New warnings about the effects of global warming paint a bleak picture for the world’s polar bear population. The U. S. Geological Survey says its series of studies show that melting sea ice in the Arctic could spell disaster for the species within 50 years, when 2/3 of them could die-off.

The studies followed the suggestion late last year that polar bears should be listed as a threatened species under the Endangered Species Act. The U. S. Fish and Wildlife Service is set to release a review of the situation in January, when it’s expected to make a recommendation whether or not to list polar bears as threatened.

The USGS meanwhile, has improved knowledge on the status of three polar bear sub-populations, projected numbers of polar bears into the future in relation to sea ice and integrated the information into a range-wide assessment of polar bear status under scenarios of future climate change.

The newly-released USGS information, presented to the Service in the form of nine administrative reports to be open for public comment, will now be considered within the context of the Fish and Wildlife Service’s one-year review. The Service will analyze it and other information provided by scientists, government agencies and the public in order to arrive at an informed and scientifically justifiable decision. That decision is due in January.

The team investigating the future of polar bears and their habitat included scientists from the USGS, other American and Canadian government agencies, academia and the private sector.

In addition to forecasts, declines in habitat have been recorded throughout the Polar Basin over the past 20 years of observations. To project future sea ice conditions, USGS scientists used 10 general circulation models that best approximated observed trends in sea-ice loss and could be expected to do the best job of simulating future conditions. Scientists characterize their conclusions as conservative because even the best available models are believed to underestimate the actual decline in Arctic sea ice.