melting of the remaining ice and snow.

“There is evidence that two components of the Arctic cryosphere -- snow and sea ice -- are interacting with the climate system to accelerate warming,” it said.