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This is not my analysis, and the first author, Gaya Herrington, explains the alignment between the model and empirical data here: https://m.youtube.com/watch?v=

This is not my analysis, and the first author, Gaya Herrington, explains the alignment between the model and empirical data here: https://m.youtube.com/watch?v=KJpvc3i5j84 https://m.youtube.com/watch?v=KJpvc3i5j84 I also react with concern. Yes there are infinite curves, but there are limits to what is possible, so in actual fact there are not infinitely many possible futures here, and those futures are likely to fall within the limits of the 4 sensitivity analyses…and indeed have over more than 4 decades of follow up.

Enginerrrd 3y ago
I know it's not your analysis. I said your interpretation of this analysis is flawed. You're misunderstanding that analysis to be confirmation of the predictive power of the model extrapolated into the logistic region. And you still are: >Yes there are infinite curves, but there are limits to what is possible, so in actual fact there are not infinitely many possible futures here, and those futures are likely to fall within the limits of the 4 sensitivity analyses…and indeed have over more than 4 decades of follow up. The key phrase there where your interpretation is flawed is: "are likely to fall within the limits of the 4 sensitivity analyses". That's so, so untrue. You simply cannot extrapolate logistic model parameters into the actual post-exponential-growth, logistic portion without seeing the actual logistic effects start to kick in. Those simply haven't been empirically verified here. And speaking of... the original model they are analyzing introduces limits on that exponential growth in a pretty arbitrary and artificial way, particularly when it comes to the pollution terms.... which, I'll add, this analysis shows is also the parameter they most over-estimated by a large amount even in the exponential portion.
- westcort 3y ago
  I want to believe in infinite growth too. Maybe asteroid mining could make this paper and model predictions way off. Indeed, that is the kind of thing we hear from Jeff Bezos: https://www.milkenreview.org/articles/mining-in-space-is-coming https://www.milkenreview.org/articles/mining-in-space-is-com... But also, yes, it IS reasonable to look at 4 sensitivity analyses comprising the most common rebuttals to limits of growth, observe alignment with more than 4 decades of empirical data, and believe based on that the model is pitching well above its weight. No need for ad hominem here.
  - snapplebobapple 3y ago
    You don't have to believe in infinite growth, the problem with the model that makes the scary bit after the slopes change to down are all BS because of: "However, it is important to note that the connections in the model and the recalibration are only valid for the rising edge, as many of the variables and equations represented in the model are not physical but socio-economic. It is to be expected that the complex socio-economic relationships will be rearranged and reconnected in the event of a collapse. World3 holds the relationships between variables constant. Therefore it is not useful to draw further conclusions from the trajectory after the tipping points" That tells you this model disregards how every single societal crisis in the past was solved or at least mitigated: A massive change to the order of society (think germanic tribes conquering rome, magna carta type stuff, Napoleon et al taking France from a monarchy to an anarchy to an empire and, after calming down a bit, to a republic, etc. etc.).

Enginerrrd 3y ago

I know it's not your analysis. I said your interpretation of this analysis is flawed. You're misunderstanding that analysis to be confirmation of the predictive power of the model extrapolated into the logistic region. And you still are: >Yes there are infinite curves, but there are limits to what is possible, so in actual fact there are not infinitely many possible futures here, and those futures are likely to fall within the limits of the 4 sensitivity analyses…and indeed have over more than 4 decades of follow up. The key phrase there where your interpretation is flawed is: "are likely to fall within the limits of the 4 sensitivity analyses". That's so, so untrue. You simply cannot extrapolate logistic model parameters into the actual post-exponential-growth, logistic portion without seeing the actual logistic effects start to kick in. Those simply haven't been empirically verified here. And speaking of... the original model they are analyzing introduces limits on that exponential growth in a pretty arbitrary and artificial way, particularly when it comes to the pollution terms.... which, I'll add, this analysis shows is also the parameter they most over-estimated by a large amount even in the exponential portion.

westcort 3y ago
I want to believe in infinite growth too. Maybe asteroid mining could make this paper and model predictions way off. Indeed, that is the kind of thing we hear from Jeff Bezos: https://www.milkenreview.org/articles/mining-in-space-is-coming https://www.milkenreview.org/articles/mining-in-space-is-com... But also, yes, it IS reasonable to look at 4 sensitivity analyses comprising the most common rebuttals to limits of growth, observe alignment with more than 4 decades of empirical data, and believe based on that the model is pitching well above its weight. No need for ad hominem here.
- snapplebobapple 3y ago
  You don't have to believe in infinite growth, the problem with the model that makes the scary bit after the slopes change to down are all BS because of: "However, it is important to note that the connections in the model and the recalibration are only valid for the rising edge, as many of the variables and equations represented in the model are not physical but socio-economic. It is to be expected that the complex socio-economic relationships will be rearranged and reconnected in the event of a collapse. World3 holds the relationships between variables constant. Therefore it is not useful to draw further conclusions from the trajectory after the tipping points" That tells you this model disregards how every single societal crisis in the past was solved or at least mitigated: A massive change to the order of society (think germanic tribes conquering rome, magna carta type stuff, Napoleon et al taking France from a monarchy to an anarchy to an empire and, after calming down a bit, to a republic, etc. etc.).