Sunday, September 22, 2013

Minimum Arctic Sea Ice Extents and Dates

Previous minimum Arctic sea ice extents**

Table 1.  Previous minimum Arctic sea ice extents
20074.171.61September 18
20084.591.77September 20
20095.131.98September 13
20104.631.79September 21
20114.331.67September 11
20123.411.32September 16
20135.101.97September 13
1979 to 2000 average6.702.59September 13
1981 to 2010 average6.222.40September 15
According to near-real-time data, this year’s minimum extent is slightly lower than 2009. However, the ranking between 2009 and 2013 is close, and may change once the final version of the data are processed. See our Frequently Asked Questions: Do your data undergo quality control? for more information about near-real-time data.
** Note that the dates and extents of the minimums have been re-calculated from what we posted in previous years; see our Frequently Asked Questions for more information.
Since ARCUS didn’t plot them, I’ve plotted all the participant forecasts below.
Figure 5: plot of September Arctic Sea Ice Extent Mean forecasts submitted to ARCUS in August 2013.

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Apparent recovery of Arctic sea ice this year is illusory, say experts
Top scientists (WHO?) dispute claims that Arctic sea ice is on the rebound.

Science Recorder | Delila James | Saturday, September 21, 2013

Climate change skeptics shouldn’t get their hopes up by the reported increase this year in sea ice on the surface of the Arctic Ocean. It isn’t a sign that global warming is abating or was a mere fantasy concocted by environment-obsessed hand-wringers. The extent of sea ice is still the sixth lowest on record and would have been a record low in 2006, according to data from the National Snow and Ice Data Center (NSIDC).

While it is technically correct that the extent of Arctic sea ice grew approximately 60 percent in August 2013 as compared to August 2012, “sea ice extent remains quite low compared to the long-term 1981 to 2010 average,” according to the NSIDC. The agency explains that the increase in sea ice this year compared to last year’s record-breaking decrease is due, at least in part, to unusually low sea level pressure over the central Arctic and Greenland. Because low sea level pressure inhibits the transport of warm air into the Arctic, temperatures this year were colder and sea ice melted less.

Climate experts also say this year’s increase in sea ice has to be viewed in light of last year’s record-breaking decline. Because the decrease in Arctic sea ice in 2012 was so extreme, they say, a less drastic reduction this year is to be expected.

Some sensible writers and bloggers have been quick to provide the public with hard data, complete with charts and diagrams, debunking suggestions from Rush Limbaugh and other die-hard pooh-poohers of climate change that this year’s increase in sea ice extent undermines the notion of global warming. Both Brad Plummer in his Washington Post blog and Dana Nuccitelli at the Guardian provide detailed and credible evidence showing that Arctic sea ice isn’t really “recovering.”

Annual variations are not as important as long-term trends when it comes to assessing the health of planet Earth. Despite this year’s dramatic recovery of Arctic sea ice this summer as compared to last year, the current extent of sea ice is still almost 400,000 square miles below the average minimum over the past 30 years. Indeed, since 1970 when satellites first began tracking sea ice extent, it has been declining at a rate of about 10.6 percent each decade.

A reduction in sea ice volume, or thickness, is even more important that sea ice extent when it comes to measuring the effects of climate change and may be a more accurate indicator when trying to predict when the Arctic Ocean will be ice-free, according to The Arctic Institute’s Center for Circumpolar Security Studies (CCSS). According to the CCSS, sea ice volume has declined rapidly since 1979 and continues to do so, saying that if this trend persists, the Arctic Ocean could be ice-free by 2015.

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goldminor said...

@ Capt of the Grey Goose...thanks for hosting this unique and interesting perspective on the NWP and the Arctic. I have enjoyed following the story.

The years to come will show whether this was a turning point or not for sea ice conditions. Just as it is not right to claim recovery, I do not see where the claim can be made that it is definitely not going to recover. That is the crux of the argument, in my mind. Yes, the infamous Limbaugh is an outrageous personality who knows little to nothing of science or Earth dynamics. Yet the mainstream press has consistently run articles over-hyping the warmist position and the cry of doom, doom, doom.
Keep in mind that no one has yet come up with an explanation of why the Arctic had a record cool summer this year, nor do they have an explanation for the record sea ice extent down in Antarctica this year. So there is much that is not known regarding what nature is up to. In science you are supposed to be open to what is being observed. If you believe that you already know the answer to the question, then you can easily walk right by the 'truth' and never see it. This is important.

Consider one more thought. What would a recovery actually look like? It is not going to happen in one year, would it? The collapse did not happen in one year either. I have read where the cyclone that destroyed so much sea ice last year was an anomaly in itself. So if it had not struck at a critical point in time last year, wouldn't we now be looking at a much more robust icepack, which would certainly have the appearance of a recovery? Of course that is how real life is.

Jim Hunt said...

It is NOT "technically correct that the extent of Arctic sea ice grew approximately 60 percent in August 2013 as compared to August 2012".

Where do they get this nonsense from?

Captain on GREY GOOSE said...

Might the "super storm" of 2012 been the great "mixer" that "seeded" with fresh water the ocean which in turn started freezing soon (fresh water freezes at a greater temperature than salt water) there was just enough 'pre-roll' momentum to get the Arctic show on the road to an increased 60%? more ice extent?

Mother Nature only takes a little nudge or push here and there to encourage more forcings... while I don't consider a super storm a man made forcing it sure caused an imbalance which resulted in a wide redistribution across the entire Arctic... melting Arctic basin FRESH WATERS + SUPER STORM MIXING = 60%? GREATER ARCTIC ICE EXTENT in one season? YABETCHA!

goldminor said...

I had a close prediction for the low of the extent for this year. This June WUWT asked for participation in the yearly guess the Arctic minimum. I stated that this year would be close to 2009, but with the below normal temps being shown, I decided to add several hundred units and so picked 5.3 million sq km. So I was close in my forecast, but the 2009 initial thought was right on the money, as the final number was 5.10.

I have a decent ability to pick out details and connect dots at times. I read some interesting thoughts on the dynamics of the changes going on since the big melt. One part of the change is said to come from an extra release of heat caused by the open water left behind from last year. It is stated that the way the process works is that the entire column of water down to 400 feet to the pycnocline, releases heat through the open waters and thus cools quite a bit. This is said to be the natural mechanism by which the Arctic maintains a balance. This also probably had something to do with the cool Arctic summer this year and so the increase in sea ice. This implies that the Arctic will never melt completely.

Jim Hunt said...

Whatever way you try to slice and dice the figures it's impossible to reach "60% greater extent" when even vaguely comparing "like with like" -

As for whether this summer is the beginning of a "change in trend", a new "stable state" or just some "weird weather" it's far too early to call. Unless you choose to wear a particularly shocking pink shade of spectacles the trend is still down

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