No Excuses on Climate Change

    At least where I was, in Champaign County Illinois, Spring 1970, the frontispiece or prolog to The Whole Earth Catalog for Earth Day (I) was Don Marquis's column on "what the ants are saying," delivered through his spokes-insect, archy the cockroach (from archy does his part, 1935). 

The lower-case letters are correct; archy types his messages and can't hold down the shift key, so of course it's all lower-case.

What the ants say is, basically, 

it wont be long now it wont be long
man is making deserts of the earth
it wont be long now
before man will have used it up
so that nothing but ants
and centipedes and scorpions
can find a living on it
man has oppressed us for a million years
but he goes on steadily
cutting the ground from under
his own feet making deserts deserts deserts

 In the 1930s, they knew about making deserts: the Great American Dust Bowl and all. And some knew the Dust Bowl was nothing uniquely new. Here's from my old (and I mean old when I bought it in my youth) Thompson & Johnson Introduction to Medieval Europe: 300-1500 (NYC: Norton, 1937) — one attempt to explain the phenomenal conquests of the Arabs in the decades following the death of Mohammed (old spelling). After rejecting theories of Islamic fanaticism in the period, and noting the weakness of the Persian and Roman Empires, the first issue is the initial rapid movement out of Arabia: "The expansion of the Arabs is best understood in the light of previous movements out of the desert into the neighboring Fertile Crescent. These were constant phenomena, to be explained by the vicissitudes of climatic conditions, which always drove nomadic people outwards. [...] The peninsula itself was experiencing a periodic desiccation, which made life within it ever more unbearable and drove its inhabitants to seek relief elsewhere" (p. 166; ch. 7, "The Empire of the Arabs"). What was to be called "the desert pump" had pumped out one of its most historically significant armies. 

    James Westfall Thompson of the U of California and Edgar Nathaniel Johnson of the U of Nebraska over-simplified and may've over-stressed migrations and the role of "nomads," but they were writing in the 1930s, and were still ahead of those who today talk of the origin of medieval Europe in, figuratively speaking, "Athens, Rome, and Jerusalem" and then throw in the Germanic tribes. Medina and Mecca, as similar figures of speech, come in here, as well as the later great cities in "The Empire of the Arabs" — the lands of Islam — that kept high civilization going when it wasn't doing very well on the peninsula of Eurasia that for a long while there was "darkest Europe." And these two historians from the American west knew about marginally fertile land becoming deserts and deserts becoming uninhabitable by humans.  

The idea of climatic influence was around and went in and out of fashion.

In 1965, Hubert Lamb, one of the first paleoclimatologists, published research based on data from botany, historical document research, and meteorology, combined with records indicating prevailing temperature and rainfall in England around c. 1200 and around c. 1600. He proposed, "Evidence has been accumulating in many fields of investigation pointing to a notably warm climate in many parts of the world, that lasted a few centuries around c. 1000–c. 1200 AD, and was followed by a decline of temperature levels till between c. 1500 and c. 1700 the coldest phase since the last ice age occurred."

The warm period became known as the [Medieval Warm Period] MWP, and the cold period was called the Little Ice Age (LIA). However, the view that the MWP is a global event was challenged by other researchers.

And is currently challenged by more and is "out." The point here is that, if anything, earlier periods of warming and desiccation were overstated geographically, but it has been understood that they could have profound affects on humans. The full title of Brian Fagan's 2008 book is The Great Warming: Climate Change and the Rise and Fall of Civilizations, and there are enough hot, dry places in danger in our world that we need to pay attention if they're getting hotter and drier and less able to support human habitation. 

    The scientific argument over earlier periods of warming, ocean-rise, and desiccation is intertwined with politics and the highly plausible idea that large-scale climate-change in preindustrial times is unlikely to have been caused by humans — plus the false conclusion in many places that people must accept the idea of "anthropogenic climate change" to take serious action to slow it down. 

    Which brings me to some of my long-delayed recent reading and a source I didn't expect: Carl Sagan's  Broca's Brain (essays and such, 1974-79), in a paperback copy I have from the Miami University Library, which means I had to have bought it on some duplicates sale when I was still at Miami U, i.e., before 2006-7. I don't recall why I bought the book, but one reason I should have is because it has significant discussions of Immanuel Velikovsky and (primarily), Velikovsky's Worlds in Collision (1950). And I should have caught up on "the Velikovsky Affair," which I had once taught as a unit in a course at the U of Illinois in "The Rhetoric of the Life Sciences."

    Okay, Velikovsky's basic thesis, a Wikipedia entry nicely summarizes, was "that around the 15th century BC, the planet Venus was ejected from Jupiter as a comet or comet-like object and passed near Earth (an actual collision is not mentioned). The object allegedly changed Earth's orbit and axis, causing innumerable catastrophes that are mentioned in early mythologies and religions from around the world." So the "Affair" was primarily about astronomy and physics, but there was enough biology involved — a form of catastrophism is mainstream science for the extinction of the dinosaurs — enough biology was involved that the unit was almost legitimate: and the debate over Velikovsky's ideas was sufficiently vociferous to be irresistible for a topic in academic rhetoric of recent times (academics are much more polite nowadays than earlier centuries, at least in public). And I knew about Velikovsky because I'd taken an undergrad seminar on D. H. Lawrence and wrote a term paper on "Catastrophism and Coition: Cosmic and Individual Development in Women in Love."

Comic digression: I lightly revised the "Catatsrophism" essay and sent it to PMLA, the premiere journal in the LitCrit field at the time (my elders advised me to start at the top and work down). I did not have the usual complaint of authors' having to wait months for a response from a journal: my manuscript was returned to me in my nice, big, self-addressed stamped envelope within a couple weeks. I stomped down our steep stairs toward the letter-carrier, who was trying to get the returned manuscript into our mailbox; and I must have been muttering louder than I thought since the mailman, without looking up, raised his hand and said, "I only return them; I don't read them" — which cracked me up and put me into the right mood to read the first rejection letter, no less, of what was to become my rather impressive collection. Very few or no rejection slips: the editors wanted to make clear to me why my efforts, though much appreciated, "do not meet our needs at the present time" (or ever, or at least until the sun goes nova). In this case: "Very interesting opening paragraph," said the referee's comment the editor wished to share with me, "before the whole thing" — and a substantial-size essay it was — "falls flat." I immediately got back on my hobbyhorse, and sent the (unrevised? probably) essay to what I was told was the second choice for something on D. H. Lawrence, TSLL: Texas Studies in Literature and Language. It was accepted with one revision the editor would make with or without my permission (titles can fall under "Editor's Prerogative"): re-subtitling to "Universal and Individual Development [...]": I had the required alliteration and a colon, but three words alliterated exceeded the bag-limit. But I have digressed.

And so I had published an essay in a respectable journal with the word "Catastrophism" in the title, which even back then (1967) was quite enough to get me on at least one Looney-Tunes mailing list, Velikovsky division. And reading Sagan on Velikovsky brought me to this:

Velikovsky writes [...] that his claim of a high surface temperature [on Venus] was "in total disagreement with what was known in 1946." This turns out to be not quite the case. The dominant figure of Rupert Wildt again looms over the astronomical side of Velikovsky's hypothesis. Wildt [...] predicted correctly that Venus and not Mars would be "hot." In a 1940 [... "Note on the Surface Temperature of Venus"] in the Astrophysical Journal [91: 266-68], Wildt argued that the surface of Venus was much hotter than conventional astronomical opinion had held, because of a carbon-dioxide greenhouse effect. Carbon dioxide had recently been discovered spectroscopically in the atmosphere of Venus, and Wildt correctly pointed out that the observed large quantity of CO2 would trap infrared radiation given off by the surface of the planet until the surface temperature would be almost 400º K, or around the normal boiling point of water. (p. 136; ch. 7, "Venus and Dr. Velikovsky," Problem VIII, "The Temperature of Venus")

 Later in Broca's Brain — again, from the 1970s — Sagan rather immodestly notes a now

fashionable suggestion, which I first proposed in 1960, [...] that the high temperatures on the surface of Venus are due to a runaway greenhouse effect in which water and carbon dioxide in a planetary atmosphere impede the emission of thermal infrared radiation from the surface to space; the surface temperature then rises to achieve equilibrium between the visible sunlight arriving at the surface and the infrared radiation leaving it; the higher surface temperature results in a higher vapor pressure of the greenhouse gasses, carbon dioxide and water; and so on, until all the carbon dioxide and water vapor is in the vapor phase, producing a planet his high atmospheric pressure and high surface pressure.

        Now, the reason that Venus has such an atmosphere and Earth does not seems to be a relatively small increment of sunlight. Were the sun to grow brighter or Earth's surface and clouds to grow darker, could Earth become a replica of the classical vision of Hell? Venus may be a cautionary tale for our technical civilization, which has the capability to alter profoundly the environment of Earth. (pp. 180-81; ch. 10, "The Sun's Family")                        

Sagan repeats the point in "The Climates of Planets," from 1975, ch. 14 in Broca's Brain. The upside of climate change for humans:

We may owe our [...] existence to climatic changes that on the average amount to only a few degrees. Such changes have brought some species into being and extinguished others. The character of life on our planet has been powerfully influenced by such variations, and it is becoming increasingly clear that the climate is continuing to change today. (pp. 222-23)

By 1975 there had been "almost a hundred different theory of climatic change on Earth," of which  Sagan selects three for closer consideration. 

The first involves a change in celestial mechanical variable: the shape of the Earth's orboit, the tilt of its axis of rotation, and the precession of that axis [...]. Detailed calculations of the extent of such variations show that they can be responsible for at least a few degrees of temperature variation, and with the possibility of positive feedbacks this might, by itself, be adequate to explain major climatic variation. 

 A second class of theories involves albedo variations. One of the more striking causes for such variations is the injection into the Earth's atmosphere of massive amounts for dust — for example, from a volcanic explosion such as Krakatoa's in 1883. While there has been some debate on whether such dust heats or cools the Earth, the bulk of present calculations show that the fine particulates [...] increase the Earth's albedo and therefore cool it. [...]

                    Finally, there is the possibility of variations in the brightness of the Sun. (pp. 226-27) [...]

 Some evidence on the trend of global temperature seems to show a very slow increase from the beginning of the industrial revolution to about 1940, and an alarmingly steep decline in global temperatures thereafter, This pattern has been attributed to the burning of fossil fuels, which has two consequences — the liberation of carbon dioxide, a greenhouse gas, into the atmosphere, and the simultaneous injection into the atmosphere of fine particles, from the incomplete burning of the fuel. The carbon dioxide heats the earth; the fine particles, through their higher albedo, cool it. It may be that until 1940 the greenhouse effect was winning, and then the increased albedo is winning.

    The ominous possibility that human activities may cause inadvertent climate modification makes the increasing interest in planetary climatology rather important [...].   (pp. 227-28)

And whatever might be the main driver of climate change manifested as global warming, makes knowledge of the greenhouse effect crucial. The tilt of the Earth or energy production of the sun is beyond human power to affect; greenhouse gasses we can do something about, and should. And, clearly, I think, should have by the 1980s.

 

Young people coming to age in the next couple of decades will have good reason to be angry with their elders. 

 

 

<https://history.aip.org/climate/Venus.htm#N_4_>

 

 

 

Climate Change / Political Changes: The Need for Historical Background

We need more books like Brian Fagan's 2008 The Great Warming: Climate Change and the Rise and Fall of Civilizations: history books, mostly, that help us understand that climate change isn't just  about changes in some abstract "the environment," but about great changes in human politics.

This book is about "the Medieval Warm Period," ca. 800-1300 C.E. and its generally positive effects in, e.g., northern Europe and utterly devastating effects elsewhere, e.g., in already warm, dry places such as long-term droughts in what's now the U.S. southwest.

These Medieval data can cut different ways, as a warning to try to reduce the speed of global warming and try to mitigate its effects — or to say that climate change ca. 900 obviously wasn't caused by human industrial activity, so we needn't reduce current economic activity with its benefits and irrelevant, or even beneficial greenhouse gas emissions. 

To quote for background one on-line pundit, "Climate scientists now understand that the Medieval Warm Period was caused by an increase in solar radiation and a decrease in volcanic activity, which both promote warming. Other evidence suggests ocean circulation patterns shifted to bring warmer seawater into the North Atlantic." So why should we try to reduce greenhouse gasses?

The question isn't rhetorical. For one thing, the article linked last paragraph notes that there's no evidence for a recent increase of solar radiation, nor, in our times, significant decrease of volcanic activity;, and I'll note that currently there's not a damn thing the human species can do about either. We can reduce emissions of greenhouse gasses, which will slow the rate of warming, and we should reduce those emissions anyway to save some easily extractable hydrocarbons for our descendants. They might find safe and efficient ways to use petrochemicals and need some — and be very pissed off at earlier generations who went and burned them. 

They may also be pissed off at a re-run, but worse, of, especially, long-term, catastrophic droughts. 

In addition to the obvious, some of the effects of climate changes indeed include the geo-political. William Grimes's New York Times review of The Great Warming has an arresting sentence indicating that what was so good for much of Europe may have had negative effects: "Although data remain sketchy, it seems probable that extended droughts dried up pastureland on the Central Asian steppe, propelling the armies of Genghis Khan westward." The career of the Great Khan (1206-1227 C.E.) achieved some impressive empire building that, in Europe, arguably set the stage for what was once called the Renaissance, but unarguably resulted in an extraordinarily high body-count. Matthew White tallies up Genghis Khan's "multicide" score at 40 million, which puts the Mongol invasions just behind World War II (1939-1945) for destruction of human life. 

And destruction of the great Muslim civilizations at the center of Eurasia — which in a twisted way brings me to where I started thinking about this post. 

I had typed out on Facebook a quotation from Introduction to Medieval Europe: 300-1500 by James Westfall Thompson and Edgar Nathaniel Johnson (New York: Norton: 1937). In an early chapter on "The Empire of the Arabs," Thompson and Johnson give Mohammed and the early leaders of the Umma credit for organizational genius and make the point that medieval Europe was a side-show as civilizations of the time went. They are far from "climatic determinists," with an Index innocent of such references. And they fully recognized the arrogance and stupidity of the remaining Roman Empire and Persia in their continuing wars and machinations. Still, Thompson and Johnson asserted (in 1937!) that "The expansion of the Arabs is best understood in the light of previous movements out of the desert [...]. These were constant phenomena, to be explained by the vicissitudes of climatic conditions, which always drove nomadic peoples outwards. [...] The [Arabian] peninsula itself was experiencing a periodic desiccation, which made life within it ever more unbearable and drove its inhabitants to seek relief elsewhere. It seems, accordingly, highly probably that what occurred would have happened even without Mohammed and Islam" (p. 166). 

"What occurred" was the end of Late Antiquity, with the final end of the Roman Empire, and the Persian — and Rome in the East (the Byzantine Empire), reduced to a regional power. T & J and those with similar theories may be wrong, but it's a point to consider, along with the possibility that the following round of "desiccation" in the Medieval Warm Period led to that drying out of parts of the Eurasian steppe leading to the western thrust of the Mongol invasions and, let's say, a figurative arrow from a powerful bow through the figurative heart of "The Empire of the Arabs."

It's possible that two major changes in the course of human history had as one basic cause the long-term droughts — the "desiccation" — brought on by global warming. Mohammed and Genghis Khan count, and their decisions are important. Still, one thing Karl Marx got right was that "Men make their own history, but they do not make it as they please [...], but under circumstances existing already, given and transmitted from the past." And those circumstances include a physical environment that is both beyond human control and influenced by our actions.

Unless we want some really bad circumstances for the next generation, we'd better get right some important decisions — and soon. 

History "Rhyming": The Fall of Rome, Post-Reformation Wars of Religion — ISIS

           "History never repeats itself; but sometimes it rhymes," is line worthy of Mark Twain, although he probably didn't say it.

            If you're a Jew or old-Lefty Pole of my generation, or a Japanese-American or some others — if World War II history is relevant to you fairly personally — you've recently had thrust at you some very disturbing "rimes." Most immediately there has been the turning away of refugees and proposing of such fascistic policies as registering Muslims in America by religion, along with mutterings of internment. There has also been the rise in Europe of political movements and parties that are near the border of fascism or over it; and the US Congress has insisted on continuing at least one policy that is hard-core fascist: the zone of statelessness we maintain at Guantanamo, outside of the Constitution and much of the Uniform Code of Military Justice. Plus, of course, the small zones of literal lawlessness at US "black sites" for captured or kidnapped suspects during "The War on Terror" and — very recently, if hyperbolically and ignorantly — bellicose threats of a return to carpet bombing by the US, which is most effective as a terror tactic, necessarily killing civilians.

            Except for precisely how despicable it is that the US still holds enemies (and maybe some relative innocents) at Guantanamo, however, such topics have been covered extensively by others, and here I'm going to handle something more general and long term, but equally … let's say concerning.

            I've been thinking of historical parallels while using a lull in "my brilliant career" in the movie biz to fill in a bit some areas of my ignorance: transitions between major historical periods. I'm talking the biggies here: the movement into cities and kingdoms in the early Bronze Age, and in the West the transition from Late Antiquity into the Medieval in the 600's (in the Christian Calendar), and, much later, the move into the Modern Period, Enlightenment, and the Age of Revolutions in the 17^th and 18^th centuries.

            We can't know much detail about the rise of the earliest civilizations, but two things seem important. First, there was frequently a big king with a close connection to "Big Gods," as a kind of god himself, as with the Egyptian pharaoh as (usually at least) the living Horus, or with the somewhat less formal godhead among the rulers in Mesopotamia, where the "first instance of self-deification […] coincides with the first world empire" — i.e., rule of the very ancient Near East — "of the rulers of Akkad." Second, a crucial thing these early kings could do was arrange irrigation projects and control the water: impressively, if "hyperbolically," imaged in Mad Max: Fury Road (2015). We don't need to worry about god-kings this side of some apocalypse, but one potential of long-prolonged and severe drought and other climatic stress would be an increasing willingness to succumb to a Führerprinzip and follow capital "L" Leaders who could promise stability and water — and other necessities. To continue with the Mad Max "mythos," at stake along with water might be power; in Mad Max [3] Beyond Thunderdome (1985), those who control hydrocarbon power control proto-capitalist civilization.

            In a world that has returned to widespread scarcity, the condition for most people for much of the history of civilization, liberal democracy could come to be widely seen as an unaffordable luxury.

            But that's a rough sort of "partial rime," and warning about the danger of renewed scarcity is a cliché. There are parallels to current events where we've seen the movie before as a Western (as in Europe as the West):

                        * The invention of new and powerful means of communication,

                        * reforming theorists calling for return to the fundamentals of the pure, original religion,

                        * the entanglement of movements for reformation into long-standing political tensions,

                        * civil and international wars among competing monotheistic sects.

            My reference here is to the printing press, the Protestant Reformation from Tyndall and Luther through the radical Calvinists — and the Counterreformation and the various theological and political splits and military unpleasantnesses concurrent and following. We are not there yet, and ISIS is the "junior varsity," as Pres. Obama said; but successor groups to ISIS may prove as successful as John Calvin in Geneva and the Puritan Roundheads in England; and our wars of religion, possibly starting with Shia vs. Sunni, will be in a world with nukes.

           

            I for one am happy that the West moved from the Early Modern world of the Renaissance and Reformation into the Modern one of the Enlightenment and the Revolutions: the "Glorious Revolution" in England in 1688, the American, the French, the scientific, and the industrial. But there were costs, and those costs included two to four million dead of famine and disease, war and massacres in France (1562-98), the Thirty Years' War (1618-48), with massive casualties, and the English Civil War (1642-51), with death, exile, and enslavement resulting in losses of population estimated at 3.7% for England, 6% for Scotland, and forty-one percent (41%) for Ireland. Indeed, even as in America we are still dealing with our Civil War, that war and some of our deepest divisions go back to the English Civil War and the struggle between radical-Protestant Puritans and Royalist "Cavaliers."

            There is no "clash of civilizations" between Islam and the West, but there was no clash of civilizations between Catholics and Protestants — and their splinter groups — during the Wars of Religion; and, for that matter there wasn't that much of a clash of civilizations during the Crusades, except perhaps between the relatively high culture of Islam and the more … basic, let's say, culture of Christendom (Matthew White estimates the body count from the Crusades of 1095-1291 at about three million, putting it in a tie with his estimate for the French Wars of Religion).

            An extended Sunni vs. Shia civil war/war(s) of religion would be horrendous. If it brings in elements of a revived Christendom and then Israeli Jews and Indian Hindus, it would be catastrophic.

            Which is the background reason why it is so important to defeat ISIS while it's still the JV, and before they've found a charismatic Leader to act as a new Saladin or a more secular — Caliph at most, not Prophet — Mohammed. And which brings us to what I've skipped over: the move from Late Antiquity and the Roman Empire in western Eurasia to the Middle Ages, with Rome reduced to the Byzantine Empire as a relatively small and threatened entity and Europe evolving into perhaps nation-states, for sure smaller, generally poorer, less sophisticated political units. That is, I want to get to what is often thought of as the decline and fall of the Roman Empire and/or the run-up to, and then the rise of, "The Empire of the Arabs."

            And here I'm going to give you two long quotations from my old text books for ancient and medieval history: Joseph Ward Swain's The Ancient World, Volume Two, The World Empires: Alexander and the Romans After 334 B.C. (New York: Harper & Brothers, 1950), and James W. Thompson and Edgar Nathaniel Johnson's An Introduction to Medieval Europe: 300-1500 (New York: W. W. Norton & Company, 1937). I'm going to repeat the dates, 1950 and 1937; when I said "old," I meant old — at least old as textbooks go, comparatively speaking, given that it's been over half a millennium since the end of the periods they cover. Anyway, these books were written before the middle of the twentieth century and can have no axes to grind, no agendas concerning current events in the second decade of the twenty-first.

            The quotation from Swain ends the period he covers in his second volume, from the reign and conquests of Alexander the Great (336-323 BCE) to the end of the ancient world. The quotation from Thompson and Johnson doesn't come at the beginning of their book. Thompson and Johnson start their survey about the time of the Roman emperor Constantine and what they call "The Græco-Oriental Conquest of the Roman Empire," then move through "The Christian Conquest of the Roman Empire," "The German Conquest of the Roman Empire" (from early migrations to 600 CE), to a summary discussion of "The Byzantine Empire" — a rump Rome in the east that lasted until the fall of Constantinople in 1453 — and then get to "The Empire of the Arabs," which is important for their discussion for three basic reasons. First, the "long-continued struggle" between the Arabs and their Muslim allies and subordinates; second, as one of "the great civilizations of the world," and for a third point often overlooked by those raised in Christendom. The "Dark Ages" weren't total disasters everywhere, but with the fall of Rome in the West, a whole lot of ancient learning was lost or at least misplaced, while intellectuals and others in "The Empire of the Arabs" conserved a good deal and added to it. When during and after the Crusades Islam again directly "encountered the civilization of western Europe[,] they had rich treasures of science and philosophy quite unknown to the west. They accordingly contributed one of the basic elements in the composition of western culture" (p. 153).

            To the "Græco-Oriental," Greco-Roman, Germanic, and Christian threads in the fabric of western European civilization, one must add the Arab-Islamic, but we need to make that addition while carefully noting that Arab-Islamic conquests marked both the beginning of one era in the West and the end of another.

            Joseph Ward Swain begins his coda to his story of the ancient world with the end of the reign of the East Roman Emperor Justinian in 565 CE.

          A few years after Justinian's death, Mohammed was born in Arabia, and when he died in 632 his new religion was accepted in many parts of that country. Within ten years[,] Moslem armies had conquered Syria, Palestine, Persia, and Egypt, and while their advances were less rapid thereafter, they did not stop until they reached the frontiers of India and China in the East and the Atlantic in the West. They entered Europe at Gibraltar in 711, and overthrew the Visigothic Kingdom. Though the Moors were turned back by the Franks at the Battle of Tours in 732, and soon left Gaul, they retained large parts of Spain for several centuries [and kept a toe-hold until 1492]. Throughout this vast territory, Christians and pagans accepted Mohammedanism [sic] readily. 

         Such military and religious successes are amazing, even though many factors aided the Moslems. Exhausted Constantinople could not raise the armies needed to hold its provinces. The peoples of Asia and Africa often looked upon the Arabs as liberators freeing them from the bureaucrats and bishops of the hated Byzantine autocracy. But in the long run Moslem successes may best be regarded as the triumph of the [ancient] Orient over European invaders. Almost a thousand years had passed since Alexander overthrew the first Persian Empire. During all that time a small aristocracy of Europeans and Europeanized Orientals had dominated a vast oriental population. Orientals now became masters in their own house once more. Except during the Crusades [1095-1291 CE, ca. three million dead], they remained so until the nineteenth century. (pp. 613-14)

Persia was an independent empire, the Sasanian, never conquered by Rome, but Syria, Palestine, Egypt, North Africa, and Spain had been in the Roman Empire, as was, of course, much of Europe; and the causes of their fall to various conquests has been a matter of debate since at least St. Augustine's City of God (426 CE), written after the sack of the City of Rome by the Visigoths, while the Empire was in decline but not yet fallen. So significant in the quotation from Swain are the ideas of the Muslim conquests as initially anti-colonialism on a massive scale and the issue of the weakness of the Roman Empire: as Edward Gibbon put it, it was The Decline and Fall of the Roman Empire (publication starting in 1776, an appropriate date).

            The reasons for that weakness of course are many, from economic failures to civil wars. I'm going to mention two that are significant for "rimes" and aren't, I hope, total clichés.

            The first is discussed in a book by William Rosen with the intriguing title Justinian's Flea and the alternative subtitles Plague, Empire, and the Birth of Europe and, for the Reprint and/or British Edition, The First Great Plague and the End of the Roman Empire (2007). One of the reasons the Roman and Persian Empires were weak was that both had been hit by a new and virulent form of bubonic plague: "One of the greatest plagues in history, this devastating pandemic resulted in the deaths of an estimated 25 million (initial outbreak) to 50 million (two centuries of recurrence) people." The immediate source of plague in Justinian's empire were rats from grain ships from Egypt; recent "Genetic studies point to China" as the ultimate "source of the contagion."

            And how would a disease from China get to Egypt and from Egypt into the Mediterranean commodities trade? One obvious route would be the complex system in the trade of commodities more compact and precious than grain coming over what's usually called "The Silk Road."

            There wasn't exactly globalization in the ancient and medieval worlds, but very early on there was long distance trade that covered surprisingly large stretches of Eurasia. Trade is overall a good thing — or so I believe, living next to a deep-water port — but among things inadvertently exchanged in commerce are pathogens, and those pathogens can have world-historical effects. Yersinia pestis using fleas as vectors thrived in much of Eurasia at least for a while, or a while from an epidemiological point of view; it did less well — at least in this visitation of the plague — in the hot and dry deserts of Arabia, where people do not grow, store, and transport large quantities of rat chow (i.e., grain).

            In a time of increasing global trade, in a time when the last unexploited areas of the Earth are being entered and/or exposed by a warming climate, in a time of continuing resentments against forms of colonialism far gentler but perhaps more invasive than those of Alexander's Greeks or Imperial Romans: in our time, such "rimes" should give us pause. We know about germs and quarantines, so we will not have plagues similar to that of the time of Justinian or the medieval Black Death; but we modern folk are uniquely unfamiliar with death from infectious diseases, and even a pandemic like the flu following World War I could proved disastrous not just in body count but also for social order and confidence.

            A second reason for the weakening of Rome was, initially and mostly at one remove, the movement west of the Huns across the Eurasian steppes, driving before them large numbers of refugees; "The Huns may have stimulated the Great Migration" of "barbarians" into the Roman world: "a contributing factor in the collapse of the Western Roman Empire."

            Aiding refugees is an ethical obligation and for many of us a religious duty; still, to "welcome the stranger" can be an obligation and duty with risks, and however one judges the often racist and fascistic resistance to welcoming refugees from conflict in Syria and elsewhere, the extent of the influx and migration of refugees is destabilizing in Lebanon, Jordan, Egypt, and the Balkans, and contributes to tensions in Turkey, the European Union, and elsewhere.

            For people who know my obsessions, it will be clear that the major "rime" I'm moving toward is the fanaticism of ISIS and the competing fanaticisms it will inspire. Still, there is one more ingredient to throw into the brew, and it comes from an alternative suggestion endorsed by Thompson and Johnson for the incredible early expansion of Islam.

          The easy explanation has long been that Mohammed first succeeded in giving political cohesion to Arabia, and then so fired the Arabs with the burning zeal of religious fanaticism that almost en masse they dashed out of the [Arabian] peninsula with the fierce determination to convert they world by the sword, knowing that, if they died in the attempt, Islam guaranteed them the most precious of all booty, the fruits of paradise.

          The facts are quite otherwise. In the first place, it is impossible at this early date to speak of Mohammedan [sic] fanaticism, except possibly in isolated instances. Mohammed himself in his conquest of Mecca displayed a fierce enough zeal; but in general no such militant intolerance as, for example, characterized the struggle of Christianity against paganism, characterized Mohammedan expansion. The fanaticism of Islam is that of much later converts, and even so Mohammedanism has normally been marked in practice by its tolerance. For all its expansion and conquest, from Mesopotamia to Spain, Judaism and Christianity by no means ceased to exist by its side. The only impositions made by the Arab conquerors upon unbelievers were a special poll tax and the prohibition of the possession of weapons. […]

          In the second place, it is impossible to speak of Mohammed's creating any such thing as Arabian unity, nor can it be supposed that in any substantial way the nomadic Arab tribes were suddenly consolidated into a unified state after his death. Unified states are not organized in the desert. In fact, after Mohammed's death it was only by hard fighting […] that a recognition of the loose political overlordship of Medina over the other Arab tribes was secured. Even then there was not, and could not be, any interference with tribal organization. As for the early Arabian conquests, few of Mohammed's followers in Medina participated in them, and those Arabs who did knew and cared little about Islam. 

         The expansion of the Arabs is best understood in the light of previous movements out of the desert into the neighboring Fertile Crescent. These were constant phenomena, to be explained by the vicissitudes of climatic conditions, which always drove nomadic peoples outwards. [… There was a slow Arab expansion previous to Mohammed, and in his time] The [Arabian] peninsula itself was experiencing a periodic desiccation, which made life within it ever more unbearable and drove its inhabitants to seek relief elsewhere. It seems, accordingly, highly probable that what occurred would have happened even without Mohammed and Islam. [Still,] After the conquest of Mecca[,] the tribes subject to Medina had for the moment no outlet for their customary warlike activities. The new Moslem tribes that became subject after the Ridda Wars [under Abu Bakr, the first Caliph] were constrained in their intertribal warfare by the dictates of the new religion, which preached that Moslems should help rather than fight other Moslems.

        At just the right moment[,] a revolt of Arab mercenaries of Byzantium on the Syrian frontier led to their calling for assistance against Byzantium upon Medina, whose military reputation had by then pervaded all Arabia. Here was an opportunity for expansion, the most pressing need, for relief of hunger and for booty. Islam found it easy to sanctify such opportunities with the seal of religious approval of a holy war, as Christianity had done for Clovis's war against the heretic Visigoths. Such unity as was gained in the conquests of the Arabs was produced by enthusiasm for the profits of expansion and for escape from "the hot prison of the desert" rather than by enthusiasm over the opportunity to spread the true gospel — with which by no means all of them were even acquainted. "Had it not been for the disaffection rife among these disciplined Arabs of the marches [of Syria], it is likely that the religion of Mohammed would have gone the way of other minor eastern heresies. Hunger and covetousness, far more potent forces than fanaticism, drove the Arabs from their arid peninsula to the fair places of the earth." [In Bevan and Singer, The Legacy of Israel (1927), p. 150] (Thompson and Johnson pp. 164, 166).

A good deal has changed in the writing of history since the 1920s and 1930s, and reductive materialist explanations (geographic, climatic) are no longer convincing. More important, a great deal has changed since the seventh century Anno Domini and the first couple centuries Anno Hegirae — i.e., of the Christian and Muslim Eras — when nomadic tribes could march and ride out of the desert to conquer large swaths of the world. Still, in ISIS there is a fundamentalism impossible back in the time of Mohammed and Abu Bakr when the "fundamentals" were still getting worked out, and ISIS is a fanatical organization that could evolve into the core of a fanatical mass movement that appeals to peoples made desperate in "desiccations" of hot and dry places of the Earth far beyond the Arabian Peninsula.

            "History never repeats itself; but sometimes it rhymes." The rise of ISIS should not get us to panic (spreading terror is what terrorism is about), but it should give us a sense of concern and cautious urgency. ISIS must be destroyed — to recycle and modernize a dumb-ass slogan from Roman rhetoric and a Roman senator — but carefully and as part of much broader programs.

            Those programs would include working to slow climate change and ameliorate its damage, projects we should be working on anyway. And they need to include warfare by a wide coalition against ISIS, and a coalition using economic and psychological warfare as well as the sort that shoots people or blows them up. The refugee problem needs to be worked on cooperatively as well, spreading out the burdens and costs; the countries of the world need to be much better prepared for the public health challenges of infectious diseases. The neo-colonial aspects of globalization must be restricted, and potential True Believe fanatics need to be offered decent jobs and the possibility of relatively meaningful lives in societies that work. And every Bible-pounding, Quran-pushing, Likudnik-equivalent, heresy-hunting zealot should be shamed into studying the history of the Sunni/Shi'a split, the horrors of the Crusades, and the utter catastrophe for Europe of the Catholic vs. Protestant Wars of Religion.

            History never repeats itself, but "Those who cannot remember the past are condemned to repeat it," or may be so condemned, sometimes: condemned,  sometimes, to repeating historical tragedies as bloody, horrific farce. To repeat a point that needs repeating, in the first quarter of the twenty-first century we risk repeating historical tragedies in Dr. Strangelove-ian farces with nukes in the hands of Hindus and Jews, two varieties of Muslims, Confucian Communists, the occasional outlier weirdo (Kim Jong-un, maybe Donald Trump), and a variety of Christians, from Evangelical to Russian Orthodox. 

         So, be not afraid, but do "Be concerned; be very concerned."