A few people have already remarked on some pretty surprising numbers in Arctic sea ice extent this year (the New York Times has also noticed). The minimum extent is usually in early to mid September, but this year, conditions by Aug 9 had already beaten all previous record minima. Given that there is at least a few more weeks of melting to go, it looks like the record set in 2005 will be unequivocally surpassed. It could be interesting to follow especially in light of model predictions discussed previously.
There are a number of places to go to get Arctic sea ice information. Cryosphere Today has good anomaly plots. The Naval Sea ice center has a few different algorithms (different ways of processing the data) that give some sense of the observational uncertainty, and the National Snow and Ice Data Center give monthly updates. All of them show pretty much the same thing.
Just to give a sense of how dramatic the changes have been over the last 28 years, the figures below show the minimum ice extent in September 1979, and the situation today (Aug 9, 2007).
The reduction is around 1.2 million square km of ice, a little bit larger than the size of California and Texas combined.
Update: As noted by Andy Revkin below, some of the discussion is about ice extent and some is about ice area. The Cryosphere Today numbers are for area. The difference is whether you count ‘leads’ (the small amounts of water between ice floes) as being ice or water – for the area calculation they are not included with the ice, for the extent calculation they are.
Update: From the comments: NSIDC will now be tracking this on a weekly basis.
Jeffrey, it’s a longterm variable. Look for info on
Arctic and North Atlantic Oscillations (AO/NAO)
RE: #395 – RE: Siberian river impacts / salinity – the truth is, as I stated here previously and over on other blogs, it’s an area warranting further study. That has been and remains my point. Try as you may to pigeonhole me into some politcal category you may have, the science is what it is, and the gaps in the science are what they are. If you deny this, then, you are anti science.
RE: #397 – I am confident that since 1979, there has indeed been a trend in sea ice extent reduction at summer minimum. Prior to 1979, there are some real challenges with data. By the way, 5m thick ice is a formidible thing. It that as thick as it gets, obviously not. But it’s nothing to sneeze at either.
Re #398
Wayne,
I have identified the error in the atmospheric trend calculations. The OLR scheme used in all the GCMs (they all use roughly the same scheme) is wrong. Put simply, it is based on the idea that the forcing from greenhouse gases originates high in the atmosphere. In fact the greenhouse gases absorb in the bottom 30 m of the atmosphere. It is this warming of the air adjacent to the ice which is causing it to melt.
The skeptics have pointed out this error, but claimed that since the the greenhouse bands are saturated increasing CO2 cannot cause global warming. What they are missing is that as CO2 increases the saturation happens closer to the ground. This causes surface ice to melt, reducing planetary albedo, and so CO2 indirectly causes global warming.
Of course, any criticism of the models by the skeptics has been shouted down very loudly, as no doubt will this post if it appears.
*Also Horrified #379,
On it’s own a 12.5% difference on a timescale of 1 year would not undermine the models, 1 year is weather, not climate, and nobody says that the climate models do weather. The key issue is that of ice thickness which is a consequence of age, the older the thicker. It’s the loss of perennial ice starting with the behaviour of the Arctic Oscillation that has so weakened the ice sheet that we now might be facing an ice-free summer Arctic Ocean much earlier than modelled.
The mechanism for the loss of perennial ice in the 1990s has been identified, it was the Arctic Oscillation (AO), read more on this page: http://www.jisao.washington.edu/ao/
Now if you look at a plot of the AO: http://www.arctic.noaa.gov/detect/climate-ao.shtml you’ll see it was a period dominated by low pressure over the pole, or a +ve AO index. And if you look at the message below (to Larry) you’ll see a link to a paper. Figure 3 of that paper shows how in 1989 there was a change in the ice area(and extent) from 1989, and going back to that plot of the AO you see it’s strongly positive for some years after 1989. For a more detailed monthly plot of AO see the bottom of this post.
So yes the AO behaviour in the 1990s did pre-condition the whole sheet to where it is now. The only one of your list I wouldn’t reject as having a big role in what we’re seeing is the polar cyclones, don’t know enough (yet) to make an intelligent comment.
If we are at a transition point in ice sheet behaviour caused by a loss of the integrating (time averaging) effect of old ice, then I don’t think modelling will be useful over decadal timescales. The good news is that by 2100 the modellers will have the data they need to make skillful models of icesheets. ;)
*Larry #391,
I too can heartily recomend the link you posted.
Sourced from that pdf, here’s another: “Variations in the age of Arctic sea-ice and summer sea-ice extent.”
Rigor/Wallace GRL 2004.
http://seaice.apl.washington.edu/IceAge&Extent/Rigor&Wallace2004.pdf
That’s well worth reading. Doubtless there’s other good stuff at the end of the links in that Environment Canada pdf.
*Jeffrey Davis #399,
I don’t know, but it doesn’t sound like a naive question to me. You can see a detailed plot of the AO here: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/month_ao_index.shtml The red, +ve anomalies relate to high pressure north of 20deg.
This is off topic as my comments usually are, but I can’t resist.
#394 (SteveSadlov): “Wrong Bloom. I am a responsible, scientifically informed environmentalist. I want facts. Science. Numbers. Accuracy. I abhor politics, blather, hype, feelings-based decision making, etc. Is it too much to ask?”
From the “The Human Hand in Climate Change” RC post earlier this year:
#60 (Steve Sadlov) environmentalists were “recruited by the KGB during the late 1960s and early 1970s to undermine Western strategic defenses.”
Sorry for the OT, but since Bloom dragged me down into the mud …. ;)
Since we are (or at least I am) open kimono here today, allow me to share my actual politics, just so we can move on once and for all from the subject. I am a former Trotskyite. Currently, I mix and match. Take a dab of JFK-ism, mix in some Reaganism. Add a dash of Disraeli. Season with Churchill. Bring to a boil. Top off with a bit of John Jay. Allow to cool. Garnish liberally with Jeffersonian Democracy. Serve.
OK Bloom, your turn.
RE395
Oh go on, post the link! I enjoy a good laugh…
FYI:
http://aasi-campaign.gsfc.nasa.gov/processstudy.htm
re: 406
Add a dash of Disraeli. Season with Churchill. Bring to a boil. Top off with a bit of John Jay. Allow to cool.
You’re a cannibal?
With regard to KG’s question about the age of the ice (#400), the first figure in this report referred to by Larry gives a good idea, basically not much as old as 10 years anymore (most
Please allow me to come back on this (provocative) #360 2008-bet topic. Should I understand nobody here can scientifically proove (you know, using some Popper’s Falsifiability) that it won’t happen? Such a bet was just not conceivable only two years ago, in 2005. Reality now makes all of us consider that Arctic Collapse can really happen, say, by 2015 – right now, more people would probably bet on 2015 rather than on 2080!
So, I feel that Models Collapse has already happened… this year. Events don’t follow a linear curve these days… so, the next question should be: which credit can be given to other predictions on THC evolution or Greenland Ice… as I feel a) they are complex phenomenons, b) data series are short and incomplete… just as the Arctic equation?
> nobody here can scientifically proove … that it won’t happen?
Nobody in the sciences will prove that anything won’t happen.
If you want proof, you want either mathematics, or religion.
Readers here have seen me rant and rave about the importance of marine-freshwater-sea ice interactions and feedbacks as being important to the loss of Arctic sea ice. However, I never posted a cite. Here is one: http://www.acia.uaf.edu/pages/scientific.html Chapter 9 Marine Systems; or, ,http://www.acia.uaf.edu/PDFs/ACIA_Science_Chapters_Final/ACIA_Ch09_Final.pdf
Sorry I’m a slow learner, it would appear that the ‘less than’ symbol terminates a post!
With regard to KG’s question about the age of the ice (#400), the first figure in this report referred to by Larry gives a good idea, basically not much as old as 10 years anymore (most less than 5 years old).
http://seaice.apl.washington.edu/IceAge&Extent/
#403 Allastair,
30 meters seem a bit shallow, but for your hypothesis to be correct, inversions must weaken all over the world, especially in the mornings with places which have normal days and nights. In the Polar region (the ultimate long day or night) inversions have been mainly weakening as it got warmer, that is a sign that you may be correct. It would be nice to have access to a super computer now and identify the the height were the warming is mostly strengthening.
In favour of higher altitude warming there is some visual evidence, when the twilights of the long Polar nights are seen brighter (refractive mirror made at the boundary between cold surface and a warmer mid troposphere) , again I suspect that Upper Air data will confirm that the mid troposphere is warming as well.
This leaves us with the dilemna, where is the code error? It is probably in computer programmed rejections, such as abnormal weather conditions, like “hot”Polar anticyclones, as said before they are hard to explain, yet alone accept. The fact that they exist and appear at random intervals and locations favours the warmer mid troposphere though. Otherwise if everywhere warms at 30 meters at the same time, you would see a more uniform effects. The Polar Ice appeared to have melted more around where there were semi permanent anticyclones, the ice didn’t appear to melt just as much say North of Spitzbergern right by the hottest North Atlantic in years. Please look at
http://arctic.atmos.uiuc.edu/cryosphere/sea.ice.movie.2007.mov
The question begs to look back prior to the melt down, taking us to the very location where the last ice remains today, at that same location there was extremely cold weather in March of 2007, -50 C up there, and -46 in Resolute. If there was a continuous warming at 30 meters everywhere, there wouldn’t be this massive meltdown only over the Arctic gyre area but also over the ice next to the archipelago, especially near land, given that the whole Canadian High Arctic had a very warm summer. In March as well, while the Canadian Arctic was freezing really strongly Coastal Siberia had very mild weather, again assymetric conditions which can happen with a warmer mid troposphere, but not with a lower troposphere. Remains to find many other clues given the uniqueness of this extensive meltdown. But you have to explain why there was assymetric melting before convincing that it melted from warmer air 30 m high.
Someone had mentioned that they thought the East passage would open this year:
http://www.natice.noaa.gov/pub/West_Arctic/Laptev_Sea/2007/currentcolor.pdf
Anyone up for a bet?
There is also a small fallacy in believing that this is a “normal” year, the deadlines for ice minima extent times shouldn’t be the same , 20 September is always used, freezing under the low sun may occur at a later time, the calculation to make would be to find the exact sun elevation when it is not high enough to have any effect. At 30 degrees its hot enough to melt the most frozen snow scape. Now the surface which was once snow on ice is sea water at +4 degrees C…
I’ve been lurking here a long time and reading, with interest, the different views. After reading RealClimate, the IPCC reports, and many different sources on the Arctic Ocean and Ice and the Greenland Ice Cap, it seems obvious to me that we have seen a tipping point crossed with respect to the Arctic Ocean. Summer Arctic Ocean Ice after 2015 (my time-series analysis said 2012) would require a change in the other direction.
Greenland, yesterday, saw religious leaders praying for the glaciers to stop melting. Reported on many online news sites. IMO, the climate reports I read did not appreciate, or at least literally state, the speed of change that could occur on Greenland with the positive feedback of meltwater movement and an exposed, warming landmass. By 2050, the business as usual scenario with fossil fuels will provide the distinct possibility of a Greenland that is, well, pretty green.
All these reports, and the speculation they bring, are interesting but in facing reality individuals, businesses, and, most of all, governments should consider today where all the water that’s coming from those glaciers will be in a very few years.
For you and I, we need to remember, that car key in our hand is a dangerous weapon. Think before using it.
http://www.natice.noaa.gov/icefree/FinalArcticReport.pdf
Does this page make these penguins look fat?
http://science.natice.noaa.gov/images/newbanner.png
And when did these two start hanging around together?
http://science.natice.noaa.gov/images/symbol.png
But seriously, Mr. Sadlov points to last week’s picture; checking this week’s data, it’s cooling a bit, that’s true.
http://science.natice.noaa.gov/icImages/85_07251_n_12z.png
http://science.natice.noaa.gov/icImages/cv_07251_n_12z.png
http://science.natice.noaa.gov/icImages/bs_07251_n_12z.png
RE # 418, Mike T,
you said:
[it seems obvious to me that we have seen a tipping point crossed with respect to the Arctic Ocean.]
Amen.
You told us what the science community will need 20 years to verify. At which point, what will it matter when they report what you already know.
I believe what I read and see; and I accept the reality that Artic ice will never return to its pre-1979 state. Now what?
We would not know a tipping point if it was hitting us in the face.
With the dramatic melting of the Arctic ice this year , even affecting the arctic basin where most of the multiyear ice is to be found I can forsee the arctic being largely ice free by 2012 unless a dramatic reversal takes place .
Hank,
Thanks for the spelling help, but what I really am looking for is a specific citation of or reason why you believe climate feedbacks are fundamentally different from those in electronics or control systems theory, or even why this would be an important distinction. Nothing I have read indicates this to be the case (apart from non-specific blog assertions without substance).
Regarding “Hansen’s early work”, would this be the 1984 paper where, “We use procedures and terminology of feedback studies in electronics (Bode. 1945) to help analyze the contributions of different feedback processes?”
I read this site regularly, and wholeheartedly support it. If you or RealClimate choose to alienate all of the technical engineering folks, so be it. By not using the topic of feedback concepts as opportunity for some cross-discipline understanding, or worse, assert that they are wholly different between disciplines, you perform a disservice to the cause of this site.
Instead of relying on these software-generated maps, why not use the polar orbiting MODIS satellites and see the visible picture yourself in real-time (hour or two old that is.)
http://rapidfire.sci.gsfc.nasa.gov/realtime/
Alastair McDonald (#403) wrote:
Its simply radiation balance theory. For the climate system to reach equilibrium, the rate at which energy is leaving the system must equal the rate at which radiation is entering the system. This equilibrium has to be established at the top of the atmosphere where energy is both entering the system in terms of sunlight, leaving the system in terms of albedo, and leaving the system due to the earth’s longwave emissions. The average surface temperature must rise until this equilibrium is reached – simply as a matter of the conservation of energy.
Alastair McDonald (#403) wrote:
I gave you a large body of evidence that reemssion takes place throughout the atmosphere at many wavelengths. (Please see: Part II: What Angstrom didn’t know, comment #555.) Likewise, if water vapor rises, energy will be lost by collisions to thermal emissions by greenhouse gases at any given altitude where it reaches. And given the Maxwellian distribution of kinetic energy and its long tail, collisions will result in thermal emissions which will take place throughout the atmosphere. (See my comment #444 and Ray Ladbury’s #619 in “Part II: What Angstrom didn’t know.”) And for radiation to escape the climate, it must climb through the upper layers. If it is within part of the spectrum which the atmosphere is particularly opaque to, it will be subject to absorption and reemission.
Alastair McDonald (#403) wrote:
If it were truly saturated at all wavelengths and for all altitudes, then global warming due to additional greenhouse gases could not occur. But the absorptivity of the wings increases as the centerline becomes saturated. But there is line broadening do to pressure and band broadening due to temperature.
Alastair McDonald (#403) wrote:
Within that part of the spectra where carbon dioxide would operate at the surface, the spectrum is already saturated due to water vapor – which exists in far greater quantities. Doubling the amount of carbon dioxide where water vapor dominates will be quite neglibible. In fact, this is precisely what A Saturated Gassy Argument was about. However, water vapor drops quite rapidly as the altitude increases, and carbon dioxide plays a very significant role at the higher altitudes even when the center of a given line or band is completely saturated – as the marginal absorption takes place further and further into the wings. This is what Part II: What Angstrom didn’t know was about.
But you may also want to see what Eli has to say over at his blog.
Alastair McDonald (#403) wrote:
Shout. Shout.
Re #405: Thank you, Joseph. There’s lots more like that to be found for anyone who cares to do a search.
Re #407: Here ya go, Sadlov in all his glory. Start with comment #73 and read through to the end.
As I say, what bothers me is not so much that he’s a denialist, but all the evidence-free hand-waving.
Re #420: Yep, if he keeps predicting it, eventually he’ll be right, and this could even be that time. The problem is that he started with these prognostications at least two weeks ago. It wastes everyone’s time.
This article on events in Greenland this summer quotes some pretty amazing statistics. The associated scientific reports should make for gripping reading. Excerpt:
‘Robert Corell, chairman of the Arctic Climate Impact Assessment, said in Ilulissat yesterday: “We have seen a massive acceleration of the speed with which these glaciers are moving into the sea. The ice is moving at 2 metres an hour on a front 5km [3 miles] long and 1,500 metres deep. That means that this one glacier puts enough fresh water into the sea in one year to provide drinking water for a city the size of London for a year.”
‘He is visiting Greenland as part of a symposium of religious, scientific, and political leaders to look at the problems of the island, which has an ice cap 3km thick containing enough water to raise worldwide sea levels by seven metres.
‘Yesterday Christian, Shia, Sunni, Hindu, Shinto, Buddhist and Jewish religious leaders took a boat to the tongue of the glacier for a silent prayer for the planet. They were invited by Bartholomew I, the spiritual leader of 250 million Orthodox Christians worldwide.
‘Dr. Corell, director of the global change programme at the Heinz Centre in Washington, said the estimates of sea level rise in the IPCC report were based on data two years old. The predicted rise this century was 20-60cm (about 8-24ins), but it would be at the upper end of this range at a minimum, he said, and some believed it could be two metres. This would be catastrophic for European coastlines.
‘He had flown over the Ilulissat glacier and “seen gigantic holes in it through which swirling masses of melt water were falling. I first looked at this glacier in the 1960s and there were no holes. These so-called moulins, 10 to 15 metres across, have opened up all over the place. There are hundreds of them.”
‘This melt water was pouring through to the bottom of the glacier creating a lake 500 metres deep which was causing the glacier “to float on land. These melt-water rivers are lubricating the glacier, like applying oil to a surface and causing it to slide into the sea. It is causing a massive acceleration which could be catastrophic.”
‘The glacier is now moving at 15km a year into the sea although in surges it moves even faster. He measured one surge at 5km in 90 minutes – an extraordinary event.’
Related to the arctic sea ice is the fate of the polar bear. The NY Times has a good article on this issue from Andy Revkin. The title tells it all: “Warming Is Seen as Wiping Out Most Polar Bears”.
An interesting sentence: “The wildlife agency (the Federal Wildlife Service) had to make a determination on the status of a threatened species because of a suit by environmental groups like Greenpeace and the Natural Resources Defense Council.”
http://www.nytimes.com/2007/09/08/science/earth/08polar.html?em&ex=1189483200&en=42d971c103c46def&ei=5087
Re #427: there’s a typo in this article, of “year” for “day”. In fact, Ilulissat melts enough water every day to supply London with tap water for a year.
The Independent has more coverage:
http://environment.independent.co.uk/climate_change/article2941866.ece
Re #415
Wayne,
The 30 m comes from p250 of McIlveen’s “Fundamentals of Weather and Climate.” It refers to both carbon dioxide and water vapour.
I don’t understand what you mean when you say “inversions must weaken all over the world.” However I might be able to answer your objection by explaining that water vapour plays an important role as a greenhouse gas. It effect depends on its concentration, and the more warming it creates the more water vapour there is. It is driven by a positive feedback. So if you have enough solar radiation and carbon dioxide it will completely dominate the greenhouse effect. This is what happens in the tropics where we see daily storms. Increasing CO2 there will have little effect, and this has been confirmed by Christy and Spencer, and given rise to the tropical lapse rate problem, which has still not been solved despite three simultaneous papers in Science.
In arctic regions where the surface is covered in ice, water vapour does runaway, because its concentration cannot rise above that of melting ice i.e. 0C. But an increase in CO2 will lead to a raising of the snow line, both in altitude and latitude. That is what we are seeing worldwide.
You mention “hot Polar anticyclones” and I will try to explain them. In the current models the greenhouse gases produce back radiation and I imagine you believe that this is what is melting the ice. In fact greenhouse gases produce little back radiation since all the energy they absorb gets converted into the kinetic energy of the air molecules. This produces a warm layer of air over the snow surface, and when the sun shines onto the ice it loses some of that energy by thermal radiation and the rest by conduction with the surface air. It this air is warm because the CO2 has absorbed the thermal radiation the snow/ice will melt. Therefore most melting will happen where there are clear skies.
An important aspect I have not discussed is the part played by clouds, but I will leave that for another post, if you are still interested.
The Wonderer writes
in 333: “… a blog is rather ill-suited for resolving such fundamental allegations anyway …”
and in 423: ‘… If you or RealClimate choose to alienate all of the technical engineering folks, so be it. By not using the topic….”
I’m just another reader here, not one of the Contributors (see list.
I think you had it right the first time — a blog is rather ill-suited for resolving questions so important to you.
It’s a bit overwrought to get upset and think “all the technical engineering folks” share your upset because nobody answered your question to your satisfaction, yet.
That happens. It’s just a blog. Gavin’s on vacation, last anyone said.
You’re anonymous, so readers don’t know what you’ve published.
You could –on your own blog– set out your understanding and invite readers there, where you could put your contribution to the field together in a comprehensive and clear way, and invite readers. If what you have to contribute is publishable you may get a paper.
Also note the contact information in the ‘about’ link (top of page).
I posted this link in a longer ‘Friday Roundup’ answer but it belongs here:
Causes of Changes in Arctic Sea Ice
Wieslaw Maslowski
Naval Postgraduate School
______excerpts_____(lots of illustrations in original)
“Decrease from 1997 to 2002 …. If this trend persists for another 10 years (and it has through 2005) the Arctic Ocean could be icefree in summer! …
Challenges for models:
Inflow of Pacific / Atlantic Water into the Arctic Ocean
• Pacific Water enters via narrow (~60mi) Bering Strait
• outflow through Fram Strait prevents Atlantic Water inflow
• Atlantic Water entering through Barents Sea
losses* ~98% of heat to atmosphere …”
*[loses?-perhaps a typo –hr]
“Increased northward heat flux off the Chukchi Shelf coincides with the sea ice retreat in the 2000s
“Oceanic forcing can explain ~60% of sea ice melt (both extent and
thickness) in the western Arctic Ocean ….
“… NPS model shows significant skill in simulating Arctic sea ice change
— Model estimates about 33% loss of Arctic Sea Ice during 19972002
— Earlier model predictions of Arctic Sea Ice melt are possibly highly underestimated
— Up to 60% of recent decrease of sea ice in the Western Arctic can be due to oceanic forcing:
— northward inflow of Pacific Water increased inflow of warmer water
— Less ice allows more solar absorption, which leads to warmer ocean, which in turn will melt more sea ice (the so-called
ice-albedo feedback)
— The increased heat fluxes via Pacific/Atlantic Water explain the lack of correlation between sea ice and atmospheric forcing in the 2000s…”
——-end excerpt —–
His last point — great need for far more computing power, to do better modeling.
http://www.ametsoc.org/atmospolicy/documents/May032006_Dr.WieslawMaslowski.pdf
Alastair
Inversions occur naturally after a long clear night basically everywhere there is a long clear night. With extra warming originating 30 meters high, from whatever source, inversions would be less steep, this means that it would be warmer overnight. I have seen this trend in total darkness here. Not continuously, but generally weaker inversions.
The biggest question is try to narrow down why the models can’t mimic current Polar warming trends, generally speaking models succeeded for the world (so far), but not for the Arctic region. This ice melt has all the clues in it, just not found all of them all yet. Clouds play a major role in avoiding a melt every past year, under the ice biology plays a crucial role as well in creating clouds from spring time onwards to end of summer. If the models didn’t include biological and chemical (open leads sea spray) cloud seeding, then that is a major flaw which will need re-integration with current models. But there is more than that, “hot” anticyclones, at least the one in Northern Quebec in April 2005, was forecasted (either by the model or temperatures were corrected by the forecasters), yet anticyclones dominated this 2007 melt. Somehow the ice model from the met office didn’t have this real scenario as a possibility, so I suspect human programming as the source of this error, by limiting the extent of possible clear skies, or by cutting off the possibility of too much heat coming down from above. There is more to it than just that.
I believe that there is unusual warming in the Uppper atmosphere at a much wider extent
than before, therefore the chance of having a “hot” anticyclone is greater in the Polar regions, that this warm air is thoroughly mixed almost instantly all the time, but that it is more prevalent in the mid-troposphere, largely undetected by the surface observation network, certainly not picked up by satellites which have trouble differentiating between tropospheric and stratospheric temperatures.
I give one example of March 3-4 2007 over Resolute, -45 C on the ground when sun disk compressions were “normal” meaning that somewhere in the near horizontal temperature gradient there was warming. not at all extrapolated by GRIB or our local model. hence warm air out there left undetected. This is perhaps the reason why the models fail, it is because reality is not being replicated since it is not being observed.
I am all ears on your cloud theories Alastair!
This is the ‘Northeast Passage’ area?
http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?T072520930
>”Northeast Passage”
This is a bit closer I think
http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2007252/crefl1_143.A2007252111000-2007252111500.4km.jpg
Re427 and 429,
5km in 90 mins! ie 100 years worth of freshwater for London in 90 mins, from one glacier… now i don’t know the precise numbers, but thats not a glacier-size rate of discharge, its more like that of a river!
I wonder what Correll was thinking when he watched it…
RE: 432, Wieslaw Maslowski
Hank, thanks for posting the link. This is what set me off in post #347. For those who haven’t seen the projections, look at p. 6 in the Maslowski pdf. My jaw hit the floor, and I haven’t quite recovered.
In the pdf, Maslowski suggests that the Arctic Ocean may be ice-free in the summer within a decade (this prediction was BEFORE the present summer melt, by the way).
On Maslowski’s presentation:
This is the way the science makes progress. To form hypothesis, collect evidence, create conclusions. So different from the way the denialists proceed.
It looks like the inflow of warm water into the Artic Sea is related to the increase in the sea surface temperature of the northernmost Pacific starting from 2001 or so.
http://www.osdpd.noaa.gov/PSB/EPS/SST/climo_archive/anomnight.6.20.1998.gif
http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.6.19.1999.gif
http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.6.20.2000.gif
http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.6.18.2001.gif
http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.6.21.2002.gif
http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.6.24.2003.gif
Alastair writes:
[[ In fact greenhouse gases produce little back radiation since all the energy they absorb gets converted into the kinetic energy of the air molecules.]]
Alastair, this is almost word for word Chris Dodd’s pseudoscientific argument that the greenhouse effect doesn’t exist. The elevated kinetic energy of the air means it gets hotter, and that means the greenhouse gases it contains get hotter, and they radiate in all directions, including down. This isn’t just airy theoretical guesswork. The back-radiation from the atmosphere has been measured many, many times.
#336 “…that model still has residual September ice well after 2040. This is where the climate modellers do not seem to understand what positive feedback means. When positive feedback takes over, and it has done, the reduction is sea ice area will accelerate until no ice is left. That is what positive feedback means!”
I’m confused by your assertion. Firstly, positive feedbacks, such as the ice-albedo feedback, or the water vapour feedback are not specified by the climate modellers directly – they are an emergent property of the underlying physics that is part of the model.
So, for the ice-albedo feedback, the model has different albedos for open sea and for ice, so that as the ice in the model melts the albedo for open sea is used over a great area, and thus a feedback. The intervention by the modeller is in choosing the values of albedo (for which there are observational constraints) and whether they have implemented some of the “complications” (eg the variation in sea surface albedo due to the angle of the sunlight, or the variation in sea-ice albedo due to meltponds, etc)
So, the persistance of September sea-ice cannot be because the sea-ice albedo feedback hasn’t been properly understood or implemented, since the feedback is inevitable**. It is an emergent result from the model that needs examining on its own merits.
I’m not an expert, but from what I’ve seen of the model projections in the past, this residual September sea-ice is piled up on the northern coast of Greenland. Assuming the Greenland ice sheet remains essentially intact for the next few decades, then it doesn’t surprise me that this could create such a local anomaly.
The presence of Greenland, with all its ice, reduces the impact of the sea-ice albedo feedback in its vicinity and would also be a heat sink for air that flowed over it.
All the current GCMs treat Greenland as a permanent feature – none of them have an interactive ice sheet model. This is the underlying assumption that leads to a residual quantity of September sea-ice in th eprojections.
Unfortunately… if the latest news from Greenland is anything to go by, it may well have melted before the modellers manage to model it sufficiently well.
** Okay, well. I suppose that if they wanted to a modeller could specify that the albedo of open ocean in the Arctic should be the same as sea-ice. This would be a way of using the model to test what would happen if there wasn’t a feedback (by artificially surpressing it). It might be fun. Also, you would be able to see at which point the no-feedback and feedback models diverged. However, the feedback is probably important in the “normal” seasonal fluctuation in sea-ice extent, so you’d probably mess that up quite a lot.
“SteveSadlov Says:
7 September 2007 at 22:33
Someone had mentioned that they thought the East passage would open this year:
http://www.natice.noaa.gov/pub/West_Arctic/Laptev_Sea/2007/currentcolor.pdf
Anyone up for a bet?”
Did you get any takers Steve because right now it looks like it’s opening up? Also after a week or so off stasis the Ice area on Cryosphere today appears to be moving down again.
Also Hank the Maslowski presentation is very interesting, thanks.
Re #439 where Barton Paul Levenson Says:
“Alastair, this is almost word for word Chris Dodd’s pseudoscientific argument that the greenhouse effect doesn’t exist.”
Well, he must be drawing a false conclusion from a well known fact.
“The back-radiation from the atmosphere has been measured many, many times.”
And it never balances with that expected. See Some aspects of the energy balance
closure problem
Re #440 where Timothy writes:
** Okay, well. I suppose that if they wanted to a modeller could specify that the albedo of open ocean in the Arctic should be the same as sea-ice.
I think if you check, (if you can find a way,) then you will find that is exactly what they have done! (in the Hadley model at least.)
Alastair, the reference you have provided has nothing to do with radiative balance, but rather convectiveheat flow on long and short timescales.
Re #440: IIRC the residual ice is postulated because that area is to varying degrees sheltered from wind and current effects. It takes ice a lot longer to melt in place.
Re my previous: Just to add that the behavior of the Canadian archipelago channel ice this year may be cause for some reassessment of how long it’s likely to persist. A melt-out of this sort would have been pretty obvious pre-satellite, and AFAIK there’s no record of anything similar. Also, the current satellite pictures seem to show the northern NW passage has pretty well cleared out as well (although it could still be filled with small bits). Any enlightenment on either of these points, Wayne?
USF&W hasn’t made it’s determination, it must (not had to) do so in response to the suit.
The scientific assessment is one step in the USF&W’s process for making a determination.
Will the USF&W make its determination based on the scientific assessment?
Back when Bush’s daddy was president, he ordered the head of USF&W to not list the northern spotted owl, despite the scientific assessment that it was indeed in danger of extinction.
This was the basis of the lawsuit in a Washington (state) Federal District Court that led to a moratorium on the harvest of old growth in western Oregon and Washington. The Endangered Species Act is clear, the agency responsible for determining status (USF&W in these two cases) must base its determination on the known science.
So things could get quite interesting … at minimum I’m sure the administration will drag out the process as long as possible. It seems quite likely they’ll follow in daddy’s footsteps and rule that polar bears in the US do not face extinction, leading to a new lawsuit to force them to do so.
If the bear’s listed, oh my, things could get very interesting indeed. In this case, the USF&W will have to prepare a recovery plan, and anything they come up with under the current administration will probably again be the basis for a lawsuit…
Though the reality is that this process is probably going to grind on into the next administration.
RE: #441 – If you look at the NOAA link, the red area signifies what is essentially multiyear, “thick” ice – probably at least a couple or three meters thick. The thick black arrows signify the direction of drift. If you were to click on all the sectors covered by NOAA, you’d see that the multiyear ice shown at this link depicting the Laptev Sea is contiguous with the larger mass of multiyear ice up in the actual polar region. My bet stands.
Slight change of subject …. Cryosphere Today. I used to be a big fan, but lost my fervor when “adjustments” (in both their depicted record as well as ongoing algorithm) were made earlier this year. Here is but one example. The ice edge has never completely moved north of Svalbard this year. The northeastern portion of that island group has remained ice bound. And yet, CT depicts a several Km swathe of open water in a place that is not open to navigation at present.
Ray,
The Energy Balance Closure Problem is that the radiation at the Earth’s surface does not balance. They write in their introduction:
During the late 1980s it became obvious that the energy balance at the earth’s surface could not be closed with experimental data. The available energy, i.e. the sum of the net radiation and the ground heat flux, was found in most cases to be larger than the sum of the turbulent fluxes of sensible and latent heat. This was a main topic of a workshop held in 1994 in Grenoble (Foken and Oncley, 1995). In most of the land surface experiments (Bolle et al., 1993; Kanemasu et al., 1992; Tsvang et al., 1991), and also in the carbon dioxide flux networks (Aubinet et al., 2000; Wilson et al., 2002), a closure of the energy balance of approximately 80% was found. The residual is
Res = Rn − H − E − G (1)
with Rn: net radiation, H: sensible heat flux, E: latent heat flux, and G: soil heat flux.
In that paper they try to explain that the problem is with the turbulent heat flux but I am sure it is the net radiation (Rn) that is wrong. Even if I am wrong it is not correct to claim that the downwelling radiation has been measured and balanced for decades. It is what everyone assumes but it is untrue.
RE: #434 / 435 – Hank, both are correct. The first one has the eastern portion and the second one the western portion.