Sunday, November 29, 2009

The Logic Escapes Me

The UK Guardian Newspaper reports today in headlines "Climate change: Gulf stream collapse could be like a disaster movie" reports on a study (? or was it just comments ... the Guardian's report does not say) by Bill Patterson of Saskatchewan University.
"The next Ice Age could take only weeks to engulf Britain. Scientists say the last great disruption to the Gulf Stream 12,800 years ago took only a couple of months to trigger a massive plunge in temperatures across Europe."
The "trigger" in this case was:
"Such an event occurred 12,800 years ago when a vast lake – created from melting glaciers at the end of last Ice Age – overflowed and poured into the north Atlantic, blocking the Gulf Stream. Europe froze – almost instantly, said Patterson."
Mr Paterson is reported to have said:
"It was very sudden," added Patterson, "and it could happen again."
I suppose it could happen again. But what is the trigger event that could make it happen? Is there somewhere in the vicinity of the Atlantic or Arctic Oceans a vast lake that could flow into the sea? What are the threats which could cause it to "happen again".

This is a classic demonstration of the idea written here before about how people do not understand (or chose to understand) Risk. Risk is not just a situation. Risk is a threat, which causes something to happen, with results in impact.

The impact here is clear: the severe change in climate to be very cold in Northern Europe which we intuitively conclude would be a "huge" impact and a very "bad thing" indeed, caused by the shutdown of the Gulf Stream. [The Gulf Stream brings heat to Northern Europe from the Caribbean]. The "threat" or the "cause" in this scenario was "vast" freshwater lake that spilled into the sea. This makes sense.

But to "happen again" there has to be some cause that makes it happen. What are the possibilities that we can now imagine that could realistically or even unrealistically cause the Gulf Stream to shutdown? None are mentioned in this article--but we are made to be afraid because it could "happen again"!




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