The summer has just ended in the Arctic and when it speaks only of melting ice, I think a little balance is needed with this new season in terms of past state of the ice. The following summary was compiled from information from various institutes for the study of snow and ice, including the National Center for Data on the ice and snow ( National Snow and Ice Data Center ) based in Colorabo the United States.
According to the synthesis of these data, the average area of ​​sea ice in September (which corresponds to the period of the summer when the Arctic ice is less extensive each season) was 5.36 million square kilometers. This corresponds to 1.06 million square kilometers more than the worst year known what 2007 or 690 000 km ² more than the second lowest year (2008). However, the extent of sea ice in 2009 is one of 68 million square kilometers below average recorded in September of 1979 (first year of satellite records) to 2000 (see chart below).

As for the thickness of the ice, scientists use satellites to estimate the age (which is an indicator of the thickness). This year, the youngest ice so the thinner and more vulnerable to melting, represented 49% of the total coverage of the ice. Ice for two years, just over 32% against 21% in 2007 and 9% in 2008. In 2009, only 19% of the ice consisted of ice more than two years which is the lowest since satellite records (see map below).

The trend is to further decrease the extent of sea ice in summer in the Arctic in rates much lower than 2007 and 2008, but still within the overall average. More alarming was the new elapsed confirms that there are fewer "old ice". This is replaced by a new thin ice, which is more easily disturbed by wind and water temperature, which is now higher.