Admiral_Bobski

I know what you're saying and it has nothing to do with what I've been saying. You keep on missing what I've been saying, so I'm not going to say it any more. End of story. CB

Because "blue sardines" would just be silly. Besides, you'd be blue, too, if you were crammed in a tin with all those other sardines... CB

I've given up on expecting anything... Good news, though - ice extent is on the way up again. Or are we going to doom-and-gloom it and shrug it off as the ice pack breaking up? CB

Since maximum ice extent isn't reached until late February/early March, the "Ice Extent Year" runs from March to March or thereabouts. Late January is therefore, surely, a more worrying time to have a dip than early-mid December? CB

I don't see why that has any bearing on the slight - slight - dip in ice extent over the past couple of days. This type of dip has occurred in the past, there's no sign (yet) that there's anything to be especially concerned about, but you're trying to tell us that the reason for this dip is different from the reason that the many previous dips occurred. You are projecting your fears and concerns onto a phenomenon which is, in reality, rather common. CB

So do we? The disruption that has been highlighted (the recent slight dip in extent) is nothing unusual. Does this tally with "far more disruption" of the ice? CB

Questions, comments and suggestions are always welcome, even if you have no firm conclusions yet. Heck, even I haven't got any firm conclusions from it yet! :o CB

Yes, but we're not seeing the winter pack suffering similar loss in extent to the summer pack of late. I was responding to the suggestion that the slight decrease of the past few days is something to be concerned about - I was pointing out that it's not actually unusual at all. It would be nice to see the ice extent go nowhere but up, non-stop, throughout winter, but that's not very realistic, is it? CB

But this happens quite frequently - mid-December 2003 and 2008, mid-January 2003 and 2006, for example. And despite the recent dip, surely the overall trend is still upwards...? CB

It's a bit hard to put a definitive number on the lag because, due to the Stefan-Boltzmann law, the lag is constantly changing. It is determined by the input into the system and the amount of energy within the system. Since these two factors are constantly changing, the lag is constantly changing too. The main prediciton that the LI has so far made is that temperatures should start to go down within the next 3-5 years (if I remember correctly). This is assuming that the next solar cycle is a moderate to low one, and that ENSO does nothing spectacularly unusual, and that there isn't a major volcanic eruption, and that albedo doesn't change significantly. :unsure: CB

Well, we have pretty reliable records of sunspot count going back to the mid-17th Century. Using sunspots seems to give a good correlation. One of the problems with other measures of solar activity (TSI, magnetic flux and so on) is that you need to rely almost exclusively on proxies. So, using sunspots avoids the proxy issue (at least if you go back to around 1650 - going back further than that does rely on proxies...more on this later). I am well aware that the Sun warms us from a bit above absolute zero to around -18C. Bear in mind that the -18C figure is an average, though. The Sun actually has the potential to heat us to well over +100C - or one half of us at least - a swing of over 400C. Given this fact I find it quite easy to imagine that the Sun can be responsible for a 1C warming trend over 100 years, especially during the last 60 years of extremely high activity. CB

Good answer! CB

Ah, but do you agree that the Sun is responsible for the current warming trend? CB

Actually, if I may nit-pick a little here(!), AGW is not technically a theory yet - it is still a hypothesis, which is a step shy of being a theory. The word "hypothesis" introduces even more uncertainty, of course, so (as you say) it's never mentioned. CB

I suppose you could describe the LI simplistically by saying that the Sun is the main driver of climate: it is responsible for the current warming trend. That trend is modulated by ENSO, albedo, vulcanism and everything else. CB

Anybody...? CB

Good point, thereby making it all the more interesting (and, dare I say it, amazing). I'm not sure what point GW is making about Arctic sea-ice being "a different beastie" from what it once was. I don't see how that has any bearing on the LI - we have used arctic sea ice as a proxy for albedo and so, more or less, ice extent is all that is relevant to the LI. The fact that the ice may be thinner or whatever is of no enormous concern, especially as its changes (into "a different beastie") have taken place only within the last 5-10 years, and the LI goes back well over a hundred years. I am also a little unsure about GW's remark, "we should also not 'shelve' the major forcing [CO2] we have placed into the system." Calling CO2 the "major forcing" is presuming that CO2 is in fact the (or a) major forcing. The point of the LI is to see if we can take the single biggest input of energy (the Sun) and produce a result comparable with observations without any presumptions! CB

What nobody has actually addressed yet is the fact that the LI comes up with this 0.91 correlation. Doesn't anybody but me and VP find that interesting? Amazing, even? No figures were massaged, no data cherry-picked and no clever after-the-fact alterations made. All of the data used are from legitimate sources (Hadley, NOAA, etc.) and publicly-available. The only real assumption made was that solar activity (proxied by sunspot count) was the biggest contributor, and the three other factors (ENSO, vulcanicity and albedo) were chosen because they were clearly relevant to the phenomenon. Does anyone have anything to say about the correlation factor? CB

Well, firstly I don't think that the LI necessarily explains climate - not yet, at least. I think it might be able, at present, to model it, which is a rather different thing. Do I think that the LI can model climate to any degree of accuracy? Yes, I think it could do. Do I think it can do it without invoking CO2? So far it seems to be doing a rather good job of it, yes. Maybe not without any CO2 effect, but maybe with a CO2 effect that is negligibly small. I suppose, really, that I am saying that CO2 might not be the GHG we think it is - not that it isn't a GHG, but rather that we may need to redefine its effects in the climate system. You see, it's all very well and good to show that CO2 causes warming by filling a bottle with it and showing that the air inside gets hotter than in a similar bottle without CO2, but how does that relate to CO2's effect in the real world - a world with sinks and sources, positive feedbacks and negative feedbacks, a world without a solid barrier between the atmosphere and outer space: in short, a world which is dynamic? I am well aware that you accept the usual view of CO2's effects. I'm sure that I have made it abundantly clear by now that I do not accept the usual view: at least not in the real world. What do I think the effect of CO2 is? I'm not sure. Small, I think. Perhaps very small. Certainly in the quantities about which we are speaking. But this is all rather beside the point. The idea behind the LI is to see whether or not CO2 is actually necessary to explain changes in climate. The original plan was to keep on adding things to see if we could get a good match with reality - we managed to get a pretty good match with reality after adding only a couple of things. We haven't actually needed to add CO2 yet. CB

At the moment, CO2 isn't even included in the LI. The variables used are sunspots, ENSO, volcanic activity and albedo (using ice extent as a proxy). We are using a perturbative approach, meaning that we start by inputting the (assumed) largest factor first and then add in other factors, one at a time, to refine the output. With a perturbative method (if properly applied) one can determine whether the assumptions made are valid or not. If subsequent factors have a greater effect than earlier factors then the output should diverge more and more from reality. So far, starting with the assumption that solar effects are greatest, we have an output which seems to tally rather well with reality. The addition of ENSO, vulcanicity and albedo seems to have brought the output closer to reality. And all this without even needing to incorporate CO2. Any thoughts? CB I'm not sure I understand your concerns. Why do you not believe that the "self limiting function" can be used to mimic (I prefer the word "describe") nature? CB

Leaky Integrator now open for discussion...!

Well nobody else seems to be here for scientific reasons - so far only SC has commented on my previous post. In fact it seems that it goes very quiet on here whenever actual science is discussed, the leaky integrator being a prime example. At the risk of shamelessly plugging another thread, the LI thread is there for all to comment on and so far there has been pretty much nothing said. If people are so concerned with keeping discussions on a scientific track then might I suggest that certain people put their money where their mouths are and actually engage in a scientific discussion? CB

As a quick follow-up to my previous post, anyone wanting to read the Benestad/Schmidt (2009) paper can find it here: http://pubs.giss.nasa.gov/docs/2009/2009_Benestad_Schmidt.pdf Rebuttal by Nicola Scafetta can be found here: http://climaterealists.com/index.php?id=3813 I am just about to get started reading the Benestad/Schmidt paper now - if I'm not back in 5 minutes...just wait longer... CB

This may take a while because I'm writing this as I read through! I'm doing a search for the word "solar" in the text to see what references they make. Here's a list: Page 9 - Even over the past ten years, despite a decrease in solar forcing, the trend continues to be one of warming. This makes the assumption that solar effects are near-instantaneous (or at least not lagged by more than a year or two). There's plenty of evidence that this is not the case, and that solar lags can occur over far larger timescales.Page 13 - Every year this century (2001-2008) has been among the top 10 warmest years since instrumental records began, despite solar irradiance being relatively weak over the past few years. Same as above, but with the added point that if temperatures stagnate at a high level then you would expect the temperatures during those stagnant years to be among the top.Page 13 - At the same time [2008], solar output was also at its lowest level of the satellite era, another temporary cooling influence. Once again, same as the previous two points.Page 14 - Lean and Rind (2008) analyzed the role of natural factors (e. g., solar variability, volcanoes) versus human influences on temperatures since 1889. They found that the sun contributed only about 10% of surface warming in the last century and a negligible amount in the last quarter century, less than in earlier assessments. I will come back to this one another time (I have included it here so as to prove I'm not cherry-picking references!). I do recall that Lean's solar reconstructions have become odder- and odder-looking (to me mind) over the years. I shall return to this point once I've done some checking...Page 15 - Most of these short-term variations are due to internal oscillations like El Niño Southern Oscillation, solar variability (predominantly the 11-year Schwabe cycle) and volcanic eruptions (which, like Pinatubo in 1991, can cause a cooling lasting a few years). First off, I'm not sure that solar variability technically constitutes an "internal oscillation", but maybe that's just me. I am also unsure about the assertion that the Schwabe cycle is necessarily the predominant one - it is certainly one of the most frequent, but that's a different matter.Page 15 - If one looks at periods of ten years or shorter, such short-term variations can more than outweigh the anthropogenic global warming trend. For example, El Niño events typically come with global-mean temperature changes of up to 0.2 °C over a few years, and the solar cycle with warming or cooling of 0.1 °C over five years (Lean and Rind 2008). However, neither El Niño, nor solar activity or volcanic eruptions make a significant contribution to longer-term climate trends. References Lean and Rind 2008 again. Where is the evidence that solar activity makes no significant contribution to longer-term climate trends? What about the multi-year lags found by numerous scientists?Page 16 - Can solar activity or other natural processes explain global warming? No. The incoming solar radiation has been almost constant over the past 50 years, apart from the well-known 11-year solar cycle (Figure 5). In fact it has slightly decreased over this period. In addition, over the past three years the brightness of the sun has reached an all-time low since the beginning of satellite measurements in the 1970s (Lockwood and Fröhlich 2007, 2008). Once again this ignores lag effects, but it also fails to address - in fact it cleverly glosses over - the fact that incoming solar radiation has been at an all-time high for the past 50 years. Constant, yes, but also unprecedentedly high.Page 51 - briefly reiterates point 6 above.Page 54 - References the paper "Benestad, R.E. & G.A. Schmidt (2009) Solar Trends & Global Warming, Journal of Geophysical Research 114, D14101". I shall see if I can find a readable version of the Schmidt and Benestad paper later on. There are no references to "TSI" (Total Solar Irradiance) or to "sunspots", so it would appear that the above is all they have to say on the subject of solar activity. Looks like they didn't include those "forced-out" solar papers after all... CB