Arctic sea extent in the Arctic during November is shown on the left, and in the Antarctic on the right. The blue lines show the average extents for the month. (Source: ClimateReanalyzer.org, University of Maine) Dramatic losses in both the Arctic and Antarctic drove sea ice extent to record lows in both regions during November, the National Snow and Ice Data Center has announced. In the Arctic, sea ice extent averaged 753,000 square miles below the long-term average for November. This set a new record low for the month, which extends back 38 years to 1979. That makes it seven record lows in the Arctic this year. And we've still got one more month left. Meanwhile, the deficit in Antarctica stood at 699,000 square miles. This completely blew away the previous record low for the month, set in 1986. Put the numbers from the two hemispheres together and you get a total sea ice deficit for the month equivalent in extent to nearly half of the land area of the lower 48 states of the United States.