Wednesday, October 16, 2013

Arctic shifts to a new normal

Most publications about climate change fall into one of two categories:
(1) research reports in the peer-reviewed scientific literature
(2) popular articles for the lay public. Publications in the first category are typically too specialized for the lay reader. Publications in the second category often simplify because they have to in order to reach the audience.

This makes "in-between" publications rare and valuable. This is the case for an article in the latest (October 2013) issue of Physics Today, entitled the Arctic shifts to a new normal. The authors, Martin Jeffries, James Overland and Don Perovich, are research scientists with academic appointments. For brevity, the authors are referred to collectively as JOP.

JOP document the decline of sea ice. From September 1980 to  September 2012, the minimum extent of sea ice has declined by 55%. The six most recent years (2007-2012) have seen the lowest ice extents (i.e., area) since the satellite record began in 1979. This dramatic decline has been driven by an increase of CO2 at Barrow, Alaska, of only 15% from 1980 to 2012.

The sea ice is also thinner and newer: In September 1980, 62% was multi-year ice, which survives one or more more summer melt seasons, and only 38% was first-year sea ice. By September 2012, 58% of the sea ice was less than a year old.

The minimum extent of sea ice (in September) is declining at -13% per decade, relative to the 1979-2000 average. The maximum extent of sea ice (typically in March) is declining more slowly, at -2.6% per decade.  In March 2013, only  30% of the ice cover consists of ice more than a year old.

The retreat of sea ice leads to a decrease in the albedo, because ocean water absorbs more sunlight and reflects less, compared with white ice.  This causes "polar amplification", meaning that the increase in the Arctic temperature is higher than the increase in the global average temperature.

JOR state that "polar amplification" is driven by modest external forcing from mid-latitudes, combined with multiple positive feedbacks within the Arctic system itself. For details, JOR refer to a 2011 article by Mark Serreze and Roger Barry and a 2012 article by Julienne Stroeve et al.

Mean annual temperature in the Arctic is now 1.5 C higher than the 1971-2000 average. The sea-surface temperature in August is now as much as 3 C higher than the 1982-2006 average. Upper ocean heat content has increased by as much as 25% in the Canada Basin's Beaufort Gyre, compared to the heat content in the 1970's.

There is much more in the JOR article, including changes in ocean currents, plankton growth, and changes in the migration of Arctic mammals (e.g., walruses) and other sea life.

The changes in the Arctic are happening much more rapidly than expected several decades ago. In 1979, President Jimmy Carter appointed a high-level study group to investigate the possibility of global warming. The study group was headed by Jules Charney, physicist at MIT, who framed the problem thus: suppose that the carbon dioxide in the atmosphere were instantly doubled, but nothing else changed. What would be the resulting temperature rise? (This way of posing the question is still used by the IPCC today).

At the time, Charney (and everybody else) assumed that polar ice sheets would respond so slowly that their change could be neglected on a time scale of decades. It was thought that ice sheets would change mainly on millennial (thousand year) time scales. (Hansen,  p. 41)

Even today's computer models do not predict the rapid and  profound changes that are observed.  Computer models (used for the AR5 report) predict that ice-free summers will not happen until about 2060, i.e., 47 years from now. The extrapolation of today's trends predicts that this will happen in about another decade.

Among the arguments advanced by the deniers is that computer models are not perfect. The deniers then go on to claim that the threat posed by global warming has been overestimated by imperfect computer models. In fact, the threat has been underestimated because computer models underestimate the rate of change in the Arctic, the region of the earth where the rate of change is the most pronounced.

Hat's off to Physics Today for publishing the excellent JOR article!

M. C. Serreze, R. G. Barry, Global Planet. Change 77, 85 (2011)
J. C. Stroeve et al., Climatic Change 110, 1005 (2012)
James Hansen, Storms of My Grandchildren (Bloomsbury, 2009).


Anonymous said...

JOR should be JOP.

Anonymous said...

Take a look at the slope of the return from the September low. It looks like the most rapid return in the last 30 years. Wow, Arctic ice returning with a vengeance.

Hank Roberts said...

> rapid ... returning
Almost not below average.
Arctic Wobegon comment, eh?

The bigger the area of open water, the more area that will be freezing during the next winter.

So the worse the summer melt was, the "better" the fall refreeze can be claimed to be.

Yeah, I'd be ashamed to put my name to opinions such as that. Stay hidden, kid.

Hank Roberts said...

Windchasers said...

"Upper ocean heat content has increased by as much as 25% in the Canada Basin's Beaufort Gyre, compared to the heat content in the 1970's."

That doesn't seem right. Even if the upper ocean was half ice, a 25% increase in heat would be enough to raise the temperature from 0C to ~38C.
(Assuming linear heat capacity, etc.)

Anonymous said...

Hank, from your WP article:

The Met Office in Britain recently pointed out that there are all sorts of reasons why sea ice extent can bounce around from year to year:

-- temperatures naturally vary from one year to the next;
-- the amount of cloud can affect the amount of surface melting;
-- summer storms can also break up ice, which can accelerate the melting process;
-- settled conditions can be more conducive to ice forming;
-- winds may act to spread out the ice or push it together.

I wonder Hank, if the Met tried to explain 2012 in a similar fashion. Jeez, couldn't find it. Look at the slope. Pretty impressive.

Thomas Lee Elifritz said...

Anonymous idiot, do you understand the meaning of flailing? I would be surprised if you didn't because you are doing a really good job of it.

Flail away, it's amusing.

Anonymous said...

Thomas, are you capable of looking at the Jaxa and responding without your petulant ad homs.

Anonymous said...

Hank, remember when Plumer got punked by Richard Muller (who still declares he will never read another article by Mann)>

Thomas Lee Elifritz said...

Why should I waste my time on an innumerate troll any more than I already have? You have already demonstrated yourself to be disingenuous with respect to the subject and topic of this post. There is no there there.

Anonymous said...

Thomas, I guess you have nothing. Typical.

Anonymous said...

"Even today's computer models do not predict the rapid and profound changes that are observed"

That could be because they are incapable of predicting dynamic changes, the kind of which peer reviewed research told you a decade ago was causing Arctic sea ice decline.


Kevin O'Neill said...

The ironic thing is most of us who actually try to follow the science of the arctic could make far better arguments than the dimwit deniers that flail around in the dark.

Science isn't about ignoring data you don't like because it doesn't fit your personal or political agenda, it's about trying to build a reasonable theory that encompasses all of the data.

Of course there's the counter-intuitive psychological finding that 'true believers' actually have their views *strengthened* by evidence that contradicts their beliefs. Myself, I just consider these people divorced from reality.

Anyone with half a brain knows that there is natural variation within any climatic regime. Likewise SIE and SIC are going to fluctuate year to year. The scientific method has to take this into account. The true-believer method is to latch onto any one year's increase or decrease and say, "See! Proof!"

If we didn't have a single temperature record from the past - not one historical temp - we would *still* be able to piece together a general theory that the globe is warming. Plant migrations, animal migrations, crop cycles, shipping records, lake ice on/off dates, etc all point in one direction.

Deniers don't have an explanation for any of these facts. They have no theory that can explain them.

There are people that are simply ignorant of the mounds of evidence behind the theory of global warming, but most of our denialist troll friends named 'Anonymous' *could* look at *all* the data if they chose to do so. With da Google the information is just a search engine away.

Ignorant, lying, or insane - these are the categories they fall into. In the USA, given the high correlation between GW denialism, libertarian economic belief, and Tea Party affinity - I think they're just batshit crazy.

Anonymous said...

Kevin, you sound so even keeled. Pot/kettle. I guess you are oblivious to the fact that Parmesan's work has been completely refuted.

Steve Bloom said...

Eli, if the L.A. Times can manage it, why not you? This is a blog, not academia. As it is, I find myself hesitating to open the comments here.

chek said...

"I guess you are oblivious to the fact that Parmesan's work has been completely refuted. "

May it be asked refuted by which blogscientist in particular?

Anonymous said...

Steve Bloom, yeah, that is the answer. Censorship. Way to go Bloom.

Anonymous said...

Hank Roberts, take a look at this article where Romm is accused of bullying abd see how Brad Plummer ( the ref. you used in the WP about Arctic ice plays along. Good cite Hank.

Anonymous said...

Russell Seitz said...

I rather liked this Physics Today article too

dbostrom said...

Conforming: The Physics Today article is terrific. Worth seeking out but thanks to Russell, no need:

Anonymous, you sound desperate and I guess I'm not surprised; Arctic sea ice is a serious problem, not tractable by resort to magic.

EliRabett said...

From the first day, Eli has placed his trust in community (that and the Rabett Hole). Our trolls are our crusty uncles at holiday dinners. Besides, there is the opportunity to teach them a bit.

metzomagic said...

The Rabett said:

Besides, there is the opportunity to teach them a bit.

But they refuse to learn. Driven by their ideology rather than curiosity as to how things really work.

Kevin O'Neill said...

Re:Parmesan's work: Anon - you should get out more. Parmesan's work is of a piece with behavioral research that has existed for decades; just unknown to you.

Try Prof. Bob Altmeyer's 'The Authoritarians' for numerous case studies on how these minds work. John Dean wrote 'Conservatives Without Conscience' based in part on the research of Altmeyer (Univ. of Manitoba). Altmeyer's book is available as a free PDF from his website.

Russell Seitz said...

Homage to DBostrom here

Anonymous said...

Last time the september monthy extent average was this high was waaay back in 2009. Don't we all remember the steep increase that followed this recovery?

Rib Smokin' Bunny

Anonymous said...

Eunice, unwittingly advocating that climate is changing: "That could be because they are incapable of predicting dynamic changes, the kind of which peer reviewed research told you a decade ago was causing Arctic sea ice decline."

Rib Smokin' Bunny

Mal Adapted said...

Eli on trolls: "Besides, there is the opportunity to teach them a bit."

And even if the trolls can't learn, everyone else learns what kind of people deniers tend to be. They're their own worst enemies!

Anonymous said...


Would that be the same models that indicate that 5% sea ice around New Orleans is normal?


Anonymous said...

Eunice has lost the plot. The topic is changes in the arctic, not models.

Rib Smokin' Bunny

Anonymous said...

Russel,"I rather liked this Physics Today article too"

And you liked it why? Because it fits your worldview or because it is misleading? Loosen that bowtie, you'll get more O2 to your grey matter.

Thomas Lee Elifritz said...

Anonymous commentators never realize how stupid they look when they speak for others rather than themselves. I can only suggest it's hardwired into their brains, since they seem unable to recognize their malady and they continue it even when alerted to it.

dbostrom said...

If we had perfect "big data" insight we might well be able to derive a helpful equation describing the relationship between the amplitude of denier squeaking, the degrees of contortion squeakers assume and the perceived threat level from the topic of the squeaks.

Short of a formal expression it suffices to say that the louder and more ridiculous the squeaking, the more bothered is the squeaker by the topic at hand. The larger the population of similarly squeaking squeakers, the larger and more broadly threatening is the cognitive challenge with which they're colliding.

Acuity of unacceptable observation is positively correlated with inventive squeaking.

If formalized, such a relationship might be called "Goddard's Law," after one of the chief victims of this form of cognitive breakdown.

Hence a lot of loud squeaking about Arctic sea ice having been in a similar parlous state in 1922, etc. If it wasn't sea ice that was the canary in the coal mine but something else we'd be hearing more squeaking about that, similarly unhinged from reality.

Susan Anderson said...

Every time there is an extreme event, the phony skeptics sit around rubbing their hands, because they know there will be another swing, and they will be able to claim that that is the beginning of a new beginning. Heads they win, tails you lose.

So disgustingly occupied with making their points, they ignore everything and anything that might alert them to their own increasingly dangerous future, which they wish to demolish with cheap shots and politics.

The planet always bats last, and bats 1000. It doesn't care about your politics.

Susan Anderson said...

Nice point made over at Neven's as the "clever moderate"-type trolls try to distract. They are largely the only ones who say "we".

Interesting point, I think.

Russell Seitz said...

What a splendid illustration of the quality of anonymous' physical intuition :

"Loosen that bowtie, you'll get more O2 to your grey matter."

The topological reality is that tightening them losens the fit.

Anonymous said...

Rib smoker, exactly when was the climate static?

raypierre said...


You are right that the Physics Today article is spot on, but in your post you have somewhat confused sea ice with ice sheets. The term "ice sheet" should be used only for land glaciers, like Greenland or Antarctica, not the polar sea ice. Nobody ever, ever thought that sea ice had a millennial response time; there's so little of it it takes very little energy delivered in the right place to get rid of it. People did think that land ice sheets would not vary much on centennial time scales, but that's a different issue. The issue with sea ice in the Charney report was quite different -- there were only two models used, and they did not fully explore the range of ways sea ice could be modeled, so of course modern models show a greater range of responsiveness of sea ice to 2xCO2, though the Charney Report models are still firmly in the running of what might be the truth.


Scatter said...

"I wonder Hank, if the Met tried to explain 2012 in a similar fashion. Jeez, couldn't find it."

You didn't look very hard. From the press release at the time:

A severe storm over the Central Arctic brought about extremely rapid loss of ice cover in the East Siberian Sea, causing the ice to break up and melt in the strong winds. This is likely to have contributed to the record loss seen this year.

Helene Hewitt, an expert in climate modelling at the Met Office, said: "A number of factors are likely to have contributed to the record minimum ice extent this year, including a persistence of high pressure systems over the Arctic for much of the summer. This year's minimum adds to the continuing pattern of accelerating ice loss over the last 15 years."

cRR Kampen said...

"Wow, Arctic ice returning with a vengeance."

Yeah, now be disappeared :)

Anonymous said...

"Rib smoker, exactly when was the climate static?"

In respect to the topic of arctic ice, thousands of years until the recent dynamic changes pointed out by Eunice. Last time CO2 levels were 400 ppm (see, climate is not static) the temperatures in the arctic were 8 degrees C higher (whoa, not static at all). We can expect a lot more to come.

Rib Smokin' Bunny

Anonymous said...

Thomas and Hank, did you look at Jaxa today? Returning with a vengeance.

Hank Roberts said...

In case anyone missed this the first time around:

> sea ice ... vengeance

You guys are using that word "vengeance" a lot lately. I wonder why? Which step of the escalator are you on?

Understand variability? Note the gray lines on the JAXA chart? Read this:

You failed Stat 101? Or never took the class? You're doing the

Anonymous said...

“We do not believe any group of men adequate enough or wise enough to operate without scrutiny or without criticism. We know that the only way to avoid error is to detect it, that the only way to detect it is to be free to inquire. We know that in secrecy error undetected will flourish and subvert”. – J Robert Oppenheimer.

Antarctic Ice Sets New All Time Record In October
October 19, 2013

NSIDC are now back up and running again, after the Federal shutdown.

Quite astonishingly, Antarctic sea ice has set another record for maximum extent, beating the previous record of 19.513 million sq km, set on 21st September this year.

What makes the new record so astonishing is that it was set in October, on the 1st. Climatologically, the maximum extent is reached on 22nd September, so it is most unusual for the ice still to be growing 10 days later.

As at the 18th October, extent is still running at 998,000 sq km above normal.

With the Arctic ice running at 728,000sq km below normal, this means that global sea ice is 270,000 sq km above the 1981-2010 norm.

Global sea ice area is also above normal, as it has been for much of the year.

Thomas Lee Elifritz said...

That is so weird that Antarctica is a giant ice sheet covered continent at the bottom of the world, and the Arctic is an ocean, covered with a thin layer of ice at the top of the world. Better to lump them all together and hide those details, no?

Brian Dodge said...

"With the Arctic ice running at 728,000sq km below normal, this means that global sea ice is 270,000 sq km above the 1981-2010 norm."

I'm glad you mentioned this positive forcing, e.g., the Antarctic excess is occurring during local winter, when there is no albedo feedback negative forcing 'cause there's no sunlight to be reflected; further, ocean surface is constrained to be at or above the seawater freezing point, roughly 270 Kelvin, but the ice insulates the surface from the ocean heat below, allowing the surface temperature to drop to -30 to -40 degrees C - about 240 Kelvin. Due to the fourth power dependency of thermal emission versus temperature, 270000 km^2 of ice at 240 K radiates about 3e13 less watts than the seawater underneath would radiate at 270 K. In 4 months in the dead of one winter, this would amount to 3e20 extra joules in earth's climate system, enough to melt 10^12 cubic meters of ice. Polar see-saw physics? I'll leave it to the reader(s) to do the math for how many km^2 Arctic sea ice loss this is.

John said...


Thanks for your comment. I stand corrected.

Note to bunnies: The author is Raymond Pierrehumbert.

who is also the author of the book Principles of Planetary Climate.