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Admiral_Bobski

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Admiral_Bobski last won the day on July 22 2009

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  1. Ice extent is a proxy for albedo in this model. We can take it out if it makes you feel better, but your point is irrelevant.
  2. Absolutely right, Pete. The point being that there is energy "stored" in the liquid water that can be released further down the line when the water refreezes. I apologise for not making that clear. I'm sorry - I don't quite get what you're saying...?
  3. I think this is an important point you've brought up here. The LI is not really a predictive theory - it operates on the basis that the inputs at any given moment in time carry over to the next moment in time. It is an explanatory model: it explains why temperatures behave the way they do, retrospectively. The only way to use it for prediction would be to know for a fact what the Sun is going to do in the future, what ENSO is going to do, what the planet's albedo will be, what volcanoes are going to erupt. SInce these inputs are not easily predictable, the output cannot be predictive as such. So the LI shows that hysteresis can explain temperature change. Prediction is irrelevant. The difference between the LI and your analogy of leg-length is that in your proposal, all we are doing is plotting raw data and then drawing a conclusion, like the old bar graphs we did in school. With the LI, the data are undergoing a process which produces results which are then plotted - the graph is not a plot of raw data, it is data that have undergone a function. The raw data don't explain anything. Does the LI's predictive limitations invalidate it as a model of climate? Not at all. This would only be the case if climate was inherently predictable, and we know for a fact that it is not. This being the case, AGW theory - a theory that purports to be able to predict future climate - seems even less credible to me than it did before.
  4. I'd just like to chip in here and say, up front, that I have very little desire to pursue the LI any further. I immersed myself in it 3 years ago, researched my butt off, read papers, gathered datasets and so on and so forth - BW did even more than I did, a fact for which I am very grateful and also extremely sorry about - but I really no longer have the enthusiasm for the subject. To be frank, I think we struck gold with the idea and I was extremely disappointed and upset that very few others shared my enthusiasm (there are many people who say, "oh, I wish, I wish, I wish AGW weren't true!" but actually have no desire to explore alternative hypotheses). I really don't want to be dragged down into the mire, and I would be devastated if my recent rekindling of the subject were to drag BW back into it out of a sense of duty. On the other hand, and as I said in a previous post, I am happy to restate some of the thoughts we had at the time, or try to elaborate upon those thoughts. I saw a post in which the LI was sorely misrepresented and I didn't want it going down in Netweather history as some crackpot idea that was complete nonsense, on the basis of a few ill-informed posts by other members. My only regret is that we didn't go so far as to run the model into the future by 30 years, just so that we could perform a comparison every 10 years - that would have been interesting. The prediction up to 2015 is a curiosity that has held up pretty well for 3 years, but the cooling it predicts is on the basis of assumptions (the presumed datasets) that no longer hold true. I don't feel the idea can be rubbished if temperatures do not plummet in the next 2 years (though, on the other hand, if temperatures do plummet then that would be remarkably interesting). So, in conclusion, ask me questions and I'll do my best to answer them. If BW wants to get back into the thick of it and start producing models again then I'll be happy to get back into it, but if he has no desire for it then that's absolutely fine by me. I don't want to drag others in after me, especially after the grief that we got last time.
  5. As I recall, adding ENSO really snapped the LI output to match observed trends to a greater precision - I'd be reluctant to drop it on the basis that, although it could be considered to be a generic lag-causing phenomenon and hence already included in the "size of the hole", it is a greater modulator of atmospheric heat than any one other thing. In a way it almost could be considered a source of heat at certain times, while a sink of heat at others. As for the sea ice extent/albedo issue, we accepted at the time that it was not a perfect proxy, but decided that, in the absence of anything better, it should show a general trend of decreasing albedo. I am happy to disregard the albedo data until it can be replaced with a better dataset. Bear in mind, songster, that this is currently a fairly low-res chart, using only 1 datapoint per year - averaging the northern and southern hemisphere summer-only data would be a better way of getting a yearly average, I guess, but that was more work than we were able to take on at the time.
  6. That's correct: ENSO isn't a source of heat per se. However, the timings of the ENSO events are relevant in that they modulate the basic hysteresis effect (or, to put it another way, they refine the output to give a closer match to reality). As I said the other day, the timing of the heat in and heat out of ENSO can make subtle differences depending upon the timing of solar events. The only factors we included were, as you say, Solar Input (as proxied by sunspot data), ENSO, Volcanic activity and Albedo (as proxied by sea ice). The sea ice data was total global data, as I recall, and not just Arctic sea ice.
  7. Sadly, no - but I did get a new haircut Logic begs that we should be cooling? The LI doesn't show cooling, and the LI is a mathematical formula - it doesn't get much more Logical than mathematical formulae. We don't have other energy sources as such, merely a reallocation of the distribution of energy that came from the Sun, which is precisely what the LI is all about. Look at it this way - some energy from the Sun has gone into the melting of the ice and now, in your words, that energy is "free". It has taken some time for the ice to melt, so the incident energy has come into the system, performed a "task" (the task of melting sea ice) and then been "freed up". That means that energy has been trapped in the system, which means that there has been a lag between the energy coming in and its being freed up into the atmospheric system. Is this not just one of many ways in which there is a lag in the climate system? This being the case, have we not just proven a central tenet of the LI: that the climate system exhibits hysteresis? (Also, changes in albedo are factored into the LI, so that "forcing" is accommodated by the hypothesis.)
  8. That sounds about right, BW (Have to resist the urge to call you VP!) As a little tidbit of background info, in the LI, greenhouse gases are part of what determines the size of the hole. According to AGW theory, as GHG concentrations increase, the "hole" gets smaller, thereby decreasing the amount of heat that can escape into space. What got us so excited about the LI (or got me excited, at least) was that we could get a seemingly good match with actual observed real-world temperature without changing the size of the hole! If the LI were to verify as a legitimate model then it would suggest that changing GHG concentrations in the atmosphere has a negligible effect on temperatures (at least in the concentrations we are talking about). Now, obviously we met a lot of resistance to this idea, on the basis that we all "know" that GHGs have an effect. But I have always argued that, although GHGs may have a straightforward effect per se, once those GHGs are in an ever-changing, dynamic system like the real world, replete with sinks, checks and balances, the situation becomes less clear-cut. Discuss... PS - Changed my name - thought I deserved a promotion!
  9. Yes indeed, you can have the same lag with cooling, but it would not necessarily even things out, depending on the timing and duration of such events - such is the nature of the time lag. The lag issue complicates the issue beyond a simple net-effect cancellation.
  10. While I agree that, in and of itself, an ocean oscillation has a presumed net effect of zero, the issue becomes more complicated when introducing the concept of lag. If heat is stored during a period of higher solar activity, retained through a period of low solar activity, and then released during another period of high solar activity then it affects the outcome differently from the way it would if the heat was released during the earlier (or a later) period. Where the heat actually is at any given moment in time potentially makes a difference. Regardless of the particular arrangement of continents, the ocean must always have had some kind of rolling heat capacitance, due to its gravitationally-induced motion - the way this motion would affect retention and emission of heat may be different, further complicating matters, but there would have been an effect. Perhaps of more importance on these timescales is the albedo effect - long periods occurred when there were no icecaps, while at other times there were periods of enormous ice extent. How much of an effect this may have had on LI-style heat retention and lag effects I am not sure, since I lack the data.
  11. Begging your pardon, sir, that I didn't say "Oceanic Overturning/Oscillating/Currents Etc.," for there must have been some movement of the planet's oceans even 600 million years ago (we still had a Moon back then). We used the facility that ENSO has of swallowing up and spitting out heat in cycles (El Nino, La Nina) as a moderating factor in our refinement of the LI output. Now, even if there was no El Nino or La Nina a hundred million years ago, due to the configuration of continents, this facility must have existed in some format or other because - and here's the shocker - the oceans move! (gasp!)
  12. Perhaps he could clarify - we had discussed, way back in the early days of the LI, how the Earth has varied between a minimum of about 10C and a maximum of about 25C over the past 600 million years. Obviously the Vostok core doesn't even cover one half of one million years, so those extremes are only variations around the "current" average temperature of about 12C. Although those variations are obviously of interest, of more interest still (to me, at least) is that there seems to have been, for over half a billion years, some kind of cap on Earth's possible temperature extremes. A discussion of the faint young sun paradox would be interesting....it might be nice, one day, to find some proxies for the LI's various inputs going back many hundreds of millions of years and see what happens, but I don;t know if there's any way of extrapolating ENSO information back that far, or even reliable sunspot data for that matter. Please bear in mind that I haven't really thought much about the LI in about 3 years now and I'm a bit out of practice!
  13. Actually, the "impacts of AGW" were not portrayed at all - that was kind of the point of the whole exercise - and not for lack of data but rather as an exploration of the possibilities of there being no significant AGW effect. I am very wary of this whole "positive feedbacks" issue, which is kind of why I keep on saying "Time Will Tell", but I would like to call you out on your use of the word "dictate" and offer the use, instead, of the word "suggest".
  14. As a point of order, the "tap" filling the bucket was the Sun, which is not a near-constant input - it varies over the sunspot cycle, and sunspot cycles vary from cycle to cycle. The whole point of the LI was that we had a large peak in sunspot activity around the middle of last century, and we considered what might happen if this increased solar activity was equivalent to a sudden increase in the "tap's" input. Since the 1950s we have had sustained high sunspot cycles, right up until this current one, which is more in keeping with cycles prior to the 1950s. Also, the LI made no mention of CO2. CO2 was not considered to be a cause of a "narrowing hole" - my initial desire was to see what would happen if we didn't take CO2 into account...and we got a pretty nice comparison between the LI and real world temperatures. The assumption was that maybe CO2's effects are not as large as has been presumed, due, perhaps, to some balancing or mitigating natural effect. As a final point, I would like to just reiterate that the LI predicted temperatures to remain pretty much level over the next several years (barring natural year-to-year variations) before starting to drop off, if solar activity does not pick back up! So, as is now something akin to my catchphrase, I guess we'll just have to wait and see.
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