Ocean Acidification and its Consequences - Ocean in the Earth System - page 203

If the Ω a and pH greatly diminish over the course of this century in
the reference scenarios, this decrease is much less pronounced, and
even turns into an increase when mitigation is implemented. This
indicates without any ambiguity that mitigation is a very efficient way
to limit ocean acidification.
Figure 5.6. Long-term impact of CO 2 emissions of the 21st Century on the saturation
in aragonite estimated by the NCAR CSL1.4-carbon model. The three scenarios used
are the following: no CO 2 emission from 2000 (blue), high emissions according to
SRES A2 until 2100 and no emission afterward (red) and moderate emissions
according to SRES B1 until 2100 and no emission afterward (black). According to
[JOO 11] (see color section)
Another important piece of information provided by models
involves the inertia of the carbon cycle and its consequences on the
long-term evolution of the carbonate chemistry. Simulations in which
the emissions of carbon and other greenhouse gases are abruptly
brought down to 0 in 2000 or 2100 allow us to investigate the
commitment of past releases (Figure 5.6, [JOO 11]). These scenarios
are not realistic but allow us to evaluate the persistence over time of
the consequences of past emissions. In the first scenario, there is no
CO 2 release beyond the year 2000. In the second scenario, emissions
are high (SRES A2) until 2100 and are nil beyond 2100. Finally, in
the third scenario, emissions are moderate (SRES B1) until 2100 and
nil beyond that year. The first outcome of this study confirms that the
average value of Ω a in surface waters varies proportionally to CO 2