Figure 4-2: Schematic illustration
of the global circulation system in the world ocean consisting of major north-south
thermohaline circulation routes in each ocean basin joining in the Antarctic
circumpolar circulation. Warm surface currents and cold deep currents are connected
in the few areas of deepwater formation in the high latitudes of the Atlantic
and around Antarctica (blue), where the major ocean-to-atmosphereheat transfer
occurs. This current system contributes substantially to the transport and redistribution
of heat (e.g., the poleward flowing currents in the North Atlantic warm northwestern
Europe by up to 10°C). Model simulations indicate that the North Atlantic
branch of this circulation system is particularly vulnerable to changes in atmospheric
temperature and in the hydrological cycle. Such perturbations caused by global
warming could disrupt the current system, which would have a strong impact on
regional-to-hemispheric climate. Note that this is a schematic diagram and it
does not give the exact locations of the water currents that form part of the
THC.
