LONDON, Dec. 8 (Xinhua) -- Polar bear numbers could drop a third in the next 35 years, according to a study released on Wednesday in the journal Biology Letters of the Royal Society.
The study found a 70-percent chance of losing polar bear numbers due to shrinking sea ice levels.
"Polar bears depend on sea ice for most aspects of their life history," the study noted.
There are about 26,000 polar bears on Earth, classified into 19 subpopulations. They are listed as "vulnerable" species on the Red List of Threatened Species made by the International Union for Conservation of Nature (IUCN).
The newly-released study said that loss of Arctic sea ice because of climate change has become the biggest threat to polar bears, a conclusion similar to that of the IUCN assessment.