THE POLAR GARDEN - Tambora: The Eruption that Changed the World - page 69

variability of climate and that, accordingly, we should think nothing of the catastrophic ice
declines of the early twenty-first century.
What caused the breakup of the polar ice cap in 1817 that to Sir Joseph Banks was so
“inexplicable”? What were the strange “new sources of warmth” that held out the tantalizing
promise of an open polar sea? As the recent scientific literature on volcanism and climate
clearly describes, Tambora's massive eruption in 1815 precipitated—through an extended
physical chain ofdynamic events involving earth, sea, and sky—a freak, drastic, but temporary
diminution of Arctic sea ice well outside the bounds of normal variability. Fossil-fuel emis-
sions of our industrial age have the same warming impact on the Arctic as volcanic sulfate
aerosols (albeit by different mechanisms), but the influence of volcanic dust possesses the de-
cided advantage—to the Arctic and to humanity—of disappearing after a few years. Twenty-
first-century anthropogenic warming, by contrast, has no foreseeable time horizon and has set
us on an inexorable course, like the heedless explorers of yore, toward a once unimaginable
ice-free polar sea.
GLOBAL WARMING, NINETEENTH-CENTURY STYLE
In the wake of the bloody, manic conclusion to Hamlet 's revenge plot, the fallen prince's
friend Horatio, surveying the Danish throne room littered with corpses, promises to “speak to
the yet unknowing world / How these things came about.” It's a difficult task given the con-
fusion of what has just happened. Horatio alludes to “unnatural acts” and “accidental judg-
ments,” to “casual slaughters” and “purposes mistook.” 3 In short, he emphasizes the contin-
gency of events that have led to the royal massacre. The Tambora period, as I am chronicling
that global tragedy in this topic, is rife with such highly contingent events. The sudden out-
break of epidemic cholera in Bengal, for example, and the boom in opium production in the
“golden triangle” region of southwest China post-1815 depended on a multitude of causes
converging over time with an initial, triggering climate change event.
No episode in these calamitous years better conforms to Horatio's description, however,
than the British Admiralty's decision to embark on a doomed quest for the northwest passage
in 1818. Moreover, in Admiralty secretary John Barrow, we find an historical actor whose
“accidental judgments” and “purposes mistook”—not to mention “unnatural acts” of journ-
alistic propaganda—gave rise to a noble but ultimately tragic and fruitless Arctic adventure
played out on the nineteenth-century stage.