evidence: Due to climate change, polar bears have been listed as vulnerable to extinction by the International Union for Conservation of Nature (IUCN) (BBC). According to the World Wildlife Fund (WWF), there are an estimated 22,000 to 31,000 polar bears left in the wild (NBC). A new study, published in Nature Climate Change, puts a timeline of the year 2100 for possible polar bear extinction (BBC). Nearly all of the 19 subpopulations of polar bears would face being wiped out due to the increase in temperatures and loss of sea ice (NYT). If the Earth’s temperature rises 3.3 degrees Celsius (37.94 degrees Fahrenheit) above pre-industrial levels, as in the study’s scenario, polar bears will likely become extinct (One Green Planet). Currently, in 2020, the Earth’s temperature is 1 degree Celsius (33.8 degrees Fahrenheit) above pre-industrial levels (Climate Analytics). Polar bears main habitat is sea ice, where they hunt seals by waiting for them to surface at holes in the ice (NYT). Lack of sea ice forces polar bears into prolonged fasting, and reduced nursing of cubs, which will lead to rapid declines in reproduction and survival (NYT). Climate Change Will Wipe Out Polar Bears by 2100, New Study Finds https://climateanalytics.org/briefings/global-warming-reaches-1c-above-preindustrial-warmest-in-more-than-11000-years/