|
Anticipatory Adaptation in the Context of Current Policies and Conditions
A key message of the regional assessments in this report is that many systems
and policies are not well-adjusted even to today's climate and climate variability.
Increasing costs, in terms of human life and capital, from floods, storms, and
droughts demonstrate current vulnerability. This situation suggests that there
are adaptation options that would make many sectors more resilient to today's
conditions and thus would help in adapting to future changes in climate. These
options-so-called "win-win" or "no-regrets" options-could have multiple benefits
and most likely would prove to be beneficial even in the absence of climate
change impacts.
In many countries, the economic policies and conditions (e.g., taxes, subsidies,
and regulations) that shape private decision making, development strategies,
and resource-use patterns (and hence environmental conditions) hinder implementation
of adaptation measures. In many countries, for example, water is subsidized,
encouraging over-use (which draws down existing sources) and discouraging conservation
measures-which may well be elements of future adaptation strategies. Other examples
are inappropriate land-use zoning and/or subsidized disaster insurance, which
encourage infrastructure development in areas prone to flooding or other natural
disasters-areas that could become even more vulnerable as a result of climate
change. Adaptation and better incorporation of the long-term environmental consequences
of resource use can be brought about through a range of approaches, including
strengthening legal and institutional frameworks, removing preexisting market
distortions (e.g., subsidies), correcting market failures (e.g., failure to
reflect environmental damage or resource depletion in prices or inadequate economic
valuation of biodiversity), and promoting public participation and education.
These types of actions would adjust resource-use patterns to current environmental
conditions and better prepare systems for potential future changes.
The challenge is to identify opportunities that facilitate sustainable development
by making use of existing technologies and developing policies that make climate-sensitive
sectors resilient to today's climate variability. This strategy will require
many regions of the world to have more access to appropriate technologies, information,
and adequate financing. In addition, the regional assessments suggest that adaptation
will require anticipation and planning; failure to prepare systems for projected
changes in climate means, variability, and extremes could lead to capital-intensive
development of infrastructure or technologies that are ill-suited to future
conditions, as well as missed opportunities to lower the costs of adaptation.
Additional analysis of current vulnerability to today's climate fluctuations
and existing coping mechanisms is needed and will offer lessons for the design
of effective options for adapting to potential future changes in climate.
Regional Vulnerability to Global Climate Change
Africa
Several climate regimes characterize the African continent; the wet tropical,
dry tropical, and alternating wet and dry climates are the most common. Many
countries on the continent are prone to recurrent droughts; some drought episodes,
particularly in southeast Africa, are associated with ENSO phenomena. Deterioration
in terms of trade, inappropriate policies, high population growth rates, and
lack of significant investment-coupled with a highly variable climate-have made
it difficult for several countries to develop patterns of livelihood that would
reduce pressure on the natural resource base. Under the assumption that access
to adequate financing is not provided, Africa is the continent most vulnerable
to the impacts of projected changes because widespread poverty limits adaptation
capabilities.
Ecosystems: In Africa today, tropical forests and rangelands are under
threat from population pressures and systems of land use. Generally apparent
effects of these threats include loss of biodiversity, rapid deterioration in
land cover, and depletion of water availability through destruction of catchments
and aquifers. Changes in climate will interact with these underlying changes
in the environment, adding further stresses to a deteriorating situation. A
sustained increase in mean ambient temperatures beyond 1°C would cause significant
changes in forest and rangeland cover; species distribution, composition, and
migration patterns; and biome distribution. Many organisms in the deserts already
are near their tolerance limits, and some may not be able to adapt further under
hotter conditions. Arid to semi-arid subregions and the grassland areas of eastern
and southern Africa, as well as areas currently under threat from land degradation
and desertification, are particularly vulnerable. Were rainfall to increase
as projected by some GCMs in the highlands of east Africa and equatorial central
Africa, marginal lands would become more productive than they are now. These
effects are likely to be negated, however, by population pressure on marginal
forests and rangelands. Adaptive options include control of deforestation, improved
rangeland management, expansion of protected areas, and sustainable management
of forests.
Hydrology and Water Resources: Of the 19 countries around the world
currently classified as water-stressed, more are in Africa than in any other
region-and this number is likely to increase, independent of climate change,
as a result of increases in demand resulting from population growth, degradation
of watersheds caused by land-use change, and siltation of river basins. A reduction
in precipitation projected by some GCMs for the Sahel and southern Africa-if
accompanied by high interannual variability-could be detrimental to the hydrological
balance of the continent and disrupt various water-dependent socioeconomic activities.
Variable climatic conditions may render the management of water resources more
difficult both within and between countries. A drop in water level in dams and
rivers could adversely affect the quality of water by increasing the concentrations
of sewage waste and industrial effluents, thereby increasing the potential for
the outbreak of diseases and reducing the quality and quantity of fresh water
available for domestic use. Adaptation options include water harvesting, management
of water outflow from dams, and more efficient water usage.
Agriculture and Food Security: Except in the oil-exporting countries,
agriculture is the economic mainstay in most African countries, contributing
20-30% of GDP in sub-Saharan Africa and 55% of the total value of African exports.
In most African countries, farming depends entirely on the quality of the rainy
season-a situation that makes Africa particularly vulnerable to climate change.
Increased droughts could seriously impact the availability of food, as in the
horn of Africa and southern Africa during the 1980s and 1990s. A rise in mean
winter temperatures also would be detrimental to the production of winter wheat
and fruits that need the winter chill. However, in subtropical Africa, warmer
winters would reduce the incidence of damaging frosts, making it possible to
grow horticultural produce susceptible to frosts at higher elevations than is
possible at present. Productivity of freshwater fisheries may increase, although
the mix of fish species could be altered. Changes in ocean dynamics could lead
to changes in the migratory patterns of fish and possibly to reduced fish landings,
especially in coastal artisinal fisheries.
Coastal Systems: Several African coastal zones-many of which already
are under stress from population pressure and conflicting uses-would be adversely
affected by sea-level rise associated with climate change. The coastal nations
of west and central Africa (e.g., Senegal, Gambia, Sierra Leone, Nigeria, Cameroon,
Gabon, Angola) have low-lying lagoonal coasts that are susceptible to erosion
and hence are threatened by sea-level rise, particularly because most of the
countries in this area have major and rapidly expanding cities on the coast.
The west coast often is buffeted by storm surges and currently is at risk from
erosion, inundation, and extreme storm events. The coastal zone of east Africa
also will be affected, although this area experiences calm conditions through
much of the year. However, sea-level rise and climatic variation may reduce
the buffer effect of coral and patch reefs along the east coast, increasing
the potential for erosion. A number of studies indicate that a sizable proportion
of the northern part of the Nile delta will be lost through a combination of
inundation and erosion, with consequent loss of agricultural land and urban
areas. Adaptation measures in African coastal zones are available but would
be very costly, as a percentage of GDP, for many countries. These measures could
include erection of sea walls and relocation of vulnerable human settlements
and other socioeconomic facilities.
Human Settlement, Industry, and Transportation: The main challenges
likely to face African populations will emanate from extreme climate events
such as floods (and resulting landslides in some areas), strong winds, droughts,
and tidal waves. Individuals living in marginal areas may be forced to migrate
to urban areas (where infrastructure already is approaching its limits as a
result of population pressure) if the marginal lands become less productive
under new climate conditions. Climate change could worsen current trends in
depletion of biomass energy resources. Reduced stream flows would cause reductions
in hydropower production, leading to negative effects on industrial productivity
and costly relocation of some industrial plants. Management of pollution, sanitation,
waste disposal, water supply, and public health, as well as provision of adequate
infrastructure in urban areas, could become more difficult and costly under
changed climate conditions.
Human Health: Africa is expected to be at risk primarily from increased
incidences of vector-borne diseases and reduced nutritional status. A warmer
environment could open up new areas for malaria; altered temperature and rainfall
patterns also could increase the incidence of yellow fever, dengue fever, onchocerciasis,
and trypanosomiasis. Increased morbidity and mortality in subregions where vector-borne
diseases increase following climatic changes would have far-reaching economic
consequences. In view of the poor economic status of most African nations, global
efforts will be necessary to tackle the potential health effects.
Tourism and Wildlife: Tourism-one of Africa's fastest-growing industries-is
based on wildlife, nature reserves, coastal resorts, and an abundant water supply
for recreation. Projected droughts and/or reduction in precipitation in the
Sahel and eastern and southern Africa would devastate wildlife and reduce the
attractiveness of some nature reserves, thereby reducing income from current
vast investments in tourism.
Conclusions: The African continent is particularly vulnerable to the
impacts of climate change because of factors such as widespread poverty, recurrent
droughts, inequitable land distribution, and overdependence on rain-fed agriculture.
Although adaptation options, including traditional coping strategies, theoretically
are available, in practice the human, infrastructural, and economic response
capacity to effect timely response actions may well be beyond the economic means
of some countries.
|
