6.7. Synthesis and Integration
This chapter is concerned with two closely related but geographically different
environments. The oceanswhich cover more than 70% of the Earth's
surfaceare open, expansive, and spatially continuous. By contrast, coastal
zones are long, narrow, and discontinuous. As a result, climate change impacts
on marine ecosystems may be accommodated more readily in the open ocean (e.g.,
by migration) than in coastal regions, where mobility is restricted, there are
more environmental constraints, and human impacts may be more severe.
Figure 6-2: The role of natural and human adaptive capacity and resilience
on the socioeconomic impacts of climate change following climate forcing,
sea-level rise, and nonclimate forcing. The equity arrow in the bottom box
indicates that impacts will not be uniform and that there will be wide inequalities,
depending on socioeconomic conditions.
The potential biological and physical impacts of climate change and sea-level
rise vary considerably between the oceans and coastal regions. The least vulnerable
coastal and marine ecosystems have low exposure or high resilience to the impacts.
Similarly, coastal communities and marine-based economic sectors that have low
exposure or high adaptive capacity will be least affected. Countries, communities,
and individuals in the higher range of economic well-being have access to technology,
insurance, construction capital, transportation, communication, social support
systems, and other assets that enhance their adaptive capacity. Those that do
not have access have limited adaptive capacity. Unequal access to adaptation
options, therefore unequal vulnerability, are attributable largely to different
socioeconomic conditions. Poor adaptation or "maladaptation" also
may lead to increased impacts and vulnerability in the future, with implications
for intergenerational equity. These concepts are summarized in Figure
Whereas the estimated costs of sea-level rise and other climate-related impacts
in developed countries typically are limited to property losses, the reported
outcomes of coastal floods in developing countries often include disease and
loss of life. Vulnerability assessments in the developing world often do not
consider the costs of business interruptions and failures, social disruption
and dislocation, health care, evacuation, or relocation. A full accounting of
the economic costs associated with lost, diminished, or disrupted lives would
require estimates of the economic productivity losses they represent. Because
this level of cost accounting is rare in developing countries, inequities may
be significantly underestimated.
Turner et al. (1996) note that coastal zones are under increasing stress
because of an interrelated set of planning failures, including information,
economic market, and policy intervention failures. Moreover, moves toward integrated
coastal management are urgently required to guide the co-evolution of natural
and human systems. Acknowledging that forecasts of sea-level rise have been
scaled down, they note that (1) much uncertainty remains over, for example,
combined storm-surge and other events; and (2) within the socioeconomic analyses
of the problem, resource valuations have been only partial at best and have
failed to incorporate sensitivity analysis in terms of the discount rates utilized.
They suggest that these factors would indicate an underestimation of potential
damage costs and conclude that a precautionary approach is justified, based
on the need to act ahead of adequate information acquisition and use economically
efficient resource pricing and proactive coastal planning.
More recently, Turner et al. (1998) have aimed to elicit the main forces
influencing the development of coastal areas and the means available to assess
present use and manage future exploitation of the coastal zone. Their way of
analyzing coastal change and resource management is through the pressure-state-impact-responses
(P-S-I-R) conceptual framework. They analyze a variety of pressures and trends
(including climate change, population changes, port development, marine aggregate
extraction, and pollution). In the P-S-I-R framework, all of these factors are
examined in the context of sustainable use of coastal resources and on the basis
of an interdisciplinary ecological economics approach.
Several changes that might be expected to accelerate with global warming in
the future already are detected in some regions and systems. Examples include
global sea-level rise, increases in SST, and regional decreases in sea-ice cover.
Impacts associated with these changes have included shoreline erosion, wetland
loss, seawater intrusion into freshwater lenses, and some impacts on coral reefs.
These impacts provide contemporary analogs for potential impacts in the future,
recognizing that future changes and impacts may be of greater magnitude than
those experienced so far and that changes and impacts may become more geographically
widespread, including expansion into new areas that have not experienced such
conditions previously. The contemporary environment gives us some insights into
potential ecosystem impacts, some idea of costs, and some experience with potentially
useful adaptation strategies.
We have found very few studies that indicate benefits of climate change and
sea-level rise in coastal and marine systems. Recent studies, however, point
to possible economic benefits from adaptation measures. Such benefits are likely
to be restricted, particularly in the areas most at riskincluding a large
number of developing countries. Furthermore, the extent of impacts in those
regions and the range of potentially effective adaptation measures remain poorly
defined. Although there is growing acceptance of the need for integrated management
strategies, progress has been slow in implementing these concepts in many jurisdictions.
Part of the reason is limited development of understanding and tools for integrated
assessment and management needs, involving various levels and aspects of integration,
each of which may be difficult to implement. For instance, integration between
the different disciplines involved in coastal and marine impact and adaptation
analysis has been identified as a key issue by Capobianco et al. (1999).
This and other integration needs are summarized in Box 6-7.
Box 6-7 Integration for Assessment and Management of
Marine and Coastal Systems
Integration of marine, terrestrial, and coastal processes and a better
understanding of their interactions with human development could lead
to substantial improvements in the quality of adaptation strategies. Integration
must take place in several areas, including the following:
- Subject/topic-area integration (e.g., climate-change
related stresses plus non-climate stresses; biophysical and socioeconomic
susceptibility, resilience, vulnerability, impacts)
- Geographical/spatial integration (e.g., linkages between
terrestrial, coastal, and oceanic systems and feedbacks; global, regional,
- Methodological integration (e.g., integrating physical,
social, and economic models)
- Integrated implications (e.g., for sustainable development,
intergenerational equity and ethics)
- Integration of science, impacts, and policy.
Estuaries as an example of the need for integration
Changes in salinity, temperature, sea level, tides, and freshwater inflows
to estuaries are considered likely consequences of climate change on estuarine
systems. Estuaries are among the world's most-stressed ecosystems
because of their close proximity to areas of population growth and development.
Understanding of regional differences in the physical drivers that will
cause changes in estuarine ecosystems and their ecological functions is
limited. Uncertainty also exists regarding changes to dissolved carbon,
nutrient delivery and pollutant loading, and their interactions. For example,
intensive forestry and agriculture that may be implemented as some regions
adapt to climatic change could increase the transport of nutrients such
as nitrogen and phosphorus to estuaries. Linkage of hydrological models
for surface waters with ocean-atmosphere models is needed to integrate
marine and terrestrial ecosystem change. Estuaries illustrate the need
for vertical integration among the foregoing subject areas and issues,
spatial scales, and methodological approaches, with implications for habitation
and use of coastal environments and ecosystems.
Some progress has been made since the SAR in developing and refining methodologies
for assessing impacts of sea-level rise. Environments under particular threat
include deltas, low coastal plains, coastal barriers, heavily utilized seas,
tropical reefs and mangroves, and high-latitude coasts where impacts from warming
may occur sooner or more rapidly.
Some topic areas rarely have been addressed, however. For instance, only a
few case studies attempt to integrate potential impacts of sea-level rise and
increased precipitation and runoff in coastal watersheds in assessing coastal
vulnerability. Techniques for similar integration between biophysical and socioeconomic
impacts are developing slowly, while human development and population growth
in many regions have increased socioeconomic vulnerability and decreased the
resilience of coastal ecosystems. Few studies provide details or any quantitative
measures. We believe that integrated assessment and management of open marine
and coastal ecosystems and a better understanding of their interaction with
human development could lead to improvements in the quality of sustainable development
Global climate change will affect the biogeophysical characteristics of the
oceans and coasts, modifying their ecological structure and affecting their
ability to sustain coastal residents and communities. Impacts in the coastal
zone will reflect local geological, ecological, and socioeconomic conditions
within a broader regional or global context. Shorelines are inherently dynamic,
responding to short- and long-term variability and trends in sea level, wave
energy, sediment supply, and other forcing. Coastal communitiesparticularly
on low-lying deltas, atolls, and reef islandsface threats of inundation,
increased flooding, and saltwater intrusion, with impacts on health and safety,
water supply, artisanal fisheries, agriculture, aquaculture, property, transportation
links, and other infrastructure. In some coastal areas, particularly in developed
nations, a shift in emphasis toward managed retreat appears to have gained momentum.
Enhancement of biophysical and socioeconomic resilience in coastal regions increasingly
is regarded as a cost-effective and desirable adaptive strategy. Growing recognition
of the role of the climate-ocean system in the management of fish stocks is
leading to new adaptive strategies that are based on determination of accepable
removable percentages in relation to climate change and stock resilience.
Vulnerability to climate change and sea-level rise has been documented for
a variety of coastal settings via common methodologies developed in the early
1990s; these assessments have confirmed the spatial and temporal variability
of coastal vulnerability at national and regional levels. New conceptual frameworks
include biophysical and socioeconomic impacts and highlight adaptation and resilience
as components of vulnerability. Recent advances include models to evaluate economic
costs and benefits that incorporate market and nonmarket values. Sustainable
approaches to integrated coastal management can now include new financial accounting
approaches that include ecological services and traditional cultural values.
Nevertheless, adaptive choices will be conditioned by policy criteria and development
objectives, requiring researchers and policymakers to work toward a commonly
acceptable framework for adaptation.