Fill in the Blanks Unit 1: Arctic Sea IceOnline version Arctic Sea Ice Review from Unit 1 from Climate Change by Mr. Mundo 1 15% minimum sensors Arctic sea ice reaches its extent each September , defined as the area where satellite detect at least ice coverage per pixel . 2 shrinking average decade Since 1979 , September Arctic sea ice has been at an alarming rate of 12 . 2% per compared to the 1981 ? 2010 extent . 3 2012 lowest satellite The year holds the record for the sea ice extent observed in the record .