29 January 2011

De-moralizing climate change: archaeology and the terraforming of earth

This month three major studies on historical climate change have hit the press. They all seem like great pieces of research and could help us rethink our twisted, overly moralistic approaches to dealing with the global climate change that is now in progress.

The most widely circulated was the work of a German-Swiss-Austrian-American team, who created a record of Europe’s summer climates for the last 2,500 years from tree-ring data. The database itself is a major accomplishment: they assembled over 9,000 samples to build the longest and most comprehensive dendrochrological record to date. (The process is fascinating - since Europe has no 2,500-year old trees, you have to find overlaps between rings in many different samples.)

Sampling a tree (Dendrodan)

The research, reported in Science Daily and Science, suggests that Europe’s climate was warm and stable in the period of the high Roman Empire (0-250 CE), and colder and changeable during the later Roman Empire and the Migration period (250-600 CE). Intuitively, this makes sense: running a stable empire is easier when your basic source of revenue (in the Roman case, agriculture) stays more or less the same from year to year, especially if you have to import huge amounts of grain to feed enormous cities like Rome, Alexandria, and Ephesus. While the authors themselves warn us about drawing cause-and-effect conclusions, newspapers were above such subtlety. The Daily Mail, for instance, asks “Was climate change responsible for the rise and fall of the Roman Empire?”, with the media's typical enthusiasm for finding simplistic, mechanical explanations for human events.

Model of a Roman grain ship (right). These babies made the Empire go 'round (Hotz Artworks)

The other two publications help us understand how complicated the story actually is. Researchers from Lausanne have created a climate model of the last 8,000 years that suggests that humans have been modifying the earth’s climate for at least that long, beginning with deforestation connected to the introduction of farming and the Neolithic revolution. The data show

a first major boom in carbon emissions already 2000 years before our era, corresponding to the expansion of civilizations in China and around the mediterranean.

Deforestation reduces the absorption of carbon in the atmosphere, burning wood adds it, and farming releases yet more stored in the soil - thus a big bump in atmospheric CO2, even without petroleum. It’s not entirely a one-way street, though: a significant decrease in global emissions began in the late 16th century, leading to a colder period in the 1700s and 1800s. Jed Kaplan, one of the researchers, speculates that this cold snap was connected to the destruction of Native populations of eastern North America by disease (at least 80% of the indigenous population of the Americas died between 1492 and 1650), leading to a swift reforestation of large areas of the continent and a reduction of atmospheric CO2. The sophisticated agricultural cultures of eastern North America used land a lot more intensively, and cleared more forest, than we learned about in school – something to think about the next time you have a fit of romantic yearning for a pure, ‘sustainable’, 'indigenous' lifestyle.

So what we see here is a more complicated relationship: people affected climate, and climate affected people, often in unpredictable ways. If Kaplan is right, you could say that for a minute, smallpox played a major role in regulating atmospheric CO2. It’s a depressing but accurate point: mass death reduces greenhouse gas emissions. Which brings me to the last of the three studies, reported with one of the most disgusting headlines I’ve ever read:

“Was Genghis Khan history’s greenest conqueror? The Mongol invasions scrubbed nearly 700 million tons of carbon from the atmosphere, according to surprising new research”

Aside from the science, such unbelievably idiotic rhetoric is why a lot of people hate environmentalists (though this ‘Mother Nature Network’ outfit, funded by Coca-Cola, General Electric, Coors, and Georgia-Pacific, seems like a disinformation operation to me). Genghis Khan and his predecessors destroyed a number of civilizations and killed (after raping and torturing) something like 40,000,000 people. Hulagu Khan’s gory destruction of Baghdad in 1258 was the worst thing to happen there until the recent American invasion.

Hulagu takes Baghdad (Wikimedia)

Of course, killing all those people means massive reforestation for a couple centuries, which takes a huge amount of carbon out of the atmosphere. Unfortunately the environmentalists’ tendency to treat carbon dioxide as an immoral substance lends a kind of triumphal air to discussion of genocide.

To be fair, the research itself (by scholars from the Carnegie Institution and the Max Planck Institute) seems sound and makes the important point, along with the other two studies above, that people’s actions affect the environment just as much as the environment affects us. It’s a complex relationship that can’t be reduced to simple platitudes like ‘climate change caused the fall of the Roman Empire’.

Understanding this dynamic is important. The debate about climate change has been immature and moralistic in a really counterproductive way. “The environment” is presented as a monolithic, passive thing that corrupt humans are “destroying” with their evil actions. This view flows directly from Christian mythology about original sin (the corrupt nature of humanity) and the Fall from Eden.

These myths have a deep emotional resonance for people of European-Christian cultural backgrounds but are a stupid – and misanthropist - way to approach climate change. If people are evil and reducing carbon dioxide is good, then one starts to flirt with genocide as a ‘moral solution’ to our ‘climate problem’. And indeed, some strains of Deep Ecology and ecological anarchist philosophy make exactly this point. Primitivist anarchists, like John Zerzan even go so far as to imply that language and symbolic thought are the origin of human “crimes against nature”, with the implication that the only way to “save the earth” is for us all to die, or stop being human. Despite the obvious self-hatred and borderline insanity contained in these ideas, they are extremely influential on the way people think about the environment in Western countries today.

John Zerzan's utopia: back to caveman grunts (image by SEAN)

Good archaeological and ecological research have an important role to play in countering this stupidity, and (if I may be so bold), redeeming humanity. The research above shows that as long as there have been humans, we have influenced the Earth’s climate and ecosystem. Human history has been one big terraforming project, and no ecosystem on the planet has been unaffected by human activities. In fact, many landscapes we revere as ‘pristine’ are actually the product of human interventions. Even that darling of conservationists, the Amazonian rainforest, may be anthropogenic: huge areas of human-created soils left by much larger pre-Columbian populations nourish the primary forests we seek to preserve today. Let that sink in for a second: your biodiversity hotspot is an ecosystem that was created in concert with humans.

Terra Preta, Brazil (Philip Coppens)
This story of human omnipresence in ancient ecosystems can be told about many places. I myself remember hiking up to a remote pass in the John Muir Wilderness – a zone legally off-limits to most human activities – and finding a giant scatter of flaked obsidian, remnants of a trading zone where people from the eastern side of the mountains came to trade good-quality stone for goods from the western side. That isolated, rugged place, marked off in our contemporary rhetoric of nature as ‘holy’, ‘untouched’, and ‘pristine’, had been a lively summer trading center some hundreds of years before. For me, it made it more beautiful to know that people had been there before, that the place had functioned as part of a social system as well as an ecosystem.

The fact is, we have coevolved with our home planet. It’s time to get over the idea that there is any ‘nature’ separate from ‘culture’. Archaeological evidence shows that humans are an integral part of Earth’s ecosystem and have been for a long time - and we will continue to be until we go extinct. The research also shows that stable climates make it easier to create stable and prosperous human societies. The question then becomes not ‘how do we stop hurting the earth’, but ‘how do we manage the climate for stability’? If we stop treating carbon dioxide like a new age Satan – invisible, omnipresent, fed by our sins – we improve the prospects for making progress on the real threat of climate instability. It's not a question of "saving the earth" (the earth would do just fine without humans) but of saving ourselves.


  1. If climate fluctuations contributed to the downfall of the (western) Roman empire, why didn't this affect the eastern empire?

  2. A Brief History of Agricultural Time
    Our farming for over 10,000 years has been responsible for 2/3rds of our excess greenhouse gases. This soil carbon, converted to carbon dioxide, Methane & Nitrous oxide began a slow stable warming that now accelerates with burning of fossil fuel. The unintended consequence has been the flowering of our civilization. Our science has now realized the consequences and developed a more encompassing wisdom.

    Modern Agriculture has evolved in the ability to remove the limitations to plant growth, from burning forest for ash fertilizers, to bison bones, to Guano islands, then in 1913, to crafty Germans figuring out how to suck nitrogen from the air to now with natural gas derived fertilizers. These chemical fertilizers have over come nutrient limits to growth for 100 years.

    NPK and the “Green Revolution” in genetics have brought us to where we are, all made possible by basically mining soil carbon stocks. So we have now hit a carbon limit in two distinct ways. The first is continued loss of soil carbon content, the second is fossil carbon energy cost. The present farming system spends ten cents of fossil energy delivering one cent of food energy.

    We can not go back, but we can go forward with our newly acquired wisdom.
    Agriculture allowed our cultural accent and Agriculture will now prevent our descent.

    In the “Annals of the Association of American Geographers”,
    I’m glad this work by Dr. Dull is getting attention. Together with Dr. William Woods and citing Bill Ruddiman’s work, the pieces of anthropogenic climate change fall into place.

    The Columbian Encounter and the Little Ice Age: Abrupt Land Use Change, Fire, and Greenhouse Forcing

    The implications are really important. Dull, et al, argue that the re-growth of Neotropical forests following the Columbian encounter led to terrestrial biospheric carbon sequestration on the order of 2 to 5 GtC, thereby contributing to the well-documented decrease in atmospheric C recorded in Antarctic ice cores from about 1500 through 1750. While the paper does not extend to the medieval maximum, from charcoal in lake bed studies it documents increased biomass burning and deforestation during agricultural and population expansion in the Neotropics from 2500 to 500 years BP, which would correspond with atmospheric carbon loading and global warming 1100 to 650 years BP.

    The charcoal & pollen evidence is hard to ignore.

    The Soil Carbon Standard committee’s work with USDA, EPA and Congressional Ag committees offers real hope, with expansion to ISO status, the world can all be on the same soil carbon page.

  3. @ Michael: The eastern Empire did experience some crisis as a result of the migration period - (e.g. the Gothic wars of 268, 375, and 535) but that is an important thing to point out. Even if climate affects civilizations, it doesn't have a uniform set of results.

  4. Is it too much to ask that blog posters, and blog commentators, include bibliographic citations? It seems to me that if one is making serious scholarly arguments, even in a blog, then one should conform to standard scholarly conventions of citations and bibliography. Now maybe this is all just hot air, people venting their non-scholarly opinions, in which case one would not expect to see the scholarly apparatus.

  5. @Michael: too much to ask of me, or too much in general? Me, I have mixed feelings. I disagree that there's a bright line between 'serious scholarly argument' and 'hot air'. Most people in this world don't base their actions or opinions on scholarly data, and they never will.

    Anyhow, this blog isn't really focused on the hard data as much as the way the hard data is presented in the press and pop culture, and that's a matter of me interpreting stuff I read. Scholarship is important but here I'm more interested in how scholarship is used in the world at large.

    Also, the 90% of the blogosphere without university library logins cannot see most of the scholarly literature anyhow - keeping journals behind subscription walls makes them irrelevant to the vast majority of humanity.

    That said, I see why links to articles that I discuss at length would useful to the reader. I'll get around to in in the next couple days I expect.

  6. Hi Dan,

    Just found this through google and thanks for highlighting some very interesting research.

    However, I'd question some of the conclusions you come to and judgements you make. For example, your mischaracterisation of John Zerzan's work tells me that you haven't really read much of his (quite erudite) writings, and prefer to work off immature charicatures (see the caveman photo above). In no way does he, or the deep ecology movement for that matter, "imply that the only way to “save the earth” is for us all to die, or stop being human." The arguments Zerzan makes are that pre-civilized humanity led demonstrably less mediated, less destructive lives, in some semblance of balance and integration with natural ecosystems; and that the destruction which civilization has wrought (as indicated, for example, in the work of Ruddiman and Kaplan, mentioned above) stems right from the evolution of symbolic thought, leading to civilization. This latter point is empirically backed up, e.g. see Charles Eisenstein's Ascent of Humanity, or Cauvin's Birth of the Gods and the Origins of Agriculture. Anyway, rather than arguing that humans are inherently sinful and should die out, Zerzan's point is that humans have, and can once again, live sustainable lives. He certainly doesn't call for genocide, as you suggest.

    "It's not a question of "saving the earth" (the earth would do just fine without humans) but of saving ourselves." Doesn't this precisely undermine the point your post is trying to make? The earth would not do just fine without humans, we're a fascinating and important species among many. However, I'd suggest that in some way we do have to "save the earth," in the form of stopping the juggernaut that is civilization. 150-200 species go extinct every day, at a massively elevated rate; I don't personally think this is "just fine," and it is already massively setting back evolutionary progress.

    Finally, regarding your statement: "The question then becomes not ‘how do we stop hurting the earth’, but ‘how do we manage the climate for stability’?"
    This takes a rather arrogant viewpoint of our role on the planet, and one which has been thoroughly rebuffed by, for example, James Lovelock. We certainly do have to "stop hurting the earth," at which point its Gaian mechanisms allow for a form of self-regulation. Lovelock has pointed out consistently that in no way do humans have the knowledge or ability to "manage" the climate. What we do have to do is stop undermining natural ecosystems, something which the studies you cite above indicate started in earnest with the transition to agriculture, viz. civilization.

  7. Dear Tommacg, thanks for the comment. Sorry for the late reply.

    I have read some Zerzan, mostly in Fifth Estate and Anarchy, plus the Future Primitive book (albeit back in the 90s). What I object to in his writing is the idealization of the primitive and his simplistic dualism of primitive and technological (based, I might add, on a 1960s anthropology that not everyone buys these days). I see technology as a spectrum starting with a stick. There are only gradual differences as you move up to computers, not existential ones. And in fact there is growing evidence that innovations such as hierarchy, symbolism, cities, and organized religion emerged within hunter-gatherer societies, not in opposition to them - and perhaps even catalysed agriculture. Zerzan has a valid point that large, complex societies necessarily involve more mediation and alienation. I deplore that too. But I can't accept his opposition to technology, symbolic thought and even language (!?). These are frankly the three things that make us human, and they have all existed since the palaeolithic, long before the emergence of hierarchical societies. Abolishing these things would end humanity, since they are the things that define humanity. Zerzan thinks we can live sustainable lives, yes, but only if we renounce the things that make us human and decrease our population 90+%.

    Of course a smaller population would help with ecological problems and social hierarchy. But what are the options for shrinking the population to hunter-gatherer carrying capacities, except genocide? Within the next 500 years, do you think there's any other way for achieving such a thing? If we rule out that option, smart use of technology is our only hope for sustaining the ecosystem services that support the human population. And don't get me wrong, biodiversity and smart land use are essential for humanity's physical and spiritual survival (and eventually decreasing the population to more sustainable levels). I believe that strongly. But pointing to technology as the villain and saying 'get rid of it' is like a Pentecostal trying to cast out homosexuality by prayer. It's never going to work because it completely misunderstands the root issue as good versus evil instead of as a normal aspect of human existence.