How long does it take for the ocean conveyor to circulate?
According to NOAA It takes almost a 1000 years to complete a cycle. I am not sure how accurate, or where the citation came from their information so take it with a grain of salt. Lecture notes from one of Columbia University's 2007 "The Climate System" class suggests this process takes between 100-1000 years. This paper says Thermohaline Circulation overturns deep water every 600 years or so.