evidence: The consensus is clear – as Arctic sea ice melts, polar bears are finding it harder to hunt, mate and breed. While polar bears have shown some ability to adapt to changes in their surroundings – for example, by foraging for food on land, or swimming more to hunt for prey – scientists project that as sea ice diminishes, polar bears will find it harder to survive and populations will decline. [...] Polar bears depend on sea ice for most important aspects of their lives – including hunting, mating and resting. While polar bears are strong swimmers, capable of swimming for hours on end, they find swimming much more energy intensive than walking. As such, sea ice is crucial for polar bears to survive. [...] While polar bears have shown some ability to adapt to changes in their surroundings – for example, by foraging for food on land or swimming more to hunt for prey – scientists project that polar bears will become more food-stressed as sea ice diminishes and that populations will decline.