Sentences with phrase «existence of polar bears»

Summers in parts of the Arctic could be ice free in the next 100 years, which could prove daunting for the existence of polar bears.

The important point is that if we continue on our current greenhouse - warming path, it will be far warmer in 50 years than at anytime in the existence of polar bears.

Not exact matches

U.S. District Court Judge Claudia Wilken in Oakland, Calif., on April 29 ordered the Bush administration to stop dragging its feet on the fate of polar bears and decide by May 15 whether declining sea ice in the Arctic threatens their existence.

He re-told the familiar tale of the evolution of land animals from ancient fish, and then considered the return of various groups of reptiles, birds and mammals to an aquatic existence: ichthyosaurs and plesiosaurs, crocodiles, sea - snakes, penguins, whales, dolphins and porpoises, manatees and dugongs, and seals — as well as polar bears, otters and water voles, who hunt in water.

The focus here is on polar bears and how rapid climate change is altering and threatening their existence some 150,000 years after they evolved from brown bears and adapted to the below - zero temperatures of the Earth's northernmost regions.

That is, most of the period of polar bear existence has been during continental glaciations rather than inter-glacials.

While it is true that some ringed seals give birth in stable shorefast ice close to shore, many others give birth well offshore in thick pack ice — where polar bears also live and hunt in the spring but where few Arctic scientists ever venture — and the existence of pack ice breeding ringed seals is one of the reasons that polar bears are such a resilient species.

Further evidence of the recent evolution of the polar bear is found in the existence of hybrids.