Ocean changes and the impacts in the Polar Regions

Covering about 20 % of the global ocean, the polar ocean areas are among the most sensitive regions of the Earth climate system, where today climate change is reshaping processes that influence global circulation, sea level, and climate far beyond the poles. Here, we develop an ocean narrative that integrates physical, ecological, and societal indicators, to illustrate polar ocean change. Across the region defined by the Arctic Monitoring and Assessment Programme (AMAP), which is a key scientific framework supporting environmental assessments of the Arctic Council, combined sea surface and sea-ice surface temperature has increased at an average rate of 1 °C per decade over 1982–2024, equivalent to approximately 4.2 °C of warming over the observational period. Strongest warming rates exceeding 1 °C per decade observed in the Large Marine Ecosystems (LMEs) Kara Sea, East Siberian and Laptev Sea, Barent Sea, Beauford Sea, Chukchi Sea, and Arctic Ocean. All Arctic polar LMEs with seasonal sea-ice cover have experienced sea-ice decline over the 1982–2024. LMEs, an ecologically defined framework that supports coordinated management of fisheries, biodiversity, habitat conservation, and other shared marine resources, show the strongest sea-ice cover losses in the Hudson Bay, Barents Sea, East Greenland Shelf, Chukchi Sea and Kara Sea. Also, areas of substantial sea-ice retreat consistently coincide with rapid coastal erosion in the Arctic, as sea-ice loss increases the exposure of Arctic coastlines to waves action, thereby further exacerbating coastal erosion and increasing risks to infrastructure and coastal communities. In the Southern Ocean, the spatial overlap between long-term sea-ice retreat and major penguin colonies illustrates a fundamental conservation challenge: the habitat supporting Southern Ocean biodiversity is itself changing. Effective biodiversity protection therefore requires both reducing local pressures through conservation and addressing the climate drivers of sea-ice loss through global mitigation. Together, these examples demonstrate that polar ocean change is not a collection of isolated environmental trends, but an interconnected transformation of physical systems, ecosystems, and societies, requiring integrated observations and coordinated climate, biodiversity, and ocean governance responses.