Reassessing 1972's The Limits to Growth

Over four decades ago the Club of Rome authorized a team of scientists headed by Dennis and Donella Meadows and Jorgen Randers to revisit the old problem pointed out by Thomas Malthus in his classic Essay on the Principle of Population: the interaction between exponential growth and finite resources. Using the then-new techniques of systems dynamics theory and computer modeling, they examined long-run trends in the growth of the world's population and material production and consumption (e.g. industrialization, pollution, food production, resource depletion), and published their findings in 1972's famous The Limits to Growth.

Last year of course marked the fortieth anniversary of that study's publication, and saw the release of an update, which did get some attention in the press – much of it negative (like Timothy Worstall's assessment in Forbes), just as was the case with most of the attention the original study received.1 As Ugo Bardi has noted,

In the 1980s and 1990s, the study was attacked, demonized, and ridiculed in all possible ways. With the apparent end of the oil crisis, in the late 1980s, the ensuing general wave of optimism consigned the Limits study to the dustbin of "wrong" scientific ideas; together with the dinosaurs of Venus and the evolution of the giraffes' necks according to Lamarck. Urban legends on the "mistakes" of the Limits study are still common today, despite being just that: legends.

Those legends all remain alive and well, and not only in online forum debates between the ill-informed, but the pages of prestigious mainstream publications (including many which offered comment on the 40 year update). Indeed, it is hard to think of a book of recent decades that has suffered more intense or prolonged attack based on sheer misinformation or disinformation than 1972's The Limits to Growth.

The authors of the first edition of Limits are quite clear in their book about its not being "intended as a piece of futurology," but "an analysis of current trends" and the implications of their continuation.2 In keeping with this assertion the authors not only avoid actual forecasting (a fact that has not stopped apparently erroneous forecasts from being attributed to them), but repeatedly express a leeriness about the idea, instead discussing multiple projections (about such things as the GNP of selected nations) and explicitly making it clear that they do not actually expect to see real-life figures match their numbers.

Rather their multiplicity of models demonstrated the obvious, intuitive and logically irrefutable point that the exponential growth of population and "capital" cannot continue indefinitely within a finite system, such as they take the Earth to be. The exhaustion of key natural resources, and the toll taken by pollution, would become increasingly heavy burdens on economic growth and human well-being, ultimately precipitating the system's collapse – and with it a sharp rise in mortality, and a sharp drop in consumption and living standards. They also contended that the population and capital growth rates of their time, if continued through the twenty-first century, would bring on collapse before 2100 at the latest – an assessment that still appears quite plausible, and perhaps even the common expectation among those attentive to such issues.

None of this seems particularly controversial, and in fact a considerable body of analysis by other researchers has since substantiated many of the study's claims. A 2008 study by Graham M. Turner found that the observed trends reflected the anticipations of the authors, while in a broader sense, so do such findings as the Global Footprint Network's argument that "overshoot" of the planet's ability to replenish the resources being consumed by humanity had occurred by the 1970s, and that we are today consuming the equivalent of 1.5 Earths' worth of resources (in 2012, using up a full year's supplies by August 22). Indeed, in the book's early sounding of the alarm about carbon emissions and their connection with anthropogenic climate change Limits was actually ahead of its time (ironically, a point rarely acknowledged even by those most attentive to environmental issues).

What proved more problematic was the solution the authors prescribed, namely the limiting of material output to specified "sustainable" levels (that particular term was not yet in use) to be met within the coming years.3 The sacrifice of that part of economic growth coming from the consumption of ever-growing quantities of natural resources, especially through the kind of central control required to implement such a project at a global level, was simply unacceptable to the conventional wisdom of the time.

Such ideas were to become even less acceptable as mainstream thought on such matters moved rightward – so much so that it can seem a surprise that this was ever proposed at all.4 One might argue over whether the solution the study's authors prescribed was desirable or realistic, but it is a reminder that today we are far less likely to imagine our social, political and economic arrangements as being so adaptable, let alone adaptable in the name of enlightened, long-term, collective self-interest. The imagination – and the political flexibility – which would even permit this to be envisioned in principle, let alone a workable program, has proved to be yet another resource in too-short supply.

1. This was the third such update, previous updates having appeared in 1992 and 2002, at the 20 and 30 year marks.
2. It should be noted that The Limits to Growth is not a dense scholarly text but very clearly and simply written, making it unlikely that the "intelligent lay reader" (scarce as these may be) will get seriously confused about what it is trying to convey at any point. Instead, as is the case with most Important Books, even ones as short and easy to read as this one, most of those discussing them have only secondhand knowledge of them gleaned from questionable sources – and are motivated by an enthusiasm for dubious ideology.
3. Sustainable economic activity is defined in the 30-year update as activity which does not consume renewable resources more quickly than they can renew themselves; does not consume nonrenewable resources more quickly than substitutes can be found for them; and does not produce more pollution than the Earth system can absorb.
4. The Limits to Growth did not call for "zero growth." One reason was that material output represented only part of economic production and consumption, with services like education and health, for instance, materially "lighter" and so still expandable. Another was that the recommendations allowed for continued increases in material output where technological advance permitted more to be done with a given stock of resources.