Post by sublime on Sept 7, 2004 4:36:37 GMT -5
An excerpt from the following article:The Guardian - Will global warming trigger a new ice age?
Please also refer to this article from UCS which cites a Pentagon report on this issue: Abrupt climate change.
There is little doubt that if the Gulf Stream were to cease or weaken significantly, the temperature in North Western Europe would drop considerably. One wonders what effects such a climate change would have on Western Europe, especially in relation to its economies and security.
In the past, the slowing of the Gulf Stream has been intimately linked with dramatic regional cooling. Just 10,000 years ago, during a climatic cold snap known as the Younger Dryas, the current was severely weakened, causing northern European temperatures to fall by as much as 10 degrees. Ten thousand years before that, at the height of the last ice age, when most of the UK was reduced to a frozen wasteland, the Gulf Stream had just two-thirds of the strength it has now.
What's worrying is that for some years now, global climate models have been predicting a future weakening of the Gulf Stream as a consequence of global warming. Such models visualise the disruption of the North Atlantic Meridional Overturning Circulation (Namoc), including the Gulf Stream, as a result of large-scale melting of Arctic ice and the consequent pouring of huge volumes of fresh water into the North Atlantic, in a century or two. New data suggest, however, that we may not have to wait centuries, and in fact the whole process may be happening already.
What's worrying is that for some years now, global climate models have been predicting a future weakening of the Gulf Stream as a consequence of global warming. Such models visualise the disruption of the North Atlantic Meridional Overturning Circulation (Namoc), including the Gulf Stream, as a result of large-scale melting of Arctic ice and the consequent pouring of huge volumes of fresh water into the North Atlantic, in a century or two. New data suggest, however, that we may not have to wait centuries, and in fact the whole process may be happening already.
Please also refer to this article from UCS which cites a Pentagon report on this issue: Abrupt climate change.
Past changes in thermohaline circulation have occurred during periods of relatively rapid climate change, such as transitions in and out of glaciations. Similarly, the rapid warming we are currently experiencing could trigger an abrupt thermohaline shutdown and subsequent regional cooling. While a shutdown of thermohaline circulation is unlikely to occur in the next century, scientists have recently found that freshwater inputs have already caused measurable "freshening" of North Atlantic surface waters over the past 40 years. Human activities may be driving the climate system toward a threshold and thus increasing the chance of abrupt climate changes occurring.
There is little doubt that if the Gulf Stream were to cease or weaken significantly, the temperature in North Western Europe would drop considerably. One wonders what effects such a climate change would have on Western Europe, especially in relation to its economies and security.