evidence: Sea Ice — At 1.5 degrees Celsius warming, the IPCC special report scientists expect the Arctic Ocean to be sea ice-free one summer per century, but at 2 degrees Celsius warming, the likelihood increases to at least one ice-free summer every decade. Loss of sea ice at 1.5 degrees Celsius warming will impact the habitats of many organisms, from phytoplankton, to marine mammals like polar bears and whales, especially in the Arctic Ocean and the Western Antarctic Peninsula. [...] Impacts will vary by region due to many factors such as the ability of populations to adjust to changes in their environment, vulnerability of populations, their human-made surroundings and access to air conditioning.