5.3.1.5. Littoral and Pelagic Zones
Littoral and pelagic zones often are forgotten in studies of climate change
impacts. However, important changes have already been observed (e.g., a significant
increase in average temperatures of the waters in the western Mediterranean
basin over the past 20-30 years) (Francour et al., 1994). Temperature changes
are reflected in substantial changes in the relative abundance of thermophilic
species; there have been increased catches of thermophilic fish species such
as Diplodus cervinus, Epinephus marginatus, Pomadasys incisus, Sphyraena
sphyraena, Balistes carolinensis, Sardinella aurita, and Pomatomus saltatrix.
5.3.1.6. Adaptation Options
Natural ecosystems may adapt to climatic change in one way or another-but not
necessarily in ways preferred by humans. Therefore, some kind of human intervention,
in the form of management, may be necessary. Adaptation options for forests
and plants could include the creation of refugia; migration corridors and/or
assisted migration; and improvements in integrated fire-, pest-, and disease-management
techniques. This approach poses problems in many parts of Europe, where ecosystems
have been so fragmented and the population density is so high that some of these
options may be impossible to implement. Reforestation would be a viable adaptation
option in some cases, as would afforestation of abandoned agricultural land-increasing
habitats and establishing corridors between fragmented nature reserves. For
wetlands and peatlands, reducing the impacts of climate change could be achieved
through wetland restoration or creation techniques; in boreal regions where
permafrost is a major feature of wetland ecosystems, however, such techniques
would not be of much use. Freshwater biological systems can be assisted in a
number of ways that could help mitigate the impacts of climate change, particularly
through the increase and protection of riparian vegetation and the restoration
of river and stream channels to their natural, adaptive morphologies. Such restoration
processes may take several decades.
For all ecological systems, the reduction of pollution and land-use stresses
in more heavily populated regions of Europe would contribute to removing major
stress factors. In some circumstances, this strategy might allow plants to adjust
more easily to the negative effects of climatic change.
An increasingly determined effort toward protection and revitalization of freshwater
ecosystems in developed countries already has shown positive achievements, particularly
through improvements in the water quality of watersheds. The protection of threatened
aquatic habitats such as wetlands has facilitated the reintroduction of several
endangered vertebrate species. This has been the case particularly in central
Europe as a consequence of increased awareness of environmental problems.
5.3.2. Agriculture and Fisheries
The impacts of climate change on agriculture can be defined at different scales-including
crop yield, farm or sector profitability, regional economic activity, or hunger
vulnerability. Impacts depend on biophysical and socioeconomic responses.
In the past decade, substantial amounts of research have focused on regional
and national assessments of the potential effects of climate change on agriculture.
Relatively little work, however, has included systematic assessments that identify
vulnerable socioeconomic groups, integrate effects across sectors, describe
impacts at different spatial and temporal scales, or address the efficacy of
the range of practical responses (see Parry et al., 1992). For the most part,
studies have treated each region or nation in isolation (see IPCC, 1996, for
a complete reference list of studies to date; see also Sirotenko et al., 1997),
without regard to changes in production in other places, and have not addressed
in an integrated way interactions with other related systems (e.g., water resources,
socioeconomy, policy). Global assessments of climate change impacts in agriculture
and agricultural markets have been few to date (Parry et al., 1988; Smit, 1989;
Martin et al., 1990; Kane et al., 1992; Rosenberg and Crosson, 1991; UK Department
of the Environment, 1991; Rosenzweig and Parry, 1994; Darwin et al., 1995).
In addition, a major shortcoming of most climate impact assessments has been
their lack of in-depth treatment of adaptation, in part because of its complexity
and in part because of the lack of a suitable methodological framework.
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