The study, to be released next week, says the Arctic ice melt will cause sea levels to rise and could lead to the extinction of some species such as polar bears.
"The melt has begun," said Jennifer Morgan, director of the Climate Change Campaign for the environmental organisation WWF, which published excerpts of the upcoming Arctic Climate Impact Assessment (ACIA) report.
Commissioned by the Arctic Council and compiled by more than 250 scientists, the report concludes that climate change is happening in the Arctic and that it will get worse unless emissions of carbon dioxide are cut.
The report presents several potential scenarios which would occur if the Arctic ice were to disappear in summertime by the end of the 21st century.
It said sea levels could rise by one metre, noting that there are currently 17 million people living less than one metre above sea level in Bangladesh. It said places such as Florida and Louisiana in the United States and the Asian cities of Bangkok, Calcutta, Dhaka and Manila were also at risk.
However, on the positive side, rising sea levels could create a northern passage for shipping between the Pacific and Atlantic Oceans, and would open up new areas for fishing, mining and oil and gas exploration.
The melting of the Greenland ice sheet, which is expected to take hundreds of years, could ultimately lead to a seven-metre rise in sea levels, the report said.
"Polar bears could become extinct by the end of this century. They are unlikely to survive if there is an almost complete loss of summer sea ice cover," the WWF said.
"Polar bears could become extinct by the end of this century. They are unlikely to survive if there is an almost complete loss of summer sea ice cover"
World Wildlife Fund
Polar bears feed mainly on seals living under the ice, which the large mammals break to catch their prey.
The ACIA report is to be published in its entirety on 8 November.
The WWF welcomed the report, but stressed the hypocrisy of the eight members of the Arctic Council - the United States, Canada, Russia, Japan, Finland, Sweden, Iceland and Norway -which sponsored it, noting that they emit more than 30% of global carbon dioxide emissions.