Environment & Energy
Related: About this forumArctic Sea Ice Likely At Seasonal Minimum; Likely 6th-Lowest Extent In Milennia - Guardian
As Suzanne Goldenberg reported in The Guardian yesterday, Arctic sea ice appears to have reached its annual minimum extent, at approximately 5.1 million square kilometers. This is the 6th-lowest extent since the satellite record began in 1979.
But in fact, scientists have also reconstructed Arctic sea ice extent data much further into the past. For example, Drs. Walsh & Chapman from the University of Illinois have estimated sea ice extent as far back as the year 1870 using a vast array of data (for example, records kept by the Danish Meteorological Institute and Norwegian Polar Institute, and reports made from ocean vessels). While climate contrarians will sometimes try to argue that Arctic sea ice extent may have reached similar lows to today's in the 1920s or 1930s1940s, the data compiled by Walsh & Chapman tell a very different story.
EDIT
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/sep/19/climate-change-arctic-ice-sixth-lowest-in-millennia
Average July through September Arctic sea ice extent 18702008 from the University of Illinois (Walsh & Chapman 2001 updated to 2008) and observational data from NSIDC for 20092013.
Going back even further in time, a study published in the journal Nature in 2011 used a combination of Arctic ice core, tree ring, and lake sediment data to reconstruct Arctic conditions going back 1,450 years. The result is shown below.
Reconstructed Arctic sea ice extent over the past 1,450 years, from Kinnard et al. (2011)
A study published in 2010 by 18 leading Arctic experts examined Arctic records throughout geologic history and concluded,
"The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities." Thus the scientific data and literature indicate that this year's minimum Arctic sea ice extent is not just the 6th-lowest in the past 34 years, but most likely the 6th-lowest in at least the past few thousand years.
EDIT
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/sep/19/climate-change-arctic-ice-sixth-lowest-in-millennia
Jackpine Radical
(45,274 posts)Quit collecting the data.
CRH
(1,553 posts)regaining the losses since 2008, the volume is bottoming near the fourth lowest exceeding 2010, 2011, 2012.
http://neven1.typepad.com/blog/piomas/
Better than it could have been, but not a significant recovery, either.
phantom power
(25,966 posts)truebrit71
(20,805 posts)See, I just KNEW that Al Gore was full of shit....
But seriously folks...looking at the graph and taking just the curve of the lowest points we could see a really big downward drop in the next year or two..