18.2. Adaptation Characteristics and Processes
Adaptation refers both to the process of adapting and to the condition
of being adapted. The term has specific interpretations in particular disciplines.
In ecology, for example, adaptation refers to changes by which an organism or
species becomes fitted to its environment (Lawrence, 1995; Abercrombie et
al., 1997); whereas in the social sciences, adaptation refers to adjustments
by individuals and the collective behavior of socioeconomic systems (Denevan,
1983; Hardesty, 1983). This chapter follows Carter et al. (1994), IPCC
(1996), UNEP (1998), and Smit et al. (2000) in a broad interpretation
of adaptation to include adjustment in natural or human systems in response
to experienced or future climatic conditions or their effects or impactswhich
may be beneficial or adverse.
18.2.1. Components and Forms of Adaptation
As both a process and a condition, adaptation is a relative term: It involves
an alteration in something (the system of interest, activity, sector, community,
or region) to something (the climate-related stress or stimulus). Description
of an adaptation requires specification of who or what adapts, the stimulus
for which the adaptation is undertaken, and the process and form it takes (Downing
et al., 1997; Krankina et al., 1997; UNEP, 1998; Pittock et
al., 1999; Risbey et al., 1999; Reilly and Schimmelpfennig, 2000).
These elements are summarized in Figure 18-2 and addressed
in turn in subsequent subsections.
18.2.2. Climate Stimuli for Adaptation
Figure 18-2: Adaptation to climate change and variability
(from Smit et al., 2000).
Figure 18-3: Climate change, variability, extremes,
and coping range (after Hewitt and Burton, 1971; Fukui, 1979; Smit et
al., 1999; and others).
Most impact and adaptation studies to date have been based
on climate change scenarios that provide a limited set of possible future climatesinvariably
specified as average annual conditions, such as temperature and moisture. Yet
the climate change-related stimuli for which adaptations are undertaken (i.e.,
adaptation to what?) are not limited to changes in average annual conditions;
they include variability and associated extremes. Climatic conditions are inherently
variable, from year to year and decade to decade. Variability goes along with,
and is an integral part of, climate change (Mearns et al., 1997; Karl and
Knight, 1998; Berz, 1999; Hulme et al., 1999): A change in mean conditions
actually is experienced through changes in the nature and frequency of particular
yearly conditions, including extremes (see Figure 18-3).
Thus, adaptation to climate change necessarily includes adaptation to variability
(Hewitt and Burton, 1971; Parry, 1986; Kane et al., 1992b; Katz and Brown,
1992; Downing, 1996; Yohe et al., 1996; Smithers and Smit, 1997; Smit et
al., 1999). Downing et al. (1996), Etkin (1998), Mileti (1999), and
others use the term "climate hazards" to capture those climate stimuli,
in addition to changes in annual averages, to which the system of interest is
vulnerable. Climate change stimuli are described in terms of "changes in
mean climate and climatic hazards," and adaptation may be warranted when
either of these changes has significant consequences (Downing et al., 1997).
In water resource management, changes in the recurrence interval of extreme conditions,
which are associated with changes in means, are the key stimuli (Beran and Arnell,
1995; Kundzewicz and Takeuchi, 1999).
Figure 18-4: Classification of adaptation options
Furthermore, for most systems and communities, changes in the mean condition
commonly fall within the coping range (see Figure 18-3),
whereas many systems are particularly vulnerable to changes in the frequency
and magnitude of extreme events or conditions outside the coping range (Baethgen,
1997; Schneider, 1997; Rayner and Malone, 1998; Kelly and Adger, 1999). Interannual
variations are key stimuli in many sectors (Rosenzweig, 1994; Adams et al.,
1995; Mearns et al., 1997; Bryant et al., 2000).
Natural and human systems have adapted to spatial differences in climate. There
also are examples of adaptation (with varying degrees of success) to temporal
variationsnotably, deviations from the annual average conditions on which
climate change scenarios focus. Many social and economic systemsincluding
agriculture, forestry, settlements, industry, transportation, human health,
and water resource managementhave evolved to accommodate some deviations
from "normal" conditions, but rarely the extremes. This capacity of systems
to accommodate variations in climatic conditions from year to year is captured
in Figure 18-3 in the shaded "coping range." This capacity
also is referred to as the vulnerability or damage threshold (Pittock and Jones,
2000). The coping range, which varies among systems and regions, need not remain
static, as depicted in Figure 18-3. The coping range itself
may change (move up or down, expand or contract), reflecting new adaptations
in the system (De Vries, 1985; de Freitas, 1989; Smit et al., 2000).
The coping range indicated in Figure 18-3 can be regarded
as the adaptive capacity of a system to deal with current variability. Adaptive
capacity to climate change would refer to both the ability inherent in the coping
range and the ability to move or expand the coping range with new or modified
adaptations. Initiatives to enhance adaptive capacity (Section
18.6) would expand the coping range.
18.2.3. Adaptation Types and Forms
Adaptations come in a huge variety of forms. Adaptation types (i.e., how adaptation
occurs) have been differentiated according to numerous attributes (Carter et
al., 1994; Stakhiv, 1994; Bijlsma et al., 1996; Smithers and Smit,
1997; UNEP, 1998; Leary, 1999; Bryant et al., 2000; Reilly and Schimmelpfennig,
2000). Commonly used distinctions are purposefulness and timing. Autonomous
or spontaneous adaptations are considered to be those that take placeinvariably
in reactive response (after initial impacts are manifest) to climatic stimulias
a matter of course, without the directed intervention of a public agency. Estimates
of these autonomous adaptations are now used in impact and vulnerability assessment.
Planned adaptations can be either reactive or anticipatory (undertaken before
impacts are apparent). In addition, adaptations can be short or long term, localized
or widespread, and they can serve various functions and take numerous forms
(see Table 18-1).
Adaptations have been distinguished according to individuals' choice options
as well, including "bear losses," "share losses," "modify
threats," "prevent effects," "change use," and "change
location" (Burton et al., 1993; Rayner and Malone, 1998). The choice
typology has been extended to include the role of community structures, institutional
arrangements, and public policies (Downing et al., 1997; UNEP, 1998; see
|Table 18-1: Bases for characterizing and differentiating
adaptation to climate change (Smit et al., 1999).
Concept or Attribute
Examples of Terms Used
Retreat - Accommodate - Protect
Prevent - Tolerate - Spread - Change - Restore
Structural - Legal - Institutional - Regulatory - Financial
Cost - Effectiveness - Efficiency - Implementability -