With Speed and Violence Fred Pearce - Global Commons Institute

The idea that the South may lead in this particular dance gained ground
late in 2005, when results were published from new ice cores in Antarctica.
A European group found that the tightest "coupling" between temperature
and carbon dioxide levels in the atmosphere is to be found in Antarctic cores,
rather than their Greenland equivalents. "The way I see things is that the
tropics and Antarctica are in phase and lead the North Atlantic," says Peter
deMenocal, of Lamont-Doherty. "Even though we may see the largest events
in the North Atlantic, they are often responding, not leading." By this
reading, the onset of the Northern glaciation may have its origins in the
Southern Hemisphere.
This apparently obscure debate could matter a great deal in the
twenty-first century. Right now, the world has become worried that melting
ice in the Arctic could freshen the far North Atlantic and shut down the Gulf
Stream. This is a real fear. But maybe, while we are researching that
possibility, we are ignoring the risk that large stores of freshwater in the
Antarctic might break out and disrupt deepwater formation there. Arguably,
the risks are far greater in the South, where, besides the potential breakout
of ice from Pine Island Bay, recent radar mapping studies have revealed a
large number of lakes of liquid water beneath the ice sheets of Antarctica.
They might set off a cascade of freshwater into the Southern Ocean, similar
in scale to the emptying of Lake Agassiz. Yet nobody, so far as I am aware,
has studied what the effects of such a breakout might be for deepwater
formation and the Southern arm of the ocean conveyor.
Or, rather than shutting down deepwater formation in Antarctica, might
we be about to trigger a switch in the bipolar seesaw, so that deepwater
formation in the South takes over from that in the far North? Could that