evidence: The IUCN assessment does not look at the extinction risk for polar bears over a time span of longer than about 35 years – or three generations of polar bears. But without action to tackle climate change, it is likely that many polar bear subpopulations will cross "tipping points" over the next century if sea-ice loss continues as forecasted, says Cator. [...] However, the trend in populations for which there is data points to a species in decline, compared to two or three decades ago. And with the impacts of warming on polar bear habitat and feeding well-understood, scientists are clear that polar bears face a profound threat to their survival in the coming decades. [...] A press release (pdf) released following the review said that, of 10 key threats identified, "human-caused climate change and the effects of such changes on polar bear habitat and prey is considered the primary threat". It emphasised "the need for the global community to reduce greenhouse gas emissions in order to conserve polar bears and their habitat".