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compared to the model for the present (see Figure 2.24(a)), we can
state that the global anomaly remains positive over Europe. Therefore,
by imposing a melting rate, this model shows much strong feedback
between the ice and the ocean-atmosphere climate system with a
significant lessening of warming in Europe, but it does not reverse the
warming tendency, as some other dynamic models suggest.
Figure 2.24.
Anomalies in annual global temperature calculated by the coupled
ocean-atmosphere model in a simulation in which the concentration of CO
2
is
doubled with an imposed melting rate for ice. Map of the difference after 500 years
with the temperature of the model for the present state 9 a), map of the difference
after 500 years with a coupled simulation without ice melting 9 b) (© Didier
Swingedouw (LSCE/IPSL, CEA/CNRS/ UVSQ)) (see color section)
2.5. Some questions for the future
Observations of temperature, salinity, and carbon show that the
ocean is in the process of slowly accumulating anomalies linked to
modifications in the climate. On a global scale, the ocean is warming,
with signs that are well marked in the first 700 m but difficult to detect
at depth. The penetration of surface disturbances at depth depends on
phenomena that renew the waters of the interior ocean: thus the depth
reached by the anomalies in warming and anthropic carbon is maximal
in the subpolar regions of the North Atlantic. In the same way, regions
of subduction are also particularly important for accelerating the
penetration of signals in the deep ocean. The oceanic observations
however remain difficult to interpret: very few long oceanic series, for
several decades, exist; this length of time is necessary to construct a
chronology long enough to distinguish a tendency toward warming
from natural variability, which has a very rich spectrum, notably on
