Update January 3, below.
This year end report shows there is no reason to worry about Arctic ice melting. Against the odds, 2015 recovered from:
The blob melted Bering Sea a month early; it’s now well ahead of 2014.
An August storm pushed extent down for 28 days; it now nearly matches 2014.
MASIE measurements show that 2007 ice extent was lower than any year since. It is now confirmed that 2015 average annual extent exceeds 2007 by about 400,000 km2. That difference arises from comparing 2007 annual average of 10.414 M km2 with 2015 average through day 365 of 10.808. That makes 2015 virtually tied with 2009 for fourth place in the last ten years.
Arctic ice declined in the decade prior to 2007, but has not declined since.
Alarmists chafe at the words “growing” and “recovery”, and I use them poetically to counter “death spiral” terminology. What we have seen in the last decade is a plateau in Arctic ice extent, analogous to the plateau in surface temperatures. The rise since 2007 is slight and not statistically important, just as the loss of ice from 1979 to 1994 in the NOAA dataset was too slight to count as a decline.
Note: Something unusual happened in the MASIE record. After increasing ice extent steadily at a rate of 87k km2 per day after Dec. 10, MASIE stopped showing growth and declined a bit after Dec. 23. Ice extent was lost in Kara, Barents and Greenland Seas. That allowed NOAA extent to catch up and reduce its deficit. Previously, NOAA showed ~400k km2 less than MASIE, that difference being typical historically. For the year NOAA shows about 200k km2 less than MASIE, both at year end and for the annual average.
MASIE Comparison 2014 and 2015 Day 365
|Ice Extents||Ice Extent|
The small overall difference between 2014 and 2015 at this point matches the deficit in Barents Sea. The major basins have recovered: Central Arctic, BCE (Beaufort, Chukchi, East Siberian), Canadian Archipelago. Bering Sea is freezing well ahead of last year, as is Baffin Bay, offsetting deficits elsewhere except for Barents.
Technical Note: Changes in Ocean Water Structure drive changes in Arctic Ice Extent, and air temperature varies as a result, not the cause.
Update January 3, 2015
Neven is the first to attack this post in comments below, followed by a post at his own blog in which he says:
“misleading and embarrassing statements”
“mind set in concrete”
“taken apart by Tamino”
And on cue Tamino’s (Foster’s) attack dogs are coming here. Now I responded to all of Neven’s and Foster’s bogus objections in Sept. (here). Since they either did not read or did not understand, I will repeat the salient points again.
Warmists fail to see that having two different tracking methods for a climate phenomenon is a good thing. With temperatures they favor the land surface record and abhor the satellite temps. With Sea Ice they like the satellite reports and abhor the navigational observations. JAXA, DMI, NORSEX and NOAA (or NSIDC) are all using data from passive microwave sensors on satellites to estimate ice extents. Some differences arise from differing algorithms at each center.
Naval authorities have for centuries prepared ice charts for the safety of ships operating in the Arctic. There are Russian, Danish, Norwegian, and Canadian charts, in addition to MASIE, the US version. These estimates rely on multiple sources of data, including the NASA reports. Charts are made with no climate ax to grind, only to get accurate locations and extents of Arctic ice each day.
MASIE is not the only dataset to show this lull in Arctic ice decline. It is also obvious in Foster’s final graph. I showed how the same pattern appears in the NOAA (technically NOAA@NSIDC) dataset (here). Those who object that a decade is too short to claim a recovery were quick to claim a decline (even a “death spiral”) based on a decade-long loss of ice ending in 2007.
Some were upset that I used the MASIE data, despite NSIDC cautions against it. For the record, the NSIDC Background cites as support a study by Partington et al (2003). Reading that study, one finds that the authors preferred the MASIE data and said this:
“This analysis has been based on ice chart data rather than the more commonly analyzed passive microwave derived ice concentrations. Differences between the NIC ice chart sea ice record and the passive microwave sea ice record are highly significant despite the fact that the NIC charts are semi-dependent on the passive microwave data, and it is worth noting these differences. . .In summer, the difference between the two sources of data rises to a maximum of 23% peaking in early August, equivalent to ice coverage the size of Greenland.” (my bold) For clarity: the ice chart data show higher extents than passive microwave data.
In any case, NSIDC’s last word was this: “In June 2014, we decided to make the MASIE product available back to 2006. This was done in response to user requests, and because the IMS product output, upon which MASIE is based, appeared to be reasonably consistent.” And thus, the data appeared this September.