Behaving like Spiders

Tim Flannery

  • The Long Summer: How Climate Changed Civilisation by Brian Fagan
    Granta, 284 pp, £20.00, May 2004, ISBN 1 86207 644 8

Can you imagine a winter so cold that the sea is frozen over all the way from Norway to Denmark? Not even the last Ice Age saw such a thing, for then the sea level was lower, and all of Scandinavia was joined together by dry land. Yet in 1837-38 the Norwegians survived such a season. And what of having to watch as every day the sea rises another 15 centimetres, until after two years what was your home lies 150 metres below the waves? This may be unimaginable to coastal dwellers today, but it was the fate of a dense population of farmers living 7500 years ago around what is now the Black Sea.

Most humans have thankfully been spared such wild swings of weather and sea level, yet abrupt shifts in the physical environment have been far from rare in recorded history, and even small variations can inconvenience or threaten millions of people. The Long Summer has a fresh approach to the way we think about shifts in climate, both large and small, and how they have affected people. Indeed, Brian Fagan takes the view that climate change has fundamentally shaped the course of civilisation. This is his third book on the topic (his earlier works examined floods and the Little Ice Age) and in it he uses the unprecedented accuracy of newly recovered records of past climates to flesh out his theory. The data Fagan brings to bear on his thesis are in some instances truly remarkable; the record for some regions provides something very close to a year-by-year account of the way the seasons, rainfall and temperature have varied over thousands of years. For the most part, however, the record is far less detailed, and in a few critical instances it’s almost non-existent.

The book’s title refers to the last ten thousand years of Earth history, known as the Holocene Period, which climatologists have often – with some justification – characterised as a period of exceptional warmth and stability. Perhaps in order to give us an idea of what conditions were like before the arrival of this long summer, Fagan begins his analysis in the alien world of the last Ice Age, around eighteen thousand years ago. Then, sea levels were more than 90 metres lower than they are today, and what are now densely populated regions of North America and Europe lay under kilometres of ice. Even areas lying south of the ice, such as central France, were treeless sub-arctic deserts, with a growing season of just eight weeks. It appears from Fagan’s account that Ice Age summers hardly justify the name, for their brief sixty days were an alternation of relentless, freezing northerly winds with a few still days when a stifling haze of glacial dust filled the air.

In comparison with such miserable conditions, the Holocene was, I suppose, some sort of long summer; but the fluctuations documented by Fagan make it clear that it was the kind of summer that can offer four seasons in a single day, all too often creating an unimaginable hell for those forced to endure the extremes. Fagan uncovers enough droughts, snap-freezes and floods during this supposed heyday of balminess to spawn enough famines, plagues and wars to see off half the Earth’s human population. Yet the capacity of such events to disrupt lives forms just one thread of Fagan’s argument, which is developed alongside two innovative hypotheses. ‘Climate,’ he writes on his final page, ‘has helped shape civilisation, but not by being benign.’ In many ways this is a climatic version of ‘what doesn’t kill you makes you stronger’; but it also represents a novel approach, for until now archaeologists have been more inclined to point to the warmth and stability of the Holocene as a key factor in allowing the establishment of cities and empires. His second hypothesis, introduced in the book’s opening pages, involves our increasing vulnerability to climatic events: ‘In our efforts to cushion ourselves against smaller, more frequent climate stresses, we have consistently made ourselves more vulnerable to rare but larger catastrophes. The whole course of civilisation . . . may be seen as a process of trading up on the scale of vulnerability.’ It is in the interplay between these three truly big, and sometimes seemingly contradictory ideas that the tension of Fagan’s work unfolds.

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