Polar bears face lengthening ice-free seasons that extend their annual fasting period beyond physiological limits, creating nutritional stress, reproductive failure, and increased human conflict.
Extended fasting is a physiological stressor that polar bears have evolved to manage for limited periods but that becomes welfare-compromising when extended beyond normal limits by climate change. Nutritionally depleted females produce fewer and smaller cubs with reduced survival. The progressive nature of this welfare harm - worsening year by year as ice-free seasons lengthen - creates a trajectory toward population-level reproductive failure. Bears that enter communities in food-stressed states face hazing, capture stress, and potential lethal control. The welfare and conservation solutions are identical: reduce greenhouse gas emissions to stabilize sea ice.