What is Thermohaline circulation driven by?
Therm means temperature and haline means salinity ( salt content).Thermohaline circulation is driven by change in temperature and salinity.
Due to change in temperature the water near equator gets more hot and less dense , this causes it's movement upward towards the poles.
At poles where the salinity increases due to ice formation, the water becomes more dense and falls back towards equator . More precisely it's the density which derives it.