On Wed, 17 Feb 2016 10:59:21 +0000
John Hall wrote:

In message -jade, Graham P
Davis writes
One tipping point that may be worth considering is the one
associated with the bistable nature of the North Atlantic current
system. The NAD may flip from being a warm offshoot of the Gulf
Stream to a cold one sourced from the Labrador current. Over the
past week or so, I've been wondering whether this flip, which I read
about nearly fifty years ago, may be the result of surface water
salinity changes rather than the much-trumpeted Ocean Conveyor.

Interesting. Do we know roughly when previous flips may have occurred?

Sorry, I can't remember whether the book mentioned particular instances
and, if it did, when they were. It mentioned that the flips were
sudden and had been correlated to cold periods in the climate of NW
Europe. The data on the changes in current were derived, as
I recall, from foraminifera in ocean-bed cores whilst climate-change
data came from Greenland ice-cores. If any of this sounds familiar,
it's because the scientists in "The Big Chill" Horizon programme
claimed to have done the same thing for the first time - only they were
actually beaten to the punch by thirty years or more.

One reason why I'm doubtful of the theory that the reduction in
salinity of the deep currents causes a slowdown in the Gulf Stream is
that I was totally unimpressed by the scientists on the programme.
Claiming to have discovered things that nobody had seen before is
either dishonest or ignorant, whereas saying that the Gulf Stream
might stop altogether is just ignorant. When they got so much wrong
on the programme, I've begun to wonder why I ever thought they were
capable of getting one thing right. Still, stopped clocks are right
twice a day so anything's possible.

--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
http://www.scarlet-jade.com/
I wear the cheese. It does not wear me.
Posted with Claws: http://www.claws-mail.org/