The Amocs Role In Heat Transport Oceanic Uptake Of Carbon And Ventilation Of The Deep Ocean

The Earth's surface takes up heat by absorbing solar short-wave radiation. On a global average this is almost exactly balanced by the Earth's emission of long-wave radiation. Regional budgets of radiative energy fluxes, however, are unbalanced, as they show pronounced heat gain at low latitudes opposing to heat loss at high latitudes [27]. One-quarter of the 5 Pw7 of maximum global heat transport that the coupled ocean atmosphere system is required to transport poleward in the Northern Hemisphere to approximately balance regional energy budgets is carried by the AMOC in the Subtropical North Atlantic [27]. While most of the remaining three quarters of the heat transport is accomplished by the atmosphere, the AMOC is by far the most important oceanic component of meridional heat transport.

The steady increase in atmospheric CO2 is widely regarded as one of the main drivers of the presently ongoing global warming. Exceeding the atmosphere in terms of carbon storage by more than a factor of 50 [28], the oceans exchange gases with the atmosphere. The CO2 solubility in sea water

7 1 Pw 1 x 1015 W; 5 Pw correspond to the output of 5 000000 power stations.

increases with decreasing temperatures. The NADW formation at high latitudes, acting to increase carbon concentrations at depth is considered a major element in the ocean's carbon uptake ('solubility pump'). Changes in the strength and spatial structure of the AMOC might affect atmospheric CO2 concentrations and thus global temperatures.

The flow of well oxygenated near-surface water to the deep ocean that goes along with the NADW formation at high latitudes and its subsequent export to the world ocean help to maintain the deep ocean basins as habitats for a diverse biota. This is probably the least known component of biodiversity on Earth. Substantial changes in the rate of deep-water ventilation by the AMOC are thus expected to have consequences for deep-ocean habitats.

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