Science in Society Archive

Why Civilisations Collapse

A Lesson for Climate Change

Modern society is technologically far superior to any that has gone before, we have all the means to head off the worst effects of climate change and adapt to those we cannot avoid. History tells us however that the most common reason societies collapse is not inadequate science or technology but failure to take the difficult decisions necessary for survival Prof. Peter Saunders

Surviving environmental disasters

As the world faces the challenge of climate change, it is instructive to recall that this is by no means the first time humans have had to cope with similar problems. Many societies have found themselves in serious trouble because of an unwelcome change in their environment. It may have been something over which they had no control, like the onset of the Little Ice Age in the 15th century, or they may have brought it upon themselves, all too often by clearing forests, or perhaps a combination of the two. Some societies survived, others did not.  

Long before the Spanish arrived, the Mayans of Central America had already abandoned their magnificent cities because of drought. Deforestation destroyed the Easter Island society that erected the famous statues, though a very much reduced population continued to live on the island. Others, like the Norwegian settlers in Greenland, and the original inhabitants of Pitcairn Island, died out completely.

On the other hand, the Inuit who arrived in Greenland while the Norse settlements were flourishing are still there. The 18th century Tokugawa Japanese reversed the deforestation that had threatened their way of life. The inhabitants of Tikopia, a tiny island in the Pacific, have adopted a whole series of measures that allow them to survive in a difficult environment; one of the most striking 400 years ago was to kill all their pigs - high status animals in Melanesia and at one time a major source of protein on Tikopia - because they were too inefficient for feeding humans.

Societies collapse through failing to take decisive action

In his fascinating book Collapse [1] Jared Diamond describes and analyses these and other examples and looks for common features that would help explain why some civilisations survived environmental challenges and others did not.

There are many reasons why societies have failed to cope. They may not have anticipated the problem, and so neither tried to head it off, nor made sure they were ready when it came. The Mayans might have been better able to deal with the great drought of the 9th century if they had known such things could happen in their part of the world. Unfortunately, the last great drought was in the 3rd century, and had been forgotten. The Mayans did keep careful records, but only of things they considered important such as the exploits of their kings, not trivia like climate data.

A society may not even be aware of a serious problem when it is actually upon them, especially if the effect is slow. An increase in mean temperature of a degree or two per century can easily be masked by annual fluctuations or dismissed as part of some cycle.

It may also be that the problem is just too difficult. If you live an already marginal existence on an isolated island in the South Pacific and the rainfall decreases even further, there is not much you can do.

Diamond found that in the many societies he studied, the most common reason for their collapse was none of the above, but the failure to take decisive action that could have saved them. Surprisingly, even when it had become obvious that there was a serious problem, little or nothing was done to address it.

Why do societies fail to save themselves?

Why would a society that knows it is in danger not do all it can to survive? There are a number of possible reasons, most of which arise from the fact that a society is not an individual but a collection of human beings. There can be significant conflicts of interests, and these often lead to decisions that suit one faction but are not in the best interests of the society as a whole.

The most obvious source of conflict is that the interests of the ruler or the elite are not always the same as those of the rest. It is easy to think of examples, from the chiefs who devoted so much of Easter Island’s resources to building the famous statues (squandering large amounts on prestige projects is a common failing of rulers) to the owners of the companies that are clearing the rain forests and the politicians who are allowing that to happen. Even a group that does not have much intrinsic power may be given what it wants because it is more determined to get it than the majority are to refuse it. That is essentially why we continue to subsidise fishermen when the seas are already overfished.

There is also the “tragedy of the commons”: a fisherman lands more fish than he knows he ought to because he fears that if he holds back in the hope of preserving stocks, others will take them instead. [2].

Societies also have deeply held values and find it very difficult to take any action that conflicts with them. The obvious example is religious taboos, but values do not have to be expressed in terms of a religion. The Greenland Norse, for example, reduced their chances of survival by keeping as close as they could to Norwegian customs and farming practices [3], and refusing to learn from the Inuit.

Will we survive climate change?

If collapses were usually due to one of the first three reasons that Diamond identifies - failure to anticipate the problem, failure to be aware of it when it materialises, and lack of the technology to cope - we could be quite confident about our prospects. It is more than a century since Arrhenius showed that if we burned too much fossil fuel the Earth would get warmer, so this isn’t coming as a complete surprise. Meteorologists and climatologists have been measuring the upward trend in the mean temperature and comparing it with the greenhouse gas concentration, so we know the scale of the problem. We already have the technologies to limit climate change and mitigate its effects (see  Which Energy? [4] and Food Futures Now: *Organic *Sustainable *Fossil Fuel Free  [5]), and more are being developed (see SiS 31-43).

The crucial question is whether we have the ability to take the right decisions; and it is not at all obvious that we are any better placed to do that than earlier societies.

The problem that faces us is planet-wide, and to solve it we need cooperation at an unprecedented global level. Any agreement to limit climate change will have to take into account the quite different interests of the developed countries and developing countries. The tragedy of the commons operates in the same way whether we are talking about individual fishermen or national fishing fleets. Worse, it can act at both levels simultaneously.  

There are two serious obstacles in trying to resolve such conflicts. First, any society has some form of government, from an autocratic ruler to an informal congress of the entire community, or something in between. The form of government obviously affects the decision-making. Diamond argues that those near one end of the spectrum of government or the other are more able to cope with environmental challenges than those in the middle. As there is no world government of any kind, formal or informal, we find ourselves having to make difficult choices with no framework for reaching decisions and no means of enforcing the decisions that are taken.

Second, attempts to overcome conflicts of interests among states have to take account at the same time of those within states. Because the consequences of any agreement will impact differently on different groups, a country may be unable to make a concession to which an influential minority is strongly opposed. Most of the 44 Democrats in the US House of Representatives who almost defeated the recent climate change bill were from states that either produce coal or are heavily dependent on it [6]. It is too soon to know how much the struggle to get the bill through Congress will affect the US negotiating position, but it shows there can be a multiplier effect.  A small but determined group within one society can have a significant effect on the whole world, even though on that scale they are very small indeed.

Thus what Diamond identified as the greatest obstacle to success has become double layered and even more difficult to overcome. We must not give in to pessimism, but neither should we underestimate the size of the challenge that faces us.

How we can save ourselves

It is easy to delude ourselves into thinking either that climate change will not happen or that if it does, those of us who live in the developed world will be immune from its consequences.

Climate change is happening, and the consequences will be global; if we don’t do something soon they will be much worse. And if we do not act quickly and effectively, our society may well collapse. The human species will probably not go extinct, but we may suffer the same fate as the Mayans: reduced to a much smaller, marginal agrarian population. If you find that an ultimately attractive prospect, think of the social unrest, wars, famines and other disasters that would happen along the way.

We have all the science and technology we need to avert the catastrophe. What is more, as the Stern Report [7] has shown  (The Economics of Climate Change, SiS 33 [8]), we can do it at a price we can easily afford. The question is whether we have the will, and an early test of this will be whether we can preserve the world’s remaining forests.

Deforestation has been a key factor in many collapses because trees serve many vital purposes, such as holding the soil in place on slopes, providing timber for housing and boats, sequestering carbon dioxide from the atmosphere, and above all helping to stabilise the climate. Unfortunately they grow very slowly. Once a forest has been cleared it takes a long time to replace, if it can be replaced at all. Our society, like so many before us, is squandering this resource. We seem unable to stop the destruction of the Amazonian and Indonesian rain forests even though the Stern Report has shown that this would be by far the most cost effective contribution we can make towards mitigating climate change. The second most effective is reforesting areas already cleared (see also Saving and Restoring Forests Saves Far More Carbon Emissions than Biofuels, SiS 37 [9]). It needs international cooperation because the forests that have to be preserved lie largely in developing countries, those in the developed world having been cleared long ago (Old Growth Forests Are Carbon Sinks and Must Be Protected, SiS 40 [10]).

If we cannot find a way of working together even on this, it is hard to see how we can cooperate on the more difficult problems like reducing the use of fossil fuels while allowing developing countries to raise their standards of living.

The danger is not that we won’t do anything about climate change, especially now that the USA and China are on board. It is that what we do will be too little and too late. The effects are cumulative, and the longer we delay, the harder our task will be. It is already too late to begin with symbolic acts and good intentions. We need to make real changes, and we need to start making them now.

Article first published 29/07/09


  1. Diamond J. Collapse: How Societies Choose to Fail or Succeed. Viking Penguin, New York, 2005.
  2. Hardin G.  The tragedy of the commons. Science, 162, 1243-1248, 1968.
  3. Twentieth century examples of a society refusing to learn how to live in a different environment are provided by Noel Coward in his song Mad Dogs and Englishmen, e.g., “In the Malay States there are hats like plates, which the Britishers won’t wear.”
  4. Ho MW, Bunyard P, Saunders PT, Bravo E and Gala R. Which Energy? Institute of Science in Society, London, 2006,
  5. Ho MW, Burcher S, Lim LC et al. Food Futures Now: *Organic, *Sustainable, *Fossil Fuel Free. Institute of Science in Society, London, 2008, ISBN 0-954-44923-4-X,
  6. “House passes bill to address threat of climate change”, Jim Broder, New York Times, 26 June, 2009.
  7. Stern N. The Economics of Climate Change. Cambridge University Press, Cambridge, 2007, ISBN 0-521-70080-9.
  8. Saunders PT The economics of climate change. Science in Society 33, 20-23, 2007.
  9. Ho MW. Saving and restoring forests saves far more carbon emissions that biofuels. Science in Society 37, 17, 2008.
  10. Ho MW. Old growth forests are carbon sinks and must be protected. Science in Society 40, 29-30, 2008.

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