It was much less obvious in the last book than this one, but Fagan has a big rage on about civilization. He's very, very concerned about the possibility of a climatological catastrophe, and the "vulnerability" of the global civilization. That was clear enough in The Little Ice Age, but in The Long Summer that concern has become a didactic hammer with which he will pummel every skull within arm's reach. Every culture that could be dignified with the appellation "civilization" is properly labeled "vulnerable" or "precarious", usually both, in exactly those terms. Non-literate agrarian cultures get a half-pass on account of their inability to tell us directly of their agony, but it's only non-literate, non-sedentary hunter-gatherers and nomads that earn the gold star in Fagan's moral climatology: "effortless". When somewhat sedentary cultures like the Middle-Eastern Natufians harvest gazelle herds in job lots:
The hunters did not bother to harvest individual animals. Rather, they culled herds en masse, killing animals of all ages, including the youngest beasts, over a few weeks in early summer, when the gazelle moved north to the river valley in search of lush pasture. Sometimes they slaughtered entire herds.
However, when good, climatologically moral Cro-Magnons hunted in the same fashion, this is how Fagan describes the scene:
Judging from modern-day caribou hunts, the Cro-Magnons would let the leaders of the herd pass through the water unharmed, then set upon the animals behind them, harvesting beast after beast with effortless skill. The animals would rear and whirl in panic, bellowing, their dead companions floating downstream where other members of the hunting band hauled the carcasses into the shallows. Many would escape to the far bank, to regroup and continue their exorable march. But the hunters would cull dozens, even hundreds of beasts, butchering the carcasses with brisk efficiency on the riverbank.
Note the key-words "effortless" and "efficiency". Meanwhile, Cro-Magnons get work-words like "butcher" while the civilizing Natufians get value-words like "slaughter". The activity was the same. But the Cro-Magnons didn't threaten the landscape by being successful, by growing in population. They scraped along on a thin edge, in small, long-term stable numbers. The Natufians would eventually produce new agricultural technologies, grow, be forced off their lands by a climatic downturn, and then return as the first true farmers, and eventually, literate peoples. Bad. BAD.
This cycle of "nomad good, sedentary bad", "literate bad, oral tradition good" and "herd-following good, hunter-gathering OK, farming WICKED" continues throughout the book, at varying levels of emphasis and didactic force. Fagan doesn't recognize the added value to a culture of a social base of a hundred thousand over a social base of five thousand, and this bias expresses itself throughout the narrative. Risibly, literate cultures are portrayed as having "short generational memories" while the even-shorter, even-narrower cultural memories of oral-tradition cultures are ignored, or even lauded as sturdy and knowledgeable.
In my considered opinion, Fagan has fallen into the classic trap of disbelieving in things that he has no direct knowledge of. That is, literate cultures record exactly, within the same generation, the results of famine, disaster, chaos and terrain abandonment. Oral tradition cultures, swept away by the same or similar disasters, either leave no records due to the collapse of the story-telling chain, or else pretty up the story, in a very human attempt to consider their beloved ancestors in the very best of lights.
But Fagan even thumbs the scales when there is evidence, when he has the bloody evidence in front of him, but won't tell us. I didn't realize this for the better part of the book, due to my college-survey-course paucity of knowledge on the subject of pre-literate history. But I've seen stuff about the Anazasi collapse (which he insists on calling "Ancestral Pueblo" for political reasons he doesn't detail, but which I can guess), and it wasn't the calm and collected migration that he paints in such placid colors. It was a period of chaos, cannibalism, and slaughter like every other drought-and-famine collapse one might care to consider. It's exactly the same situation as the others which he details in such damning terms among literate cultures. But because the Anazasi, excuse me, "Ancestral Pueblo", were not literate, Fagan gives them a pass, and describes them in the most glowing terms he will offer for miserable, overpopulous farmers.
In short, Fagan displays in this book one of the worst cases of Cain-and-Abelism I've yet encountered in a scholarly work.
On the other hand, he does go over some climatological theories about the Holocene which I haven't encountered before, backing up his previously-mentioned worries about a collapse of the Gulf Current via a freshwater collapse of the northern ice cap. The examples he offers, however, are not sudden, world-wide meltings, as described in The Little Ice Age. Rather, he describes vast freshwater glacial lakes, formed on the edge of glacial plates over long periods of time, which eventually cut through the edge of the icepack in a catastrophic flood that creates the freshwater pool in necessary to shut down the North Atlantic Conveyor. This is not a subtle series of events, difficult to discern, or fast-moving. The glacial lakes he describes are not something the formation thereof would escape modern detection. That isn't currently happening. Nor are there any other threatened inundations, such as the Euxine Lake disaster, currently pending. These actually seem to weaken his case for impending doom.
All in all, a very infuriating book, but it has enough detail, and I'm disinclined enough to take any of it as gospel word, that I don't regret reading it.