So, i concede that "predicted or "arguably predicted or "very strongly implied" might have been better choices than "very clearly predicted and your agreement on "implies" is certainly defensible. Nevertheless, my mildly imprecise wording warranted rebuttal and not exile from the main page; my interpretation of ltg is a valid counterpoint. User:Chrisa798 I have no significant objection to you working on the phrasing and content of the article. And for what it's worth, i did not remove you text (I thought I was too biased to safely.). I certainly agree that the world3 model fails to take into account market mechanisms. I do wonder what would have happened if opec had not caused high prices in 1979, and instead the natural causes had caused an oil shortage in the 1990s. Meadows et al explicitly state that their model does not take into account political events, so i think opec is a fair reason for their ideas to fail. I encourage you to find examples of"s where they are implying sudden collapse, or if that is difficult, find examples of contemporary (1970s) interpetations to that effect.
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Lomberg clearly claims that Limits to Growth states that we will run out of oil in 1992, but the reference is to the table of exponential indexs. This table does not say that we run out of oil in 1992. I can certainly believe that the book implies that we will start noticing running low of resources in the 1980s, but I question the statement that it very clearly does. If it very clearly does, than please enlighten me as to where? Jrincayc 23:18, (UTC) From its very title to its overall tone to its dire warnings, ltg strongly implies that the rundowns would begin in the near then-future-as you note. From the intensity of their implications, i think the inference that their implications rise to the level of predictions is reasonable. Of course, the authors were surely aware that use of mere strong implication and qualifying language would allow them kalam to straddle their quasi-predictions and abandon them without acknowledging how totally wrong they were-just as this technique would have allowed them to claim vindication had history. Inferences are interpretations, so by definition the book does not necessarily have to state expressly what i inferred. However, publishing a tract full of alarmist pseudo-science and then hiding behind qualifiers stinks of intellectual cowardice (citing opec is all fine and well, but it reminds us that ltg didn't take adaptation, market mechanisms, technology, etc. Sufficiently into account, calling the entire premise of the ltg model's utility into question). To me, the thrust of their implications amounted to very clear predictions, but that might take the interpreting dangerously far.
Such irresponsible work undermines legitimate efforts to improve the summary earth. 1 Writing for the michigan Law review, Alex kozinski discussed Limits to Growth at length at the beginning of his heavily sourced, comprehensive review of The skeptical Environmentalist. Lomborg earned the enmity of the environmentalists because he demonstrated the manner in which many leading environmentalists manipulate statistics to bolster political agendas. I was unable to find justification of the claim that: The book very clearly predicted that we would start running out of resources in the 1980s, 1990s, and later unless we implemented radical changes to our economy and polity in the 1970s. The 'standard run' chart figure 35 for example shows the industrial output collapse begining at around 2010. On page 66, limits to Growth states: given present resource consumption rates and the projected increse in these rates, the great majority of the currently important nonrenewable resources will be extremely costly 100 years from now. That would be in 2072. If you actually look at the growth rates of for example petroleum consumption from 1960 to 1970 2, the growth rate is exponential.9 (higher than the.9 figure that Limits to Growth uses). The primary reason that there was no collapse of oil was because of opec raising prices dramatically, instead of hitting a geological limit.
What Limits to Growth actually shredder has is the above table which has the current reserves for oil running out in 1992 assuming constant exponential growth. Divorced from context, the above statement is misleading. The book very clearly predicted that we would start running out of resources in the 1980s, 1990s, and later unless we implemented radical changes to our economy and polity in the 1970s (changes of a magnitude that, as a practical matter, would have required central. The truth of the above"tion is central to the weakness of the book; the authors assumed constant exponential growth in consumption and arbitrarily decided that everything else (productivity, technology, replenishment) would remain relatively summary fixed. In essence, the authors chose parameters that guaranteed the desired outcomes but had little relationship to reality (the pace of evolution in the decades preceding publication suggested anything but a sudden halt). Limits to Growth was a pseudo-scientific attempt to justify a radical environmental ideology. It was wrong and has negligible value.
Assuming a growth rate.1 percent per year (low compared to growth rates of energy after the industrial revolution k ln(1.0.001).0009995, and b ln(9.995e-4 1e111.995e years, which is only about four times longer than human recorded history, or definately less than. Jrincayc 12:40, (UTC) Controlling the birth rate edit well said! (see above: Exponetial index formula) Very well said and well illustrated. This is exactly the point. Unless humanity is willing to stabilize its birth rate which means there has to at some point be zero population growth - then humanity is doomed! None of the world's problems have a solution while people think they can have x number of kids where x is a number much greater than. Swipe at skeptical Environmentalist edit User:User: wrote: Swipe at skeptical Environmentalist exemplifies deficiencies of the limits to Growth approach.
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It ran on an ibm 360/370 platform.- ozzie66 17:31, (UTC) Exponential index formula edit limits to growth does not give the exponential index formula, so i had to rederive. The question is how long with the resource be used. Since the exponential assumes that there is a constant rate of growth, it can be done as so: S0bektdtdisplaystyle sint _0bektdt where s is the static index (this normalizes the first years use to 1 kln(1.0r)displaystyle kln(1.0r) where r is the annual rate, and. So, after integrating and solving for essay b, this works out to bln(k(S1)kdisplaystyle bfrac ln(k(S1)k. Jrincayc 20:58, (UTC) Here is an example.
On page 250-251, Introduction to nuclear Concepts for Engineers by robert. Mayo has the following": "For the year 1995, about.71030displaystyle.7times 1030 j of electrical energy was consumed worldwide. Catalyzed d-d burning of seawater can then supply this constant rate for more than 100 billion years. Even allowing for a very liberal growth in electrical energy demand and complete elimination of all fossil fuel burning still does not detract from the conclusion. There is more fusion fuel available than earth inhabitants will ever need." so, for this example, the static index in 100 billion years, or 1e11 years.
I think the problem is the step sizes. I'd try playing there first. What we really need is to find the Thesis. We do not know _which_ integrations the guy was talking about. Hopefully someone will step forth.
Replicating doesn't prove convergence. It might just prove similar non-convergance. The algorithm can head into the hills but in both machines it might have headed in a similar (worng) direction. Terr It is possible that jay forrester's dynamo simulator was used to generate the results. I used dynamo to investigate international exchange rates 1972 using open difference equations. Dynamo was written in fortran and should be available somewhere.
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The cdc essays machines had 120 bit doubles. Whether you use python or any other language doesn't really matter. I don't know how we can prove whether the runge kutta integrations converge or not. I think you'll have to do some digging. Numerical Receipes might be a place to start. I have the fortran version but I'm comfortable with c and type other languages. I have never looked at the source code and I really don't have enough time to do so - however I would be willing to work with you and write some functions you could call from Python to crunch some numbers. The issue is I don't think we can get 120 bit and I do know that if we adjust the steps on the rk integrations we are not suppose to need the higher precision. I do not think the code is the problem.
be a good thing to do because it means the study was mathematically not correct in addition to all of the other criticisms. Terr 03:00, 14 September 2006 (utc hmm. I wonder what are the exact changes between World3/1974 and World3/1990, since world3/1990 was designed to run on pc's. Jrincayc 03:57, 14 September 2006 (UTC) Actually, come to think of it, i replicated the non renewable resource equations in python using doubles, without noticing any serious differences. Jrincayc 12:22, 14 September 2006 (UTC) This would make sense. The pc uses an ieee specified format which has 80 digits of precision in the fpu and 64 typically in the floats. However 80 bit floats can be used.
This article is within the scope. Wikiproject Futures studies, a collaborative effort to improve the coverage. Futures studies on wikipedia. C-class on the quality scale. High, this article has been rated. High-importance on the importance scale. Contents, runge kutta numerical integrations edit, i remember reading a thesis done at the colorado School of Mines. A chap tried to reproduce the study on a cdc and couldn't. The original study was done on an ibm which has much smaller floating point precision.
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