ICE TSUNAMI IN THE ALPS - Tambora: The Eruption that Changed the World - page 95

writes, “date from a period lost in the mists of time.” Therefore, by a simple but crucial step
of logic, he must infer that “temperature rises and falls periodically, though in an irregular
cycle.” 23 Climate change, Venetz concludes, has driven an historical cycle of glaciation, which
in turn has left its indelible mark on the geological formation of the Alps and by implication
the European continent. Amazingly, Venetz's historic 1821 paper was not published for an-
other twelve years, by which time Jean de Charpentier, after his own protracted period of
doubtful rumination, had taken up the cause. After seeing to the publication of Venetz's pa-
per, he promoted its conclusions in a far more widely read article of his own published in
1834, at which point the new glacial theory came to the attention of the new head of the
Swiss Society, Charpentier's onetime protégé Louis Agassiz. 24
We can wonder at how the course of nineteenth-century science might have been different
had Venetz possessed skills of argument and self-promotion equal to his resourcefulness as an
engineer and geological theorist. But rarely does such a combination of talents reside with
one individual. More curious, therefore, and more profitable, is to speculate upon how it was
that Venetz was converted to the radical glacialist theories of Jean-Pierre Perraudin in the af-
termath of the Val de Bagnes deluge, when so many other observers saw in that event only a
confirmation of the received wisdom—that a diluvian catastrophe had shaped the geological
history of the Alps. On what grounds did Venetz come to the opposite conclusion and thus
initiate the slow march toward the scientific truth of glaciation?
Where casual or more distant observers had seen proof of diluvian theory, Venetz had the
benefit of close examination of the gorge and hillsides of the Val de Bagnes impacted by the
violent deluge. There he found no new striations on the surface of rocks. While it was true the
rushing tide of water had left moraine-like lines of debris at high elevation and had displaced
rocks in large quantities, neither of these actions was on a scale to allow him to persist in the
belief that water or mud alone could have been the agent of Alpine formation. With flooding
eliminated, only a theory of glacial transport remained.
Though Venetz left no detailed account of the progress of his discoveries, there must have
been a day, in 1819 or 1820, when his thoughts returned to his dramatic summer in the Val
de Bagnes. There, amid all the pressures of the dam crisis on the River Dranse that it was his
professional duty to resolve, his eccentric local guide had pestered him with wild ideas about
mile-high glaciers. In the urgent anxiety of those days, he had paid them little mind. But now,
as he cast his eye across the devastated valley with its unrecognizable, moon-like terrain, he
must have realized that Jean-Pierre Perraudin was right. One couldn't rely on the evidence of
one's senses or on mere common sense. The Earth was capable of radical and total transform-
ation, a fact that required a great leap of imagination to accept. After the close-up, traumatic,
life-changing experience of the Val de Bagnes debacle, Venetz was ready to make that leap.
It took a village to derive the modern theories of climate change and the Ice Age.
Isolated speculations on glacial theory in prior decades by James Hutton and others had gone
nowhere, lost in that strange historical limbo of unrecognized truths. The chance meeting of
Perraudin, Venetz, and Charpentier in the cold Tamboran spring of 1818 lit the initial fuse
of speculation, while a second crucial meeting of glacialist minds occurred almost two dec-
ades later in the summer of 1836 when Louis Agassiz arrived with his family for a holiday at
Charpentier's mountain chalet at Bex. Charpentier had been careful to invite Venetz to join
them, and after several all-night disputations on Alpine geology, the three men decided on a