I read The Limits to Growth recently, and I was surprised to find almost none of the criticisms regularly leveled at the report have any substance. I guess if you prefix a piece of research with the words ‘now discredited’ enough times, eventually even the smartest people will follow suit.
Here are some of the accusations I’ve heard, and what the book actually claims.
The predicted crash by 2000 never happened
I’ve read a number of times that The Limits to Growth predicted a collapse of the industrial system by the year 2000. A decade on, cue much jeering from people who clearly haven’t read the book – it doesn’t put dates to a crash, but suggests growth cannot carry on beyond 2100. This criticism is a whole century too early, and I imagine it originated either as a lie or a typo. If economic growth is still flying in 2100, the report will be proved wrong, but this is the most nonsensical of the common objections.
Computer modelling is inherently flawed and unreliable
This is an argument familiar to anyone who’s ever heard a climate skeptic, and the same points are made in reference to The Limits to Growth. Considering this was done in the earliest era of computing, there’s no doubt that the model is oversimplified in places, but it depends what you’re expecting. Exact predictions are impossible from a model like World3, but the authors know this. They describe their process as “‘prediction’ only in the most limited sense of the word”.
The aim is not to predict exactly what will happen, but to show the shape of the future if current activity continues. They compare it to throwing a ball into the air. You couldn’t say exactly how high it will rise to the nearest centimeter, or what velocity it will attain on its way down, but you know what its basic behaviour will be: It will rise, arc, and fall. That is it’s ‘behaviour mode’, and that is what the computer model here aims to do for industrial society. What it suggests is that if growth is not managed, the general shape of the future is overshoot and collapse.
The report gets the dates wrong for resource depletion
Another regular criticism is that the book predicted the depletion rates of various metals, and got the dates hopelessly wrong. In fact there are very few dates in the book. As I described above, the report is concerned with general trends, and there are too many uncertainties to make specific predictions. The authors are adamant throughout that “the exact timing of these events is not meaningful”.
In the whole book, there is only one spread that contains specific dates. There’s a table that lists a series of non-renewable resources and the dates at which current stocks would be exhausted at current levels of consumption. It offers a range of dates allowing for future discovery or recycling. Copper reserves for example, either had another 21 years left to run, or 36 or 48, depending on the assumptions. That gives you 1993, 2oo8 or 2020. These aren’t predictions, but a range of depletion scenarios extrapolated from the consumption rates of the time.
Interestingly, in 2008 a research report compared the Limits to Growth models with “30 years of reality”, and found that “historical data compares favourably with key features of a business-as-usual-scenario”.
This graph, for example, shows aggregate non-renewable resource depletion (in purple) tracking pretty close to the Limits to Growth ‘standard run’ projection.
The model fails to anticipate technology
This objection emerged at the time of publication and has been repeated ever since, that the computer model doesn’t allow for advances in technology. This isn’t true. “Mankind has compiled an impressive record of pushing back the apparent limits to population and economic growth by a series of spectacular technological advances” say the authors. The technology component of the model factors in huge advances in nuclear energy, high-yield agriculture, recycling, and off-shore drilling, among other things.
Some critics suggest that the report assumes linear change, while technological change is actually exponential. There is something to this argument – the authors admit they struggled to find a suitable way to factor in changes that you can’t possibly foresee. But while this may extend the limits by a few years, it doesn’t change their fundamental conclusion that continuous growth can only end in overshoot and collapse.
The Limits to Growth is neo-Malthusian, and Malthus was wrong
I’ve read before that the Limits to Growth predicts a ‘Malthusian catastrophe’ by suggesting we’ll run out of food. And since the green revolution proved Malthus wrong, the conclusions of the Limits to Growth are also wrong. (I don’t understand the fixation with Malthus. It seems you can’t raise the possibility of food shortages without someone mentioning him, as if he’s the only person to have written about the topic.) The authors were well aware of the dramatic progress of the green revolution and discuss them in some detail. The computer model allows for similar advances into the future, and actually errs on the side of optimism. Like technology however, agricultural advances only buy us more time rather than change the eventual outcome.
The Limits to Growth supported industrial elites by calling for an end to change
This is a newer one, and perhaps not so common, but worth mentioning. It’s cropped up in Adam Curtis’ documentary All Watched Over by Machines of Loving Grace, (see comments below) where he argued that The Limits to Growth supported the status quo of industrial capitalism when it suggested a steady state economy.”World governments should give up on the idea of promoting continual economic growth,” Curtis paraphrases, but then equates this to saying that politicians and governments “should give up trying to change the world” and instead, focus on managing the existing system. It may have been understood that way by some, but it would not be the view of the authors. “Global equilibrium need not mean an end to progress or human development” they write, and the last chapter argues for an ‘equilibrium society’ that is more equal and more free. It is true that they avoid politics, but it is certainly not a call to inaction. “A decision to do nothing is a decision to increase the risk of collapse”, they say.
The Limits to Growth has been badly misrepresented, which is suppose is inevitable after almost 40 years of telling people something they don’t want to hear. Reading it now, what surprises me is just how few claims the authors makes, far fewer than the critics imagine. There are legitimate arguments of course, and the report isn’t perfect. But the basic conclusions are far from being disproved. There was a 20 year review in 1992 and a 30 year final review in 2004. Both of these are bigger books than the original and engage in the various arguments and counter-arguments.
For more on how The Limits to Growth stands up today, see the CSIRO report mentioned above, or Matthew Simmons’ review. “There was nothing that I could find in the book that has even vaguely been invalidated” he writes.