Collapse: How Societies Choose to Fail or Succeed (5 page)

The Evolution of Human Sexuality
compared different animal species, espe
cially different species of primates, in an effort to figure out why women
(unlike females of most other animal species) undergo menopause and lack
obvious signs of ovulation, why men have a relatively large penis (by animal
standards), and why humans usually have sex in private (rather than in the
open, as almost all other animal species do). There is a large scientific litera
ture on the obvious pitfalls of that comparative method, and on how best to overcome those pitfalls. Especially in historical sciences (like evolutionary
biology and historical geology), where it's impossible to manipulate the past
experimentally, one has no choice except to renounce laboratory experi
ments in favor of natural ones.

This book employs the comparative method to understand societal
collapses to which environmental problems contribute. My previous book
(Guns, Germs, and Steel: The Fates of Human Societies)
had applied the
comparative method to the opposite problem: the differing rates of buildup
of human societies on different continents over the last 13,000 years. In
the present book focusing instead on collapses rather than on buildups, I compare many past and present societies that differed with respect to environmental fragility, relations with neighbors, political institutions, and other "input" variables postulated to influence a society's stability. The
"output" variables that I examine are collapse or survival, and form of
the collapse if a collapse does occur. By relating output variables to input variables, I aim to tease out the influence of possible input variables on
collapses.

A rigorous, comprehensive, and quantitative application of this method
was possible for the problem of deforestation-induced collapses on Pacific
islands. Prehistoric Pacific peoples deforested their islands to varying de
grees, ranging from only slight to complete deforestation, and with societal
outcomes ranging from long-term persistence to complete collapses that
left everybody dead. For 81 Pacific islands my colleague Barry Rolett and I
graded the extent of deforestation on a numerical scale, and we also graded values of nine input variables (such as rainfall, isolation, and restoration of
soil fertility) postulated to influence deforestation. By a statistical analysis
we were able to calculate the relative strengths with which each input vari
able predisposed the outcome to deforestation. Another comparative ex
periment was possible in the North Atlantic, where medieval Vikings from
Norway colonized six islands or land masses differing in suitability for agri
culture, ease of trade contact with Norway, and other input variables, and
also differing in outcome (from quick abandonment, to everybody dead af-

ter 500 years, to still thriving after 1,200 years). Still other comparisons are possible between societies from different parts of the world.

All of these comparisons rest on detailed information about individual
societies, patiently accumulated by archaeologists, historians, and other
scholars. At the end of this book I provide references to the many excellent
books and papers on the ancient Maya and Anasazi, the modern Rwandans and Chinese, and the other past and present societies that I compare. Those
individual studies constitute the indispensable database for my book. But
there are additional conclusions that can be drawn from comparisons
among those many societies, and that could not have been drawn from de
tailed study of just a single society. For example, to understand the famous
Maya collapse requires not only accurate knowledge of Maya history and
the Maya environment; we can place the Maya in a broader context and gain further insights by comparing them with other societies that did or
didn't collapse, and that resembled the Maya in some respects and differed from them in other respects. Those further insights require the comparative
method.

I have belabored this necessity for both good individual studies and
good comparisons, because scholars practicing one approach too often be
little the contributions of the other approach. Specialists in the history of
one society tend to dismiss comparisons as superficial, while those who
compare tend to dismiss studies of single societies as hopelessly myopic and
of limited value for understanding other societies. But we need both types
of studies if we are to acquire reliable knowledge. In particular, it would be
dangerous to generalize from one society, or even just to be confident about
interpreting a single collapse. Only from the weight of evidence provided
by a comparative study of many societies with different outcomes can one
hope to reach convincing conclusions.

So that readers will have some advance idea where they are heading, here is
how this book is organized. Its plan resembles a boa constrictor that has
swallowed two very large sheep. That is, my discussions of the modern
world and also of the past both consist of a disproportionately long account of one society, plus briefer accounts of four other societies.

We shall begin with the first large sheep. Part One comprises a single lengthy chapter (Chapter 1), on the environmental problems of southwest
ern Montana, where Huls Farm and the ranches of my friends the Hirschys
I to whom this book is dedicated) are located. Montana has the advantage of

being a modern First World society whose environmental and population
problems are real but still relatively mild compared to those of most of the
rest of the First World. Above all, I know many Montanans well, so that I can connect the policies of Montana society to the often-conflicting moti
vations of individual people. From that familiar perspective of Montana, we
can more easily imagine what was happening in the remote past societies that initially strike us as exotic, and where we can only guess what moti
vated individual people.

Part Two begins with four briefer chapters on past societies that did
collapse, arranged in a sequence of increasing complexity according to my
five-point framework. Most of the past societies that I shall discuss in detail
were small and peripherally located, and some were geographically bounded,
or socially isolated, or in fragile environments. Lest the reader thereby be
misled into concluding that they are poor models for familiar big modern
societies, I should explain that I selected them for close consideration precisely because processes unfolded faster and reached more extreme out
comes in such small societies, making them especially clear illustrations. It
is not the case that large central societies trading with neighbors and located
in robust environments didn't collapse in the past and can't collapse today.
One of the past societies that I do discuss in detail, the Maya, had a popula
tion of many millions or tens of millions, was located within one of the
two most advanced cultural areas of the New World before European arrival
(Mesoamerica), and traded with and was decisively influenced by other ad
vanced societies in that area. I briefly summarize in the Further Readings
section for Chapter 9 some of the many other famous past societies
—
Fertile Crescent societies, Angkor Wat, Harappan Indus Valley society, and
others—that resembled the Maya in those respects, and to whose declines
environmental factors contributed heavily.

Our first case study from the past, the history of Easter Island (Chap
ter 2), is as close as we can get to a "pure" ecological collapse, in this case due
to total deforestation that led to war, overthrow of the elite and of the fa
mous stone statues, and a massive population die-off. As far as we know, Easter's Polynesian society remained isolated after its initial founding, so that Easter's trajectory was uninfluenced by either enemies or friends. Nor
do we have evidence of a role of climate change on Easter, though that could
still emerge from future studies. Barry Rolett's and my comparative analysis helps us understand why Easter, of all Pacific islands, suffered such a severe
collapse.

Pitcairn Island and Henderson Island (Chapter 3), also settled by Poly
nesians, offer examples of the effect of item four of my five-point frame
work: loss of support from neighboring friendly societies. Both Pitcairn and
Henderson islands suffered local environmental damage, but the fatal blow came from the environmentally triggered collapse of their major trade partner. There were no known complicating effects of hostile neighbors or of
climate change.

Thanks to an exceptionally detailed climate record reconstructed from
tree rings, the Native American society of the Anasazi in the U.S. Southwest
(Chapter 4) clearly illustrates the intersection of environmental damage
and population growth with climate change (in this case, drought). Neither
friendly or hostile neighbors, nor (except towards the end) warfare, appear
to have been major factors in the Anasazi collapse.

No book on societal collapses would be complete without an account
(Chapter 5) of the Maya, the most advanced Native American society and
the quintessential romantic mystery of cities covered by jungle. As in the
case of the Anasazi, the Maya illustrate the combined effects of environ
mental damage, population growth, and climate change without an essen
tial role of friendly neighbors. Unlike the case with the Anasazi collapse,
hostile neighbors were a major preoccupation of Maya cities already from
an early stage. Among the societies discussed in Chapters 2 through 5, only
the Maya offer us the advantage of a deciphered written record.

Norse Greenland (Chapters 6-8) offers us our most complex case of a prehistoric collapse, the one for which we have the most information (be
cause it was a well-understood literate European society), and the one war
ranting the most extended discussion: the second sheep inside the boa
constrictor. All five items in my five-point framework are well documented:
environmental damage, climate change, loss of friendly contacts with Norway, rise of hostile contacts with the Inuit, and the political, economic, so
cial, and cultural setting of the Greenland Norse. Greenland provides us
with our closest approximation to a controlled experiment in collapses: two
societies (Norse and Inuit) sharing the same island, but with very different
cultures, such that one of those societies survived while the other was dying.
Thus, Greenland history conveys the message that, even in a harsh environ
ment, collapse isn't inevitable but depends on a society's choices. Com
parisons are also possible between Norse Greenland and five other North
Atlantic societies founded by Norse colonists, to help us understand why
the Orkney Norse thrived while their Greenland cousins were succumbing.

One of those five other Norse societies, Iceland, ranks as an outstanding
success story of triumph over a fragile environment to achieve a high level
of modern prosperity.

Part Two concludes (Chapter 9) with three more societies that (like Ice
land) succeeded, as contrast cases for understanding societies that failed.
While those three faced less severe environmental problems than Iceland or than most of those that failed, we shall see that there are two different paths
to success: a bottom-up approach exemplified by Tikopia and the New Guinea highlands, and a top-down approach exemplified by Japan of the
Tokugawa Era.

Part Three then returns to the modern world. Having already consid
ered modern Montana in Chapter 2, we now take up four markedly different modern countries, the first two small and the latter two large or huge: a Third World disaster (Rwanda), a Third World survivor-so-far (the Dominican Republic), a Third World giant racing to catch up with the First
World (China), and a First World society (Australia). Rwanda (Chapter 10)
represents a Malthusian catastrophe happening under our eyes, an over-populated land that collapsed in horrible bloodshed, as the Maya did in the
past. Rwanda and neighboring Burundi are notorious for their Hutu/Tutsi ethnic violence, but we shall see that population growth, environmental damage, and climate change provided the dynamite for which ethnic vio
lence was the fuse.

The Dominican Republic and Haiti (Chapter 11), sharing the island of
Hispaniola, offer us a grim contrast, as did Norse and Inuit societies in
Greenland. From decades of equally vile dictatorships, Haiti emerged as the
modern New World's saddest basket case, while there are signs of hope in
the Dominican Republic. Lest one suppose that this book preaches environ
mental determinism, the latter country illustrates what a big difference one
person can make, especially if he or she is the country's leader.

China (Chapter 12) suffers from heavy doses of all 12 modern types of
environmental problems. Because China is so huge in its economy, popula
tion, and area, China's environmental and economic impact is important
not only for China's own people but also for the whole world.

Australia (Chapter 13) is at the opposite extreme from Montana, as the
First World society occupying the most fragile environment and experienc
ing the most severe environmental problems. As a result, it is also among the countries now considering the most radical restructuring of its society,
in order to solve those problems.

This book's concluding section (Part Four) extracts practical lessons for