Changes in sea ice cover until now
Long-term variation of sea ice extent is a good indicator of climate change in the Arctic. Satellite observations have shown a steady downward trend in sea ice for the last two decades. Since the beginning of satellite observations in 1979 the minimum seasonal sea ice area observed in September every year has been decreasing by 9% per decade, and in September 2007 ice cover had a minimum value ever recorded, 4.3 million km2 (1).