A raised beach on Greenland could just as well be caused by post glacial rebound of the crust (readjustment from the removal of ice load), which for instance in Stockholm amounts to an uplift of some 10 mm per year at present. I don’t know the rate of uplift in Greenland but it must have been, and probably still is, very significant. At the rate of the Stockholm uplift, 7000 years would cause a Holocene beach deposit to be raised by some 70 meters. On the other hand I cannot imagine that the NGU geologists wouldn’t have accounted for that.

Your own quote said:
“Underground stores of methane are important because scientists believe their sudden release has in the past been responsible for rapid increases in global temperatures”
So, it has happened [assuming that your quote is meaningful] so it was at such times warm enough [and therefore can be again].

Second, building up organic material in the Arctic is a slow process, 6500 years ago there may not have been much buildup yet.

Third, perhaps the temperature 6500 years was just not high enough [maybe that one tenth of a degree to small], but as Al Gore will lecture you, THIS time it will be, so repent.

It looks to me that your real argument is that because the methane was not released, it was not warm 6500 years ago.

No answer to this question except one that posited that all of the methane was trapped there during the Holocene since then, which is ridiculous. It is almost as if commenters are making it up as they go along.

It will have to get a LOT warmer for this time bomb to go off and this catastrophic feedback event has to be filed under “extremely unlikely”, along with large comet strikes, Betelguese (yeah, I probably spelled that wrong) going supernova, gamma ray bursts in the celestial neighboryhood, attack by an extraterrestrial civilization, the kind of risks we all have to live with as members of the human race that can’t be assigned a probability of zero.

BTW Lief [btw, it's Leif], I really do want to know … Since the climate has fluctuated many times since the glaciations began, why haven’t we seen the spikes in methane predicted by the warm scaremongers in periods warmer than today in the Arctic?

Some geologists claim we have, it looks like Leif has picked up on that.

Others report highly localized spikes that produce highly localized disasters, i.e. fish boats floating over a methane release essentially fall into the bubble and sink.

http://dsc.discovery.com/news/afp/20031020/methane.html

Third, your reply is snark, you caught me out in a bit of careless writing. Good for you. It doesn’t change the basic facts of the matter.
I can only go by what you write :-)
And I don’t know what the basic fact is [see my comment a few lines up]. Maybe you mean that temperatures in the past were higher at times? This I think is a fact that is not disputed by any serious worker. So, I’m at a loss to what the ‘basic fact’ is.

This very likely didn’t collect since the glaciers most recently melted, as you claimed upthread in your just so story. Second, the context of the question was this warming that most recently occured in the Arcti 4000 years ago that was far greater than today’s warming. And the methane time bomb didn’t go off.

It seems pretty obvious that, for this “time-bomb” to go off, a carbon sensitivity much higher than that which has been observed so far will be required. Prior to the recent era of glaciation, the Earth was much warmer than today, and the “time-bomb” didn’t go off.

Third, your reply is snark, you caught me out in a bit of careless writing. Good for you. It doesn’t change the basic facts of the matter.

Good! Now we just have to get the remaining 99.999% to see the light too :-)

I would also bet that this low df problem cuts both ways in the climate debate, or it should. If AGW theory is also based on some correlations they found, they have the same problem. Very low df. That doesn’t delete the fact that some things happen (re: methane in the Arctic, CO2 absorbing properties in the lab). It is just that these smaller things and their measurements are buried in the larger and very noisy data.

This makes sense, but what doesn’t make sense is why are we expecting a huge spike that potentially can lead to mass extinction, if we have already experienced far greater warming in the Arctic than today just a few thousand years ago.

“Underground stores of methane are important because scientists believe their sudden release has in the past been responsible for rapid increases in global temperatures, dramatic changes to the climate, and even the mass extinction of species. Scientists aboard a research ship that has sailed the entire length of Russia’s northern coast have discovered intense concentrations of methane – sometimes at up to 100 times background levels – over several areas covering thousands of square miles of the Siberian continental shelf.

In the past few days, the researchers have seen areas of sea foaming with gas bubbling up through “methane chimneys” rising from the sea floor. They believe that the sub-sea layer of permafrost, which has acted like a “lid” to prevent the gas from escaping, has melted away to allow methane to rise from underground deposits formed before the last ice age.”

http://www.independent.co.uk/environment/climate-change/exclusive-the-methane-time-bomb-938932.html

Why wasn’t this methane an issue in the past?

You are no bother at all and it is a pleasure to share what I know [or think I know] with you [and the general readership].

That’s very magnanomous of you.

Take, for instance, the LIA. It began well before 1600, yet solar activity when Galileo [and others] observed the spots during the first three decades of the 1600s was high [possibly as high as today]. During the early 20th century, temperatures peaked well before solar activity did, etc. For each of these mismatches [that reduces the df] an explanation can be cooked up: the temperature data is unreliable, aerosols, volcanoes, etc. But for each ad-hoc extra special pleading you have to add, the significance drops. Careful studies, e.g. by Lean and Rind find that no more that 10% of the climate variability can be correlated with solar activity.

It all goes to show that the climate is a complex thing, but whatever caused the LIA we at least know it was natural. Ultimately, the energy that drives our climate comes from the sun (barring some unknown glactic force). If, as you say, the direct correlation between the solar activity and the LIA is weak, then the question is what other natural variations exists on top of Solar variation that can explain the LIA or the Medieval Warm Period? I don’t expect you to answer that one :-)
Until that is explained and backed up with good empirical evidence, then I don’t see how anyone can be sure that the late 20th century warming was both unusual and mostly due to C02. Thanks again.

I can be slower in responding, if that would increase my credibility [my being less 'quick'] :-)
The organic material in the Arctic that has build up when it was warm is scraped off by the advancing ice and buried under hundreds of feet of debris and moraines at lower latitudes. The Arctic is not a very efficient biomass producer [low sunlight, cold, dry] and the production of methane from decaying leaves etc, at mid and low latitudes is much higher. That, combined with a much larger area an mid/low latitude means that the additional methane was small compared to the methane produced by decaying biomass already present at mid latitudes. So, no conspicuous spikes are seen, as the additional methane simply drowns in the background.

“The problem with this is that the albedo does not vary with the solar cycle [as TSI, SSN, and GCRs do]“
I got the graph from Enric Palle [and Goode] whom I know quite well. They are working on a paper with their latest results up to this summer. Here is an email from Enric:
Enric Palle to leif@leif.org
date Wed, May 7, 2008 at 4:58 AM
Hi Leif, I am just now writing up the paper. I will send you a draft once I have something readable if you want.
—-
The important thing about this graph is the red line [at one solar max, at a high value of the albedo] and the grey strip [at the next solar max, at a low value of the albedo] that shows that there is no 11-year solar cycle in the albedo. Real enthusiasts might counter, ‘ah, but maybe there is 22-year Hale cycle, or a 35-year Bruckner cycle, or a 33-year Ahluvalia cycle, or an 88-year Gleissberg cycle, or a 1500-year Bond cycle, or a 2300-year Halstett cycle’, or what have you, lots of possibilities, but hardly something to commit trillions of dollars to.

Again my mistake, although I still think there could be a correlation there if you apply a sort of low pass filter :-)
It is a favorite sport in this business to hunt around trying this, trying that, unless a desired outcome appears.

Are you saying that the cooler temperatures observed during the Maunder and Dalton mimimums, along with the late 20th century warming and increased solar activity are random chance? If the sun goes into a period of lower activity over the next few cycles, or into another Dalton minimum and global temperatures fall, that again it’s all random chance?

No discussion of correlations is meaningful unless the statistical significance of the purported correlation is estimated. Fundamental to this is the notion of ‘number of degrees of freedom’ [abbrev. df], see e.g. [ http://www.creative-wisdom.com/computer/sas/df.html ] which roughly is the number of ‘independent’ data points minus 1.

If you have only two data points [x1,y1 and x2,y2] you can fit a straight line and the correlation coefficient is 1 – perfect correlation. But because the df is only 1, there is no statistical significance in the otherwise perfect correlation. Now, your statement: “the cooler temperatures observed during the Maunder and Dalton minima, along with the late 20th century warming and increased solar activity are random chance?” has three degrees of freedom. That is still not enough information, see the above link. So, yes, that could easily be just chance.

Or are you just saying that you see no correlation at all between sunspot activity and the climate from the Maunder onwards?
There is always some correlation if you have more than one data point; the question how significant it is depends on the df. If you had 400 years of data with every little wiggle present in two time series [even though there may be some scatter in the sizes, and perhaps a handful didn't match up] you would have a large number of df and one would have to accept the correlation as significant even if no mechanism is known or the claim is ridiculous on its face [like number of sunspots versus the last three digits of telephone numbers on page 417 of the phone book]. So, in the details are where the answer lies. and the details don’t match up very well. Take, for instance, the LIA. It began well before 1600, yet solar activity when Galileo [and others] observed the spots during the first three decades of the 1600s was high [possibly as high as today]. During the early 20th century, temperatures peaked well before solar activity did, etc. For each of these mismatches [that reduces the df] an explanation can be cooked up: the temperature data is unreliable, aerosols, volcanoes, etc. But for each ad-hoc extra special pleading you have to add, the significance drops. Careful studies, e.g. by Lean and Rind find that no more that 10% of the climate variability can be correlated with solar activity.