Notes from The Gathering #5: Arctic sea ice: is it tipped yet?
The summer of 2007 was apocalyptic for Arctic sea ice. The coverage and thickness of sea ice in the Arctic has been declining steadily over the past few decades, but this year the ice lost an area about the size of Texas, reaching its minimum on about the 16th of September. Arctic sea ice seems to me the best and more imminent example of a tipping point in the climate system. A series of talks aimed to explain the reason for the meltdown.
Sea surface temperatures were warmer this past summer also; I forget how many standard deviations the temperature was off the trend, but it was definitely anomalous. The region of the meltback is just inside the Bering Strait, where warm water flows in from the Pacific, but in the analysis of Steele et al. this inflow of comparatively warm water was not particularly anomalous in 2007 relative to other years. It could be that the exposure of the sea surface to the atmosphere by the melting ice could have an impact, although the meltback is so late in the solar heating season (September) that this effect seems of limited explanatory value also. Bit of a chicken and egg problem here.
Melting ice can be seen from space, I believe as puddles sensed by the QuickSCAT satellite. The puddles are most abundant in mid-summer when the sunlight is strongest, and by mid-September when the ice meltback was the strongest, the melting season was largely over. Apparently the reason for the disappearance was an anomalous weather system which generated a strong jet of surface winds blowing straight over the pole southward toward the Atlantic ocean, a “Polar Express”. A research ship frozen into the ice in 2006 crossed the Arctic in about a year, about three times faster than the transit time of the Fram in the 1890’s. To summarize, the ice cubes in the freezer tray didn’t melt because the freezer is broken exactly, but because the ice cube tray fell out of the freezer onto the warm floor.
The disappearance of the ice was set up by warming surface waters and loss of the thicker multi-year ice in favor of thinner single-year ice. But the collapse of ice coverage this year was also something of a random event. This change was much more abrupt than the averaged results of the multiple IPCC AR4 models, but if you look at individual model runs, you can find sudden decreases in ice cover such as this. In the particular model run which looks most like 2007, the ice subsequently recovered somewhat, although never regaining the coverage before the meltback event.
So what is the implication of the meltback, the prognosis for the future? Has the tipping point tipped yet? When ice melts, it allows the surface ocean to begin absorbing sunlight, potentially locking in the ice-free condition. Instead of making his own prognosis, Overland allowed the audience to vote on it. The options were
- A The meltback is permanent
- B Ice coverage will partially recover but continue to decrease
- C The ice would recover to 1980’s levels but then continue to decline over the coming century
Options A and B had significant audience support, while only one brave soul voted for the most conservative option C. No one remarked that the “skeptic” possibility, that Arctic sea ice is not melting back at all, was not even offered or asked for. Climate scientists have moved beyond that.
13 December 2007 at 12:57
Of course if it is B, as the models might seem to somewhat suggest (and wouldnt be too surprising as just an effect of variability), then no doubt next year the contrarians will start telling everyone how the arctic melt has reversed, in the same way that 1998 has been touted as the ‘end of global warming’ in some corners.
13 December 2007 at 13:05
This is a little confusing. There’s no need to explain anything particular about September this year. The sea ice was at a record low level before we even got to September. September was more-or-less routine: we lost ice as we do in every September, but not a remarkable amount. The really exceptional time for sea ice loss this year was the second half of June.
Check the tale of the tape: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg, or the last 12 months: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.365.jpg
[Response: Yeah… hmm. The speaker’s statements seemed to make sense to me at the time, but your point now seems like a good one. I could choose excuse A This is not my speciality, I’m only trying to report stuff that seems interesting, or B This meeting is exhausting. Good thing I don’t have to operate any heavy machinery. David]
13 December 2007 at 13:12
A recurring problem with public perceptions of excursions in weather and climate is a widespread innumeracy, notably (a) an insufficient appreciation for what it means to have random excursions from a strong trend, and (b) inappropriate assessments of risk, even sizeable ones. The latter really came through in the conclusion of Professor Lonnie Thompson’s talk yesterday. I’ve heard the same from others, that until dead bodies start being carted away from the intersection, noone’s going to think about putting up traffic controls. Unfortunately, here we are talking about numbers of dead much greater than the Shoah, and much greater than the numbers lost in all of World War II. And the powers that are in charge of these things are playing it like a poker game.
It is just so damn sad.
13 December 2007 at 13:26
Will the melting of the Ice Sheets have an effect on the orbit of the earth around the sun?
For that matter does a rising/falling sea level have an effect on the earth’s orbit (5ft-50ft-200ft-tides)?
Is the suns radiation still increasing over what it was in the past and do the climate models take this into account?
13 December 2007 at 13:41
Interesting sea ice maps on http://www.arctic-warming.com , when another arctic warming started about 90 years ago.
13 December 2007 at 14:12
paul m,
Earth’s orbit will not be affected, as Earth’s mass will remain constant. The rate of rotation may be slightly affected as mass shifts from pole toward the Equator and changes (slightly) the moment of Inertia.
13 December 2007 at 14:34
Is there some percentage of ice coverage at which point the ice doesn’t recover much in the winter enough to stop complete melting the next time summer comes around?
13 December 2007 at 15:50
Paul M asked about the solar trend, assuming it’s going up. Check your assumption for significance, Paul:
Measured at +0.05 percent (one twentieth of one percent, or five-one-hundredths-of-one-percent — per ten years. Awfully close to zero, eh, compared to the rate of change of fossil fuel use, and temperature.
>http://www.nasa.gov/centers/goddard/news/topstory/2003/0313irradiance.html
“The accurate long-term dataset, therefore, shows a significant positive trend (.05 percent per decade) in TSI between the solar minima of solar cycles 21 to 23 (1978 to present). This major finding may help climatologists to distinguish between solar and man-made influences on climate….”
13 December 2007 at 16:01
I went golfing one day and started the day by shooting 2 birdies in a row. Well I immediatly extrapolated this to the 18 holes, and concluded that a 54 was in order, due to the results from my limited data set. Unfortunately, I learned the error of my way, and my score returned to the mean.
The history of the Arctic Ocean, is a blank slate. Any attempt to draw conclusions from the limited amount of data available, is destined to fail. If you can’t tell me what it was like 200, 600, 1000, 4000, 10000, etc. years ago, you can’t tell me where it will be in the future.
[Response: I rolled a sphere down an inclined plane twice, measured the time it took and calculated the acceleration. I predicted that the for the next 16 rolls the acceleration would be constant. Lo and behold, I was able to predict how long it took the 18th time. See the difference? - gavin]
13 December 2007 at 16:09
Well, I agree that A and B are correct. “The meltback is permanent” and it “will continue to decrease” at the same rate until it has gone completely!
13 December 2007 at 16:20
It is obvious none of you listened to this presentation at AGU on Monday morning: “PP11A-0203
Ice free Arctic Ocean, an Early Holocene analogue.”
Yes, the Arctic Ocean has been ice free many times in the past and that state has lasted many hundreds of years [edit]
13 December 2007 at 16:33
A study relating to this - “Our study confirms many changes seen in upper Arctic Ocean circulation in the 1990s were mostly decadal in nature, rather than trends caused by global warming,” said Morison.
http://www.nasa.gov/vision/earth/lookingatearth/ipy-20071113.html
[Response: Note that this has very little to do with the ice melt. - gavin]
13 December 2007 at 16:34
Paul writes:
[[Will the melting of the Ice Sheets have an effect on the orbit of the earth around the sun?]]
Not enough to measure, no.
[[For that matter does a rising/falling sea level have an effect on the earth’s orbit (5ft-50ft-200ft-tides)?]]
Again, not enough to measure.
[[Is the suns radiation still increasing over what it was in the past and do the climate models take this into account?]]
The Solar constant has shown no trend up or down since about 1950.
13 December 2007 at 16:48
Gavin’s response to Russell’s comment about golf is a terrible analogy. I would equate the changing climate to a game of golf long before I would equate it to rolling a ball down an incline. There is very little variability in rolling a ball down an incline. There are innumerable factors that affect climate just as there are in a game of golf. Gavin is suggesting that a linear relationship can be extrapolated out of limited climate data, when it obviously can’t be.
[Response: No I wasn’t. I was using the analogy of predictability of a system where you have a good idea of the physics vs. an empirical statistical model based on a low number of past occurrences. Physics is extrapolatable, statistics (in this specific case), is not. - gavin]
13 December 2007 at 16:56
Re 8:
Go ahead, Gavin, and predict the extent of arctic sea ice for the next 5 years. I hope that sphere you were rolling is crystal, cause you’re gonna need it…
[Response: I go with option B. - gavin]
13 December 2007 at 17:25
It is not obvious to me that an ice free north pole is necessarily a positive feedback. The conventional thinking is that the albedo of the ice is much higher than open water, therefore the sunlight will warm the arctic water rather than being reflected back into space. I have never seen the ice free heat exchange condition quantified and compared to the ice cap condition. Please direct me to a reference if handy.
The upper layer of the ocean is heated by direct sunlight, mostly in the tropics. On average, the ocean surface is warmer than the atmosphere, and that is certainly the case near the north pole. The ocean is cooled by net back (ir) radiation, conduction on contact with the cooler atmosphere, and heat loss due to evaporation.
So with the ice cap in place, there is no direct solar heating of the arctic water. Without the ice cap, there is only limited solar heating because of the low angle of the sun, 11 degrees above the horizon on average during the six months of sunlight at the pole. At this angle, the albedo of water is about 0.3 or an order of magnitude higher than in the tropics. With the albedo of older snow and ice at about 0.6, the open ocean will absorb more heat than the ice capped ocean.
With the ice cap in place there is essentially no cooling of the arctic ocean. The ice effectively blocks net back radiation, eliminates contact with the atmosphere and therefore conduction, and blocks evaporation. So the question is, is the small increase in direct solar heating of the arctic water larger than the cooling that occurs when the warm arctic water is left exposed? Qualitatively, it appears obvious that the arctic ocean will net cool. With the sun continuing to heat the ocean water at the tropical latitudes regardless of ice cap conditions up north, it would seem that the presence of an ice cap would result in a warmer ocean over the long term, with the converse also being true. Perhaps this is why there are long term warm/cold climatic cycles, rather than runaway heat or cold. At the peak of each cycle, the oceans are acting counter to temperature trends.
13 December 2007 at 17:29
Re “There is very little variability in rolling a ball down an incline”
This is true only if you’re measuring in the sorts of units that match our unaided senses - watching the ball roll and counting full seconds to yourself, for example. Use an oscillator to time the ball and you’ll find all sorts of variability, measured in small fractions of a second, in the ball’s travel. The important point is that despite this variability, we can predict adequately well for many purposes, because we understand something about the basic physics. Similar argument for climate…
13 December 2007 at 17:32
There is hope:
Arctic Sea Ice Re-Freezing at Record Pace
After Record Summer Melt, Recovery Still Lags
http://www.thedailygreen.com/environmental-news/latest/arctic-sea-ice-47121205
13 December 2007 at 17:34
Umm, it seems someone can’t count or I’m missing something. Dispatch #4 is the same as dispatch #3. cheers
13 December 2007 at 17:34
Re 13:
Option B? That’s lame. Draw a graph of the next 5 years. It’s physics right? It should be similar to predicting an eclipse or rolling a ball down an incline.
13 December 2007 at 17:37
Isn’t Option B is too easy? If ice of any sort comes back by a sliver for a moment in time, it’s a partial recovery?
I think the question should be posed in terms of perennial ice, and a recovery should have to exceed 5% to be make it count.
If slightly more annual ice survives the melt season, is that really significant?
13 December 2007 at 18:02
RE #3 Paul m’s question about melting glaciers and Ray’s response (#5):”The rate of rotation may be slightly affected as mass shifts from pole toward the Equator and changes (slightly) the moment of Inertia.”
An interesting point in light of a report several years ago in Science suggesting that the extensive damming of rivers in the northern hemisphere has altered the earth’ moment of intertia, hence, its rotational velocity (increasing it, if I’m not mistaken). Unfortunately, I couldn’t track down the article. But, the following articles do deal with the effects of melting glaciers and rising sea level on the earth’s rotation (not its orbit, of course):
Global Sea Level and Earth Rotation
W. R. PELTIER
Science 13 May 1988:
Vol. 240. no. 4854, pp. 895 - 9011
Recent analyses of long time scale secular variations of sea level, based on tide gauge observations, have established that sea level is apparently rising at a globally averaged rate somewhat in excess of 1 millimeter per year. It has been suggested that the nonsteric component of this secular rate might be explicable in terms of ongoing mass loss from the small ice sheets and glaciers of the world. Satellite laser ranging and very long baseline interferometry data may be used to deliver strong constraints on this important scenario because of the information that these systems provide on variations of the length of day and of the position of the rotation pole with respect to the earth’s surface geography. These data demonstrate that the hypothesis of mass loss is plausible if the Barents Sea was covered by a substantial ice sheet at the last maximum of the current ice age 18,000 years ago.
Oceanic Effects on Earth’s Rotation Rate
Clark R. Wilson
Science 11 September 1998:
Vol. 281. no. 5383, pp. 1623 - 1624
Changes in the mass distribution of water in Earth’s oceans in turn leads to variations in its angular momentum. In his Perspective, Wilson discusses results presented in the same issue by Marcus et al. in which techniques of radio astronomy were used to measure changes in Earth’s angular momentum. The variations were observed by measuring changes in the length of day, and therefore Earth’s rotation rate. Measurements such as these may serve as an indicator of oceanic behavior, much as other indices are used to keep track of atmospheric climate.
13 December 2007 at 18:10
Aren’t a lot of scientific bodies now predicting total loss of Arctic ice during the summer in just a few years? How could that square with even partial recovery of perennial ice? Shouldn’t we expect regular loss of ice every year? Haven’t the models been wildly optimistic about this until quite recently?
13 December 2007 at 18:23
Sorry, more questions: Is there a possibility that all that fresh water from the melting Arctic ice will find its way into the northern Atlantic, decrease the salinity there, and slow or stall the thermohaline circulation?
And once the entire Arctic Ocean is ice free, won’t that mean the whole thing will be sucking up solar energy 24/7 during midsummer? Won’t that lead to a super-heated body of water? Will that accelerate the melting of the tundra in Siberia and Alaska, releasing ever more massive volumes of methane?
Could the Arctic Ocean heat enough in these circumstances to melt the clathrates locked underwater along the continental shelves releasing even more massive amounts of methane? What are we looking at here?
As I recall from high school chemistry, melting of ice is an endothermic reaction–it cools the water and air around it as it melts. With no more ice melting to cool the water, will we see even higher levels of solar heating?
Sorry for so many questions, but these have been on my mind for a while.
13 December 2007 at 18:30
I know my city isn’t the one causing all this American pollution:
http://www.efficientenergy.org/Top-Ten-Green-Cities-in-the-United-States
this article shows who is and who isn’t. I also too the carbon calculator at www.earthlab.com and I can see that I am not the one who is polluting, you guys should take it too to reaffirm that you aren’t either (I could be preaching to the congregation here)
13 December 2007 at 18:48
Re “Go ahead, Gavin, and predict the extent of arctic sea ice for the next 5 years. I hope that sphere you were rolling is crystal, cause you’re gonna need it…”
Well this was from my brother. I am very happy to see it here because he is always elbowing me about how www.realclimate.com doesn’t post his comments. So presumably now we will not have to cover that ground any more.
I have not read the original post yet so I won’t comment further until I have.
13 December 2007 at 19:00
Re: “Option B? That’s lame.”
Did you want the correct answer or to be “impressed” with something false?
What is YOUR prediction for arctic ice extent over the next five years? If we’re going to call people out for forecasting skill, then by all means let’s have some superior forecasting skill.
13 December 2007 at 19:23
Preferential warming at the poles due to CO2 dominance in a dry environment.
1. It is certainly true that water vapour has a huge and overpowering greenhouse effect.
2. It is also true that in the polar latitudes there is very little water vapour in the atmosphere. It is mostly locked up as ice or snow or has been simply precipitated out.
3. Co2 will diffuse throughout the entire atmosphere in accordance with the gas laws.
4. As the CO2 content at the poles increases it will have the effect of increasing the polar temperatures slightly, particularly during the polar summers. (The effect of Increased CO2 on the tropical latitudes will tend to be swamped by the
high humidity).
5.Thus the effect of increasing CO2 since c.1900 will differentially tend to heat the polar regions.
6. This rise in temperature will allow the water vapour to penetrate further into the polar region before it gets turned into ice
7. This in turn increases the “greenhouse effect” due to both water vapour and CO2, remember that the effect is circumferential and thus a small linear change is multiplied by piXr2XH(H= atmospheric depth). Presumably there is a vapour diffusion zone centred upon some latitude.
8. Add in Albedo effects due to ice melt and you possibly have a recipe for rapid change
This is the sort of feedback mechanism that concerns me.
Dale Butler
13 December 2007 at 19:45
The Earth has already experienced a globally averaged 0.7 or 0.8 degree C warming,over the past century, and it may be 3or 4 times that in some regional polar areas.
Anyone who accepts that sunlight falling on ice free waters which has less reflectivity than sunlight falling on a large ice mass covering those waters and also accepts that this reduction in albedo has a positive feedback effect,leading to further warming, can’t help but opt for A or B, it seems to me.
The initial warming, over the past century, has caused a condition at the North Pole, that will only add to this warming, which will lead to further melting, which will lead to a further temperature increase. We may well have arrived on the slippery slope as far as the North Polar region is concerned.
13 December 2007 at 19:50
Who has examined the impact of an ice-free summer Arctic and warmer Arctic waters with release of tundra and Siberian ghg sinks? This looks like a place where feedbacks could multiply.
13 December 2007 at 19:51
AndrewM, while your site says past warming in the Arctic was “largely ignored by alarmist scientists”, it has actually been acknowledged by those concerned about the current, ongoing and global trend. Not only on this site, but on NASA’s, where they point out that regional warming through the early 30’s was much slower. Even at this point (and clearly it ain’t done yet), the current trend is broader in scope.
13 December 2007 at 20:10
Don’t know a thing about what may or may not be in the IPCC models.
However, what seems obvious is that it’s not that the freezer is
completely broken as much as it is that the ice cubes have fallen out.
In other words, what we are seeing is a dramatically more fluid artic.
(at least during the summer and fall)
The increased fluidity is allowing the sea ice to flow out of the artic
at an unprecedented rate.
Perhaps some have noticed that the record minimum sea ice extent when
expressed as a millions-km2 from normal actually occured in October.
This was well after sun set, but at a time before enough freezing took
place to lock everthing into place.
13 December 2007 at 21:10
The difference in albedo between open ocean and ice/snow in the polar region is small due to the low sun angle. An ice-capped ocean cannot cool because the ice blocks outgoing ir radiation, conductance with the atmosphere and evaporation, all potent cooling effects. Net result, arctic ocean cools without ice cap, warms with it, therefore negative feedback.
13 December 2007 at 21:33
A curious difference between the measurement of loss of ice from the Greenland ice cap and loss of Artic sea ice is the different ways these are measured.
Greenland ice loss is measured by volume (or equivalently, mass), which makes sense in terms of the implications for sea level rise. Arctic ice loss is measured by loss of area (extent). Yes, sea level rise is not an issue, and ice thickness is difficult to measure.
Physically arctic sea ice area is important due to it’s influence on albedo, but in terms of melting rate, surely ice volume is more important for the physics?
I’ve had trouble finding estimates of loss of ice thickness, but it is clear that arctic sea ice has thinned considerably. It is quite possible that we are well past half-way - maybe at 75% in terms of loss of arctic sea ice mass.
13 December 2007 at 21:42
I hope Santa is reading this, because it won’t be long before he’ll be needing a boat. He needs to start cracking now, so rather than his little helpers packing Christmas presents, he needs to be making some long term investments in timber and nails for a sustainable infrastructure……hmmmm, perhaps that’s what we should all be doing. I can imagine some future artist showing Santa careering through the skys in his boat, the sledge being redundent, with the reindeer, now extinct, replaced by dolphins.
I think your options are a bit vague. Do options “A” and “B” for instance allow even a small recovery?
What about then option “A”, rapid meltdown of ice until summer free by or before 2013, option “B” no summer ice by 2030, and option “C” summer ice gone by 2080. My option is for “A”, and indeed I think the ice will be gone by 2010.
We will then have the open Arctic Ocean absorbing, from my understanding, about a third more solar energy each summer due to the difference in albedo between Arctic sea ice and open water. This will dramatically accelerate temperature rises in the northern hemisphere, melt the Greenland ice cap, and for a while we are going to have a planet of two halves - a rapidly warming northern hemisphere and a much more modestly increasing temperature in the southern. I am no climate scientist but what would be the estimate of the maximum difference in temperature rises in the two hemispheres and how long is this state of affairs likely to continue?
Merry Christmas everone.
13 December 2007 at 21:57
RC authors: #4 is link spam from our naval-warfare-caused-warming friend. IMHO it should be removed, but at a minimum the live link should be killed.
On the general subject of the early 20th century Arctic warming, scientists inspired by Jim Hansen’s ideas had a look and this was the result:
20th-Century Industrial Black Carbon Emissions Altered Arctic Climate Forcing
Abstract: Black carbon (BC) from biomass and fossil fuel combustion alters chemical and physical properties of the atmosphere and snow albedo, yet little is known about its emission or deposition histories. Measurements of BC, vanillic acid, and non–sea-salt sulfur in ice cores indicate that sources and concentrations of BC in Greenland precipitation varied greatly since 1788 as a result of boreal forest fires and industrial activities. Beginning about 1850, industrial emissions resulted in a sevenfold increase in ice-core BC concentrations, with most change occurring in winter. BC concentrations after about 1951 were lower but increasing. At its maximum from 1906 to 1910, estimated surface climate forcing in early summer from BC in Arctic snow was about 3 watts per square meter, which is eight times the typical preindustrial forcing value.
To see the full paper, go here and scroll down to the publication list.
13 December 2007 at 22:45
John,
I heard a rumor that “Santa” is firing the elves and moving the operation to a coal-powered factory in China. Say it isn’t so.
13 December 2007 at 23:23
John, David reported the choices presented by the speaker, they’re not David’s choices to argue with — David reported what the audience heard and voted on. I was puzzled too, since we know there’s been some refreezing. David, can you clarify what option A meant as presented in the meeting?
I’d guess that looking at the chart, A might mean what seems to be happening now, if the ice doesn’t recover quite a bit in the next couple of weeks. Comparing the last couple of weeks of December for all the years on the chart record, the line did drop about as low last year and then recover as it dropped the last few days. But look back at where it’s been at the end of December in past years.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg
[Response: There wasn’t really any more presented than what I wrote, but I assumed the issue is whether the summer minimum in 2008 will match that of 2007, or whether it would recover somewhat. David]
13 December 2007 at 23:24
Bruce Tabor (#31) wrote:
The NASA satellite data is coming, apparently. But for a some previews…
13 December 2007 at 23:53
I thought I had seen the year 2013 mentioned somewhere before…
13 December 2007 at 23:57
Arctic sea ice thickness:
In 1999 Rothrock et al published a paper showing research from sonar data collected by US Navy submarines that showed arctic ice thickness had declined over large areas of the artic from an average of 3.1 metres to 1.8 metres (about 40%) from 1958-76 to 1993-97.
http://psc.apl.washington.edu/thinning/thinning.html
The following site projected the Rothrock data to predict the arctic sea ice would be virtually all gone by this year, 2007.
http://www.daviesand.com/Choices/Precautionary_Planning/Arctic_Ice/
Not surprisingly there is evidence that this projection is slightly wrong
The following site states German researchers from the Alfred-Wegener-Institute for Polar and Marine Research found that mean ice thickness in September 2007 is 1 metre, down by half from 2001.
http://news.mongabay.com/2007/0914-sea_ice.html
I wont pretend this is a thorough literature review, but it suggests to me that ice thickness is more important than ice extent in determining when the arctic will be sea-ice free in summer, and that we have less than a decade until this occurs - it may be as early as September 2012.
On the plus side, it will be extremely difficult for sceptics to argue against AGW after this “tipping point”. You could always invite them to take an expedition to the north pole by foot, sled, all-terrain vehicle etc.
14 December 2007 at 0:19
If #32, last para., is correct, what effect would a warming northern hemisphere and relatively cooler southern hemisphere have on ocean currents and weather patterns?
14 December 2007 at 1:09
Sea ice coverage in the Antarctic has been larger this summer than last, and shows an opposite trend to the Arctic coverage since the 1970s.
http://www.gsfc.nasa.gov/topstory/20020820southseaice.html
If I were a contrarian saying that, I would be answered “you shouldn’t invest your understanding in just one geographical location - you have to see the whole,” but the same criticism can be applied to the post at the top of this thread.
In the interests of robustness, wouldn’t it be worthwhile acknowledging that qualification and responding to it?
14 December 2007 at 1:35
I’ll put my money on B, but it’s closer to A than you like to admit. The sea ice will continue to accellerate it’s decline until it’s gone- (house of cards scenario) for the short term only during summer, for the medium term until it’s permantly gone, year round. As mentioned by nasa, the apocalyptic ice melt this year preconditions the region for an even more drastic melt the following year (positive feedback at it’s most apparant and stark!) No-one has mentioned the fate of polar bears yet, do we just wash our hands of this species or do we try to relocate as many as possible to sactuaries and zoos?. Canada is a poor option since it will also be largely swamped as sea levels inevitably rise as the greenland melt intensifies. What do you guys think?
14 December 2007 at 4:38
#40 Barry,
The point about the Antarctic is that it’s trend is not considered statistically significant.
Here’s the Arctic - significant.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.area.jpg
Here’s the Antarctic - not significant.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.area.south.jpg
Furthermore there are changes in the Arctic that add to the significance - widespread thinning - see below.
#38 Bruce Tabor,
I agree. There’s good reason to suppose ice thickness is the major factor.
1) It takes as much energy to melt an amount of ice as it takes to warm that same amount from 0degC to 80degC.
2) Thin ice is less mechnically strong than thick. Leads can more easily open in winter allowing ocean to atmosphere heat transfer.
3) In terms of conductive heat loss through the ice, the thickness is the denominator term.
i.e. Q = Ki(To-Tf)/h,
where Ki is a constant, To-Tf is the temperature difference between surface and underside, and crucially the heat flux is Q, h is thickness. So flux is proportional to the inverse of the thickness.
4) By definition the thicker “perennial” ice takes more than one season to re-grow. So natural variation will have a time-lag on ice growth that does not apply to ice loss. Once thinning has occurred this time-domain asymetricality can “take advantage” of weather events.
I see sea-ice thickness as a key factor in limiting the impact of summer melt under ice-albedo feedback. A thin sheet of ice will respond all the more quickly in the melt-season thank will a thick. It’s useful to try to qualitatively visualise the differences between the “old” regime as shown in the first link above, and where we seem to be headed.
14 December 2007 at 5:28
We are talking about it being gone in the Summer only as it is not possible for it to be gone in the winter I presume due to the sunless nature of the arctic but I guess that energy from the summer air and water can reduce the extent of sea ice recovery. Is this what we are seeing?
Due to Antarticas nature of not being surrounded by continents and being a continent its melting potential is different but what is the reality there.
I know that the arctic is warming quicker than antartica but surely the implications of the antartic warming reach further than the arctics warming due to its continental nature a 2 mile thick ice sheets.
The bernard convection cells that are expanding at the tropics are down to the arctic shrinking. Is the same true for the southern hemisphere?
14 December 2007 at 5:41
What is very worrysome here is that arctic sea ice is now being lost faster than thought, and that so little is understood about accelerated glacier flow. Not sure I agree with gavin’s “rolling ball” analogy here. What worries me, in terms of these “tipping points” is that when decadal variability (ex. the positive “natural” AO was mentioned from Morrison) is superimposed on a rising trend in the nonlinear world of sea ice, the system can be pushed across a critical threshold and is unable to return to the initial cyclic state. So if the arctic crosses some point like this, even if we could magically bring conditions back to pre-industrial, the ice may still be like today or worse (and could easily get option “A”). Then you have anthropogenic effects on AO; nearly all scenarios have the AO rising (though not as fast as the ’90s swing).
Unfortunately, the world of ice is a doom and gloom situation (see Lonnie Thompson’s presentation at AGU). Very alarming, but as Ray Pierrehumbert mentioned in the “latest dispatch” this probably doesn’t mean much when we talk about “tipping point or not” because in any case, there are problems. In either case, emissions need to be lowered.
14 December 2007 at 6:05
Re. 36 and 37. Timothy Chase.
Thanks Timothy,
I can see that my line of thinking has been put before - in the National Geographic article you cite and on Real Climate:
http://www.realclimate.org/index.php/archives/2007/08/arctic-sea-ice-watch
I notice (in that thread) Walt Bennett even made the prediction of all permanent arctic sea ice gone in 5 years (2012) and Chris Dillion puts it at 2011. (I posted @38 before seeing your posts.) neither would surprise me, but at this stage I would be surprised if it WASN’T all gone by 2017.
In line with others’ observations, I suspect the reason we get surprised by sudden reductions in the extent of arctic sea ice is that we don’t have a good handle on what matters - the regional distribution and change in ice thickness.
Also I loved Chris Gillon’s suggestion for the name of the new geological epoch: the Ohshitocene - my god what have wwe done!
14 December 2007 at 6:45
Re 32,
“I can imagine some future artist showing Santa careering through the skys in his boat, the sledge being redundent with the reindeer, now extinct, replaced by dolphins.”
We’ve been doing this for a while where I live in Florida.
BTW some of us celebrate alternative holidays around this time of year:
Some call it Squidmas, or Octonoël,
To some, it’s Kopffüßerweihnachten as well
In Spain they will wish you “Feliz Nautilidad”
And think nothing of it–it isn’t that odd.
There are similar phrases in Greek and Etruscan
Expressing a good celebration molluscan
From ocean to ocean, the banner’s unfurled:
It’s Cephalopodmas all over the world!
Posted by: Cuttlefish | November 25, 2007 1:15 PM
http://scienceblogs.com/pharyngula/2007/11/squidmas_is_coming.php
14 December 2007 at 7:02
Naw, we might point out that the second half of your statement is based on a study published five years ago, and ask why didn’t you say “as of five years ago”, rather than imply that your link shows the trend continues today.
14 December 2007 at 7:26
Re 25
Check out Gavin’s responses in 8 & 13. Gavin was the one who brought up predictability, not me. Gavin suggested the analogy of rolling a ball down a plane, not me. Gavin gets to draw the graph, not me.
My opinion is that predicting the climate is NOT a slam dunk. Climatologists are getting better, but they still have a ways to go.
14 December 2007 at 7:30
Bruce at # 38.
Afraid the BBC’s motor programme, Top Gear, did just your last point,
http://www.bbc.co.uk/topgear/show/production_notes/polar_special.shtml
They raced a 4×4 (SUV) versus husky dogs pulling a sled to the magnetic north pole. Though I’m not sure when they held the race, but I think it was shown on TV a couple of months ago.
14 December 2007 at 9:48
re: #40 (barry)
This has been discussed often on other threads. If I recall correctly, the decreasing arctic trend is considerably larger than the increasing antarctic trend. The antarctic increase is does not offset the arctic decrease.
14 December 2007 at 9:49
RE # 16
Mitchell, re-freeze at a rapid pace is not a headline nor is it a sign for hope. Think thickness; not area.
And, the open water of the far Western top of the Bering Strait appears to be adding heat to Barrows AK.
See the following:
13 December, 2007 Global Monitoring Division Hot Items
Exceptionally Warm Winter Temperatures at Barrow, Alaska Baseline
Observatory
Global Monitoring Division - ESRL-GMD
This story entered on 12th Dec, 2007 09:55:45 AM PST
The NOAA ESRL Barrow, Alaska, Atmospheric Baseline Observatory located on the most northerly habited point of land in the U.S, has been continuously measuring meteorological parameters since 1977. In November of this year, the average temperature at the observatory was +14.3F (+8C) warmer than the monthly norm. From December 1-10, 2007, the average temperature has been
+22.2 F (+12.3C) warmer than the long term average for December. These exceptionally warm temperatures are likely due to heat from the warmer Arctic Ocean off shore from Barrow that is still not frozen for this winter.
The Barrow Observatory chief, Dan Endres, who has been at the Barrow observatory for 23 years, notes that in the 1980s the ocean would generally freeze by the middle of October. In recent years, freeze-up has been
occurring progressively later.
14 December 2007 at 9:50
As NASA has reported, the Arctic ice sheet lost half of its volume since 2004. Given the accelerated rate of meltdown, there seems to be little reason to be believe the ice will survive the 2009 summer.
I’m interested in knowing whether sea level rise will affect the equator more than the higher and lower latitudes. Once Arctic ice melts off, I would guess that sea level will start rising rather fast.
14 December 2007 at 10:34
I’ve also heard that decreased cloud cover played a role in this summer’s melt. Was there any discussion about this at the AGU meeting?
Also, climate models used to overpredict summer cloudiness I’m not aware if this is still a problem for the more current models.
Lastly, is there any research on how summer cloudiness in the arctic might change in the future? Or is this something we aren’t able to answer yet, as I suspect?
14 December 2007 at 10:58
Does anyone have a reaction to the sea ice coverage comparisons shown on these images?
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh
14 December 2007 at 11:11
I am selecting option D. It will return to the mean (if we actually know what that is).
Gavin your analogy needs a little improvement. How about rolling a non-spherical ball down an incline of variable slope, that has snow and patchy ice, and a gusting wind, on a rocking boat.
The variability of the ice coverage is an unknown quantity, and the current coverage, although outside the norm to our short record, is most likely to be well within the natural pattern of the system.
Without a coresponding meltdown in Antarctica, there are many situations that can cause the current coverage, and most of them are not indicators of future calamity.
I will agree that it is a solvable problem. But at today’s understanding it is not. This is multi-variable choas modeling, that exceeds our current ability. So make your prediction, and I will make mine, and 5 years from now we will compare notes. Maybe by then we will be closer to understanding a system that continues to hold more mysteries, than the fiction section at the local library.
[Response: Sure. My point was not that climate was as simple as a rolling a ball down an inclined plane but simply that physics allows you to make predictions when extrapolations from short time series do not. - gavin]
14 December 2007 at 11:17
I’ve not found an estimate of how much of last years ice melted within the Arctic Ocean and how much of it left the Arctic Ocean. It looks to me like very favorable conditions for carrying ice out of the Arctic are in the cards.
14 December 2007 at 12:46
Re #54: [How about rolling a non-spherical ball down an incline of variable slope, that has snow and patchy ice, and a gusting wind, on a rocking boat.]
Which might be a better analogy for the current state of climate prediction. But I’d have you notice that while it’s hard to predict exactly what path that ball will take on its descent, or exactly when it will reach the bottom, it’s still a pretty darned good bet that it WILL reach the bottom.
14 December 2007 at 13:18
Patrick, his point was that predictions made from underlying physics differ significantly from predictions coming purely from statistics. It’s still up to you to understand the nature of the predictions made on the basis of physics and form your questions accordingly.
More specifically, the study of climate doesn’t involve predicting specific events or conditions. Asking what the underlying physics predicts for a trend is a valid climate question, asking for an exact prediction of next years ice extent is actuly a question about weather. Perhaps you are under the impression that you must be able to predict events specifically to predict an overall trend, but this could not be further from the truth.
On the topic of Arctic vs Antarctic sea ice, it’s worth point out that the comparison is between summer ice in the Artic and winter Ice in the Antarctic. Winter ice in the Artic is largely bound by the land masses around it, while summer ice in the Antarctica is almost non-existent and therefore also quite stable. Less summer ice in the Artic means lots of sunlight landing on dark water vs reflective ice which can cause further warming. Clearly this isn’t nearly as big an issue for winter ice in the Antarctic.
14 December 2007 at 13:21
Re 54:
Well said.
If it were easily predictable we wouldn’t need smart people like Gavin spending time on the issue.
14 December 2007 at 13:28
Well, my reasoning is - if I vote for sea ice it’s gotta come back!
14 December 2007 at 13:39
Re 57:
I understood Gavin’s point. He picked a very misleading analogy; that was my point.
I understand the distinction between weather and climate. Granted, 5 years is on the very low end of “climate”, but I don’t think you’ll get many meteorologists claiming that predicting arctic sea ice 5 years into the future is in their ballpark.
14 December 2007 at 13:42
Yes it will reach the bottom, except under the extreme scenerio, boat rocks at the same time wind blows, and UFO passes over head at low level
But that only equates to: The ice volume will be greater in January of 2020, than it will be in July of 2020. I am very willing to go out on that limb. It doesn’t take much bravery.
Currently we have such a small signal-to-noise ratio, that most people have become frustrated and impatient, and want to call anything that meets a very broad category, a signal.
If you want to maintain that this is science, and not crystal ball readings, then you have to make sure you can determine the distinction, between the signal and the noise.
14 December 2007 at 15:06
Re: #48. Do you know the difference between the geographic north pole and the magnetic north pole?
14 December 2007 at 16:13
barry (#40) wrote:
Of course — but then let’s look at the whole.
Simply as a matter of the distribution of the continents, we do not expect the Antarctic Ocean to behave in quite the same way as the Artic Ocean, not in the short-run. There is more landmass in the Northern Hemisphere, and ocean has more heat capacity than land, land should warm more quickly, therefore the Northern Hemisphere should warm more quickly.
The Southern Hemisphere sea-ice area broke its previous maximum by 0.9%, the Northern Hemisphere sea-ice area broke its previous minimum by 27%. These really aren’t comparable. Antarctica’s trends are mixed. While there is cooling which been taking place in the continental interior (which is believed to be largely the result of ozone depletion and possible increased snowfall), depending upon the start and end year, much of Antarctica may show either a warming or cooling trend. However, since the beginning of the satellite era, Southern Hemisphere sea ice extent has declined — with most of the decline occuring in the 1960-70s. (See Tamino’s Sea Ice, North and South, Then and Now.)
We had expected the ice mass of Antarctica to show a slight rising trend for some time simply as the result of projected increased snowfall, but according to Grace gravity measurements, Greenland and now Antarctica are losing ice mass, and satellite imaging shows that weeks of melt have been occuring in recent far into the continental interior of Antarctica as close as 310 miles of the South Pole. Meanwhile, nearly the entire coastline of Antarctica is showing strong warming, not cooling.
Finally, when dealing with contrarians it might help to remind them every once in a while that heat melts ice. So long as we continue to raise the levels of gases which are opaque to thermal radiation, we can expect the rising trend in temperatures continue. In broad outline at least, the nature of the response from Greenland and the West Antarctic Peninsula will more or less be a given. And with the feedbacks we have been discovering, the response of both is likely to be quite strong.
14 December 2007 at 16:28
For those keeping score, the global sea ice anomaly is now positive, granted with all that thin ice.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg
14 December 2007 at 17:13
How about coming down the hill at lickety split units of distance per second, and wondering if the driver knows where the cliff is, and if he has a clue where to start stopping to avoid going over the edge. Oh yes, the driver has been known to attempt suicide before. Details about the economics of the situation at the uncertainty principle
14 December 2007 at 18:16
Re #64
I am yet to be convinced that the “end is near”. Your analogy pre-supposes the mountain and the cliff. What if we are just cruising along the interstate in Nebraska, doing the speed limit? Is it approriate to slam on the brakes, just in case there might be a cliff ahead (in Colorado)?
My understanding indicates the CO2 does not have enough ir thermal radiative capacity to warm the planet to a significant degree, and that the fear is that it will trigger positive feed back warming. So far I am not impressed with the real-world evidence that this is actually occuring. My faith in the models, is also not that strong. I looked through Galvin’s model and I was certainly impressed with all the effort that went it to it. But the reality is he has a rich uncle who is willing to put up with it’s lack of real-world performance. If it was a private sector project, and I had to sell it to a paying customer, it would have to match up with the observed data from the real-world. Tweaking the dials on a model that is grossly over-reaching is an exercise in “GIGO”.
I view this as an important issue, but it has not crossed the threshold of “the end is near”.
14 December 2007 at 19:22
Re the golf-versus-bowling-ball comparison in 8:
isn’t this the difference between stochastic and dynamical systems? The central point is to understand that climate equations are not stochastic, they’re in the realm of continuum dynamics. So they comprise differential equations that we can integrate into the future. The GCMs are essentially Navier-Stokes equations on steroids.
At least, that’s how I understand Gavin’s comparison.
14 December 2007 at 19:44
More happy news from the cryosphere:
14 December 2007 at 19:49
Re Russel’s skepticism of the greenhouse power of CO2 in 65, what do you think is keeping the Earth warm? You do know that without CO2, the planet would be something like 33C cooler…right?
14 December 2007 at 20:08
barry (#40) wrote:
Of course — but then let’s look at the whole.
Simply as a matter of the distribution of the continents, we do not expect the Antarctic Ocean to behave in quite the same way as the Artic Ocean, not in the short-run. There is more landmass in the Northern Hemisphere, and ocean has more heat capacity than land, land should warm more quickly, therefore the Northern Hemisphere should warm more quickly.
The Southern Hemisphere sea-ice area broke its previous maximum by 0.9%, the Northern Hemisphere sea-ice area broke its previous minimum by 27%. These really aren’t comparable. Antarctica’s trends are mixed. While there is cooling which been taking place in the continental interior (which is believed to be largely the result of ozone depletion and possible increased snowfall), depending upon the start and end year, much of Antarctica may show either a warming or cooling trend. However, since the beginning of the satellite era, Southern Hemisphere sea ice extent has declined — with most of the decline occuring in the 1960-70s. (See Tamino’s Sea Ice, North and South, Then and Now.)
We had expected the ice mass of Antarctica to show a slight rising trend for some time simply as the result of projected increased snowfall, but according to Grace gravity measurements, Greenland and now Antarctica are losing ice mass, and satellite imaging shows that weeks of melt have been occuring in recent far into the continental interior of Antarctica as close as 310 miles of the South Pole. Meanwhile, nearly the entire coastline of Antarctica is showing strong warming, not cooling.
Finally, when dealing with contrarians it might help to remind them every once in a while that heat melts ice. So long as we continue to raise the levels of gases which are opaque to thermal radiation, we can expect the rising trend in temperatures continue. In broad outline at least, the nature of the response from Greenland and the West Antarctic Peninsula will more or less be a given. And with the feedbacks we have been discovering, the response of both is likely to be quite strong.
14 December 2007 at 20:24
Re: #67 The mother of all GHGs is H20. The rest of GHGs are like planets orbiting the sun. They exist, but are a tiny fraction of the whole. If we don’t have a positive feedback, we don’t have an emergency. We have a very managable situation.
14 December 2007 at 20:47
Re the old water vapor claim in 68:
Water vapor is responsible for about 50% of the greenhouse effect, clouds contribute about 25%, and CO2 and other GHGs contribute the rest. Not “a tiny fraction”. You also need to account for the large difference in residence time between H2O and CO2, which is important for dynamics over long time scales.
14 December 2007 at 22:18
Russell, where on earth are you getting your “understanding”? First we have the empirical fact that Earth is warming rapidly–something must be providing the energy driving this warming. If it is not CO2, then what is is. Second, why do you think GCMs have all these adjustable parameters that can be freely tweaked. Most of the forcings are determined independently of the current warming trend, and greenhouse forcing in particular is nailed down to a narrow range by several independent lines of evidence.
14 December 2007 at 22:30
> I assumed the issue is whether the summer minimum in
> 2008 will match that of 2007, or whether it would
> recover somewhat. David]
Thanks, David, that makes sense.
Heck, we can simplify it — will they have to again add new white space to the anomaly chart, to have room for the line to fit on it, as they did (twice, I think) in the past year.
14 December 2007 at 23:31
Here’s a chance for you to educate us, then.
Please give us an itemized list of the real evidence that warming is occurring, and for each tell us why you find that evidence unimpressive.
My guess is that your list is going to quite short and is going to reveal just how little you know about the overwhelming evidence that’s accumulating, but this is your chance to prove me wrong.
14 December 2007 at 23:47
68,69:
In absolute terms H2O GH forcing is greater than CO2. Unfortunately H2O levels respond very well to temperature increases. If I add a little CO2 (or other forcing) the directly induced warming evapoartes more water, and the H2O forcing increases. This is refered to as a positive feedback -and in this case it operates on a pretty fast time scale ( a couple of weeks ). Some of the other potential positive feedbacks involving methane-hydrate release, or albedo changes due to loss of glacier ice operate on much longer time scales tens to hundreds to thousands of years.
The real difficulties come with some of the feedbacks that are harder to characterize. Potential changes in cloudiness or cloud albedo. Changes of vegeatation, changes in oceanic and/or atmospheric circulation. My nonprofessional opinion is we haven’t encountered all of the surprises in these areas yet. Didn’t the rapidity of the arctic/subarctic vegetation feedback largely catch the climate community by surprise?
To what extent might the black carbon become more important if a significant area of the greenland ice sheet becomes an ablation zone (net melting)? Could the BC become concentrated at the surface as older and older ice melts? This is a big effect on mountain glaciers, but these are many times dirtier than polar ice caps.
15 December 2007 at 4:04
Re: Gavin 65 I have been very impressed as to the accuracy of the computer models the IPCC researchers have been using..they overall forcast current trends very accurately given a narrow standard deviation for unforseens. The rise in ocean temp is bang on the money, the concentrations of CO2 in the atmosphere has been predicted 10 years ago again by computer modelling and it’s also very accurate. What I have noticed however is that most models are slightly too conservative coz they dont factor in the effects of methane and nitrous oxide, ozone and other lesser but contributing greenhouse gasses. So I happen to have a lot of faith in computer modelling, not just because it’s all we have at this point in time but because their history vindicates their effectiveness in the real world. That’s right russell..GIGO….scientists have always been very fastidious and fanatical NOT to feed garbage into their algorithms.
15 December 2007 at 4:06
Re Russell #65:
As someone who has developed models for complex hydrodynamic systems in academia in astrophysics, in national labs on weapons programs, and in the private sector to boot, my $.02 is that you don’t know jack. It is a complete free-market fantasy notion that gov’t funded scientists have models that wouldn’t survive the “real world” of the private-sector, and that somehow having Uncle Sam pay the tab means the quality goes down. Quite the opposite. In my private-sector job, I depend daily on research funded by NASA, NSF, and the NIH, and on models developed by gov’t-funded researchers. That stuff is the best there is. Boeing wouldn’t last a minute without the decades of fundamental aerodynamics research and modeling done by NASA and NACA for the last 60 years. Similar statements could be made about any high-tech industry; take your pick.
As for your opinions on the models, uhm, what is your background? Got radiative transfer and geophysical hydro nailed down? If not, why should anybody other than you place any value whatsoever on your opinion of the models? If you disagree, hey, follow your free-market muse and start a climate model company. Let me know when the IPO is so I can sell short.
15 December 2007 at 4:27
If you really want to know how well the private sector makes models, take a look at how companies model their exposure to risk. Now see, free market forces have made these models very reliable and robust, and this keeps the credit system running smoothly, and…. oh, wait.
15 December 2007 at 4:56
First of all, I didn’t mean to sound shrill in my last posts. I had a bad afternoon, and I didn’t have a proper outlet, so I vented a bit of frustration on the blog, that I should have re-directed to thermal radiation of the troposphere.
I don’t have time to go into a line-by-line discussion of this issue, right now, but I will give you a chance to get your jabs in, soon.
15 December 2007 at 7:18
Russell writes:
[[My understanding indicates the CO2 does not have enough ir thermal radiative capacity to warm the planet to a significant degree,]]
That’s kind of a meaningless statement. What is “thermal radiative capacity?”
[[…So far I am not impressed with the real-world evidence that this is actually occuring.]]
That one quote says it all, I think.
15 December 2007 at 7:20
Russell writes:
[[Re: #67 The mother of all GHGs is H20. The rest of GHGs are like planets orbiting the sun. They exist, but are a tiny fraction of the whole. If we don’t have a positive feedback, we don’t have an emergency. We have a very managable situation.]]
According to Kiehl and Trenberth’s 1997 energy budget for the Earth-atmosphere system, water vapor causes 60% of the clear-sky greenhouse warming and carbon dioxide causes 26%. Also, the water-vapor feedback is indeed a “positive feedback,” so by your own definition, we have an emergency.
15 December 2007 at 7:23
Ref 71 dhogaza writes “Please give us an itemized list of the real evidence that warming is occurring, and for each tell us why you find that evidence unimpressive.” Surely you have got this wrong. What we should be discussing is all the things that show that while the earth’s temperature did increase at the end of the 20th century, temperatures have now stabilized, and the earth is now starting to cool. Such things as the fabulous ski season there was in the southern hemisphere in 2007, followed by an equally impressive one now occurring in the northern hemisphere. The killing frost there was in Argentina on November 14th 2007, which destroyed millions of dollars worth of crops. The enormous freeze of arctic sea ice that occurred in November 2007. The RSU MSS satellite data that shows the earth’s temperature had a negative anomaly in November 2007; the first negative this century. Do you want me to go on?
15 December 2007 at 8:12
Hank Roberts@71: yes, they grew the chart twice in 2007, once from -2 to -2.5, once from -2.5 to -3. I think that the second time they grew the topside as well, for symmetry; at the start of the year it ran from -2 to +2.
15 December 2007 at 9:26
The total world primary energy production in 2003 was 4.4 × 10^20 Joules, which was sufficient to melt 1.3 × 10^3 Gigatons of ice, where 1 Gt = 10^9 metric tons. This figure is about twice the estimated amount of ice actually melted.
15 December 2007 at 11:05
> Do you want me to go on?
Jim Cripwell, Gavin already told you he didn’t want you to go on.
So stop.
15 December 2007 at 11:58
Re #80: [Such things as the fabulous ski season there was in the southern hemisphere in 2007, followed by an equally impressive one now occurring in the northern hemisphere.]
Did you forget the sarcasm button? Fabulous ski season in the northern hemisphere? Not in these parts (the SIerra Nevada). The downhill areas that have opened are running mostly on manmade snow. Didn’t get any significant natural snow until the beginning of this month, and only about a foot so far - conditions more typical of late October/early November.
15 December 2007 at 12:01
Re Jim’s “good news” in 80:
Then there was all that great rainfall in Australia this year that stopped the worst drought in a century… oh wait.
15 December 2007 at 12:39
Jim, (#80)
I also note that the Dow has risen 10 out of the last 21 trading days, and US GDP is at an all-time high. So clearly we can extrapolate that it would be alarmist to speak of a looming risk of a recession, right? Do you want me to go on? Ever hear of cherry-picking? It’s what people do when they’re trying to sell you something, or what they do on talk radio when they want you to feel the delight of righteous indignation. Hardly scientific. Besides, you didn’t even explain why your laundry list was evidence of cooling. Without a framework of understanding, it’s not clear what those isolated events indicate. Why is a very fast refreeze of Arctic ice evidence of cooling? I’m not remotely an expert on that, but gee, seems kind of what you might expect, given the radiative efficiency of open water. If I really wanted to know, I’d ask an expert, not someone with a list of talking points.
Besides, the ski season in the Sierras is lousy so far, so you’re doing cherry-picking upon cherry-picking. Don’t quit the day job.
15 December 2007 at 13:09
#65 Russell:
If it was a private-sector project, it would likely come without source code, and of course it would match up beautifully with past observations
15 December 2007 at 14:39
“No-one has mentioned the fate of polar bears yet, do we just wash our hands of this species or do we try to relocate as many as possible to sactuaries and zoos?. Canada is a poor option since it will also be largely swamped as sea levels inevitably rise as the greenland melt intensifies. What do you guys think?”
At this point, the sea ice in contact with the northern part of Ellesmere Island and the northern part of Greenland is still there year round. The polar bears in the western Hudson bay seem to do fine with the abscense of sea ice for 3 to 4 month a year. It would take quite a bit more warming to achive an abscense of sea ice at the northern part of Ellesmere and Greenland for 3 to 4 month a year. And until that occures there is probably no danger of polar bear extinction.
Speaking of Ellesmere Island, there are fossilized forrests on the island. This would tend to indicate much warmer weather there in the past. Probably warm enough to produce ice free summers at the pole. How did the polar bear survive such a time.
[Response: They didn’t. The Ellesmere forests are from the Eocene (50 million years ago). - gavin]
Concerning the discussion of the tipping point and the heating effect due to loss of albedo, the question I have is, how did we then get back to ice ages in the past, when all of the polar ice was melted and there was no ice caused albedo. Shouldn’t the earth have continued to stay too hot to allow ice ages to return under that scenario?
15 December 2007 at 15:48
Jim Cripwell, you’re saying that one negative temp anomaly in 7 years is proof that the Earth is cooling. That’s grotesque. It seems that you have a serious double standard on burden of evidence. Imagine all the things I could say on GW and AGW if I allowed myself to make such a jump to conclusion. Gee, the possibilities…
15 December 2007 at 16:22
Tilo Reber@87: “It would take quite a bit more warming to achive an abscense of sea ice at the northern part of Ellesmere and Greenland for 3 to 4 month a year. And until that occures there is probably no danger of polar bear extinction.”
This is exactly what the arctic sea ice specialists are talking about. What else do you suppose they mean when they say “an ice-free arctic summer”? Which they predict for, variously, 2040, 2035, 2030, 2025, 2017, ….
And the models say that once the summer ice is gone, it’s not easy to bring it back. The heat that could melt a single metre of sea ice (e.g. first-year ice) can heat (say) the top 40 metres of open ocean by 2 degrees C.
The polar bears are in serious jeopardy. There are presumably some areas of fast ice, e.g. on the coastal areas which you mention, especially the northern coast of Greenland - cooled by the ice sheet - which might work as natural refuges.
While I’m here, can I encourage anyone wittering about the rapid November regain in sea ice firstly to notice that this was predicted by the experts and secondly to take a look at the chart.
15 December 2007 at 17:11
Re 34: STOP PRESS:
A most recent and reliable information, although not yet corroborated by independent sources, is that Mr. Santa will be mothballing his multiple North-European industrial operations due to the dismal near term forecasts of snow availability. This will, of course, be a great loss to the regional economies.
He is reported to be negotiating a transfer of the Swiss/French treaty covering the CERN facilities. These extensive cave labyrinths will be on the market in the near future as the elusive Higgs boson will soon be trapped. Their proposed major project of actually demonstrating the Big Bang has now definitely been rejected for EU Framework Program funding.
The CERN facilities are ideal for political reasons. Santa’s famed Earth Rotation Switch (ERS) has to be guarded at all costs against any and all prospects of weaponizing. As has been known for some time, the ERS allows its possessor to perform quite impossible feats of global delivery - although with some undesirable side-effects. For instance, it actually has been observed to turn minutes into hours during some evenings, after the sunset.
The new facility will be powered by a New Sahara Solar Corporation plant to be located nearby.
The plan is reportedly backed by serious money from the usual suspects in Shanghai. We are formally assured by our confidential sources that the trademark photo opportunity “Me, on the knee of Santa” will continue to be available to the millions, but without the current airport congestion problem.
Season’s Greetings!
Pekka
15 December 2007 at 17:23
Re # 87 Tilo Reber’s question about polar bears on once-forested Ellesmere Island and Gavin’s response:
Had polar bears existed when Ellesmere Island was forested, they probably would have been eaten by the carnivorous dinosaurs that lived in that region:
http://www.athropolis.com/arctic-facts/fact-dinosaur.htm
15 December 2007 at 17:49
“They didn’t. The Ellesmere forests are from the Eocene (50 million years ago).”
Good point Gavin. So let’s bring the time in some. How did the polar bears cope during the Holcene optimum? If the temperatures were higher than today, then can we also assume that the Arctic sea ice melted in the summer? I seem to remember hearing that there was a period of time when the Atlantic and Pacific bowhead whales could visit each other in the Arctic.
15 December 2007 at 23:19
I have a couple of temperature charts that I would like you all to verify. One is an RSS temperature anomaly chart and the other a HadCRUT3 temperature anomaly chart. These would seem to be very important, but I don’t know if I can trust them, considering their source.
http://www.junkscience.com/MSU_Temps/RSSglobe.html
http://www.junkscience.com/MSU_Temps/HadCRUG.html
If these can be verified, then it seems that we are in the same place - temperature anomaly wise - in Dec of 07 as we were in Dec of 79. How would that be possible with CO2 having gone from 340 PPM to 380 PPM and with the Arctic albedo having significantly decreased?
Thanks for any information.
16 December 2007 at 5:48
#80
You’re kidding, right? That’s the sort of pop science thinking plaguing the White House and congress, members of whom don’t appear to understand grade school science.
As an aside, I’ll second the new epoch, ‘ohshitocene’. My eleven year old son nearly choked laughing…until he remembered that it was the epoch in which he’d be growing up.
16 December 2007 at 11:44
“You’re kidding, right? That’s the sort of pop science thinking plaguing the White House and congress, members of whom don’t appear to understand grade school science.”
Thank you Sonny. I don’t mind the personal attack. But it would have been nice if you had answered my questions as well.
16 December 2007 at 12:41
Re #87: [Speaking of Ellesmere Island, there are fossilized forrests on the island. This would tend to indicate much warmer weather there in the past.]
Or perhaps, given that it was 50 million years ago, that Ellesmere Island was located somewhat further to the south?
Continents do move around, you know. In connection with which, we might consider the formation of the Central American land bridge, which separated the Atlantic & Pacific oceans. It’s interesting to note that this happened only about 3 million years ago, IIRC about the same time that the current cycle of ice ages kicked off. Maybe some cause & effect?
16 December 2007 at 13:30
You can’t just compare two points as you seem to be doing with the RSS data, at least.
Ask yourself: why has the junkmeister failed to plot a trend line on that graph?
Um, in December the Arctic is dark 24 hours a day, why would its albedo have any effect during this month?
16 December 2007 at 14:28
Re: 89
Draw a straight line through their graphs, and you see undeniable warming surrounded by random noise (and a few unpredictable, yet significant factors such as El Nino and Volcanoes). The anomaly at any given moment depends on any number of things. We’ve seen warming of 0.4 to 0.5 degrees over the satellite era, which is just about the same as the magnitude of the noise from year to year. So you can take “cold” months from the last few years, and compare them to “warm” months 30 years ago, and then conclude that “there is no warming.” That is Cherry-Picking in the extreme.
These is the temperature anomalies for GISS (instruments), Hadley (instruments), UAH (satellites), and RSS (satellites) since the beginning of the satellite era. The X axis is “months since Jan 1979.” The anomalies have been shifted upwards or downwards to give each trend a y intercept of 0.
http://cce.000webhost.org/giss.jpg
http://cce.000webhost.org/hadcrutv.jpg
http://cce.000webhost.org/uah.jpg
http://cce.000webhost.org/rss.jpg
Tamino has a few posts on this subject:
http://tamino.wordpress.com/2007/12/16/wiggles/
http://tamino.wordpress.com/2007/08/31/garbage-is-forever/
http://tamino.wordpress.com/2007/10/16/many-factors/
16 December 2007 at 14:31
Re #89
Tilo read this: http://tamino.wordpress.com/2007/12/16/wiggles/
16 December 2007 at 16:47
Polar bears may be the most visible potential victims of an ice-free actic, but the entire ecosystem may be in peril. Turns out that “Ice algae are a very important part of the marine food web, contributing on average 57% to the total Arctic marine primary production.”Krembs & Deming
Worst case both the pelagic and benthic arctic ecosystems could collapse. So walrus, seals, and the acrtic cod are endangered.
Tipping points indeed. Why, exactly, did we bother to save the baby harp seals?
Tim
17 December 2007 at 9:33
Just this last week December 13, 2007 RUSH Limbaugh bravely announced that artic ice coverage was recovering at a record rate. Well that IS a load off! (sarcasm) I can’t wait to find out what the man thinks about peak oil.
Patrick
17 December 2007 at 11:05
As another piece of the 2007 Arctic sea ice puzzle, my group at Colorado State just submitted a paper to GRL on the 2007 ice anomaly. We found that 2007 was quite anomalous in terms of cloud cover over parts of the Arctic, especially the western Arctic where much of the ice anomaly occurred. Amazingly, Fox covered the story at AGU - you can read about it here:
http://www.foxnews.com/story/0,2933,316753,00.html
The paper will not appear for a while, but the gist is that cloud cover in 2007, especially June and July, was 10-15% lower in the western Arctic, and this coupled with the especially thin sea ice probably played an important role in the massive ice melt. The extra sunshine was enough to melt roughly 0.3 m of ice directly, or warm the surrounding oceans by about 2.4 K.
17 December 2007 at 12:10
Re #106
Since AGW is contagious through-out our solar system, Mars should be melting its ice-cap any day now. That will release CO2 and water vapor, and all kinds of nasty GHG’s into the atmosphere. It will reach the tipping point, and make the planet habitable.
It could be the perfect refuge for polar bears, walrus, and all manner of cold weather critters.
17 December 2007 at 12:29
Any idea what has gone wrong with the charts over at Cryosphere Today?
17 December 2007 at 13:26
I will no longer be commenting on this blog as I’ve begun work on my first novel. It’s called “The Sea Ice Also Refreezes.”
17 December 2007 at 13:41
Tim, thank you very much for this link, it’s answered a lot of questions I’ve had about how and when and where in the sea ice the algae grows. And _that_ answers what changes in the absence of sea ice. Repeating it:
http://www.arctic.noaa.gov/essay_krembsdeming.html
This is part of “primary productivity” — scary to see changes at this basic level.
17 December 2007 at 14:14
Re #111, Uh, Russell, do you have even a vague notion of what drives climate on Earth, let alone on the other planets? Venus is dominated by a runaway greenhouse effect. On Earth insolation and greenhouse gases are important. On Mars, insolatin and dust storms are the main drivers. By the time you get to Jupiter, insolation is less important–Jupiter gives off more energy than it receives from the Sun. Maybe you should listen to Mr. Twain: “What gets us into trouble is not what we don’t know. It’s what we know for sure that just ain’t so.”
17 December 2007 at 16:11
Re #110: Chris, the decreased cloud cover had been mentioned as a major factor at the time of the minimum. I’ll look forward to reading the paper to see the details, but does it include (or do you have) any thoughts as to why there was such a large reduction or whether there’s any reason to expect more of the same in the near future? Also, I believe Maslowski’s results don’t assume a major trend in cloud cover (or at least that wasn’t mentioned in the abstract or press coverage), so I’d appreciate knowing your view as to what can be expected if cloud cover recovers.
17 December 2007 at 16:51
re: #110. Chris, does this mean Arctic heat transfer processes are dominated by the direct radiative process and less so by convective heat transfer between the ice and the atmosphere? It would seem that during the long Arctic Winter radiative cooling dominates over convection from the tropics as ice is added during this period.
How do the structural-dynamics causing breakup, and thus increasing the surface area-to-volume ratio between the liquid water and the solid ice, fit in? The surface area to volume ratio between the ice and the atmosphere also increases, but 90% of the ice is under water.
In general I’m asking what are the dominant structural, hydrodynamic, and energy-balance related (radiative and convective heat transfer, for both the atmospheric and the ocean) phenomena and processes that govern the decreases and increases in Arctic ice volume?
Thanks
17 December 2007 at 17:00
Re #116 - Steve, we really do not know the ultimate reason for the decreased cloud cover this year. There was anomalously high Arctic SLP this year - so it could be related to the phase of the NOA or AO, but we’re really not sure at this point. We only conclude that thinner sea ice in the future will be more vulnerable to the variability in cloud cover. It could very well be that there is a feedback loop between sea ice and cloud cover, but that remains an open question and is beyond the scope of our paper. By the way, a rough time series of June+July cloud cover over the western Arctic from MODIS-Terra data for 2000-2007 is
2000: .54
2001: .65
2002: .57
2003: .63
2004: .52
2005: .46
2006: .58
2007: .40
(70+ N latitude, 120-180W longitude)
So you can see that 2007 was quite anomalous, but so was 2005 (which also had a very low ice amount). -Chris
17 December 2007 at 17:14
Re #117. Dan, I think I’ll have to defer this question to an expert on Arctic sea-ice modeling, which I am unfortunately not. I am more of an expert in the remote sensing of cloud properties using satellite instruments, which is my connection to the paper I referred to. I can only speculate that all the processes you mentioned are important, and that probably their relative level of importance changes from the arctic winter to the arctic summer. Certainly direct radiative processes are very important in both summer and winter, but then again I would guess that so are vertical (ocean-atmosphere) and horizontal (ocean-ocean) convective processes. -Chris
17 December 2007 at 17:18
Who’s going to the Orlando meeting on the oceans and climate? March 2-7
http://www.sgmeet.com/aslo/orlando2008/allsessions.asp
17 December 2007 at 18:04
552 billion tons of ice melted this summer from the Greenland ice sheet, according to preliminary satellite data to be released by NASA Wednesday. That’s 15 percent more than the annual average summer melt, beating 2005’s record.
By SETH BORENSTEIN (quoting f.i. abdalati and serreze NSIDC)– 5 days ago / associated press
Can anyone confirm this? Is this 552 km3 for real? That would be a pretty awkward melt-explosion.
17 December 2007 at 18:32
re #104 “Or perhaps, given that it was 50 million years ago, that Ellesmere Island was located somewhat further to the south?”
James, this is from a link that Gavin was kind enough to provide.
“Paleolatitude studies suggest that the forest lay close to its present high-latitude position during the Eocene.”
17 December 2007 at 18:40
re #108 “Turns out that “Ice algae are a very important part of the marine food web, contributing on average 57% to the total Arctic marine primary production.””
Tim, it’s fascinating that there is enough energy inside the ice to allow these creatures to thrive. One thing did catch my eye in the article.
“it provides a habitat for photosynthetic algae and nursery ground for invertebrates and fish during times when the water column does not support phytoplankton growth;”
If the ice melted and the water was warmer, then would phytoplankton growth be supported? And would phytoplankton be a replacement microscopic food source? In Hudson bay, where it is melted 3 to 4 month a year, what is the microscopic food source that supports the food chain all the way up to seals and polar bears?
17 December 2007 at 19:43
Re #107
Phil - thanks I read the article. It was very informative. It also brought up some questions. Let me try them out on you.
1. How do you select a timescale to determine if a trend is significant? Let’s say we throw out the El Nino year of 1998. Then we are saying that the slope established in the 22 years from 1975 to 1997 is significant, but the slope established in the 8 years from 1999 to 2007 is not. Somehow that doesn’t have a good intuitive feel to it.
2. Let’s say that I accept that the slope from 1999 to 2007 is noise. Then comparing our current temperature chart to the hypothetical one created at your site, it would look like we are now at the very edge of the noise band. In fact, one might argue that the RSS data puts us over the band. This means that the temperature will have to start back up very soon or we will be out of the band and the data will become signal rather than noise. Guess we’ll have to do a wait and see for that one.
3. The modeling experiment that we are talking about only tells us that the noise bands are just wide enough so that the temperatures that we have seen for the last 8 years could be noise. It doesn’t tell us that they are noise. That will be decided by the data that comes out in the next 2 to 3 years.
4. I have a bit of a problem regarding anything in nature as noise in the same way that we generate computer noise. I don’t think that there is such a thing as noise in nature. We may identify major forcing trends and say that they represent the long term trend. And we may say that the noise represents a large number of minor and possibly unidentified forcing factors. But when you say that a forcing factor is and will remain the major forcing factor when you only have 22 years of data, and when the other forcing factors are neutalizing your dominant factor, even for 8 years, I think that is saying too much.
5. The other thing that I wonder about is the modelers desire to use a 0.018 deg.C/yr CO2 forcing factor. And let’s say I accept that. But CO2 forcing is not linear. Supposedly the frequency band that CO2 is good at absorbing is already mostly absorbed by the current level of CO2. So more and more CO2 gives us less and less forcing. Can we know that there is enough residual forcing in CO2 to maintain a 0.018 deg.C/yr slope for any significant number of years?
17 December 2007 at 21:17
Re #121
552 km^2 is nothing compared with the additional 1.5 million km^2 of sea-ice that melted in the arctic in excess of the previous record.
17 December 2007 at 23:34
Re #118: Thanks for the response, Chris. What’s most interesting is 2006 since it would have been another record low had it not been for an August cold snap (see NSIDC’s 2006 season report here). So perhaps Maslowski is right that it’s the warm water intrusion.
18 December 2007 at 4:08
The polar bears are on land, and eat very little if at all, during those months. Then when it freezes, off they go. Mmmmmm, fat juicy seal, smack-smack, chew-chew, tastes good after not eating for so long!
Those who claim that polar bears will easily adapt to a more terrestrial lifestyle seem unaware that they’ve lost the habit (and perhaps the