Limits to Growth , The: The 30-Year Update [Paperback]

In the Authors' Preface, they provide important background information to their "30-Year Update": Published in 1972, "The Limits to Growth (LTG) reported that global ecological constraints (related to resource use and emissions) would have significant influence on global developments in the twenty-first century. LTG warned that humanity might have to divert much capital and manpower to battle these constraints -- possibly so much that the average quality of life would decline sometime during the twenty-first century." Then in 1992, the authors conducted a 20-year update of their original study and published the results in Beyond the Limits. "In BTL we studied global developments between 1970 and 1990 and used the information to update the LTG and the World3 computer model. BTL repeated the same message: In 1992 we concluded that two decades of history mainly supported the conclusions we had advanced 20 years earlier."

However, BTL (1992) offered one new finding: "...humanity had already overshot the limits of Earth's support capacity. This fact was so important that we chose to reflect it in the title of the book." If you have not already read one or both of the two earlier volumes, these brief excerpts from the Authors' Preface to Limits to Growth: The 30-Year Update will suggest a context within which to understand and appreciate the significance of what Meadows, Randers, and Meadows share in this third volume.

If I understand their key point, it is this: Humanity's consumption of Earth's resources (i.e. humanity's "ecological footprint") proceeds at an increasingly faster rate than Earth's available resources can accommodate (i.e. its "carrying capacity"). There must be prudent physical growth constraints on consumption in combination with replenishment of the Earth's resources. Otherwise, over time, "the world will experience overshoot and collapse in global resource use and emissions."

The authors clearly identify the global challenge (page xv), explain their reasons for writing this update (pages xviii and xix) in response to that challenge, and then conclude their Preface with the prediction that "it will take another decade before the consequences of [global ecological] overshoot are clearly observable and two decades before the fact of overshoot is generally acknowledged." They intend to provide another update in 2012, on the 40th anniversary of their first book.

In the 14 chapters which follow, Meadows, Randers, and Meadows explain why it is not only desirable but indeed imperative to

1. increase the consumption levels of the world's poor

2. reduce humanity's total ecological footprint

3. support technological advances (e.g. to achieve #1)

4. support personal change (e.g. to achieve #2)

5. think in terms of longer planning horizons

The authors offer a range of alternative scenarios (i.e. ten different "pictures" of how the 21st century may evolve) to encourage their reader's learning, reflection and personal choice. For me, Chapter 7 is especially valuable. Based on their structural analysis of the world, they offer seven general guidelines to expedite transitions to sustainability: extent the planning horizon (#5 previously), improve the "signals" (i.e. early-warning system for global ecology), speed up the response time to ecological crises, minimize use of nonrenewable resources, prevent the erosion of renewable resources, use all resources with maximum efficiency, and slow -- and eventually stop -- exponential growth of population and physical capital.

In the final chapter, Meadows, Randers, and Meadows briefly discuss the agricultural and industrial revolutions and then assert that the next revolution should respond to the need for sustainability of humanity on Earth. They share their vision of the sustainable society which such a revolution could achieve and even provide a ("by no means definitive") list of its dominant characteristics, urging their reader to develop it further. I agree with the authors that a sustainable world "can never be fully realized until it is widely imagined." Hence the importance of their ("by no means definitive") list...hence the even greater importance of having as many other people as possible also imagine precisely what kind of a world they would much prefer to live in.

There are obviously limits to how much of Earth's resources can be consumed or corrupted, without replenishment or purification, before they are significantly depleted and eventually exhausted. However, I believe that almost all limits on human imagination are self-imposed. If so, then there should be no limits on our collaborative efforts to reduce "humanity's ecological footprint" to achieve global sustainability of our precious natural resources if we can but summon and then (yes) sustain sufficient resolve to do so.

Limits to Growth: The 30-Year Update is a look at the resources of the planet and how they are being used, using the tools of systems dynamics computer modeling, with an eye to seeing if the current practices of unchecked growth in the use of resources is a viable, sustainable approach to living (an idea that on it's face appears to be an obvious no-brainer). The authors have produced two prior books on these issues, Limits to Growth and Beyond the Limits. The central questions are these: Are current policies leading to a sustainable future, or collapse? What can be done to create a human economy that provides sufficiently for all? They quote another researcher who points out that humanity surpassed sustainability in the 1980s, a statement that is congruent with their computer modeling.

The basic idea is that resource use will exceed resource capacity, a condition called overshoot, which will lead to collapse of many of the institutions of humanity, as we know them. They define a sustainable society as one that `meets the needs of the present, without compromising the ability of future generations to meet their own needs.' Sounds very similar to the current state of the social security program, which will be bankrupt in the near future, without major changes.

One major limit to the consumption of resources that is often not considered, are `sinks', methods, ways and places of disposing of waste products generated by humanity. The authors make this a focus by using a phrase called `ecological footprint of humanity', defined as `the land area that would be required to provide the resources (grain, feed, wood, fish, and urban land) and absorb the emissions (carbon dioxide) of global society.'

The other major ideas have been described very well in other Amazon.com reviews, so I won't repeat those. I will add that Dennis Meadows in a private email to me described the book thusly: "Our book is about three aspects of society - growth in the physical parameters, growing damage to natural systems, and delays in the response."

The historian Arnold Toynbee studied the collapse of civilizations from another angle. He looked at all the known civilizations in the history of mankind, and noticed that some were able to adapt to what he called "the challenge of stimulus", and some were not. He attempted to understand what characteristics allowed some to adapt, and what caused the others to fail. In fact, some aspects of the chapter "Tools for the Transition to Sustainability" seem to be directly informed by Toynbee's works. (Dr. Meadows professed not to know. That chapter was written by his wife prior to her passing away, and was left largely unchanged.)

Is it possible Toynbee was describing the results of 'overshoot and collapse', or 'overshoot and adaptation to actions within sustainability', only at the regional or civilizational level, not the global? Clearly humanity has not experienced overshoot and complete collapse on the global level anytime in the past. Evidently we have only reached the potential to do this on the global level rather recently in our history. The question is: Will humanity rise to the `challenge of stimulus' of the current global situation, or will the `delays in the response' described by Dr. Meadows lead to our fall as a species?

No one likes limits, but they're with us all our lives, from the restrictions our parents place on us as children to the limits that society and Mother Nature compel us to adhere to as adults. The authors do a clear and thorough job of explaining how physical limits affect the Earth and the human society evolving within it.
Updating their mathematical model and learning from three decades of experience since the original 1972 study, the authors reinforce their earlier finding that persistently overshooting the Earth's carrying capacity could lead to any one of a variety of unhappy scenarios for humanity. While expressing due respect for technology development and the effects of free markets, they emphasize that these are necessary but not sufficient tools for getting us through the 21st century.
The authors have been criticized as doomsayers whose predictions have proven wrong. Such criticism obviously has come from people who have not actually read their work. They have not produced just a single computer run of their model and then proclaimed, "This is what will happen." They have done hundreds of runs to attempt to illustrate how important variables - such as population growth, industrial production, technological development, and pollution - interact to shape future scenarios in a 100-year timeframe. A thorough reading of this book demonstrates that rather than being disproven, their original scenarios are looking ominously accurate.
Chapter 5 is the book's good-news story, providing a case study on how the world got together to tackle the ozone depletion problem over the last quarter century. This and the final two chapters demonstrate that the authors have not given in to hopelessness.
The most critical shortcoming of the authors' work is one they clearly acknowledge. They address flows of population, materials, energy, and emissions that can be mathematically modeled, but do not include factors such as military conflict, large-scale corruption, natural disasters, pandemics, or severe economic stresses like currency and debt crises. If these things are taken into account, one could view the Limits to Growth model as wildly optimistic. What would this study look like with a non-quantitative social futurist perspective added to it?
The authors have done a remarkable job of clearly explaining concepts such as positive and negative feedback loops and the Earth's sources and sinks as they apply to the model. But the 284 pages of text may be more than can be absorbed and digested by the wider audience this book deserves. Perhaps a condensed version is needed, one that captures the message and its urgency but is short enough to get even policy-makers to read it.

› Go to Amazon.com to see all 37 reviews  4.3 out of 5 stars