2.3. The economic model
The air-sea CO2 exchanges are regarded in this study as
additional, spatially distributed, sources (or sinks) of the ecosystem
service which translate into a cost (or benefit) for society by
building up (or reducing) the concentration of greenhouse gases in
the atmosphere that are responsible for climate change (please
note that due to the customary usage of the terms in the carbon
literature, we refer in this paper to ‘‘sources’’ and ‘‘sinks’’ of carbon,
respectively as areas of carbon release and storage. Strictly
speaking, however, an area of carbon storage (release) is a source
(sink) area for the ecosystem service of carbon sequestration). The
microeconomic valuation of the benefits of carbon sequestration
relies on the use of values per unit of carbon, which are multiplied
by the carbon flux estimates resulting from the biogeochemical
model to obtain a spatially explicit estimate of the flow of values.
The flow of economic value obtained from carbon sequestration
(V0) during a specific period of time (t0, t1) and in a specific sea
surface area (A) can thus be calculated as follows: