Climate & Environment
Thermohaline Circulation
Definition
Thermohaline circulation is the large-scale ocean circulation driven by differences in water density created by temperature (thermo) and salinity (haline): cold, salty water sinks at high latitudes and flows through the deep ocean, eventually upwelling elsewhere, in a global conveyor transporting heat, carbon and nutrients. Its Atlantic component, the AMOC, carries tropical heat northward, strongly shaping European climate; observations and models indicate the AMOC has weakened and faces risk of substantial decline or collapse this century under warming — a recognised tipping element.
References
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This reference provides supporting context for how “Thermohaline Circulation” is defined and used.
Overview
How it is used
The concept structures ocean monitoring programmes (RAPID array), IPCC tipping point assessment, and adaptation scenario planning for abrupt change.
Why it matters
The thermohaline circulation is the planet's central heating pump; its faltering is among the gravest low-probability, high-impact climate risks.