This is a thread to discuss issues related to the 2011 Arctic sea ice minimum. The following graphs will update every day:
JAXA Sea ice extent:
Cryosphere Today sea ice concentration:
Arctic sea ice discussions
Climate science from climate scientists...
The globalization of the MWP was being discussed on another bog, and I ran across this: Medieval Climate Anomaly. Some might find it interesting.
>> Chris G at 173 … lower ice volume …
>Chris O at 198 .. water is denser …
Ice melts to water (the volume of ice decreases the volume of water increases); absorbing energy, while the temp. stays around 0 C
I have updated the East Siberian Sea animation. Finally a relatively clear picture. The difference is absolutely stunning.
Comment by Neven — 25 Jul 2011 @ 3:53 PM
A more complete treatment of the Northwest and Northeast Passages is here:
http://aperfectstormcometh.blogspot.com/2011/07/current-state-of-arctic-sea-ice-laymans_21.html
Original post here: http://aperfectstormcometh.blogspot.com/2011/07/current-state-of-arctic-sea-ice-laymans.html
I’ve added annotations to the latest image of ice in the East Siberian Sea and found a depth chart for the ESS and linked it.
http://aperfectstormcometh.blogspot.com/2011/07/current-state-of-arctic-sea-ice-laymans_21.html
Looks like the open water route is only between 1 and 3 fathoms, probably unrealistic for seagoing vessels, no? If so, they’ll have to go through the pretty loose-looking sea ice fields. Looks very doable, particularly with ice breakers on standby or along for the trip, as seems to be the case in the last couple of years.
That ice is amazingly resilient, not having changed much for a number of days. Six more days to August. I think it will be unambiguously open by then…. maybe.
This is not a prediction!
;-)
167 Didactylos:
“The most striking feature of our pan-Arctic sea-ice cover reconstruction is the abrupt and sustained decrease in summer ice extent observed during the second half of the 20th century, which is apparently unprecedented in the previous ~9 centuries. Our results suggest that as of 1985, Arctic summer sea ice cover extent dropped below the lower bound of the reconstructed minimum for the Medieval Warm Optimum (ca AD 1150). These findings support the contention that human influence on Arctic sea ice became detectable after the early 1990s. ”
+ another hockey stick.
“unprecedented in the previous ~9 centuries” says it all.
“detectable” is so far understated that it just isn’t reasonable. Here is where the correct word is “obvious” and scientists should use it. If it said “The crossover point to warmer for sure than the MWP happened in 1990” that would make sense.
179 Radge Havers: Sorry, I don’t see the connection to any translation of “The Wanderer”. I was talking about a defect in the design of the human brain that must be overcome.
Updated the Fram Strait images to include 22nd – 25th. I can’t make a slide show on Blogger, but I can link to one. If anyone can suggest a good site to host a slideshow I can link to, let me know, please.
Correction:
OK, modelling is hard, we cannot expect perfection but we must publicise their defects.
194, Why would you think that?
Annals of Applied Statistics, vol5, no. 1, March 2011, pp 5 – 124.
ccpo,
Please email me at levenson1960@gmail.com
Kevin O’Neill:
I don’t want to be overly pedantic, but the minor peak in ice extent you are talking about saw an increase during the 40s, and decreased sharply in 1953. It is also only really notable in the summer extent – it doesn’t exist in the annual data. And, as you observe, it isn’t “significant” in any sense, especially given the caution in the documentation for the data:
This makes the discontinuity at 1953 all the more suspect. My point that there was no significant change to ice extent in this period stands.
Looking at a regional breakdown, it seems that most of the “increase” is likely to be observed in Hudson Bay, so maybe Titus does remember some regional news story.
I notice that the Antarctic Ice extent has been trending upwards for the past 30 years and this trend is still continuing
ref: http://nsidc.org/data/seaice_index/images/s_plot_hires.png
My question is – How much does this offset the Arctic increase in terms of albedo? Also, since this ice extends further towards the equator then would it also provide more reflection per sq. km ?
How long do you expect the Antarctic ice trend to continue along with the continued cooling trend in the Southern Ocean ?
My previous comment appears to have been lost so I’ll try again. This will be the third attempt. It was an addition to my comment at #161 and several folks have commented so I’m giving the curtosy of a reply.
To check my memory I consulted one of my old encyclopedias (Book of Knowledge by Waverley 1950’s edition). It talked about Russia building out towns on the north coast of Siberia and setting up a sea trade along the route for the ice free months. It also talked of growing flax and sugar beet inside the Arctic Circle.
Then I remember the ice came back in the 50’s and 60’s (maybe some of 70’s) and put a stop to this expansion. Similar type stories for the Baltic Sea.
Your data does not seem to identify this very well.
So my memory was not too far out. Our current extents seem pretty similar to what they were back in the 1940’s and 50’s having receded since about the 80’s. Looks more of a cyclical process to me.
Titus: rather than trying to piece together a viewpoint from old encyclopedia articles, you can look at compiled data from old sea ice charts:
http://nsidc.org/icelights/2011/01/31/arctic-sea-ice-before-satellites/
Whatever local conditions existed in whatever Siberian towns you have read about, for arctic sea ice as a whole, extents are not remotely similar now to what they were in the 1950s.
Titus, you can do better than an old 1950s encyclopedia for the facts.
Long day length during the summer allows both farming and travel and has for a long time — for annual plants and small shallow draft vessels.
http://www.google.com/search?q=flax+“sugar+beet”+”arctic+circle”+siberia
You’re going beyond the facts to claim a cycle — that’s not in the facts:
http://www.agu.org/pubs/crossref/2011/2010JD015341.shtml
Look at what’s actually happening. Cite sources from the science.
You can do this. Make the effort. Look for the facts first, don’t decide what you believe then go looking for support. That kind of ‘reverse citation’ fails because you can find anything you want, if you look only for what you want.
http://www.biogeosciences-discuss.net/8/1445/2011/bgd-8-1445-2011-print.pdf
SM’s pointing to this journal for his “isn’t it generally accepted” question assuming the ‘Medieval warm period’ was a Northern Hemisphere pattern:
http://projecteuclid.org/DPubS?service=UI&version=1.0&verb=Display&page=toc&handle=euclid.aoas/1300715166
The main article in that is: “A statistical analysis of multiple temperature proxies: Are reconstructions of surface temperatures over the last 1000 years reliable?” – Blakeley B. McShane and Abraham J. Wyner; 5-44
Those who’ve been reading a while will understand the problem. If you’re new to the subject, here’s a place to start.
http://www.google.com/search?q=site%3Arealclimate.org+mcshane+wyner
Shorter: Nope, it’s not generally accepted.
If it were in the IPCC Report, it would be, but as it isn’t, it ain’t.
SM wrote:
> Isn’t it accepted that the MWP applied to the Northern Hemisphere generally?
I pointed out that it isn’t:
http://www.google.com/search?q=site%3Aipcc.ch+medieval+warm
SM wrote:
> Annals of Applied Statistics, vol5, no. 1, March 2011, pp 5 – 124.
The paper SM’s citing:
http://projecteuclid.org/DPubS?service=UI&version=1.0&verb=Display&page=toc&handle=euclid.aoas/1300715166
is McShane and Wyner, claiming it’s “generally accepted”
Check that out:
http://www.google.com/search?q=site%3Arealclimate.org+mcshane+wyner
Further on McShane and Wyner for SM:
http://www.google.com/search?q=site%3Atamino.wordpress.com+mcshane+wyner
So, SM, your reason for asking “isn’t it accepted” — was that it?
That one problematic paper?
There’s a reason for the slow grinding process by which the IPCC puts together what’s generally accepted every five years or so. You can’t pick one contentious paper out and claim general acceptance for a quirky notion.
Or can you?
Oh, dear, SM, I’d forgotten most of that.
McShane and Wyner was the hot item at the denial sites, a while back, and thoroughly dissected. Here’s another take:
http://shewonk.wordpress.com/2010/08/15/the-eternal-return/
> isn’t it accepted …?
Nope. Except perhaps by those who believe climate is just repeating cycles.
Edward Greisch @ 203
I know. In the context of the general thread on how scientists should communicate, your comment sparked a synapse. The association is loose, but the summary of attitudes and expectations seemed evocative to me:
Edward Greisch @ 151
The Wander (here goes, more or less):
Also:
“…Therefore a man cannot call himself wise, before he has
a share of years in the world. A wise man must be patient,
He must never be too hot-hearted nor too hasty of speech,
nor too weak a warrior nor too reckless,
nor too fearful, nor too cheerful, nor too greedy for riches,
nor ever too eager for boasting, before he can have clear understanding.
A warrior shall wait when he speaks oaths,
until stout-hearted he sees clearly
whither the intent of his heart will turn.
A wise hero can perceive how ghastly it will be,
when all this world’s wealth stands waste,
as now in various places throughout this middle-earth
walls stand, blown by the wind,
covered with frost, the buildings storm-swept….”
Sorry ’bout multiple posts. ReCaptcha said each had failed, so I rewrote and retried several times — and now I see all of the ‘rejected’ tries showed up.
Titus: I would strongly question any information from that period. The cold war was fought mainly with misinformation – unpicking the reality is not simple.
The truth is that differences in various reconstructions show that the margin of error is far greater than any perceived “peak”. The fact that you can’t pin this peak down to even a specific decade should be a clue to this.
You’re chasing data ghosts and memories.
We can be very certain that the current ice loss is not comparable to anything in the last century, and probably not comparable to anything in the last millennium.
Titus said: “Our current extents seem pretty similar to what they were back in the 1940’s and 50’s having receded since about the 80’s. Looks more of a cyclical process to me.”
I think this claim needs addressing directly, since it is flat out false. Titus, where are you getting this crazy idea from? You must have SOME source for this idea, since you keep repeating it.
We have supplied at least three reputable sources that flatly contradict the claim.
Jonas:
My understanding is this – ice albedo has the greatest effect during the polar summer. This coincides with the period of melt and sea ice minimum.
Because Antarctic sea ice reduces to almost nothing in the summer/autumn, there is very little trend in the ice minimum, and consequently any albedo effect is greatly constrained.
In the Arctic, the minimum is not constrained in any way, since there isn’t a continent in the way. This means that albedo already plays a significant role in the Arctic.
This isn’t the end of the story, though, because additional sea ice in the Antarctic winter does have consequences. I just don’t know what those consequences are.
Jonas (211):
The increase in Antarctic sea ice extent has mainly been occurring in the winter (see the graph of the past few years on Cryosphere Today), when albedo is insignificant. Also, the Southern Ocean has been warming (in fact, warming faster than the global trend), not cooling, as Skeptical Science explains:
http://www.skepticalscience.com/antarctica-gaining-ice-intermediate.htm
Overall, global sea ice is decreasing:
http://tamino.wordpress.com/2011/01/14/monckton-skewers-truth/
[Response: These are nice links, but as usual they ignore the fact that Antarctica sea ice increase is limited to East Antarctica, whereas West Antarctic and Peninsula sea ice is in fact decreasing, and has been for the last 30+ years, at least. The fractional increase in East Antarctica is much smaller than the decrease in West Antarctica. Like for the (glacier, as opposed to sea ice) ice sheet itself, the largest changes are occurring in West Antarctica.–eric]
220, Hank Roberts: Sorry ’bout multiple posts. ReCaptcha said each had failed, so I rewrote and retried several times — and now I see all of the ‘rejected’ tries showed up.
That has happened to me too.
218, Hank Roberts: McShane and Wyner was the hot item at the denial sites, a while back, and thoroughly dissected. Here’s another take:
I referred to the McShane and Wyner paper, the critiques, and the rebuttal. I also have downloaded the supporting online material.
Hank Roberts, Are you saying that the Medieval Warm Period is accepted to have been merely European, and not even general over the NH?
Re Titus (the dubious),
It is true that in the 1950s Siberia experienced a phase of development as part of one of the long term plans of the Communist government. This involved the construction of hydro-electric plants and following aluminium smelting industry. Furthermore the discovery of gas and oil fields.
Titus has no evidence for his/her claim of increased sea-ice and the equally baseless insinuation of a climatic cycle.
The evidence that there is shows that Titus is incorrect.
e.g. Arctic Sea Ice Extent and Anomalies, 1853 to 1984. Mysak & Manak, CRG Report No 88-8, June 1988.
The following 2 figures show monthly sea-ice anomalies for the period 1953 to 1985.
Figure 20, Barents & Kara Seas, shows no significant anomaly from 1953 to 1965. Then a peak around 1970 before a resumption of the no significant anomaly until the end of the series, 1985, where there is a steep drop from 1982.
Figure 21, Siberian & Laptev Seas, shows no significant anomaly for East for the full period 1953 to 1985.
Thanks for publishing my comment. I’m having great difficulty and this will be the second attempt at this one.
Had some time so did a Google search to complement my 1950’s encyclopedia. Came across this one which looks good to share.
http://seaice.alaska.edu/gi/publications/mahoney/Mahoney_2008_JGR_20thC_RSI.pdf
At the very least it shows that Arctic ice decreased up until 1953 and then increased. We can discuss the merits and usefulness. However, it does back up to some extent my memory and 1950’s encyclopedia:)
Titus, your link has usefulness, such as this:”Periods A and B are not evident in the HadISST data,
which show a more continual decline in summertime
Russian sea ice during the twentieth century. Although we
have reason to question the quality of the early AARI data
in autumn months, the good correlation with passive microwave
results gives us confidence in the summertime
AARI ice extents. The HadISST data therefore miss a
potentially important transition that occurred in the 1980s,
when the Arctic sea ice retreat became a basin-wide and
year-round phenomenon.”
In other words, rather than a slow decline over decades, the patient is suddenly getting worse.
Titus,
From the paper you cite, and supported by the graphs (fig 6 & 7).
“Up until the 1950s–1960s and after the 1980s, summertime sea ice extent was decreasing around the Russian Arctic. During the intervening period, the retreat of sea ice slowed or reversed.”
Summer is most relevant to your claim that shipping was stopped by an increase in ice in the 1950s. At best the increase from the mid 1950s was partial and patchy in nature (figure 6), it did not return to levels of the 1940s. That paper does not support your claim of an increasing sea-ice in the 1950s that stopped shipping as the the 1950s was a lull not a peak nor the start of a peak.
You can see from the study the context of current conditions. This is not a cyclic situation. The current recession is due to warming driven largely by human activities mainly CO2 emissions.
“Period C began in the mid-1980s and continued to the end
of the record. It is characterized by a decrease in total and
MY sea ice extent in all seas and seasons. In this regard,
period C is markedly different from periods A and B.”
> mahoney
previously cited here http://www.google.com/search?q=site%3Arealclimate.org+mahoney+jgr
to make the same argument you’re making, by Max at
https://www.realclimate.org/?comments_popup=606#comment-132431
Always look the paper up, so you can check more recent citing papers:
http://scholar.google.com/scholar?cites=10638625586393882405&as_sdt=2005&sciodt=0,5&hl=en
Don’t stop looking when you find something that supports what you _want_ to believe.
PS, this in particular is interesting:
http://www.clim-past-discuss.net/4/S600/2008/cpd-4-S600-2008-print.pdf
CPD
Interactive Discussion
Clim. Past Discuss., 4, S600–S605, 2008
http://www.clim-past-discuss.net/4/S600/2008/
Interactive comment on “Can we reconstruct
Arctic sea ice back to 1900 with a hybrid
approach?” by S. Brönnimann et al.
Short answer: the attempt was not successful — not yet
Brief quote:
“… During the work on these reconstructions, several new data sets were published, including new historical data products (e.g., Mahoney et al. 2008) as well as new reconstructions (e.g., Kauker et al., 2008). At the same time, new climate model versions are being developed in the process of preparations for the IPCC Fifth Assessment Report, and a new version of HadISST is currently being developed. We are confident that in only 4-5 years from now, such an approach can in fact be successful. Progress is much faster than we anticipated, which however raises the question of the value of publishing a “no result” in the peer-reviewed literature at this time.
In view of these thoughts, we have therefore decided not to take this manuscript further, but rather to undertake a new attempt in a few years.”
_________
That’s an example of why you find new information by looking at the citing papers, Titus, rather than just looking for something that supports what you want to believe and stopping with that older information.
There’s much more there to read. I hope you do read some of it.
> SM
> Hank Roberts, Are you saying that the Medieval Warm Period is …
You don’t care what I think about that. Neither do I.
Look this stuff up.
Your source is McShane and Wyner. Did you read the paper and its critics?
http://scholar.google.com/scholar?cites=6168230330211941140
So the paper hasn’t been cited by subsequent papers except for criticism.
Then, look at who likes it and who doesn’t.
http://www.google.com/search?q=mcshane+wyner
See a pattern in that result?
Pick someone who is not a strong advocate, with science chops, like:
http://klimazwiebel.blogspot.com/2010/08/mcshane-and-wyner-on-climate.html
(For this example, read at least the original post and his followup: http://klimazwiebel.blogspot.com/2010/08/mcshane-and-wyner-on-climate.html?showComment=1285257409464#c3504664301479074586
(If you read the other comments don’t be drinking coffee over a keyboard.)
So, SM, when you write
> Are you saying that the Medieval Warm Period is accepted to
> have been merely European, and not even general over the NH?
Nope.
http://aperfectstormcometh.blogspot.com/2011/07/tracking-arctic-sea-ice-loss-via-fram.html
Tuesday, July 26, 2011
Large Ice Shelf Breaks Free Off Eastern Greenland
Huge chunk of the ice shelf breaks off in the area of Bjornegletscher in the Fram Strait area of the Greenland Sea we’ve been watching to assess sea ice transport out of the Arctic Ocean.
The total area including the piece that had already broken maybe… 8,000 sq miles, very roughly estimated. I don’t yet know if that is a permanent or seasonal ice shelf, so I will update when I know if this is a Big Deal or not.
234, Hank roberts: Your source is McShane and Wyner. Did you read the paper and its critics?
yes. That was why I referred to pp 5-124, and the supporting online material. Their online rebuttal has more detail than their printed rebuttal.
You don’t care what I think about that.
I care what you “say” (paraphrasing my question), in this case meaning “type”.
The Northeast Passage unambiguously open as of 7/27/11.
http://aperfectstormcometh.blogspot.com/2011/07/current-state-of-arctic-sea-ice.html
Having trouble posting… the correction above refers to this:
I can’t decide if this amuses or terrifies me:
Climate change forecasters are wrong on CO2, new report claims
Are we to have a balance between the Lancaster University Management School, a triple-accredited, world-ranked management school, and the claims of the IPCC?
The IPCC use inadequate models, which obviously understate the dangers then there is a scaling down of the dangers by papers like that from LUMS.
OK, modelling is hard, we cannot expect perfection but should we not publicise their defects.
Who remembers the well-modelled box girder bridge collapses?
[Response: The actual paper this referring to isn’t as bad as this press report makes it appear. The authors made much more of an effort than previous ‘forecasting experts’ to actually learn something about what climate models are doing. However the broad statements in this piece are not supported by their study. I may do a post on this if I can find the time. – gavin]
RE 235
ccpo, please keep us informed regarding the movement of that massive new ice flow in the Fram Strait. Though the resolution was not adequate to tell for certain, it appeared to pop off on one day or less.
Visited your web page. Nice piece of work!!
So you have 30 year log of sea ice extent. Do you expect a random variable it not to exceed its previous limits from time to time (and 4 years over 30 year long period seems to be pretty reasonable interval)? If you ask why the upper limit is not shattered, then just look over to southern hemishphere.
[Response: The noise in the arctic sea ice cover is much smaller than the signal of the trend in every month and almost every region. This is not noise. – gavin]
Tegiri:
per NSIDC, there are more or less complete records for extent going back ~60 years, enough records to get a pretty good sense of it going back a few hundred (as long as people who keep records have been sailing in the arctic), and enough proxy data to know that the current situation is probably unique for at least the last 5000 years and quite possibly for the last 100,000+ years.
But even considering only the last 60 years of good coverage, that’s plenty to get a sense of what the range is for annual fluctuations in the first half of that record, making it blindingly obvious that a big change is afoot in the second half of the record, especially at the end.
Hank #232,
I don’t see criticism of the Mahoney paper in the links you posted, the link to Brönnimann et al seemed to be a self-critique of their method. Brönnimann et al examine combining climate models and data, i.e. a reanalysis type product. The Mahoney paper is based upon Russian Arctic and Antarctic Research Institue data, observations of the sea ice edge and conditions, so the criticisms of Brönnimann et al are not relevant.
To my shame I find I’ve had the Mahoney paper for over a year in my bulging ‘to be read’ folder. Which is why it seemed familiar when Titus linked to it. I’ve given it a quick once-over and remain convinced that had Titus atually read it, it would not have been raised. The pattern of changes in the frames of figure 6 doesn’t suggest an increase in sea-ice that would impede shipping in the summer to the degree implied by Titus, and it suggests that what’s happening now is odd in the historical context of 1933 to 2006. That’s a pattern I’ve come across in my reading about the Arctic.
With the current (late July) sea ice area being lower than for any September minimum in the 1980s, odd is the order of the day up there.
I believe it’s seasonal, ccpo.
Chris, your take on Mahoney seems to fit — that paper doesn’t support the claim Titus (or Max earlier) make. Brönnimann and others are citing it as data that can be useful in future attempts — but not as sufficient to determine the existence of — an Arctic trend. I think Titus and Max are eyeballing the pictures.
Hank Roberts (#117) and Spherica (Bob) (#119) seem to be more fond of casting stones than trying to understand what people actually post. I see no need to respond to them except to note that both posts are part of what I call the “shrill voices.”
Now I will post something that will no doubt bring other voices out of the void which is the internet. I’ve been reading about three historical events in “scientific” history — (1) the “discovery” of N rays in France in the early part of thre 20th century, (2) the issue of eugenics which was pat of our culture in the 1920s and (3) the denial of plate tectonics by almost all scientists for decades.
What do these three things have in common with global warming? Well — all were fiercely and passionately defended against the “denialists” of their day. Just as GW is. No room for dissenting data == consensus wins. For awhile.
If they had made room, … well, mostly they didn’t.
I continue to hold that the scientific evidence for global climate change is very strong. And so I preach (not literally) and write. But more and more “science” simply is ignored. People believe what they want to believe. Scientists are simply a bunch of wierdos and the opinions of “regular folks” are seen as stronger. I know scientists don’t want to hear this. But it seems, as I talk up global climate change to people, they immediately ask my scientific background and I can see their eyes glaze over when I respond. I have pretty much stopped responding on this question.
As I once posted, I have no solution to offer to this problem. Only the observation that throwing more science at people is not only not working but may be counterproductive. And the quick responses to people such as me who not “true believers” — responses which are derogatory — does not help — it hinders.
For instance — X says A is a fact. The usual response is that X is lying. Maybe he is, but saying so persuades nobody. The better response is to (respectfully) point out specific data which indicates A is not a fact — or, at least is not an established fact.
BTW, my favorite book on the issue is WHAT IS THE~WORST THAT COULD HAPPEN. Yes — it is low level– but one I personally find persuasive in keeping me in the GW camp.
Bye
John, what I wrote in 117 was a serious answer to your complaint.
You said you have trouble explaining the sea ice chart to people.
I said at 117, and I repeat:
Robert Grumbine’s site teaches this stuff at the high school level, and he has what you need. Try there. http://moregrumbinescience.blogspot.com/
Look at the site. He explains how the charts are created.
He’s an expert in exactly this topic — sea ice.
@John McCormick says:27 Jul 2011 at 10:13 AM
RE 235
ccpo, please keep us informed regarding the movement of that massive new ice flow in the Fram Strait. Though the resolution was not adequate to tell for certain, it appeared to pop off on one day or less.
Visited your web page. Nice piece of work!!
John, I will as long as it stays within the area I’ve been tracking. The first large bit that broke off disintegrated very quickly. Perhaps these two pieces will, also. Overall, I don’t think this is all that important a story. See below.
@Neven says:27 Jul 2011 at 1:45 PM
I don’t yet know if that is a permanent or seasonal ice shelf, so I will update when I know if this is a Big Deal or not.
I believe it’s seasonal, ccpo.
Agreed. I went looking for images as soon as I posted that and updated the post yesterday.
“UPDATE: Fun to watch, but it looks like the shelf is seasonal, at least in recent years.”
I do wonder how long it’s been seasonal; might it be only since ’98, ’05 or ’07? That’s a very active area of sea ice movement and currents, so it seems likely it’s not a very long-term bit of ice.
Continental drift != plate tectonics.
Sorry, Burgy, try harder.
To Hank in #246
You miss my point. I will try once again — I know that at age 80 I not as precise as I once was and my writing gets more vague with every passing year.
A high school student in – say`- a physics class can, no doubt, understand the chart ok. as I can. Of course, by itself, it does not support the IPCC thesis — at best it is congruent with it. It says only that the ice in the Arctic is slowly changing.
When presented to an adult, who last saw a science class (if he did) years ago, it is simply not
a relevant argument at all. Mostly, he sees scientists as “those pointy head impractical kooks.” Sort of like that character in BACK TO THE FUTURE.
Now the point is that the graph — at best — only says that over a few years span the Arctic ice cap has varied. Sure the trend is down, but this, in itself, is no particular evidence of anything. Everyone knows that “things change.”
Hank — I am simply not a “true believer.” I know most everyone else here is — that’s OK. I support the IPCC because there is, to me, at least a 66% chance they are correct — and the precautionary principle says to not support them is folly. But I remain a skeptic.
Here is another way of approaching the issue. The IPCC reports are based on 4 primary legs:
1. CO2 is a greenhouse gas.
2. CO2 levels are increasing, as we pour more of it into the air by burning fossil fuels.
3. The planet is getting warmer.
4. Complex (they have to be) models forecast the process is not sustainable.
#1 is established.
#2 is an experimental measure over some span of years and seems to be confirmed for at least one location. Probably more than one.
The planet seems to be getting warmer. But the measures of this increase are all over the place, mostly over a few decades at best, and apparently (mostly) at the ragged edge of measurability. I’m not sure a few mm of sea level rise is really measurable, for instance.
We are left then, with a heavy reliance on computer models. Models which are incomprehensible to a layman — and indeed to most science-educated people who are not involved with them. But all computer models (I have built a few of them) are based on a bunch of assumptions. And there are always some of these which must be taken on faith, for they cannot be measured.
Finally — where are the fulfilled predictions/forecasts that the models have predicted? I am reminded of the predictions of more and more violent Atlantic hurricanes. Has’t happed. I know — not yet! But a few examples of successful forcasts made by the models (IN ADVANCE — NOT HIND CASTING) woyld certainly go a long way as talking points. But these have to be macro — ones anyone can see and understand. Perhaps I’ve missed these. If so, Dr. Schmitt (sp?) perhaps you can write one of your essays here which detail them and could be used as a talking point.
Sorry for such a long response — I had not the time to make it shorter. John
john burgeson, you make some interesting points, but you seem to see things backwards.
Yes, it took a long time for the theory of continental drift to be established. This is exactly similar to the idea of global warming, which was proposed over a century ago, and re-proposed many times since, all the way through the 20th century.
But both theories had a problem. Continental drift lacked a mechanism, and global warming lacked observational evidence of an immediate problem.
This situation didn’t last. In the case of continental drift, a mechanism was proposed, and geophysical evidence supporting that mechanism began to roll in. We know well what happened in the case of global warming: an accurate CO2 record, and a global temperature record that both showed that global warming was a current problem.
And, in both cases, most of the hold-outs to the newly strengthened theory were old men, retired scientists and people who had stuck their neck out taking the opposing view when there was insufficient evidence. When their errors became obvious, they took refuge in denial.
So, yes – plate tectonics is an excellent analogy, but not in the way you seem to believe.