United States. Congress. House. Committee on Scien.

Road from Kyoto : hearing before the Committee on Science, U.S. House of Representatives, One Hundred Fifth Congress, second session (Volume pt. 2) online

. (page 78 of 137)
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which include traditional, aesthetic, and cultural values
(see Box 9-2).



Many case studies have faced a shortage of accurate
and complete data necessary for impact analysis. In
particular, it often has proven difficult to determine
accurately the impact zone in many countries due to
the lack of basic data, such as the coastal topography.



9.5.2.2. Vulnerability Assessment Case Studies

At least 23 country case studies have produced quantitative
results that can be interpreted in terms of the IPCC Common



Box 9-2. Cultural Impacts and Alternative Assessments

Conventional impact evaluation techniques and indicators, such as GNP and population at loss, protection costs, and
cost-benefit analysis, reflect only one (largely Western) approach for assessing potential damages from climate-related
events. This has led to the development of alternative methodologies that seek to assess changes in culture, community,
and habitat. In a study of coastal vulnerability and resilience to sea-level rise and climate change, Fiji is considered
(Nunn et al.. 1994a). The methodology (Yamada el iil., 1995) computes a Sustainable Capacity Index based on the sum
of ratings of vulnerability and resilience for many categories of cuhural, social, agricultural, and industrial impacts al the
local, regional, and national levels. Areas with higher concentrations of assets are judged to be more vulnerable, whereas
areas with diversity and flexibility in the system — whether natural or managerial — tend to be viewed as more resilient in
this analysis. The study has evaluated potential impacts to subsistence economies according to the view thai communi-
ties in which people feed and clothe themselves with little cash exchange are more vulnerable but that subsistence
economies in which staples can be replaced with other crops lend lo be more resilient. In addition, cultural sites have
been ranked according to the level of national interest in their preservation. The study concludes thai subsistence
economies and cultural assets are more vulnerable in Fiji and that conventional analyses of relatively high-lying islands
such as Fiji would lend lo underestimate the polenlla! vulnerability of these areas, given that most people live in the low-
lying coastal plain and the majority of cash and subsistence economic activities take place in the low-lying areas.



546



308



Coastal Zones and Small Islands



Methodology. Some results are summarized in Table 9-3, and
these show considerable variation in possible impacts from
country to country, reflecting that certain settings are more
vulnerable than others. This conclusion is widely supported by
all of the country studies that are available. Small islands,
deltaic settings, and coastal ecosystems appear particularly
vulnerable. In addition, developed sandy shores may be vul-
nerable because of the large investment and significant sand
resources required to maintain beaches and protect adjoining
infrastructure in the face of sea-level rise (Nicholls and
Leatherman, 1995a).



Several caveats are in order so that the following impact esti-
mates can be put into proper perspective (following Section
9.5.2.1). First, the impacts presented assume a 1-m rise in sea
level by 2100— which is the high estimate of the IPCC90 busi-
ness-as-usual sea-level rise scenario — and no other climate
change. The latest scientific information, however, suggests a
lower global mean sea-level rise (see Section 9.3.1.1). For a
number of nations, the impacts of a 50-cm or smaller rise have
been examined, including Argentina (Dennis el ai, 1995a),
parts of north China (Han el ai, 1993), Japan (Mimura el ai.
1994). Nigeria (G.T. French ei ai. 1995), Senegal (Dennis ei



Table 9-3: Synthesized results of country case studies. Results are for existing development and a 1-m rise in sea level.
People affected, capital value at loss, land at loss, and wetland at loss assume no measures fie., no human response), whereas
adaptation assumes protection except in areas with low population density. All costs have been adjusted to 1990 US$ (adapted
from Nicholls. 1995).



Country/Source



People Capital Value Land

AfTected at Loss at Loss

# people % Million % %

(lOOOs) Total US$' GNP km^ Total



Wetland
at Loss



km'



Adaptation/
Protection Costs

Million %
US$1 GNP



Antigua^ (Cambers, 1994)
Argentina (Dennis et ai, 1995a)
Bangladesh (Huq el ai. 1995;

Bangladesh Government, 1993) -
Belize (Pemella and Elder, 1993)
Benin' (Adam, 1995)
China (Bilan, 1993; Han et ai, 1995a)
Egypt (Delft Hydraulics et ai, 1992)
Guyana (Kahn and Sturm, 1993)
India (Pachauri, 1994)
Japan (Mimura et ai, 1993)
Kiribati^ (Woodnafife and McLean, 1992)
Malaysia (Midun and Lee, 1995)
Marshall lslands2 (Holthus etai, 1992)
Mauritius* (Jogoo, 1994)
The Netherlands (Peeibolte « a/., 1991)
Nigeria (G.T. French et ai, 1995)
Poland (Pluijm et ai, 1992)
Senegal (Dennis etai, 1995b)
St. Kitls-Nevis^ (Cambers, 1994)
Tonga^ (Fifitafra/., 1994)
United States (Titus et ai, 1991)
Uruguay (Volont^ and Nicholls, 1995)^



38



71000

70

1350

72000

4700

600

7100*

15400

9

20

3

10000

3200*

240

110*

30

136



Venezuela (Volont^ and Arismendi, 1995) 56*



50



60
35
25
7
9

80
I

15
100

100

<I

67

4

1
>1

47

<1
<1



>5000'



118

59000
4000

849000

2

160

186000
17000'
22000
>5007



1700''
330''



>5



12

204
1115

72



324

69

52
24
>12



26
1



5
3400

25000
1900
230
35000
5800
2400
5800
2300

4
7000

9

5
2165
18600
1700
6100

1

7

316008

96

5700



1.0
0.1

17.5
8.4
0.2

1.0

I.I

0.4

0.6

12.5

2.1

80

0.3

5.9

2.0

0.5

3.1

1.4

2.9

0.3

0.1

0.6



3
1100

5800

85

500
6000



642
16000

36

6000

1

17000

23
5600



71
>1800

>1000''

>400l0

13100'!
200

>156000
3



12300

>1400

1400

>1000

50

>156000
>1000
>1600



0.32
>0.02

>0.06

>0.41

0.45
0.26

>0.12
0.10



>360 >7.04



0.05
>0.04

0.02
>0.2I

2.65

>0.03
>0.12
>0.03



'Costs have been adjusted to reflect 1990 US$.

^Minimum estimates — incomplete national coverage.

^Precise year for financial values not given — -assumed to be 1992.

.^Results are linearly interpolated from results for a 2-m sea-level rise scenario.

'See also review in Nicholls and Leatherman (1995a).

"Minimum estimates — number reflects estimated people displaced.

'Minimum estimates — capital value at loss does not include ports.

*Best estimate is that 20,0(X) km^ of dry land are lost, but about 5,400 km^ are converted to coastal wetlands.

'Adaptation only provides protection against a l-in-20 year event.

'•^Adaptation costs are linearly extrapolated from a 0.5-m sea-level rise scenario.

"Adaptation costs include 30- year development scenarios.



547



Coastal Zones and Smalt Islands



309



ai, 1995b), parts of the United Kingdom (Turner e» a/., 1995a),
the United States (Titus et ai. 1991), Uruguay (Volonte and
Nicholls, 1995), and Venezuela (Volonte and Arismendi,
1995). Second, all of the country studies have assumed that the
socioeconomic situation is constant until 2100. This is unreal-
istic and ignores the rapid coastal development that is occur-
ring with little regard for existing problems, lei alone tomor-
row's (WCC'93, 1994). However, the mere threat of extensive
loss of land and other assets may stimulate macroeconomic
effects within national economies. Some assets may be relo-
cated and others may be adapted to reduce the damage impli-
cations of climate change. On the other hand, the damage-cost
estimates may represent underestimates because they neglect
some nonmarket asset values and factors such as the cost of
resettlement of coastal populations that cannot be easily pro-
tected. Finally, it has been assumed that the rise In sea level
will be a slow, gradual process, which may not be the case for
all regions. Scientific uncertainties are compounded by (he
socioeconomic adaptation uncertainties referred to above and
by the fact that economic cost estimates are very sensitive to
changes in discount rates.

Despite these limitations, these studies have offered some
important insights into potential impacts and possible respons-
es to climate change and sea-level rise. Many of the vulnera-
bility assessments emphasize the severe nature of existing
coastal problems such as beach erosion, waterlogging, and pol-
lution (e.g., El-Raey et ai. 1995; Han et al, 1995b) For many
small islands, population pressure and urbanization, coastal
pollution, and overexploitation of resources already are critical
problems. For deltas and estuaries, changes in sediment supply
and distribution are often already causing significant changes
m the coastal zone. This reinforces the message that climate
change will act on coastal systems that are already under stress.

In addition to accelerated sea-level rise, there Is widespread
concern about the coastal implications of other aspects of cli-
mate change such as changing rainfall and runoff in the catch-
ment area, as well as the effects of changes in storminess and
storm surges (e.g., Warrick et ai, 1993; McLean and Mimura,
1993). One quantitative vulnerability assessment study exists;
it shows that in The Netherlands the costs of avoiding damage
related to an adverse 10% change in the direction and intensi-
ty of storms may be worse than those of a 60-cm rise in sea
level (Peerbolte et ai. 1991). This storm-change scenario is
arbitrary, but shows that concern is justified and that there is a
need for more widespread analysis.

All of the 23 national case studies shown in Table 9-3 project
land loss as the sum of dry-land and wetland loss, assuming no
protective measures are taken. The estimated losses range from
0.05% of the national land area in Uruguay (Volonl^ and
Nicholls. 1995) to more than 12% of Tarawa. Kiribati
(Woodroffe and McLean. 1992); more than 17% of Bangladesh
(Huq el ai. 1995); and 80% of Majuro aloll. Marshall Islands
(Hollhus etai, 1992). From fifteen case studies, 63.000 km^ of
wetlands are estimated to be lost Most of these assessments
are based on first-order analy.ses. and key parameters such as



limiting vertical accretion rates and potential for wetland
migration often are poorly defined (Nicholls. 1995). The study
of the United States has considered wetland migration, esti-
mating that a 50-cm rise in sea level would erode or inundate
38% to 61% of existing coastal wetlands. Assuming that dikes
or bulkheads were not built to impede inland migration, new
wetland formation on formerly upland areas would reduce the
total loss to 17% to 43% (Titus et ai. 1991). Therefore, wet-
land migration is not projected to compensate for losses, even
under the most ideal circumstances. Many studies, however,
have found that direct human reclamation of wetlands for a
range of purposes at present is a much bigger threat than sea-
level rise (Nicholls and Leatherman, 1995a).

Fifteen case studies have provided estimates of undiscounted
capital value potentially at loss, assuming no protection.
Nearly half of the studies have concluded that capital value al
loss could exceed 50% of present GNP, illustrating the con-
centration of infrastructure and economic activity in the coastal
zones of many of the countries studied. To counter these
impacts, adaptation would be expected (see Section 9.6). Table
9-3 stresses the cost of total protection rather than other possi-
ble adaptation options, which may have lower costs. Assuming
that costs will accrue uniformly over 100 years, the annual pro-
tection costs — as a percentage of present GNP — are highest for
the Marshall Islands at 7% (Holthus et ai, 1992) and St. Kitts-
Nevis at 2.7% (Cambers, 1994). This supports the conclusion
that some small islands have a high vulnerability to sea-level
rise. However, Kiribati has a similar setting to the Marshall
Islands, yet the estimates of protection costs are much smaller,
at 0.1% of present GNP (Woodroffe and McLean. 1992). This
reflects important differences in assumptions about the mean-
ing of total protection. In Kiribati, local engineers have select-
ed existing low-technology, low-cost gabions to protect the
atoll, whereas in the Marshall Islands large and expensive sea
walls have been utilized to determine the costs. This compari-
son shows one of the weaknesses of the Common
Methodology and the need to assess a wider range of response
options in future vulnerability assessment studies.

In many locations, beaches are likely to require nourishment to
protect tourist infrastructure because existing urban and tourist
infrastructure could be damaged and destroyed. The amount of
sand required to maintain a beach in the face of long-term sea-
level rise is uncertain (Stive eiai. 1991); in some case studies,
the costs of beach nourishment could dominate basic response
costs if countries invest in such an adaptation option (Dennis et
ai. 1995b; Nicholls and Leatherman, 1995a; Volonte and
Nicholls. 1995). There isalsothequestionof the availability of
sufficient sand resources. The usual source is suitable-grade
nearshore deposits, if available. However, the implication of
the removal of such deposits must be carefully considered in
terms of its effect on the coastal sediment budget and the
nearshore wave climate.

In many industrialized countries, the main potential loss from
sea-level rise seems to be coastal wetlands, as well as sandy
beaches in some countries (e.g.. Mimura ci ai. 1994).



548



310 Coa.slul Zones and Small Islands



Box 9-3. The Vulnerable Situation of Small Islands

Many small island countries could lose a significanl part of Iheir land area with a sea-level rise of 50 cm lo 1 m. The
Maldives, for example, have average elevations of I to 1.5 m above existing sea level (Pemelta. 1992). Although bio-
geophysical processes may counter land losses (.see Section 9.4), the threat of submergence and erosion remains; this
could convert many small islands to sandbars and significantly reduce the usable dry land on the larger, more populated
islands. Saltwater intrusion and loss of the freshwater lens may be an equally binding constraint on human habitation in
some islands, particularly smaller atolls (Leatherman, 1994).

The available case studies have shown that small islands — most particularly, coral atolls such as the Marshall Islands
(Holthus el al., 1992) — are heavily onented toward coastal activities and hence are vulnerable lo sea-level rise (e.g..
Cambers, 1994; Fifila ei al., 1994). At the same time, their relatively small economies may make the costs of adaptation
prohibitive. In global terms, the population of small islands is relatively small, but a number of distinct societies and cul-
tures are threatened with drastic changes in lifestyle and possibly forced abandonment from ancestral homelands if sea
level rises significantly (Roy and Connell, 1991).

Even the less-vulnerable small islands would suffer significant economic effects from the loss of beach tourism and
recreation areas because of sea-level rise and, possibly, more storms leading to increased beach and reef erosion. In
1988, among the Caribbean islands, income from tourism as a percentage of GNP was 69% for Antigua and Barbuda and
53% for the Bahamas; for a dozen other Caribbean islands, tourism revenues make up more than 10% of the GNP
(Hameed, 1993). The Indian Ocean islands of the Seychelles and the Maldives also have seen a steady growth in
tourism. In 1991, total receipts from tourism generated foreign exchange earnings of $94 million in the Maldives. This
represented some 74% of the country's total foreign exchange earnings. Since 1985, tourism has been the single biggest
contributor to the GNP of the Maldives. Tourism to developing countries has increased significantly in recent years, and
small island developing states have experienced a particularly rapid increase. Tourist numbers to Mauritius, for example,
have increased from 1,800 visitors in 1968 to 180,000 in 1988 (UNEP, 1991).

Given accelerated sea-level rise, first-order estimates suggest that substantial investment would be required in some
developing countries in order to protect urban areas and maintain related activities such as beach tourism. Nine small
island states appear in the list of countries facing the highest coastal protection costs as a percentage of their GNP. The
global average percentage required annually for coastal protection is 0.037%; however, for many small islands it is sig-
nificantly higher — up to 34% for the Maldives (OECD, 1991). To explore the full range of potential responses, more
comprehensive assessment of the available adaptation options in these vulnerable settings is urgently required.



However, a change in the frequency, intensity, or distribution implications of accelerated sea-level rise (Hoozemans et al.,
of extreme weather events could have implications for urban 1993) has been conducted, using the same scenarios as the
areas and related capital assets in countries such as Japan. Common Methodology. The GVA has provided estimates of
Australia, the United States, and some countries bordering the the following impacts: population al risk, the average number
North Sea. of people per year subject to flooding by storm surge on a glob-

al scale; wetlands al loss, the ecologically valuable coastal wet-
From the above it is clear that all coastal zones of the world are land area under serious threat of loss on a global scale; and rice
vulnerable to the range of possible impacts from sea-level rise production at change, the changes in coastal rice yields as a
and other climate-induced impacts, although to different result of less-favorable conditions due to sea-level rise in
degrees. Studies using other approaches than the Common South, Southeast, and East Asia.
Methodology support this conclusion. Small island developing

states are often judged to be among the most vulnerable coun- Recently, an extension of the GVA has been prepared using a
tries. In Box 9-3, case material is presented for small islands, more refined approach to estimate flooding probabilities
centering chiefly on threats to small economies dominated by (Baarse, 1995). Sea-level rise scenarios of both 50 cm and 1 m
tourism. have been considered. The data sets available for global-scale

analysis are limited, and important assumptions are necessary

with regard to storm-surge probability and population distribu-

9.5.2.3. Global Vulnerability Assessment lion. Also, increases in wave height and wave run-up have not

been taken into account in these analyses, and neither have
In addition to local and country vulnerability assessments, a socioeconomic changes such as population growth. Therefore.
Global Vulnerability Assessment (GVA), which provides a the results of both studies must be considered as first-order
worldwide estimate of the socioeconomic and ecological estimates.



549



Coastal Zones and Small Islands



311



Some conclusions drawn from Hoozemans et al. (1993) and
Baarse (1995) include:

• Presently, some 200 million people are estimated to
live below the "maximum" storm-surge level (the
once-per- 1 000-ycars storm-surge level). Based on this
population estimate, as well as on first-order esti-
mates of storm-surge probabilities and existing levels
of protection, 46 million people are estimated to expe-
rience flooding due to storm surge in an average year
under present conditions. Most of these people live in
the developing world.

• The present number of people at risk will double if
sea level rises 50 cm (92 million people/yr) and
almost triple if it rises 1 m ( 1 1 8 million people/yr).

• The average number of people who will experience
coastal flooding more than once per year will
increase considerably under both scenarios (80-90%
of the respective populations at risk). This estimate
underlines that many people will have to adapt to
sea-level rise by moving to higher ground, increasing
protection efforts or other adaptation options (see
Section 9.6).

• Because of regional differences in storm-surge
regimes, the increase of flood risk due to sea-level
rise is greater than average for the Asian region
(especially the Indian Ocean coast), the south
Mediterranean coast, the African Atlantic and Indian
Ocean coasts, Caribbean coasts, and many of the
small islands.

• All over the world, coastal wetlands are presently
being lost at an increasingly rapid rate, averaging
0.5-1.5% per year. These losses are closely connect-
ed with human activities such as shoreline protection,
blocking of sediment sources, and development activ-
ities such as land reclamation, aquaculture develop-
ment, and oil, gas, and water extraction.

• Sea-level rise would increase the rate of net coastal
wetland loss. Losses of coastal wetlands of interna-
tional importance are expected to be greater than
average for the coasts of the United States, the
Mediterranean Sea, the African Atlantic coast, the
coast of East Asia, and the Australian and Papua New
Guinean coast.

• Approximately 85% of the world's rice production
takes place in South, Southeast, and East Asia.
About 10% of this production is located in areas that
are considered to be vulnerable to sea-level rise,
thereby endangering the food supply of more than
200 million people.

• Less-favorable hydraulic conditions may cause lower
rice production yields if no adaptive measures are
taken, especially in the large deltas of Vietnam.
Bangladesh, and Myanmar.

In summary, the GVA confirms that sea-level rise will have
global impacts and reinforces the need for more refined vul-
nerability assessments at regional and local scales.



9.5.2.4. Overview of Impact Assessment

Vulnerability assessment has demonstrated that certain set-
tings are more vulnerable to sea-level rise, including small
islands (particularly coral atolls), nations with large deltaic
areas, coastal wetlands, and developed sandy shores.
However, vulnerability assessment has been less successful in
assessing the range of response options to deal with the prob-
lems of climate change. Therefore, vulnerability analysis has
further utility for countries and areas where none has yet been
carried out or where only preliminary studies are available.
Even in many areas with a completed vulnerability assess-
ment, an assessment of additional sea-level rise scenarios, sce-
narios of other impacts of climate change, and a wider range
of response options remains necessary. This entails a greater
emphasis on local conditions and careful evaluation of pro-
gressive adaptation options.

Problems and deficiencies with the Common Methodology
have been indicated in several papers in O'Callahan (1994)
and McLean and Mimura (1993) [e.g., Kay and Waterman
(1993)], and recommendations have been made for integrating
vulnerability assessments into the process of coastal zone
management (WCC'93, 1994). In order to continue vulnera-
bility assessment studies in a more complete form, approach-
es should be developed that more readily meet biogeophysi-
cal, socioeconomic, and cultural conditions, as well as gov-
ernmental and jurisdictional arrangements (e.g., Yamada et
al, 1995). Common approaches or frameworks that are tai-
lored to the geographic circumstances and needs of each
nation should be consistent with the IPCC Technical
Guidelines for Assessing Climate Change Impacts and
Adaptation (Carter et al., 1994) and need to take into account
and correct the weaknesses found with the Common
Methodology (McLean and Mimura, 1993; WCC'93, 1994).



9.6. Response Strategies

There is no doubt that the threat of climate change and sea-level
rise has focused attention on coastal zones and small islands and
awakened awareness of the vulnerability of the world's coastal
regions in general — and to low-lying coasts, tidal deltas, and
small islands in particular. IPCC CZMS (1990, 1992) have dis-
tinguished three groups of response strategies: (planned) retreat,
accommodate, and protect. The first involves strategic retreat
from or the prevention of future major developments in coastal
areas that may be impacted. The second includes adaptive
responses such as elevation of buildings, modification of
drainage systems, and land-use changes. Both strategies are
based on the premise that increases in land loss and coastal
flooding will be allowed to occur and that some coastal func-



Online LibraryUnited States. Congress. House. Committee on ScienRoad from Kyoto : hearing before the Committee on Science, U.S. House of Representatives, One Hundred Fifth Congress, second session (Volume pt. 2) → online text (page 78 of 137)