Arctic Sea Ice Extent Trends: 1979-2010; Update 1

Now that the 2010 Arctic sea ice melt season is over, we can see how 2010 fits into the long-term trends Arctic  Sea Ice Extent. This post shows an R Climate chart that I have made to look at the annual  NSIDC Arctic Sea Ice Extent maximum, minimum and seasonal melt trends for the 32 year period, 1979 to 2010. Data and RClimate scripts are provided.
Update 1 (10/6/10) Added trend lines to plots based on suggestion from reader.

Here’s my RClimate script trend chart of 1979-2010  NSIDC Arctic Sea Ice Extent data.  I have plotted NSIDC’s maximum and minimum sea ice extent for each year and my calculated value for seasonal melt (maximum – minimum). (Click image to enlarge)

During the 1979 – 2006 period the maximums and minimums SIE  declined while the annual SIE melts held relatively constant.  The 2007 – 2008 period showed an increasing trend which resumed its downward slope in 2009 and 2010.

After a major drop in minimum SIE  in 2007 there has been some recovery in 2008 and 2009;  the 2010 minimum has resumed the declining trend, dropping below 2009.

Except for one year (1996), the annual melt remained within a relatively narrow band of 8.75 +- 0.75 million km^2  in the 1979 – 2006 period. The 2007 seasonal melt changed the previous pattern,  melt increased to 10.4. It increased again in 2008 to  10.6. After a decrease in 2009 to  9.8, it increased to 10.2 in 2010.

Arctic Sea Ice Extent continued its long-term decline in the 2010 melt season. The annual maximum and minimum sea ice extent values have declined significantly over the past 32 years with some year to year variation.  After holding relatively steady in the 1979 – 2006 period, the seasonal melt has increased from an average of 8.5 to an average of 10 + in the 2007-2010 period.

The 2010 melt season shows that Arctic Sea Ice continues to long-term decline.

RClimate Script Details

Here are the data and RClimate Script links:

• Data Link
• RClimate Script link

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