General Climate Change Discussion Continued:

[Iceberg]

It's quite feasible, and there are some signs that we might be moving into an era of colder winter synoptics as well in any case. I don't think the warmer global temperatures have made much of a difference to this winter over the UK- while global temperatures have been at either record or near-record warmth (depending on which source you prefer to use), they have only been elevated by about 0.5C relative to the very cold winters of the mid to late twentieth century. But in the future, if we start seeing anomalies of +1-2C across the Northern Hemisphere (which is likely to start happening at some point in the next half-century), then it will make more of an obvious difference.

Regarding the Medieval Warm Period there is still some uncertainty over how much it affected the rest of the globe as opposed to just Europe (a recent "climategate" interview supported this) and there is still a good deal of uncertainty over temperature reconstructions back to the 17th century when the Little Ice Age hit, so I remain unconvinced by the reliability of this 0.3C figure. At the same time, though, I agree with the conclusion that it's extremely unlikely that the sun would be able to come close to offsetting 2-4C worth of AGW unless something happened to the sun that was unprecedented in the last millennium and probably for much longer.

The lowest climate anomaly during the period for the UK was -0.9, taken over an average of the maunder minimum it was -0.4.

These results are pretty similar for the n.Hemiphere proxies, even the coldest proxies produced by the skeptics agree with a minimum of -0.8 average of -0.4 again.

I am really not sure why people are unconvinced of the 0.3 figure as it fits it perfectly with past climate.

BTW the current CET climatic average is +1.0 so a maunder minimum would have it's work cut out to reduce temps even to a 61-90 baseline, globally or NW europe wise.

[Admiral_Bobski]

[Iceberg]

CB I can't help but feel you've taken something the wrong way. I've just looked at all the proxies I can find, the CET figures etc and am struggling to see what there is to disagree about.

If somebody can find reliable proxies (a bit of an oxymoron I know), that shows a climatic average over the minimum much different from what I've quoted I'll gladly review my opinion.

[Admiral_Bobski]

Clearly something has got my back up. Perhaps it's the way you condescendingly spout figures out, but apparently have no interest in investigating their derivation.

Maybe I've just had enough.

[sunny starry skies]

CB, you'll hurt your head if you keep doing that! Iceberg's right, though. You can point to "up to 1C dips", but the mean is rather less dramatic than that.... in fact right in line with our understanding of a ~0.1C modern-day variation, and a ~0.3C dip in LIA. Sorry it's not in line with what you think to be right, but unless you have evidence to say otherwise, I have to agree with Iceberg. Iceberg does outline an internally-consistent and straightforward suggestion for the cause of the Maunder Minimum, and why it wouldn't have that much effect in the face of GHG forcing.

http://science.nasa.gov/headlines/y2009/29may_noaaprediction.htm

Lots of uncertainty in future predictions, plenty of revisions and competing hypotheses, but no forecast imminent Maunder Minimum, or sunspot number below 50 as per Landscheidt's predictions.

sss

[Iceberg]

Let me just recap this.

A group of scientists have done some work, which is in the new scientist.

You say the main piece of the work is unbelivable.

I look up as much as I can in 30 mins and quote some basic average figures (not cherry picked from mann etc), to say hang on the figure seems kind of reasonable to me.

Then I get accused of being condensending, patronising etc etc....Toys thrown out of prams.....

Your right I don't get it.

[Gray-Wolf]

I think we are drifting away from the other elements, on earth, that allow Maunder min type events to arise.

If we keep on warming, via our GHG outputs, then we will start to trigger the release of more and more 'natural' GHG's. With the permafrost retreating ever north and methane release from the Arctic growing faster each year how long do we have before any 'crank down' of solar energy is more than compensated by our ability to trap more energy??

As we watch the Sun pop back into life over the next 6 months keep an eye on the Polar melt. I feel the changing Arctic will have far greater sway over climate in the next 50yrs than the Sun's variability will have!

EDIT: Thanks to Ice, TWS and S.S.S. for their input, seems that even without the feedbacks we are encountering we'd have done enough to 'mild out' any repeats of short-term cooldowns.

Surely that is a cause for concern in itself?

Edited March 1, 2010 by Gray-Wolf

[Iceberg]

This was lifted from a skeptic site and includes skeptic and more mainstream proxy info.

I've put on the maunder period.

If anybody can see a sudden drop in temps of more than 0.4C caused by the maunder period I am all eyes.

Edited March 1, 2010 by Iceberg

[Admiral_Bobski]

So Iceberg - you don't find your comment about "GLOBAL temperatures" even the teensiest bit patronising, like maybe I had somehow completely missed the debates about whether the LIA was a GLOBAL or LOCAL phenomenon?

I have done a hell of a lot of research into solar activity in the past and stockpiled masses of data and graphs (many, if not all, of which I have posted up on these boards at various times) and now I find that all of these data are missing from my computer, presumably from when my PC crashed last year. At present I can't be bothered with trawling back through the web to find all of this information, refamiliarise myself with it and respond with graphs and data and analsis (which I usually do, I would like to emphasise).

This is not me fobbing you off with some excuse, although I can see how it might come across that way, but it is symptomatic of the lack of enthusiasm I have for this subject at the moment. In fact I only bothered to respond to your post in the first place because I got somewhat riled by your caps-locked "GLOBAL" comment.

Over the past several years I have had some serious problems (mainly financial) in my private life, and I think I clung to this debate for the escapism of it all - focusing my energies on this discussion took my mind off my other problems. So far this year I have had to confront these problems and now - blessedly - they are sorted and an enormous weight has been lifted from my shoulders that has been on me for almost as long as I can remember. Strangely - or not, as the case may be - now that those problems are gone I find that I don't have any real compulsion to continue these discussions. I don't like being treated like an idiot, and I will defend myself if I feel that I have been treated so, but otherwise I don't see any point in continuing with this.

I'm not "throwing my toys out of my pram" or anything, I just...don't care any more, basically. Not in a "stuff it all, I can't be naffed" kind of way, but more in an "I've got better things to be getting on with" kind of way.

I don't know what else to say, really - it all feels like a bit of a damp squib...

[Iceberg]

Sorry you've took it that way CB, GLOBAL was purly written in capitals to draw attention the fact that I was talking about global proxies and not regional ones. It wasn't meant in any other way, I had visions of somebody posting up a regional chart disputing what I wrote.

I actually feel much like you tbh, it's kind of rare for me to post in this thread, or have the inclination to. There is far more I find interesting such as hurricanes, el Nino, winter prospects, economics etc.

For me it's a way of unwinding after/during work.

I honestly hope you enjoy what you want to enjoy

In the nicest way, I think there is a difference between a damp squid, can't be bothered POV though, which I really do get and the name calling which was creeping in.

Anyway, as I said whatever you do enjoy it.

[Admiral_Bobski]

Thanks Iceberg

CB

[Guest North Sea Snow Convection]

There's a pretty obvious difference between monitoring activity and modelling future projections. Why has NASA's monitoring been dodgy?

Since when has forecasting solar activity been an exact science? It's still uncertain as to how strong cycle 24 will be, let alone 25, which is well out in the region of conjecture. So I really love your "belatedly growing admission" comment, where you try and suggest that solar physicists would be, erm... hiding the decline.... I think you'll find that the challenge of forecasting future solar activity has always been a difficult challenge, and so the signs over the last couple of years of a deep solar minimum were entirely likely to cause revisions in forecasts.

Do you have some supporting evidence as to why you think these 'minority' scientists you speak of would be more likely to be right? I know you state it as 'your opinion', but I'd be curious as to know what you based your opinion on? Or do you simply generally distrust "mainstream" scientists of all flavours, be they astrophysicists or climate scientists? Do you ever think seriously why there may be such a thing as 'mainstream' in a branch of science, given the intellectual/career advantages of finding something new?

BTW, whether or not Landscheidt was onto something is neither here nor there - unless you can show that the radiative forcing effect of anthropogenic GHGs is far less than observed and predicted. It may slow greenhouse warming (unlikely to reverse it, the forcing effect is too small) a little for a while, but then when solar activity picks up again, future generations will have to deal with both high GHG (the larger effect) and high solar...

sss

I don't need to show that the effects of anthropogenic GHG's is far less than observed and predicted. It still depends upon the presence of assumed positive feedbacks in order to amplify and sustain any warming and contribute to the suggested long term warming trend that AGW science proposes. If the proposed positive feedbacks that AGW assuages to are not actually there in reality then you can, in theory, throw as much C02 into the atmosphere you like, but it won't engage cumulative warming without the catalyst of the amplyfing feedbacks in order to sustain that warming. You accept the existence of those assumed feedbacks as a given and are asking people like me to demonstrate why they are wrong before they have even been proved to exist!

Since when, also, has forecasting the assumed effects of AGW been an exact science? Doesn't it work both ways? Well it should do even if it apparently doesn't. By that I mean it doesn't for you because you subscribe to runanway AGW theory as a given.

The future of solar science is indeed uncertain (as is AGW I'm afraid to remind you), but there are scientists such as Landscheidt who at least (had) a better insight and more accurate prediction in terms of the decadal trend wrt to solar activity and therefore his anlaysis for the future in terms of predicted solar feedback cycles needs to be taken much more seriously imo or the predicted science on this subject will keep suffering.

I know you are not happy about the 'belatedly growing admission' part but perhaps best to accept that part graciously? I think that for the benefit of science and the future of the planet his contribution and astute scientific insight is a big loss and has set the whole investigation of climate change back a long way. Alas. Surely it is vitally important that short term revisions (as you appear to believe are trivial and unimportant) if continually repeated, will further and further make ALL long term modelling estimates more and more innacurate??. If the potential negative solar feedbacks from potential ever deeper solar minima over the coming decades are not being foreseen (or are simply being dimissed in favour of AGW positive feedback assumptions) then how can we even begin to be so assertive about progressive unstoppable long term warming trends??

I think Landscheidts work was (is) very much 'onto something' as you put it and your dismissal of it is I guess down to you favouring other science and acceptance of his work would not be helpful, as it were, to bring into the equation.

It of course matters very much if he is 'onto something' because it could make a great deal of difference to the climate trends that are being assumed by the IPCC and other 'warmist factions' (for want of a better term)

In this regard I refer again also to NASA who haven't been grasping the solar outlook even in the short term.

Non consideration of the potential bigger negative solar feedbacks that the likes of Landscheidt has proposed - are something that may regretfully come back to haunt the scientific advance on this subject, I feel. Ignore it at one's peril I would suggest. Alarmist am I? No I don't think so - it is a legitimate concern that might be preventing us getting to the truth.

But such consideration threatens to bring into question the projected evaluations of the manmade theory and challenges the assumptions it makes regarding the alleged positive feedbacks it depends upon to verify that will lead, supposedly, to the runaway warming you wholeheartedly embrace before time. So it looks like it isn't going to happen any time yet - until time might show otherwise.

Edited March 1, 2010 by North Sea Snow Convection

[Thundery wintry showers]

Re. the Maunder Minimum and the like, it may appear a little pedantic but if the uncertainty bounds are in the region of -0.1 to -0.8 how can we be sure that the effect is no more than -0.3C? Depending on whereabouts the reality lies it could be in excess of half a degree- though again, not large enough to offset AGW as long as AGW produces a warming of significantly over a degree.

Another question goes back to the leaky integrator, and also studies relating to solar activity which showed a marked rise around the early twentieth century and a sustained high level since then. The LI argues for a lagged effect of solar activity- alternatively if there was no lag it is possible that the sun could have caused some of the early 20th century warming but not the warming of the past 30-40 years.

[sunny starry skies]

I don't need to show that the effects of anthropogenic GHG's is far less than observed and predicted. It still depends upon the presence of assumed positive feedbacks in order to amplify and sustain any warming and contribute to the suggested long term warming trend that AGW science proposes. If the proposed positive feedbacks that AGW assuages to are not actually there in reality then you can, in theory, throw as much C02 into the atmosphere you like, but it won't engage cumulative warming without the catalyst of the amplyfing feedbacks in order to sustain that warming. You accept the existence of those assumed feedbacks as a given and are asking people like me to demonstrate why they are wrong before they have even been proved to exist!

Since when, also, has forecasting the assumed effects of AGW been an exact science? Doesn't it work both ways? Well it should do even if it apparently doesn't. By that I mean it doesn't for you because you subscribe to runanway AGW theory as a given.

[snip for space]

We've been here before. How do you get Quaternary glacial cycles without the positive feedbacks identified in the climate system, given that the orbital forcing trigger is small, and CO2 alone cannot amplify the signal to the required magnitude? Why do you get a 'sawtooth' in the general pattern of glacial cycles? The physical feedback mechanisms are straightforward: higher temperature = more water vapour in the atmosphere, reduced albedo = less incoming radiation reflected to space. These are not hypothesised, they are demonstrable physical processes.

On forecasting - What has been the accuracy of the Met Office's annual global temperature forecast over the last 10 years, and why is it so good? Luck?

Are you seriously trying to connect uncertainties in AGW theory and forecasting of solar activity?? Time for me to do some head-banging because they are two different sciences altogether. We have a decent handle on the forcing factors of Earth's climate, whether you like it or not, and as shown many times over in attribution studies, and in year-to-year forecasting of global temperature. We do not have anything like the same handle on forecasting the activity of the Sun, and so revisions in forecasts are entirely expected, and not to be sneered at. FYI, Landscheidt does not appear to be correct either, as he forecast <50 sunspot number peak, which does not look to be happening. Reduced activity, yes, but no Maunder Minimum just yet.

Reduced solar activity will at most plausibly be Maunder Minimum in scale, as there is no palaeoclimatic evidence for more dramatic cold episodes in the Holocene, hence Iceberg's discussion of a ~0.3C global temperature drop. That pales into insignificance when compared to a ~2C to ~4C rise forced by GHGs.

"bigger negative solar feedbacks tha[n] the likes of Landscheidt has proposed"?? Too much to hope for, but.... any evidence?????

sss

[jethro]

Anyone have any idea what's happening at CERN with the cloud experiments?

[Thundery wintry showers]

BTW the current CET climatic average is +1.0 so a maunder minimum would have it's work cut out to reduce temps even to a 61-90 baseline, globally or NW europe wise.

Globally the average is +0.5, the above seems to be extrapolating the CET's +1.0 across the board? I don't disagree with the general points that are being made but there does seem to be some "AGW ramping" going on with many of the figures, as if it is needed to prove the point even though it isn't.

[Guest North Sea Snow Convection]

We've been here before. How do you get Quaternary glacial cycles without the positive feedbacks identified in the climate system, given that the orbital forcing trigger is small, and CO2 alone cannot amplify the signal to the required magnitude? Why do you get a 'sawtooth' in the general pattern of glacial cycles? The physical feedback mechanisms are straightforward: higher temperature = more water vapour in the atmosphere, reduced albedo = less incoming radiation reflected to space. These are not hypothesised, they are demonstrable physical processes.

On forecasting - What has been the accuracy of the Met Office's annual global temperature forecast over the last 10 years, and why is it so good? Luck?

Are you seriously trying to connect uncertainties in AGW theory and forecasting of solar activity?? Time for me to do some head-banging because they are two different sciences altogether. We have a decent handle on the forcing factors of Earth's climate, whether you like it or not, and as shown many times over in attribution studies, and in year-to-year forecasting of global temperature. We do not have anything like the same handle on forecasting the activity of the Sun, and so revisions in forecasts are entirely expected, and not to be sneered at. FYI, Landscheidt does not appear to be correct either, as he forecast <50 sunspot number peak, which does not look to be happening. Reduced activity, yes, but no Maunder Minimum just yet.

Reduced solar activity will at most plausibly be Maunder Minimum in scale, as there is no palaeoclimatic evidence for more dramatic cold episodes in the Holocene, hence Iceberg's discussion of a ~0.3C global temperature drop. That pales into insignificance when compared to a ~2C to ~4C rise forced by GHGs.

"bigger negative solar feedbacks tha[n] the likes of Landscheidt has proposed"?? Too much to hope for, but.... any evidence?????

sss

The Met Office has over stated the trend of the last ten years. I produced a chart on these threads somewhere last year that gave such evidence. It over cooked individual annual warming as was depicted on that chart.

Wrt to the bolded part,

Right, let me get this straight - you admit that we do not have 'anything like the same handle of forecasting the activity of the sun' and by dint of that you are saying in essence therefore there is little clue as to how upcoming negative solar feedback (minima)might potentially interact and in turn affect the climate trends but at the same time you are stating that because we allegedly have such a good handle on earth climate forcings then the 'other part' (ie solar uncertainty) can be forgotten and taken out of the equation. I find that truly astonishing.

Surely any future revison in terms of solar behaviour that is, as you admit so uncertain, is absolutely crucial!!

I think I just might rather trust a qualified solar scientist in terms of, er, solar behaviour (like Landscheidt) than a scientist, qualified or otherwise, who is making a judgement through AGW assumptive tinted glasses and admits to not knowing much about how the sun might behave!

Edited March 3, 2010 by North Sea Snow Convection

[Iceberg]

Maybe it can be turned on it's head, if Gavin is wrong with his 0.3C, what is the effect of a maunder type minimum to global temperatures ?.

Once we have this maybe we can check back to see if this alternative view is supported by previous maunders ?

[Gray-Wolf]

I'd imagine if these min are a regular feature then sediment records would highlight them. I'd imagine the Irish Bog records would give us a long enough window into past climate to instantly recognise any other maunder type temp fluctuations but we do not hear of such periods.

It'd make more sense to me if folk turned their attention to the earth bound drivers that could have conspired to produce a temp downturn of maunder type proportions.

We know of at least 1 Icelandic vent eruption, in the historic period, that was not documented so how many other eruptions in more remote regions have gone un-noted?

[Admiral_Bobski]

Maybe it can be turned on it's head, if Gavin is wrong with his 0.3C, what is the effect of a maunder type minimum to global temperatures ?.

Once we have this maybe we can check back to see if this alternative view is supported by previous maunders ?

You have a bit of a problem with that idea - trying to figure out what effect a maunder-type minimum might have on global temps is one thing, but how can we check that with "previous maunders"? The only Maunder-type minimum we have an accurate record of is the Maunder Minimum itself. Proxy reconstructions of sunspots going back beyond the mid-1600s lack the resolution to be able to identify similarly quiet periods with any accuracy. We can try to correlate our expectations with past temperatures on this basis, but we can't be anything like certain that we are making the appropriate comparisons.

CB

[VillagePlank]

I'd imagine if these min are a regular feature then sediment records would highlight them. I'd imagine the Irish Bog records would give us a long enough window into past climate to instantly recognise any other maunder type temp fluctuations but we do not hear of such periods.

It'd make more sense to me if folk turned their attention to the earth bound drivers that could have conspired to produce a temp downturn of maunder type proportions.

We know of at least 1 Icelandic vent eruption, in the historic period, that was not documented so how many other eruptions in more remote regions have gone un-noted?

Yeah - right. I say that, but I am unable despite my vast intellect* to penetrate exactly what you mean, nor, the point of your post.

*I have a measured IQ of 70.

[Iceberg]

You have a bit of a problem with that idea - trying to figure out what effect a maunder-type minimum might have on global temps is one thing, but how can we check that with "previous maunders"? The only Maunder-type minimum we have an accurate record of is the Maunder Minimum itself. Proxy reconstructions of sunspots going back beyond the mid-1600s lack the resolution to be able to identify similarly quiet periods with any accuracy. We can try to correlate our expectations with past temperatures on this basis, but we can't be anything like certain that we are making the appropriate comparisons.

CB

Very fair point CB, however can somebody come up with an alternative figure to Gavin's for just the well documented Maunder min ?

I am happy to hear another figure if that one isn't believed, my gut and what I've seen indicates something in order of 0.3 to 0.5, so pretty similar to Gavin's.

[sunny starry skies]

The Met Office has over stated the trend of the last ten years. I produced a chart on these threads somewhere last year that gave such evidence. It over cooked individual annual warming as was depicted on that chart.

Wrt to the bolded part,

Right, let me get this straight - you admit that we do not have 'anything like the same handle of forecasting the activity of the sun' and by dint of that you are saying in essence therefore there is little clue as to how upcoming negative solar feedback (minima)might potentially interact and in turn affect the climate trends but at the same time you are stating that because we allegedly have such a good handle on earth climate forcings then the 'other part' (ie solar uncertainty) can be forgotten and taken out of the equation. I find that truly astonishing.

Surely any future revison in terms of solar behaviour that is, as you admit so uncertain, is absolutely crucial!!

I think I just might rather trust a qualified solar scientist in terms of, er, solar behaviour (like Landscheidt) than a scientist, qualified or otherwise, who is making a judgement through AGW assumptive tinted glasses and admits to not knowing much about how the sun might behave!

Solar activity - there's a fundamental difference between attributing the magnitude of changes by looking at observational data in the past and forecasting what those future changes will be. We have a good handle on climate forcings, including solar, by looking at past data, and by understanding the mechanisms by which these forcings work (solar, GHG, volcanic, ENSO). From past data, we can say that solar changes have a ~0.1C effect on the short term, and up to 0.3-0.5C in deep minima, such as Maunder. Now prediction of future solar activity is, as I think we'll agree, an uncertain business. but that does not mean we have no idea about the magnitude of likely future forcing. You can hypothesise about some fantasy super-Maunder minimum, but it has no basis in science as there is no data suggesting this has happened in the recent palaeoclimatic record (which is I think what G-W was driving at?), and notably in radiocarbon production records of solar activity.

What this means is that Maunder Min provides a very reasonable low point for solar activity. A very reasonable high point for solar activity is in the last 50 years which, as some have pointed out, is pretty high on the scale for the whole Holocene. Any future forecast will be in between those ranges. If we drop quickly into a full-on Maunder Minimum, then the reduction in forcing will be equivalent to about a 0.3C drop. Maintaining our high activity values will result in no change to our current forcing. So the difference is between what you and I consider to be "solar uncertainty." I consider it to be a range of ~0.3C with recent decades' forcing at the top of that scale. We do not know exactly what the future behaviour will be, but we do have a good idea of the range within which the behaviour will lie. An assertion of a larger range does not appear supported by the facts. You have yet again not provided anything to support your assertions. Can I have a pair of your anti-AGW assumptive-tinted glasses please?

The reason it is less important than AGW is obvious - the temperature changes that will be the consequence of GHGs are an order of magnitude larger than the forcing we have seen from the Sun. And are our fault.

So no, you did not have it straight.

What's a 'negative solar feedback'? Seeing as solar activity would be a driver of any changes, it cannot be a feedback? I think you misunderstand the meaning of the word "feedback".

sss

Edited March 3, 2010 by sunny starry skies

[Admiral_Bobski]

My head is starting to clear and I'm starting to be able to string coherent thoughts together now, so let me take another stab at this (hopefully without the short fuse I had the other day!).

I had an issue with the assumption that a maunder-type minimum would cause only about a 0.3C drop in temperatures, and I think I've now managed to figure out where my objection lay.

Let's say, for now, that Iceberg's assertion that the Maunder minimum (1645-1715) caused a 0.3C drop in temperatures is correct. If so then it caused a 0.3C drop from the pre-minimum temperatures. We have established, over on the LI thread, that heat gets harder to gain the higher the temperature is, and, conversely, that heat gets harder to lose the lower the temperature is.

If the current temperature is, say, 1.0C higher than the pre-minimum temperature (for the sake of argument) then a Maunder-type minimum would cause a greater heat-loss now than it did in the 17th century.

What I am trying to say is that it is not as cut-and-dried to say that a maunder-type minimum causes a 0.3C drop in temperature because it depends upon the heat content of the system in the first place.

Does that make some sort of sense?

CB

[Thundery wintry showers]

Solar activity - there's a fundamental difference between attributing the magnitude of changes by looking at observational data in the past and forecasting what those future changes will be. We have a good handle on climate forcings, including solar, by looking at past data, and by understanding the mechanisms by which these forcings work (solar, GHG, volcanic, ENSO). From past data, we can say that solar changes have a ~0.1C effect on the short term, and up to 0.3-0.5C in deep minima, such as Maunder. Now prediction of future solar activity is, as I think we'll agree, an uncertain business. but that does not mean we have no idea about the magnitude of likely future forcing. You can hypothesise about some fantasy super-Maunder minimum, but it has no basis in science as there is no data suggesting this has happened in the recent palaeoclimatic record (which is I think what G-W was driving at?), and notably in radiocarbon production records of solar activity.

What this means is that Maunder Min provides a very reasonable low point for solar activity. A very reasonable high point for solar activity is in the last 50 years which, as some have pointed out, is pretty high on the scale for the whole Holocene. Any future forecast will be in between those ranges. If we drop quickly into a full-on Maunder Minimum, then the reduction in forcing will be equivalent to about a 0.3C drop. Maintaining our high activity values will result in no change to our current forcing. So the difference is between what you and I consider to be "solar uncertainty." I consider it to be a range of ~0.3C with recent decades' forcing at the top of that scale. We do not know exactly what the future behaviour will be, but we do have a good idea of the range within which the behaviour will lie. An assertion of a larger range does not appear supported by the facts. You have yet again not provided anything to support your assertions. Can I have a pair of your anti-AGW assumptive-tinted glasses please?

Looking at the past reconstruction graphs of the climate back to Maunder, e.g. this one (which is similar to the other ones I've seen in the past):

http://upload.wikimedia.org/wikipedia/commons/b/bb/1000_Year_Temperature_Comparison.png

I reckon it implies a range of between 0.1 and 0.6C depression for the Maunder Minimum, though with 0.3C as the middle bound. Of course even the most optimistic scenario of 0.6C wouldn't be anywhere near enough to offset 2 to 4C worth of anthropogenic forcing, so having seen the uncertainty range for real, it's more of a useless nitpick than anything else.

But regarding the data for past solar activity, do we have much in the way of reliable proxies going back well before the 1600s? I am in essence thinking of the possibility of solar minima in the next century that exceed the intensity of the Maunder Minimum. (Of course, relying upon any such thing to offset AGW would be dangerous- for it could easily lead to a much more dramatic warming if/when solar activity returns to higher levels- but I'm hypothesising here).

Re. Captain_Bobski, is the difference in Earth temperature large enough for those laws of physics to come into play regarding adding heat & taking it out of the system? I have doubts, but I'm reserving judgement for now.