English: This graph shows the decline in September Arctic sea ice between 1979 and 2007 (see also effects of global warming). From the cited public-domain source: “Large-scale measurements of sea-ice have only been possible since the satellite era, but through looking at a number of different satellite estimates, it has been determined that September Arctic sea ice has decreased between 1973 and 2007 at a rate of about -10% +/- 0.3% per decade. Sea ice extent for September for 2007 was by far the lowest on record at 4.28 million square kilometers, eclipsing the previous record low sea ice extent by 23%. Sea ice in the Antarctic has shown very little trend over the same period, or even a slight increase since 1979. Though extending the Antarctic sea-ice record back in time is more difficult due to the lack of direct observations in this part of the world.”