The one book I see in almost every house I visit on the coast is Jared Diamond’s Collapse. In it he makes a compelling case that societies, if they are not careful, undermine their own success by maintaining a short-sighted view of their ecological resources.
I think this book strikes a chord among many coastsiders not only because we live in an environmentally aware area but because in our own way the coastiside is experiencing this same dynamic.
My bookshelf holds a copy of Diamond’s book as well. This past Christmas I drive across country with my family. One night in Arizona we found ourselves gathered around a table at an Italian Restaurant in Arizona brainstorming about what to do the coming day. There were a number of national parks and other interesting destinations in the area or along our possible routes–which to choose?
The couple two tables over was having the identical conversation. They were looking at many of the same options. Map in hand the young man suddenly exclaimed to his partner, “We’re next to Chaco Canyon–we can’t get this close and not go there!” He was very excited.
I had no idea what he was talking about. But back at the hotel we googled it and discovered that Chaco Canyon was home to the best preserved Anasazi Indian ruins. Although I didn’t recognize the name “Chaco Canyon” I certainly recognized the word “Anazazi” and I remembered Diamond’s extensive discussion of the ancient civilization and his thoughts on the reason for their demise.
For those who haven’t yet had a chance to visit the site I would like to share a few snapshots of the ruins as well as part of a speech by Jared Diamond, given in 2002 at Princeton University.
My next example involves the Anasazi in our south west, in the
four corners area of Arizona, New Mexico, Colorado, Utah. How many of you
here have been to either Mesa Verde or Chaco Canyon? OK, looks like nearly
half of you. It’s very striking to visit say Chaco Canyon where there are still the
ruins of the biggest skyscrapers erected in the United States until the Chicago
skyscrapers erected in Chicago’s loop in the 1870s and 1880s. But the
skyscrapers of Chaco Canyon were erected by native Americans, the Anasazi.
Up to 6-storey buildings, with up to 600 rooms. The Anasazi build-up began
around AD600 with the arrival of the Mexican crops of corn, squash and beans,
and in that relatively dry area. Again it’s very striking today to drive through an
area where today either nobody is living at all, or nobody’s living by agriculture.
At Chaco Canyon itself there are a couple of houses of National Park Rangers
importing their food, and then nobody else living within 20 or 30 miles. And yet to
realise, and to see the remains on the ground, this used to be a densely
populated agricultural environment.
The Anasazi were ingenious at managing to survive in that environment, with low
fluctuating, unpredictable rainfall, and with nutrient-poor soils. The population
built up. They fed themselves with agriculture, in some cases irrigation
agriculture, channelled very carefully to flood out over the fields. They cut down
trees for construction and firewood. In each area they would develop
environmental problems by cutting down trees and exhausting soil nutrients, but
they dealt with those problems by abandoning their sites after a few decades and
moving on to a new site. It’s possible to reconstruct Anasazi history in great detail
for two reasons: tree rings, because this is a dry climate, the south-west. From
tree-rings you can identify from the rings on the roof beams, what year – 1116,
not 1115 AD – what year the tree in that roof was cut down, and also those cute
little rodents in the south-west, pack rats, that run around gathering bits of
vegetation in their nests and then abandoning their nests after 50 years, a pack
rat midden is basically a time capsule of the vegetation growing within 50 yards
of a pack rat midden over a period of 50 years. And my friend Julio Betancourt
who was near an Anasazi ruin and happened to see a pack rat midden whose
dating he knew nothing about. He was astonished to see in what’s now a treeless
environment, in this pack rat midden were the needles of pinion pine and juniper.
So Julio wondered whether that was an old midden. He took it back, radio
carbon-dated it, and lo and behold it was something like AD 800. So the pack-rat
middens are time capsules of local vegetation allowing us to reconstruct what
What happened is that the Anasazi deforested the area around their settlements
until they were having to go further and further away for their fuel and their
construction timber. At the end they were getting their logs, neatly cut logs,
uniform weighing on the average 600 pounds, 16 feet logs, were cut at the end
on tops of mountains up to 75 miles away and about 4,000 feet above the
Anasazi settlements, and then dragged back by people with no transport or pack
animals, to the Anasazi settlements themselves. So deforestation spread. That
was the one environmental problem.
The other environmental problem was the cutting of arroyos. In the south-west
when water flow gets channelled for example in irrigation ditches, then vast water
flow is run off in desert rains. It digs a trench in the channel, and digs a trench
deeper and deeper so those of you who’ve been to Chaco Canyon will have seen
those arroyos up to 30 feet deep. And today, if the water level drops down in the
arroyos, that’s not a problem for farmers, because we’ve got pumps, but the
Anasazi did not have pumps, and so when the irrigation ditches became incised
by arroyo cutting and when the water level in the ditches dropped down below
the field levels, they could no longer do irrigation agriculture. For a while they got
away with these inadvertent environmental impacts. There were droughts around
1040 and droughts around 1090, but at both times the Anasazi hadn’t yet filled
up the landscape, so they could move to other parts of the landscape not yet
exploited. And the population continued to grow.
And then in Chaco Canyon when a drought arrived in 1117, at that point there
was no more unexploited landscape, no more empty land to which to shift. In
addition at that point, Chaco Canyon was a complex society. Lots of stuff was
getting imported into Chaco – stone tools, pottery, turquoise, probably food was
being imported into Chaco. Archaeologists can’t detect any material that went out
of the Chaco Valley, and whenever you see a city into which material stuff is
moving and no material stuff is leaving, you think that the modern world – the
model could be of New York City or Rome, or Washington and Rome – that is to
say you suspect that out of that city is having political control or religious control
in return for which the peasants in the periphery are supplying their imported
When the drought came in 1117 it was a couple
of decades before the end. Again any of you who
have been to Pueblo Benito, will have seen that
Pueblo Benito was the six storey skyscraper.
Pueblo Benito was a big, unwalled plaza, until
about 20 years before the end, when a high wall
went up around the plaza. And when you see a
rich place without a wall, you can safely infer that
the rich place was on good terms with its poor
neighbours, and when you see a wall going up
around the rich place, you can infer that there
was now trouble with the neighbours. So probably what was happening was that
towards the end, in the drought, as the landscape is filled up, the people out on
the periphery were no longer satisfied because the people in the religious and
political centre, were no longer delivering the goods. The prayers to the gods
were not bringing rain, there was not all the stuff to redistribute and they began
making trouble. And then at the drought of 1117, with no empty land to shift to,
construction of Chaco Canyon ceased, Chaco was eventually abandoned. Long
House Valley was abandoned later. The Anasazi had committed themselves
irreversibly to a complex society, and once that society collapsed, they couldn’t
rebuild it because again they deforested their environment.
In this case then, the Anasazi case, we have the interaction of well understood
environmental impact and very well understood climate change from the tree
rings, from the width of the tree rings, we know how much rainfall was falling in
each year and hence we know the severity of the drought.
Photographs by Darin Boville