evidence: On September 10th, Antarctica's sea ice reached its largest extent of the year, but it was far smaller than average sea ice in decades past. In fact, it was nearly 350,000 square miles smaller than the previous record smallest amount, measured in 1986, according to a recent analysis by the National Snow and Ice Data Center, a research center at the University of Colorado, Boulder that is also affiliated with the federal government. Disappearing sea ice is a problem for lots of reasons. While it doesn't directly add any extra water to the ocean, missing sea ice does contribute to global sea level rise in other ways. The sea ice around Antarctica shields glaciers on land, and massive ice shelves that extend out into the water, from storms and above-freezing ocean water. Without that protection, that ice can melt more quickly, and that leads to more sea level rise. [...] "There is growing evidence that the Antarctic sea ice system has entered a new regime, featuring a much stronger influence of warm ocean waters limiting ice growth," scientists at the National Snow and Ice Data Center write in their analysis of this year's record-shattering low sea ice extent.