Environmental Engineering Reference
In-Depth Information
Figure 1
The source areas and pathways of North Atlantic Deep
Water and North Atlantic Drift (Gulf Stream) and their impact on
European climate. During the depths of the last global cold stage
18,000 years ago, combined atmospheric and oceanic currents
positioned the 'Polar Front' well to the south of north-west Europe.
Catastrophic melting of the Greenland ice cap could re-create this
condition.
surface albedo. If this were not enough, oceanic processes are also coupled to the
North Atlantic Oscillation
(NAO). Meltwater cooling of SSTs increases meridional
temperature and pressure gradients, thus increasing cyclogenesis. Increased wind flow
boosts the latent and sensible heat transfers to the north-east Atlantic in turn, cooling the
ocean at the expense of land surfaces. This oscillation is normally reversed on decadal
time scales but there is a risk that the NAO could become locked into this mode.
In the next decade, global atmospheric warming is likely to exceed any cooling related
to reduced THC, which becomes less stable as it slows down. The
Intergovernmental
Panel on Climate Change
(IPCC) 2001 Third Assessment Report reveals that most
models show the Atlantic THC slowing down in the twentieth century in response to
global warming, and some even shut it down within 10
2-3
years if warming reaches 3·7-
7·4° C
If that were to happen
Europe could be plunged into a new Ice Age
with
