The Southwest is toast.

A new paper in Nature spells doom. From the abstract:

The potential for increased drought frequency and severity linked to anthropogenic climate change in the semi-arid regions of the southwestern United States is a serious concern. Multi-year droughts during the instrumental period and decadal-length droughts of the past two millennia were shorter and climatically different from the future permanent, ‘dust-bowl-like’ megadrought conditions, lasting decades to a century, that are predicted as a consequence of warming.

Nature’s Quirin Schiermeier has an article on the study, and this eye-popping quote from Richard Seager, a Columbia University climate researcher:

The drying we expect for the twenty-first century is entirely the result of increased greenhouse forcing.

But we’re not there yet, Seager tells Nature:

A signal of anthropogenic drying is emerging, but it is still small. I’d expect that by mid-century the human signal will exceed the amplitude of natural climate variability. Then we can safely say that the Southwest has entered a new climate stage.

UPDATE: Prehistoric drought in the SW is a big interest of mine, so I’m going to provide all the relevant press coverage links, as they come in. John Fleck, a science writer for The Albuquerque Journal, has a story and a post at his blog.

Yet.

But based on my own knowledge of the drought history of the Southwest (specifically the last one thousand years), I’ve always felt that a cruel reckoning was just around the corner.

That reckoning may happen faster, according to a new study released today by Stockholm Environment Institute. Bryan Walsh at Time has a good overview:

The report found that the already dry states of the American Southwest—Arizona, California, Nevada, New Mexico and Utah—will face a major water shortfall over the next century just based on population and income growth alone. (The region has long been one of the fastest-growing in the U.S., in part because of the hot and dry weather.) But climate change could make the situation much, much worse.

Now there are a couple ways to look at this. Like the recent debate over Egypt and food prices, the underlying problems in the Southwest are not related to greenhouse gases. But when you look at the way people live in those Southwestern states (in terms of lifestyle, sprawl, and unchecked development), there is a business-as-usual attitude. Do folks out there really feel they are being pushed to the limits of their environment? My sense from afar (and based on intermittent travel and one recent year spent in Colorado) is no.

So given all this, it seems that irrespective of climate change, Southwesterners have plenty of good reasons to get their house in order. Will yet another report warning of imminent climate change related impacts nudge them in that direction? Maybe, but I doubt it.

And even if Southwestern states go ahead and implement all the Stockholm Institute’s water use recommendations, but demographic and growth trends remain the same, will it even matter?

So what happened here?  There are two main types of explanations, environmental and social, and their relative popularity has varied over the years.  The environmental explanation depends largely on the striking coincidence of the abandonment of Mesa Verde with the so-called “Great Drought” of AD 1276 to 1299, one of the earliest major climatic events to be identified in the tree-ring record.  The near-perfect alignment of the drought with the final abandonment of the area is indeed remarkable, and this explanation has been pretty popular and remains so today, but there is considerable evidence that there was more going on.  For one thing, while all of the Southwest is in some sense marginal for agriculture, within that context the northern San Juan is one of the most productive and reliable agricultural areas.  Indeed, much of southwestern Colorado is used today for commercial farming, largely using dry-farming methods not all that different from those used in antiquity.  The Mesa Verde area gets plenty of rainfall, and while a short growing season can be an issue at the higher elevations, throughout most of the region it is not generally problematic.  Models of agricultural potential based on tree-ring data have generally shown that the carrying capacity of the Northern San Juan greatly exceeded any plausible estimate of its overall population throughout prehistory, although that doesn’t necessarily mean that individual communities would always be able to support themselves on the land they happened to have.

Social factors, then, are probably involved along with the drought.  There is definite evidence for a considerable amount of violence during the thirteenth century in this area, and settlement patterns become increasingly defensive over time.  There is also an increasing diversity in public architecture among the various communities, suggesting that traditional religious or ideological structures may have been breaking down and being replaced by new ones.  A strong tendency toward settlement aggregation, perhaps due to defensive considerations, may have played a role in these religious trends.  Furthermore, all of this may have been influenced or set in motion by deteriorating environmental conditions; environmental and social factors were not necessarily separate things.

So where did the people go?  The general assumption is that they mostly went to the northern Rio Grande Valley, which sees a remarkable increase in its population right around AD 1300, just as Mesa Verde is emptying out.  This is a bit problematic, however, since there is relatively little evidence for people with obvious Mesa Verde cultural traits showing up in the Rio Grande at this time.  This may be because people were emigrating away from Mesa Verde in small groups and assimilating into existing Rio Grande communities, or it may have been because people were changing their cultures as they moved, perhaps abandoning the old social institutions that had been ineffective in preventing the abandonment and adopting new ones that seemed to work better.  It’s hard to say, really, and this is a topic of ongoing research.  One interesting effort recently has been the Village Ecodynamics Project by Washington State University and Crow Canyon Archaeological Center, which has used agent-based modeling and other innovative techniques to try to understand the culture history of the Northern San Juan.

Okay, so that’s more or less what happened.  Does it count as a “collapse”?  Let’s look back at Jared Diamond’s criteria for collapse:

1. Collapse involves a major loss of population.
2. Collapse involves a loss of complexity.
3. Collapse occurs over a large geographic area.
4. The changes brought about by collapse persist for a long time.

In this case 1, 3, and 4 are pretty obvious.  The Mesa Verde region was totally depopulated, which is about as major a loss of population as you can get.  It’s also very large, and the changes that resulted from the abandonment of the region and the influx of population to the Rio Grande have persisted to the present day; many aspects of Mesa Verde culture notable in the archaeological record were not brought to the Rio Grande, and are not present in the modern Pueblos there.  Since Diamond apparently considers only one of the first two criteria to be necessary, he probably would consider this a collapse, but most other collapse theorists, including Joseph Tainter, consider loss of complexity to be a more important consideration than loss of population, so let’s look at complexity in the Mesa Verde case.

There basically isn’t any evidence for significantly complexity in Mesa Verde before its abandonment or in the Rio Grande afterwards.  Unlike the Chaco case, the villages in the thirteenth-century Northern San Juan seem to have had relatively egalitarian social structures, at least economically and probably politically as well.  This is not to say that there were definitely no disparities in political power, but that they were likely masked and subverted by an egalitarian ideology that prevented massive accumulation of wealth and power.  This is the case in the modern Pueblos, where despite some possible inequalities in power and political influence among different clans or societies the overall ideology has enforced a general economic equality.  This seems to have been the case in the thirteenth-century Northern San Juan as well, and it could have been in part a reaction to the perceived excesses of the Chacoan era, although it’s noteworthy that a certain amount of Chacoan influence seems to have persisted, especially in the Totah area around Aztec, albeit without much evidence for the economic inequality that marked the Chacoan era itself.

Mesa Verde doesn’t get mentioned in the collapse literature as much as Chaco, although sometimes the two are kind of muddled together incoherently, and for good reason.  What we seem to be seeing at Mesa Verde is a period of societal difficulty that resulted in depopulation and migration, a common pattern in Southwestern prehistory.  While there were some changes in society during the abandonment and migration that make it difficult to tell exactly where the people ended up, these changes don’t seem to have been related to any change in the overall complexity of the society, which remained about as complex as it had been before.

The human occupation of Chaco Canyon goes back a very long way, but the key developments that made it an important regional center seem to have begun in the AD 800s with the initial building of a few “great houses,” which in that period were large masonry structures similar in layout and construction techniques to the “small houses” in which most Southwestern people lived at the time but much on a much larger scale.  These early great houses, including Pueblo Bonito and Una Vida, show considerable signs of residential use in their earliest parts, and it seems that they were at least initially residential structures.  It’s not at all clear what inspired their construction, but there were similar structures being built in other parts of the region at the time, so Chaco may not have been particularly special at first.  Over the course of the next hundred years, however, something seems to have happened to make Chaco a major regional center, and starting around AD 1030 a building boom in the canyon in which the existing great houses were expanded using much more elaborate techniques and an even larger scale of construction coincided with the construction of entirely new great houses both in the canyon and throughout the San Juan Basin of northwestern New Mexico and beyond into Colorado, Utah, and Arizona.  These “outlying” great houses were mostly placed in existing small house communities, which continued to be occupied, and were connected to the canyon via an elaborate road system.

Over the next hundred years, construction both inside and outside the canyon continued almost without pause, and at the same time a vast amount of material of all kinds was brought into Chaco from a vast surrounding region: turquoise, shell, copper bells, macaws, and other exotic materials, as well as more quotidian items such as pottery, construction timbers, and corn.  Then, around AD 1130, everything seems to have come to an abrupt halt.  Construction of great houses, after a shift around AD 1100 toward a different type of architecture, seems to stop entirely by around 1125, and activity in the canyon slowed to a crawl at that point.  There was probably at least a small population remaining until the depopulation of the whole region in the late 1200s, but it was nowhere near as large as the apparent population at the system’s height.  It is this decline in activity that collapse theorists seek to explain when they look at Chaco as a case study.

So what happened?  There are various theories out there.  Many point to a prolonged period of drought from around 1130 to 1180, which coincides suspiciously closely with the end of major activity at Chaco, as having somehow led to the collapse, although this explanation is somewhat problematic given that earlier droughts, especially a short but severe one in the 1090s, didn’t have nearly the same effects on the system.  Others argue that political, social, or economic instability within the Chaco system itself, whatever its nature, was the main cause of the collapse, with drought perhaps playing a subsidiary role.  Most people agree, however, that Chaco is indeed an example of societal collapse.

But is it?  Let’s look at some of the criteria for defining collapse, using Diamond’s list:

1. Collapse involves a major loss of population.
2. Collapse involves a loss of complexity.
3. Collapse occurs over a large geographic area.
4. The changes brought about by collapse persist for a long time.

Measuring the population of Chaco at any time is surprisingly difficult, but given the much lower level of activity after 1130 I think it’s safe to say that there was a major decline of some sort.  The extent to which Chaco was a complex society at all is disputed, but I find the arguments for complexity more convincing than the arguments against it, so let’s take relative complexity as a starting point and see if there’s evidence for a loss of it.  Recall Ben Nelson’s definition of complexity:

Social systems are considered complex if they are comparatively large demographically and spatially, encompass multiple settlements in an integrated political structure, and exhibit horizontal and vertical social differentiation. Other properties associated with complexity are hereditary ranking, production of surplus and its appropriation by an elite, craft specialization, and long-distance exchange.

Large demographic scale is basically the same as population, so that one’s covered.  We’ll get back to spatial scale and settlement pattern later.  There isn’t much evidence for horizontal social differentiation at any point in the Chacoan archaeological record, but the vertical differentiation implies by the elaborate burials in Pueblo Bonito does seem to end around 1130.  Ranking goes along with vertical differentiation, and surplus and its appropriation are controversial and hard to find in the archaeological record, as is craft specialization.  That leaves us with long-distance exchange, which does continue to go on at Chaco, but at a much lower level than before.  So yes, I think it’s fair to say that Chaco became less complex according to most of the criteria that can be used to assess complexity there.

That brings us back to spatial scale, and here’s where things get tricky.  It turns out that the evidence for reduced activity at Chaco Canyon after 1130 doesn’t correspond to a similar reduction in activity in most other parts of the Chaco system at the same time.  Indeed, some areas, such as Aztec Ruins on the Animas River to the north, see a marked increase in activity after 1130, and both Aztec and the Mesa Verde area further north see continued activity on a large scale, indicative of a large population, until the depopulation of the whole area in the late 1200s.  The area to the west doesn’t see such dramatic growth, but it does seem to keep on going without much change after 1130.  Similarly, while the area immediately south of Chaco seems to have been largely depopulated even earlier than the canyon itself, the area further south continued to see activity long after, indeed up to the present day at Zuni Pueblo.  And in many of these areas, especially at Aztec and at the northern and southern extremes of the original Chaco system, the outlying Chacoan great houses seem to have continued to be used, though perhaps not the same way as they were originally intended to be used, long after the cessation of great house construction in Chaco itself.

So it seems that the Chaco “collapse” really only applies to a single location, Chaco Canyon itself, and not to the society as a whole.  Indeed, some archaeologists have interpreted these data as showing not so much the collapse of the system centered on Chaco but a series of changes in it, possibly including a shift in emphasis away from Chaco itself toward Aztec, which replaced it as the center of the system.  Whether or not some form of the system that developed at Chaco continued at Aztec, it’s clear that there were a lot of changes going on in the region during the 1100s, including an apparent movement of population away from Chaco, probably at least in part to Aztec and Mesa Verde.  The lack of continued construction on the scale seen from 1030 to 1130 and the reduced level of trade do seem to suggest that the Chacoan system declined in power and influence after 1130 whether or not it moved to Aztec, but there turns out to be very little evidence of a “collapse” occurring over a large spatial scale, although the changes do seem to persist for a long time.

So what are the implications of this for studies of collapse in general?  It’s hard to say, but I think one lesson is that it’s important to look at these things on the societal level rather than on individual sites or localities, no matter how important or central they seem.  Some Southwestern archaeologists now prefer the term “reorganization” to “collapse” for situations like the changes at Chaco after 1130 and the contemporaneous events in the Mimbres Valley of southwestern New Mexico.  It’s certainly quit different from the massive depopulation of the whole Four Corners region in the late 1200s, which however doesn’t fit well into “collapse” models either because there’s little evidence of a system on any level larger than the individual community during this period, with the possible exception of a rump Chacoan system operating on a small scale out of Aztec.  That event, which corresponds to another prolonged drought, is of interest in its own right, but this post is long enough already.

Now before I get into the piece that follows I should explain that I don’t hold any particular animus towards the states of Colorado, Utah, Wyoming or Idaho, and so when I start talking about disposing of nuclear weapons in those states by making use of them it should be taken as merely a technical discussion (grin).

Hey, nothing personal guys. If peak oil hits sooner than expected, what’s a hungry, oil-starved world gonna do?   You’ll just have to grin and bear it.

UPDATE: The nuke the shale out hypothesis has largely generated disgust and disdain from Oil Drum readers. But this person cautions that nothing will be off the table if there’s a true energy shortage:

Well, most may think this is a non starter, but if Peak Oil decline is half as bad as some here think, then you should not be surprised by what actually happens to keep gas tanks full.

Except it’s not some off-the-cuff riff. Thompson writes a poignant meditation on the complicated feelings he has about a quintessentially Western issue. It’s so pitch perfect I don’t even want to quote from it. I just encourage anyone with his own soulful remembrance of a landscape to read it.

After you’ve done that, I’ve got something else for you to consider. So head over to Thompson’s piece, then come back.

Okay, if you’ve ever spent time hiking or camping in the Southwest, particularly southern Utah, chances are you’re acquainted with a legendary nature writer, who, in the best damn book introduction I know of, reels the reader in with this kicker:

Finally a word of caution:

Do not jump into your automobile next June and rush out to the Canyon country hoping to see some of that which I have attempted to evoke in these pages. In the first place, you can’t see anything from a car; youv’e got to get out of the goddamn contraption and walk, better yet crawl, on hands and knees, over the sandstone adn through the thornbush and cactus. When traces of blood begin to mark your trail you’ll see something, maybe. Probably not.

In the second place, most of what I write about in this book is already gone or going under fast. This is not a travel guide but an elegy. A memoir. You’re holding a tombstone in your hands. A bloody rock. Don’t drop it on your foot–throw it at something big and glossy. What do you have to lose?

Well, if this iconic book left its mark on you, as it did with me, then you know I’m quoting from Ed Abbey’s classic. And you also probably know how deeply influential that book has been since it was published in 1967. How the hordes that now descend annually on Arches National Park (and, to a lesser extent, Canyonlands), make a mockery of Abbey’s mournful testimonial from four decades ago.

Yet what he felt to be already lost was surely true to him.

Still, where does that leave the rest of us who came after? Those of us who perhaps went there because of Desert Solitaire? I can only tell you that I keep going back, and that I now bring my own children too.

And one last thing. If you’re wondering about the enchanting spell of a landscape, how it sometimes takes hold in the mind,  in the case of Abbey and Desert Solitaire, consider this interesting supposition from a biology professor:

When Edward Abbey signed and dated the author’s introduction to Desert Solitaire, he appended the location as Nelson’s Marine Bar, Hoboken.  After his first term as a seasonal ranger in 1956, Abbey left Arches National Park for Hoboken, New Jersey, where his wife and son were living.  On his ostensible last day at Arches, Abbey wrote in Desert Solitaire:  “After twenty-six weeks of sunlight and stars, wind and sky and golden sand, I want to hear once more the crackle of clamshells on the floor of the bar in the Clam Broth House in Hoboken.  I long for a view of the jolly, rosy faces on 42nd Street and the cheerful throngs on the sidewalks of Atlantic Avenue.” I’m uncertain how much of Desert Solitaire was composed in Hoboken or whether any of the author’s introduction was written in one of the city’s bars.  The earliest surviving outline of what would become Desert Solitaire dates from July 1962, when Abbey was working as a welfare caseworker in Hoboken.  The possibility that Desert Solitaire, one of the most beautiful books about the Colorado Plateau, was conceived and composed in Hoboken is fascinating; it raises the question how one place influences our view of another.  Abbey’s longing on city streets and in Hoboken bars must have elicited a memory shadowed by distance, shifting subtly the tones of the sandstone landscape of Utah.   I am curious about the desires we fulfill in prose rather than place.

That might take us into the realm of nostalgia, which is deserving of another post some other time…

UPDATE: Gambler’s House weighs in with a thoughtful post. Some mighty interesting recollections of attitudes towards Abbey, too.

But there are two newspaper reporters who are connecting the dots, bit by bit. I’ve been following their reporting with great interest over the last month. Their latest scoops can be read here and here.

Incredibly, we decided to extend the insanity by a day.

Back to regularly scheduled programming tomorrow.

On the outskirts of Albuquerque, the desert has surrendered the bones of 12 young women.

I’m a little uneasy with the larger theme of the piece, though, mainly because I think violence to women need not be compared–even for literary purposes–to a landscape torn up by gas drilling and real estate development.

The brutality that scores of women experience everyday and everywhere in the world–and the shameful response in some cases–is a blight on humanity.  The blight to our treasured landscapes may be heinous to some, but that is another moral realm altogether.

Yet they are proceeding.  “Among us biologists, climate change is a real issue that we have to deal with now,” Scott Richardson, a FWS biologist based in Tucson, Arizona, told me today. There, in the biodiversity-rich Sonoran desert, where  invasive species and sprawl are already stressing the native ecosystem to a near breaking point, climate change is a devilish wild card.

“Most of the [climate] models out there show the Southwest becoming hotter and drier, beyond what it already is,” says Richardson. “It’s assumed that many species will shift north, but in some places like the Sky Islands–our mountain ranges–you can’t go north. You can go higher, but you can only move up so far.” That means less suitable habitat for at-risk species such as the Mexican spotted owl and mount Graham squirrel.

As if crafting these new recovery plans  weren’t complex enough, federal biologists also have to decide which species have the best shot at making it. Says Richardson, “The really frustrating thing about this is that you have to prioritize because resources and funding are limited. What you hope for is that you’re basing your decision on the best information available.”

Even then, success is far from assured. As described in its draft strategic plan, the FWS identifies two types of adaptive managment for climate change: “reactive” and “anticipatory.”

For example, “combating rising sea level by pumping sand ashore to replenish beaches and maintain habitat for nesting sea turtles and shorebirds” is considered reactive adaptation.

The second approach manages “toward future, and often less certain, landscape conditions by predicting and working with the effects of climate change.” So to use the same example, anticipatory adaptation would mean sacrificing existing beaches to rising sea level to focus instead on establishing “new shorelines landward for nesting sea turtles and shorebirds.”

And you got pissed off at piping plovers because their seasonal nesting protections cut into your beach volleyball. How does no beach at all strike you?

I jest. What I’m getting at here is that safeguarding vulnerable wildlife from climate change will require many tough calls in the months and years ahead. Land managers and biologists are already agonizing over this.

Tomorrow, Florida FWS biologists weigh in with their titanic climate change quandry.