Originally posted by majic
"When Gulfstream is covered with a layer of fresh water, it will never make it to the top - no matter how warm the saline water, it will be heavier than fresh one. "
No heat exchange between fresh and saline?
It's a matter of degree. You do not need to stop the heat exchange to make things cooler - just slow it down. Of course there is a phase transition events - since the greater loop of a heat exchange from tropics to north atlantic is driven by heat exchange between salt water and air up there, once the later slows down enough the former will stop abruptly - there will be no more heat coming in.
With all that tropical heat not coming into polar regions polar ice cap will stop thawing and start growing while the fresh water layer slowly mixes in and/or freezes untill there is no more of it in few centuries time. Than Gulfstream will probably slowly restart and begin the next cycle.
miko