Arctic ice minimum extent, September 2016. This image, showing the Arctic above North America (bottom) is based on satellite data. The Arctic sea ice (white) reaches a minimum in September at the end of the Arctic summer. This minimal ice area is called the perennial ice cover. The perennial ice has been steadily decreasing since satellites began observing it in 1979, at a rate of about 10 percent per decade. The 2016 minimum is the second lowest on the satellite record. This decrease is attributed to global warming and climate change. The sea ice data for this image, obtained on 10 September, is from the Advanced Microwave Scanning Radiometer 2 (AMSR2) on the Global Change Observation Mission 1st-Water 'SHIZUKU' (GCOM-W1) satellite.