"The proportion of polar bear females around the Arctic islands of Svalbard who gave birth to cubs crashed to just 10% in 2014, according to a small scientific survey of the animals. It follows a series of warm years and poor sea ice.
The Barents Sea population of a few thousand polar bears is one of the biggest in the world. But global warming is rapidly reducing the extent of sea ice on which the bears hunt seals, their main food.
The annual survey undertaken by Jon Aars and his colleagues at the Norwegian Polar Institute was conducted in April, just after cubs and mothers leave their dens. They discovered that just three of the 29 adult females they tracked and examined had a cub born that year."