Tuesday, January 10, 2012

The return of "The Limits to Growth"

The main results of the "base case" scenario of "The Limits to Growth" study, from a recent article on the New Scientist by Debora McKenzie (available upon registration)

The return of interest in "The Limits to Growth" continues. After decades of ridicule and insults, the value of the 1972 study and of its sequels is more and more recognized. The latest item in the series of revisitations is the article published by Debora McKenzie in the New Scientist on Jan 10, 2012 and titled "Boom and Doom, revisiting prophecies of collapse" (can be read on the New Scientist site after registration)

On the whole, the article by McKenzie is very well done and it summarizes all the main points of the story: how Limits never made the mistakes it was accused to have made, how the study was demonized, and how its scenarios are still relevant to our situation today. The article has been extensively researched and it cites the opinion of most of the researchers who have been working on the reappraisal of the study and of its methods, including my book, "The Limits to Growth Revisited".

A point that is less than satisfactory in the New Scientist's article is about the relation of the Limits scenarios with the present findings of climate science. It says that Limits "was too optimistic about the future impact of pollution," but I think this is not the case. The study did contain at least one scenario in which economic collapse took place because of the rapid rise in pollution. But the main point is that Limits was perhaps the first study able to identify the interaction of pollution and the industrial system that produces it. What the authors of Limits called "persistent pollution" in 1972 could later be identified with the forcing effect of greenhouse gases. It is not possible, today,  to say whether the economy will collapse because of resource depletion or because of global warming; but that the terms of the dilemma were already clarified in 1972 must be considered as a remarkable intuition!

The other point that connects "The Limits to Growth" to climate science is the demonization treatment that the study received after its publication. This point is well covered in McKenzie's article. The smear campaign set up against Limits and its authors is surprising similar to the one unleashed in our times against climate science and against climate scientists. The only difference is that the methods used nowadays against science are much more aggressive. The authors of "The Limits to Growth" were often ridiculed and insulted; occasionally they also received death threats, but the level of abuse that climate scientists have been receiving in recent times is much higher. That is, perhaps, because the consequences of global warming on our society could be much more radical and fearsome than anything that Limits had foreseen decades ago.

This said, it is clear that we can learn a lot from the story of the Limits and its demonization. Unfortunately, one of the things we learn from history is that we almost never learn from history.


  1. Surely the "Limits to Growth" (LTG) includes Global Warming as a pollution outcome. This is one of the strengths of the gross level of aggregation of the model.

    LTG and Global Warming are both the results of globalization, of living beyond and depending upon sustainable, local resources. Your comment that "we almost never learn from history" is very apposite because 9 out of 10 pundits propose further globalization as the solution to these problems.

  2. John, would rather say that globalization was made possible by the availibity, and usage, of cheap fossile energy, and that in itself can only follow an LTG scenario, as well as bringing CO2 levels towards GW.
    As to pundits they can propose, but the "wall" is there, and for sure we indeed don't learn much from history..

    Happy new year to all anyway !

  3. Jorgen Randers discussed the pollution scenario at the 2007 System Dynamics Conference. He praised Jay Forrester's insights in designing the pollution scenario with long delay responses, because of the lack of immediate pollution effects.

    Tom L

  4. I alays thought it was the biggest scientific story of the first half of my life. Then came Climate Change.
    Deborah McKenzie was always thorough, and had integrity and an intellectual grasp. I remember her well. Many years ago, she took an interest in genetically modified salmon and some strange 'goings-on' in a Scottish sea loch.
    Thanks to Ugo for being faithful to evidence and for testing information.
    I lost any 'faith' in 'The Economist' a very long time ago. Or in Tony Blair who repeated the 'technology' mantra before he was forced to leave office.

  5. Professor Bardi, thanks for sharing this new evidence about what the system dynamics tells us about the future, and nominally that the studi from 40 years ago is still essentially valid not just a tendency analysis, but even as actual predictor of world wide macro data.

    By the way did the autors of the article tryed to ''recalibrate'' the model with the up to date data and run again a 100 years future scenario?

  6. Thanks, Trinetra; I think you know that there have been two sequels to the first study: one in 1982, the other in 2004. The model was recalibrated with new data and slightly modified in various part. The results were basically the same. The authors say that they have no intention to do that again; by now we are running on the rollercoaster all the way to the end!



Ugo Bardi is a member of the Club of Rome and the author of "Extracted: how the quest for mineral resources is plundering the Planet" (Chelsea Green 2014). His most recent book is "The Seneca Effect" to be published by Springer in mid 2017