In yet another sign of climate change’s decimating effects on Arctic sea ice, the National Oceanic and Atmospheric Administration (NOAA) just kicked off a program to update some of its nautical charts.

As Climate Central reports, routes through the Arctic Ocean have great economic value. They can serve as a shortcut between Europe and Asia, which can save shipping companies many thousands of miles of travel and thus considerable costs. But these passages have generally been blocked by ice, making extensive mapping of the sea floor to guide ships unnecessary.

Now that situation is changing. In 2012, the “minimum extent” for Arctic sea ice — the low point in the cyclical shifts the ice coverage goes through annually — reached a measure lower than any that’s been recorded since scientists began collecting satellite data in the late 1970s. At 3.41 million square kilometers, 2012′s minimum beat out the previous record, set in 2007, of 4.17 million square kilometers. For reference, that drop of roughly 800,000 square kilometers — an 18 percent collapse — constitutes an area larger than the state of Texas.

And with all that melting, the arctic routes are opening up, requiring NOAA to lay down 14 new charts in order to keep commercial traffic along the new paths as safe as possible:

The revisions affect Alaska’s coast, which has America’s only Arctic seafront. As a result of global warming, ice that has historically blocked Arctic waters, even in summer, has been plummeting in recent years, with 2012 ice melting back to the smallest extent since satellite records began. And as sea ice recedes, said NOAA Coast Survey director Rear Admiral Gerd Glang in a press release, “vessel traffic is on the rise.” [...]

Already by 2010, both the Northwest Passage across the Arctic coast of Canada and the Northern Sea Route, across Russia, had been ice-free simultaneously for an unprecedented third year in a row, encouraging a flurry of interest by commercial ship companies. Last summer a Chinese ship navigated the even more reliably frozen route right across the North Pole. [...]

“We don’t have decades to get it done,” said Capt. Doug Baird, chief of the Coast Survey’s marine chart division, in the press release describing the agency’s new Arctic Nautical Charting Plan. “Ice diminishment is here now.”

In fact, the collapse in the coverage area of Arctic sea is a radical shift unprecedented in at least 2000 years, as far as scientists are able to determine. It’s been matched by an equally dramatic drop in the volume of ice — a plunge to one fifth its level in 1980 — that was recently confirmed by the work of Britain’s Natural Environment Research Council (NERC) using the European Space Agency’s CryoSat-2 satellite. At this point, most experts think a completely ice-free Arctic could be a reality as soon as 2030.

Due to feedback loops, global warming actually affects the Arctic faster than other areas. Sea water absorbs much more of the sun’s heat than the relatively reflective ice cover — so as the ice recedes and exposes more of the ocean to sunlight, the ocean temperature rises. That in turn warms the local air, which makes the formation of new, thicker, lasting ice even more unlikely, and the process circles around again.

All this can in turn effect the wider planet: Warmer and and moister air in the Arctic atmosphere can alter the climate patterns that keep frigid air circling northward, along it to plunge south — a possible factor in the extreme winters the Northern Hemisphere has been seeing recently. It can also speed up the melting of glaciers and ice caps in Greenland or the Canadian Archipelago, and even speed up the melting of northern permafrost. That latter result threatens to damage homes, roads and other infrastructure that rests on soil which typically remains frozen. And melting permafrost also promises to release many gigatons of methan, an even more potent — though shorter-lived –greenhouse gas than carbon dioxide.

The Arctic sea ice minimum volume dropped sharply this year. Data from PIOMAS, Graph by L. Hamilton

By Nevin Acropolis via the Arctic Sea Ice Blog

We already knew a few weeks ago that the PIOMAS sea ice volume record had been broken, but with the latest data release by the Polar Science Center at the University of Washington we now know the minimum sea ice volume for 2012, as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS).

Here’s the graph from the PSC:

Yearly minimum sea ice volume for the 2005-2012 period (in km3):

• 2005: 9159
• 2006: 8993
• 2007: 6458
• 2008: 7072
• 2009: 6893
• 2010: 4428
• 2011: 4017
• 2012: 3263

So this year’s melting season has gone 1165 and 754 km3 below the 2010 and 2011 minimums. That’s, how shall I put it? A lot! More than at the time of the last update. Almost double the difference between the 2010 and 2011 minimums. Half the 2007 minimum.
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Photo credit: National Snow and Ice Data Center

by Ramez Naam, via Scientific American

On September 19^th, NSIDC, the National Snow and Ice Data Center, announced that Arctic sea ice has shrunk as far as it will shrink this summer, and that the ice is beginning to reform, expanding the floating ice cap that covers the North Pole and the seas around it.   The Arctic Sea Ice extent this September was far smaller than the previous record set in 2007.  At 3.4 million square kilometers of ice coverage, this year’s Arctic minimum was 800,000 square kilometers smaller than the 2007 record.  That difference between the previous record and this year’s is larger than the entire state of Texas.  An ice-free summer in the Arctic, once projected to be more than a century away, now looks possible decades from now. Some say that it looks likely in just the next few years.

What’s happening in the Arctic?  Why is it happening?  And does it matter for the bulk of us who live thousands of miles away from it?

Faster and Faster

Conditions in the Arctic change dramatically through the seasons. In the depths of winter, the Earth’s tilt puts the Arctic in 24 hour-a-day darkness. Temperatures, cold year round, plunge even lower. The sea surface freezes over. At the height of summer, the opposite tilt puts the Arctic in 24 hour-a-day sunlight. While it’s a cold cold place even at these times, the constant sunshine, warmer air, and influx of warm waters from further south serve to melt the ice.  The ice cap usually starts shrinking in March, and then reaches its smallest area in mid-September, before cooling temperatures and shorter days start the water freezing and the ice cap growing once again.

When scientists and reporters talk about an ice-free Arctic, they’re usually speaking of the Arctic in summer, and especially in September, when ice coverage reaches its minimum.

The amount of ice left at that minimum has indeed been plunging. In 1980, the ice shrank down to just under 8 million square kilometers before rebounding in the fall.  This year’s minimum extent of 3.4 million kilometers is less than half of what we saw in 1980.  Strikingly, two thirds of the loss of ice has happened in the 12 years since 2000.  The ice is receding, and the process, if anything, appears to be accelerating.

As recently as a few years ago, most models of the Arctic ice anticipated that summers would remain icy until the end of the 21^st century, and well into the 22^nd century.  But the trend line above makes that look unlikely.   The amount of ice remaining, this year, is about the same as the ice lost between the mid-1990s and today.  If ice loss continued at that pace, we’d see an ice free summer sometime around 2030, give or take several years.

Is that plausible?  Opinions differ substantially, even among climate scientists.

At one end of the spectrum are those who see the ice lasting in summer for another 20 or 30 years, or perhaps even a bit longer.

For example, Lars-Otto Reierson, who leads the Arctic Monitoring and Assessment Programme told Reuters that most models predict the summer ice disappearing by 2030 or 2040.

Similarly, a paper published this year in Geophysical Research Letters by multiple scientists, including several from the National Snow and Ice Data Center, found that an ice-free summer in the Arctic in the “next few decades” was a “distinct possibility.”

A recent assessment from Muyin Wang at the University of Washington and James Overland at the National Oceanographic and Atmospheric Administration, using the most up to date Arctic ice models and data, projected a nearly ice free Arctic around 2030.

And Ceclia Bitz, a professor of Atmospheric Sciences at the University of Washington at part of the Polar Science Center sees a 50/50 chance that the Arctic will be ice free in summer in the next few decades.

On the other end of the spectrum are those who think the melt could happen much sooner.  Peter Wadhams, who leads the Polar Ocean Physics Group at the University of Cambridge, has predicted since 2008 that the Arctic ice could be gone in summer by 2015.  He now believes there’s a chance that it could happen even sooner.

Similarly, Mark Drinkwater, the European Space Agency’s senior advisor on polar regions and a mission scientist for the CryoStat satellite that measures arctic ice, believes that the Arctic could be ice free in September by the end of this decade.

When will the ice melt? While the range of possibilities is wide today, it’s shrunk dramatically from just a few years ago, when most climate scientists expected the ice to survive through the 21^st century.  Now the question is whether it will be gone in decades – or in mere years.

Why is the Ice Melting?

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Figure 1. Arctic sea ice reached its minimum on September 16, 2012, and was at its lowest extent since satellite records began in 1979. Image credit: National Snow and Ice Data Center (NSIDC).

by Jeff Masters, via the Wunderblog

The extraordinary decline in Arctic sea ice during 2012 is finally over. Sea ice extent bottomed out on September 16, announced scientists at the National Snow and Ice Data Center (NSIDC) on Wednesday.

The sea ice extent fell to 3.41 million square kilometers, breaking the previous all-time low set in 2007 by 18%–despite the fact that this year’s weather was cloudier and cooler than in 2007. Nearly half (49%) of the icecap was gone during this year’s minimum, compared to the average minimum for the years 1979 – 2000.

This is an area approximately 43% of the size of the Contiguous United States. And, for the fifth consecutive year–and fifth time in recorded history — ice-free navigation was possible in the Arctic along the coast of Canada (the Northwest Passage), and along the coast of Russia (the Northeast Passage or Northern Sea Route.)

“We are now in uncharted territory,” said NSIDC Director Mark Serreze. “While we’ve long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic, few of us were prepared for how rapidly the changes would actually occur. While lots of people talk about opening of the Northwest Passage through the Canadian Arctic islands and the Northern Sea Route along the Russian coast, twenty years from now from now in August you might be able to take a ship right across the Arctic Ocean.”

When was the last time the Arctic was this ice-free?

We can be confident that the Arctic did not see the kind of melting observed in 2012 going back over a century, as we have detailed ice edge records from ships (Walsh and Chapman, 2001). It is very unlikely the Northwest Passage was open between 1497 and 1900, since this spanned a cold period in the northern latitudes known as “The Little Ice Age”. Ships periodically attempted the Passage and were foiled during this period. Research by Kinnard et al. (2011) shows that the Arctic ice melt in the past few decades is unprecedented for at least the past 1,450 years.

We may have to go back to at least 4,000 B.C. to find the last time so little summer ice was present in the Arctic. Funder and Kjaer (2007) found extensive systems of wave generated beach ridges along the North Greenland coast, which suggested the Arctic Ocean was ice-free in the summer for over 1,000 years between 6,000 – 8,500 years ago, when Earth’s orbital variations brought more sunlight to the Arctic in summer than at present. Prior to that, the next likely time was during the last inter-glacial period, 120,000 years ago. Arctic temperatures then were 2 – 3°C higher than present-day temperatures, and sea levels were 4 – 6 meters higher.

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When Arctic sea ice fell to its lowest level ever recorded this August, the ice covered an area 45 percent smaller than it did in the 1990′s. The amount of ice that melted in the Arctic this year is roughly the size of Canada and Texas combined.

The National Oceanic and Atmospheric Administration has just released a video illustrating the record melt:

NOAA’s National Climatic Data Center also released its latest data on Arctic ice on Monday. The previous record for Arctic ice melt was in 2007; however, as the data show, this year brought an additional loss of ice equivalent to the size of Texas. During August of 2012, Arctic ice disappeared at a rate of 35,400 miles per day.

Researchers are calling the melt “astonishing” and  “urgent.” One prominent scientist, Cambridge University’s Peter Wadhams, is now projecting that summer sea ice in the Arctic may entirely disappear in the next four years — calling the implications “terrible.”

“As the sea ice retreats in summer the ocean warms up (to 7C in 2011) and this warms the seabed too. The continental shelves of the Arctic are composed of offshore permafrost, frozen sediment left over from the last ice age. As the water warms the permafrost melts and releases huge quantities of trapped methane, a very powerful greenhouse gas so this will give a big boost to global warming,” he told the Guardian newspaper.

The National Climatic Data Center also released data showing this summer was the third-warmest ever recorded globally, with August marking the 330th consecutive month when temperatures were above the 20th century average.

IPCC 2007 projections for Arctic sea-ice 2080-2100 (right image)

by David Spratt, via Climate Code Red

The Arctic sea-ice big melt of 2012 “has taken us by surprise and we must adjust our understanding of the system and we must adjust our science and we must adjust our feelings for the nature around us”, according to Kim Holmen, Norwegian Polar Institute (NPI) international director.

From Svalbard (halfway between mainland Norway and Greenland), the BBC’s David Shukman reported on 7 September that Holmen had described the current melt rate “a greater change than we could even imagine 20 years ago, even 10 years ago”.

As detailed last week, the thin crust of sea-ice which floats on the north polar sea is now only half of the average minimum summer extent of the 1980, and just one-quarter of the volume twenty years ago.

Yet the IPCC 2007 report suggested sea-ice would last all, if not most, of this century: “in some projections using SRES scenarios, Arctic late-summer sea ice disappears almost entirely by the latter part of the 21st century”. One modelling image in the IPCC report (below)shows sea-ice still existent in period 2080-2100. This has proven to be dramatically conservative.

“As a scientist, I know that this is unprecedented in at least as much as 1,500 years. It is truly amazing – it is a huge dramatic change in the system”, says the NPI’s Dr Edmond Hansen. It is “not some short-lived phenomenon – this is an ongoing trend. You lose more and more ice and it is accelerating – you can just look at the graphs, the observations, and you can see what’s happening.”

And the trend is clear. Cambridge Professor and Arctic expert Peter Wadhams predicts Arctic summer sea ice “all gone by 2015”, except perhaps for a small multi-year remnant. Other Arctic specialists are now saying we will see an ice-free Arctic in summer within a decade or so.

Clearly the  IPPC 2007 report is no longer scientifically adequate on the Arctic – and much else – and Holmen’s call to “adjust our understanding of the system and… adjust our science” is timely. The nub of the problem is that climate policy-making in Australia, and internationally, is stuck in the IPCC 2007 frame and is thereby disconnected from what is occurring on the ground, in the seas and at the poles. For that reason it can only fail.

The IPCC 2007 report dramatically underestimated sea-level rises to 2100, as being in the range of 0.18–0.59 metre this century, “excluding future rapid dynamical changes in ice flow”. Because ice sheet melting and carbon-cycle feedbacks such as permafrost are non-linear or difficult to model, the IPCC report projections “do not include uncertainties in climate-carbon cycle feedbacks nor the full effects of changes in ice sheet flow, therefore the upper values of the ranges are not to be considered upper bounds for sea level rise.” The use of paleo-climate (climate history) data as a guide to future sea levels, as advocated by researchers such as James Hansen of NASA, was excluded.

Four of six emissions IPCC scenarios found the “best estimate” of warming to 2100 to be at or below 2.8°C, whilst the trigger for substantial Greenland ice mass loss was put at at 2.7°C with a range of 1.9-4.6°C, “if global average warming were sustained for millennia” (my emphasis).

Put this IPCC 2007 picture together, and the science frame we get is:

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by Dana Nuccitelli, via Skeptical Science

The record Arctic sea ice decline this year has predictably and deservedly received a fair amount of media attention.  Jonathan Leake of the Sunday Times recently penned an article on the impending sea ice record.  The bulk of the article was quite good, but at the end succumbed to the standard mainstream media practice of seeking “balance,” thus including some comments by John Christy.  Christy has become very reliable for arguing that anything and everything related to climate change probably just boils down to natural variability, as he recently told US Congress was the case with regards to the frequency of extreme weather events, contrary to the body of peer-reviewed scientific literature.

As we will see in this post, Christy once again misrepresented the body of scientific literature with regards to Arctic sea ice extent in his efforts to paint the Arctic sea ice death spiral as nothing out of the ordinary.

2012 vs. 1940

In Leake’s article, Christy was paraphrased as saying that there is

“…anecdotal and other evidence suggesting similar melts from 1938-43 and on other occasions.”

Christy’s comments to Leake via email slightly differed from Leake’s paraphrasing, as Christy claimed that evidence suggests summer melts during 1938-43 were “very low extent.”  This is a rather vague and subjective statement – very low relative to what?  Given the context, Leake understandably appears to have assumed that Christy meant very low relative to recent years, and perhaps he did, but it is also possible that he meant ‘very low’ relative to the early 20th Century, for example.

This begs the obvious question – in the scientific literature, how does Arctic sea ice extent during the period 1938-43 compare to the rest of the 20th Century and current levels?  One of the most widely used long-term estimates of Arctic sea ice extent comes from Walsh and Chapman (2001), whose data are available from the University of Illinois (updated through 2008).  A description of the vast array of data used by Walsh and Chapman is available via tamino here, and the data are plotted in Figure 1.

Figure 1: Average July through September Arctic sea ice extent 1870-2008 from the University of Illinois (Walsh & Chapman 2001 updated to 2008) and observational data from NSIDC for 2009-2011 (blue), with a fourth order polynomial fit (black soiid line).  Black vertical dashed lines indicate the years 1938-43.

Clearly the extent of Arctic sea ice during 1938-43 was nowhere near as low as current levels, based on these data.  According to this reconstruction, the minimum extent during that timeframe (9.8 million square kilometers in 1940) was higher than it has been at any time since 1979.  In other words, Arctic sea ice extent has been lower than it was in 1938-43 during the entire satellite record, and the current average summer extent is approximately 4.3 million square kilometers lower than the 1940 minimum.

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by Daniel Bailey, via Skeptical Science

It’s happened to all of us. Whether as a child on the school playground missing the call to come back in from recess or later, as teenagers, forgetting to return a library book until it was overdue or as adults realizing with a start that it’s the day after taxes were due and we haven’t done a thing, we’ve all wakened from a walking sleep to realize something we’ve just been missing all along.

For the mainstream media and the average person in general, that thing is the ongoing demise of the Arctic sea ice cover.  And nothing puts facts, especially record-breaking facts, into perspective like a visual aid.  Consider this visual aid provided from RealClimate of the NSIDC Arctic Sea Ice Extent:

Virtually every sea ice metric there is shows a record-breaking loss of the Arctic sea ice “cap” in 2012. With Arctic sea ice dropping off the bottom of existing sea ice graphs, the noted sage Chief Brody from the movie “Jaws” might put it this way:

“We’re gonna need a bigger graph.”

This piece was originally published at Skeptical Science and was reprinted with permission.

This visualization shows the extent of Arctic sea ice on Aug. 26, 2012, the day the sea ice dipped to its smallest extent ever recorded in more than three decades of satellite measurements…. The line on the image shows the average minimum extent from the period covering 1979-2010, as measured by satellites. Every summer the Arctic ice cap melts down to what scientists call its “minimum” before colder weather builds the ice cover back up. The size of this minimum remains in a long-term decline. The extent on Aug. 26. 2012 broke the previous record set on Sept. 18, 2007. But the 2012 melt season could still continue for several weeks. Image credit: NASA

News via the University of Colorado Boulder

The blanket of sea ice floating on the Arctic Ocean melted to its lowest extent ever recorded since satellites began measuring it in 1979, according to the University of Colorado Boulder’s National Snow and Ice Data Center.

On Aug. 26, the Arctic sea ice extent fell to 1.58 million square miles, or 4.10 million square kilometers. The number is 27,000 square miles, or 70,000 square kilometers below the record low daily sea ice extent set Sept. 18, 2007.  Since the summer Arctic sea ice minimum normally does not occur until the melt season ends in mid- to late September, the CU-Boulder research team expects the sea ice extent to continue to dwindle for the next two or three weeks, said Walt Meier, an NSID scientist.

“It’s a little surprising to see the 2012 Arctic sea ice extent in August dip below the record low 2007 sea ice extent in September,” he said.  “It’s likely we are going to surpass the record decline by a fair amount this year by the time all is said and done.”

On Sept. 18, 2007, the September minimum extent of Arctic sea ice shattered all satellite records, reaching a five-day running average of 1.61 million square miles, or 4.17 million square kilometers.  Compared to the long-term minimum average from 1979 to 2000, the 2007 minimum extent was lower by about a million square miles — an area about the same as Alaska and Texas combined, or 10 United Kingdoms.

While a large Arctic storm in early August appears to have helped to break up some of the 2012 sea ice and helped it to melt more quickly, the decline seen in in recent years is well outside the range of natural climate variability, said Meier. Most scientists believe the shrinking Arctic sea ice is tied to warming temperatures caused by an increase in human-produced greenhouse gases pumped into Earth’s atmosphere.

CU-Boulder researchers say the old, thick multi-year ice that used to dominate the Arctic region has been replaced by young, thin ice that has survived only one or two melt seasons — ice which now makes up about 80 percent of the ice cover.  Since 1979, the September Arctic sea ice extent has declined by 12 percent per decade.

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by Neven Acropolis

Whoever said watching the Arctic during the melting season is boring, needs to put his glasses on. After a record low reflectivity of the Greenland ice sheet (with accompanying floodings on the west coast of Greenland), the calving of another enormous iceberg from Petermann Glacier, and the general rapid decline of Arctic sea ice despite adverse weather patterns, we can now add to the 2012 melting season bonanza the appearance of a cyclone the likes of which are rarely seen in winter, let alone in summer.

The storm came in from Siberia, intensified and then positioned itself over the central Arctic, reaching sea level pressures of below 965 mb in the storm’s centre, engendering 20 knot winds and 50 mph wind gusts:

Data source: Danish Meteorological Institute

The storm is now losing its strength and dissipating, but its effect on the sea ice has been enormous so far. In this phase of the melting season when decline starts to slow down, large swathes of sea ice just disappear from one day the next, and the next, and the next (which is why I refer to it as flash melting). It can clearly be seen on this animation of sea ice concentration maps that are updated daily on the Cryosphere Today website, showing the sea ice decline of the past couple of days:

Although technically not all of the ice that disappears on these maps is completely melted (some of it doesn’t get picked up by satellite sensors due to clouds and waves submerging ice floes), the gale-force winds displace and break up ice floes, and churn the waters below causing warmer, saltier layers under the thin film of fresh water to mix upwards and melt the ice some more from the bottom. This storm is the worst thing that could have happened to an already weakened and dispersed ice pack.

One development on these sea ice concentration maps that stand out particularly, is the detachment of a large swathe of ice floes from the main ice pack. I’ve never seen such a thing before, and I wouldn’t be surprised if it is unprecedented in the satellite era. But I guess that is what highly unusual Arctic summer storms can lead to.

The effects on the ice pack are also staring to get picked up on sea ice area and extent graphs. The most remarkable decline can be seen on this sea ice extent graph from the Danish Meteorological Institute:

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