The Gulf Stream and the Next Ice Age
Nikolaus Koutsikas (2008)
This documentary examines the climatic effects of the Gulf Stream, which was first charted and named by Benjamin Franklin in 1762. This is a powerful current that transports warm water from the Gulf of Mexico to the west coast of France, Britain and Norway. It’s thanks to the Gulf Stream (aka the North Atlantic Drift, aka the Thermohaline Conveyor) that western Europe enjoys far milder winters that parts of Canada at the same latitude.
Paleoclimatologists who collect ocean sediment and ice core samples have been studying past disruptions of the Thermohaline Conveyor going back 100,000 years. They’ve identified a clear pattern in which the Conveyor “turns off” in response to rapid warming periods that cause the Arctic and Greenland ice sheets to melt. This in turn has triggered mini ice ages in which all of northern Europe experiences Siberian winters.
The mechanism that causes the Conveyor to turn off is apparently triggered by the rapid influx of fresh water into the North Atlantic. Under normal conditions, the Conveyor is driven by sharp temperature differentials when abrupt Arctic cooling causes it to sink rapidly, sucking in warm water above it.
Fresh water behaves differently than salt water (it doesn’t sink). According to ice core records, rapid influxes of fresh water from ice melts repeatedly switched the Conveyor off and on until about 10,000 years.
Surprisingly the risk of the Conveyor “turning off” in response to global warming has received little attention in recent publicity about impending catastrophic climate disruption. Apparently the Pentagon takes it very seriously. In 2003, they issued a report about the threat a new European Ice Age poses to national security.
It’s impossible to predict exactly how much ice has to melt before the Conveyer shuts off. The 2003 Pentagon report predicted a worse case scenario in which it might shut off in 2010. Obviously this didn’t happen. However in 2008 when this film was made, scientists had already detected a slight decrease in salinity and a gradual slowing of the current.
Most climatologists feel the Conveyor is unlikely to shut off before the Arctic Ice cap melts. Some are predicting the Arctic will be ice free in summer by 2020.
Record cold winters in the North Atlantic suggest slowing of the Conveyor has already begun: What’s Going on in the North Atlantic