With Speed and Violence Fred Pearce - Global Commons Institute

But that doesn't mean that the Arctic tells the whole story. What pulled
the world out of the Younger Dryas, for instance—an event that happened
even faster than its onset? And while big climate change during and at the
close of the ice ages does seem to be associated with polar events, the
evidence concerning climate change since is far less secure. Thompson
argues that most of the global climatic shudders of the Holocene, such as
events 5,500 and 4,200 years ago, must have been tropical in origin: "In
climate models, you can only make such things happen in both the Northern
and Southern Hemispheres by forcing events from the tropics, and I am
convinced that is what is happening."
Hockey-stick author Mike Mann, though not a fully paid-up member of
the tropical school, says: "I increasingly think that the tropical Pacific is the
key player. When you see La Nina dominating the medieval warm period
and El Nino taking hold in the little ice age, it begins to look like the tropics,
rather than the North Atlantic, rule." The argument is that heat flows from
the tropics are the true intermediaries between Bond's solar pulse and
temperature fluctuations in the North Atlantic.
The tropical school also accuses the polar fraternity of being blinkered
about what constitutes climate change. Besides overly focusing on events in
North America and Europe, it stands accused of being overly concerned with
temperature. In the tropics, the hydrological cycle matters more than the
temperature. Megadroughts are as damaging as little ice ages, and the rains,
rather than extra warmth, bring plenty. Witness the drying of the Sahara
5,500 years ago, and the importance of the vagaries of the Asian monsoon.
The tropical school doesn't stop there. Its adherents argue that many of
the big climatic events in the Northern polar regions have their origins in the