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4. Mediterranean Basin five islands: Ecosystems

SRES A1FI and B1

Gritti et al. (2006)

Alien plant invasion under climatic and disturbance scenarios

• Climate change impacts are negligible in many simulated marine ecosystems.

• Invasion into island ecosystems become an increasing problem. In the longer term, ecosystems will be dominated by exotic plants irrespective of disturbance rates.

5. Mediterranean: Migratory birds (Pied flycatchers - Ficedula hypoleuca)

None (GLM/ STATISTICA model) Sanz et al. (2003)

Temperature increase, changes in water levels and vegetation index

• Some fitness components of pied flycatchers suffer from climate change in two of the southernmost European breeding populations, with adverse effects on reproductive output of pied flycatchers.

6. Pacific and Mediterranean: Siam weed (Chromolaena odorata)

None (CLIMEX model) Kriticos et al. (2005)

Increase in moisture, cold, heat and dry stress

• Pacific islands at risk of invasion by Siam weed.

• Mediterranean semi-arid and temperate climates predicted to be unsuitable for invasion.

7. Pacific small islands: Coastal erosion, water resources and human settlement

SRES A2 and B2

World Bank (2000)

Changes in temperature and rainfall, and sea-level rise

• Accelerated coastal erosion, saline intrusion into freshwater lenses and increased flooding from the sea cause large effects on human settlements.

• Less rainfall coupled with accelerated sea-level rise compound the threat on water resources; a 10% reduction in average rainfall by 2050 is likely to correspond to a 20% reduction in the size of the freshwater lens on Tarawa Atoll, Kiribati.

8. American Samoa; 15 other Pacific islands: Mangroves

Sea-level rise 0.88 m to 2100 Gilman et al. (2006)

Projected rise in sea level

• 50% loss of mangrove area in American Samoa; 12% reduction in mangrove area in 15 other Pacific islands.

9. Caribbean (Bonaire, Netherlands Antilles): Beach erosion and sea turtle nesting habitats

SRES A1, A1FI, B1, A2, B2 Fish et al. (2005)

Projected rise in sea level

• On average, up to 38% (±24% SD) of the total current beach could be lost with a 0.5 m rise in sea level, with lower narrower beaches being the most vulnerable, reducing turtle nesting habitat by one-third.

10. Caribbean (Bonaire, Barbados): Tourism

None

Uyarra et al. (2005)

Changes to marine wildlife, health, terrestrial features and sea conditions

• The beach-based tourism industry in Barbados and the marine diving based ecotourism industry in Bonaire are both negatively affected by climate change through beach erosion in Barbados and coral bleaching in Bonaire.

increase slightly during December, January and February (DJF) in the Indian Ocean and southern Pacific and during June, July and August (JJA) in the northern Pacific (Christensen et al., 2007). Even so, the scarcity of fresh water is often a limiting factor for social and economic development in small islands. Burns (2002) has also cautioned that with the rapid growth of tourism and service industries in many small islands, there is a need both for augmentation of the existing water resources and for more efficient planning and management of those resources. Measures to reduce water demand and promote conservation are also especially important on small islands, where infrastructure deterioration resulting in major leakage is common, and water pollution from soil erosion, herbicide and pesticide runoff, livestock waste, and liquid and solid waste disposal results in high costs, crudely estimated at around 3% of GDP in Rarotonga, Cook Islands (Hajkowicz, 2006).

This dependency on rainfall significantly increases the vulnerability of small islands to future changes in distribution of rainfall. For example, model projections suggest that a 10% reduction in average rainfall by 2050 is likely to correspond to a 20% reduction in the size of the freshwater lens on Tarawa Atoll, Kiribati. Moreover, a reduction in the size of the island, resulting from land loss accompanying sea-level rise, is likely to reduce the thickness of the freshwater lens on atolls by as much as 29% (World Bank, 2000). Less rainfall coupled with accelerated sea-level rise would compound this threat. Studies conducted on Bonriki Island in Tarawa, Kiribati, showed that a 50 cm rise in sea level accompanied by a reduction in rainfall of 25% would reduce the freshwater lens by 65% (World Bank, 2000). Increases in sea level may also shift watertables close to or above the surface, resulting in increased evapotranspiration, thus diminishing the resource (Burns, 2000).

Lower rainfall typically leads to a reduction in the amount of water that can be physically harvested, to a reduction in river flow, and to a slower rate of recharge of the freshwater lens, which can result in prolonged drought impacts. Recent modelling of the current and future water resource availability on several small islands in the Caribbean, using a macro-scale hydrological model and the SRES scenarios (Arnell, 2004), found that many of these islands would be exposed to severe water stress under all SRES scenarios, and especially so under A2 and B2. Since most of the islands are dependent upon surface water catchments for water supply, it is highly likely that demand could not be met during periods of low rainfall.

The wet and dry cycles associated with ENSO episodes can have serious impacts on water supply and island economies. For instance the strong La Niña of 1998 to 2000 was responsible for acute water shortages in many islands in the Indian and Pacific Oceans (Shea et al., 2001; Hay et al., 2003), which resulted in partial shut-downs in the tourism and industrial sectors. In Fiji and Mauritius, borehole yields decreased by 40% during the dry periods, and export crops including sugar cane were also severely affected (World Bank, 2000). The situation was exacerbated by the lack of adequate infrastructure such as reservoirs and water distribution networks in most islands.

Increases in demand related to population and economic growth, in particular tourism, continue to place serious stress on existing water resources. Excessive damming, over-pumping and increasing pollution are all threats that will continue to increase in the future. Groundwater resources are especially at risk from pollution in many small islands (UNEP, 2000), and in countries such as the Comoros, the polluted waters are linked to outbreaks of yellow fever and cholera (Hay et al., 2003).

Access to safe potable water varies across countries. There is very good access in countries such as Singapore, Mauritius and most Caribbean islands, whereas in states such as Kiribati and Comoros it has been estimated that only 44% and 50% of the population, respectively, have access to safe water. Given the major investments needed to develop storage and provide treatment and distribution of water, it is evident that climate change would further decrease the ability of many islands to meet their future requirements.

Several small island countries have begun to invest, at great financial cost, in the implementation of various augmentation and adaptation strategies to offset current water shortages. The Bahamas, Antigua and Barbuda, Barbados, Maldives, Seychelles, Singapore, Tuvalu and others have invested in desalination plants. However, in the Pacific, some of the systems are now only being used during the dry season, owing to operational problems and high maintenance costs. Options such as large storage reservoirs and improved water harvesting are now being explored more widely, although such practices have been in existence in countries such as the Maldives since the early 1900s. In other cases, countries are beginning to invest in improving the scientific database that could be used for future adaptation plans. In the Cook Islands, for example, a useful index for estimating drought intensity was recently developed based on analysis of more than 70 years of rainfall data; this will be a valuable tool in the long-term planning of water resources in these islands (Parakoti and Scott, 2002).

16.4.2 Coastal systems and resources

The coastlines of small islands are long relative to island area. They are also diverse and resource-rich, providing a range of goods and services, many of which are threatened by a combination of human pressures and climate change and variability arising especially from sea-level rise, increases in sea surface temperature, and possible increases in extreme weather events. Key impacts will almost certainly include accelerated coastal erosion, saline intrusion into freshwater lenses, and increased flooding from the sea. An extreme example of the ultimate impact of sea-level rise on small islands - island abandonment - has been documented by Gibbons and Nicholls (2006) in Chesapeake Bay.

It has long been recognised that islands on coral atolls are especially vulnerable to this combination of impacts, and the long-term viability of some atoll states has been questioned. Indeed, Barnett and Adger (2003) argue that the risk from climate-induced factors constitutes a dangerous level of climatic change to atoll countries by potentially undermining their sovereignty (see Section 16.5.4).

The future of atoll island geomorphology has been predicted using both geological analogues and simulation modelling approaches. Using a modified shoreline translation model, Kench and Cowell (2001) and Cowell and Kench (2001) found that, with sea-level rise, ocean shores will be eroded and sediment redeposited further lagoonward, assuming that the volume of island sediment remains constant. Simulations also show that changes in sediment supply can cause physical alteration of atoll islands by an equivalent or greater amount than by sea-level rise alone. Geological reconstructions of the relationship between sea level and island evolution in the mid-to late Holocene, however, do not provide consistent interpretations. For instance, chronic island erosion resulting from increased water depth across reefs with global warming and sea-level rise is envisaged for some islands in the Pacific (Dickinson, 1999), while Kench et al. (2005) present data and a model which suggest that uninhabited islands of the Maldives are morphologically resilient rather than fragile systems, and are expected to persist under current scenarios of future climate change and sea-level rise. The impact of the Sumatran tsunami on such islands appears to confirm this resilience (Kench et al., 2006) and implies that islands which have been subject to substantial human modification are inherently more vulnerable than those that have not been modified.

On topographically higher and geologically more complex islands, beach erosion presents a particular hazard to coastal tourism facilities, which provide the main economic thrust for many small island states. Ad hoc approaches to addressing this problem have recently given way to the integrated coastal zone management approach as summarised in the TAR (McLean et al., 2001), which involves data collection, analysis of coastal processes, and assessment of impacts. Daniel and Abkowitz (2003, 2005) present the results of such an approach in the Caribbean, which involves the development of tools for integrating spatial and non-spatial coastal data, estimating long-term beach erosion/accretion trends and storm-induced beach erosion at individual beaches, identifying erosion-sensitive beaches, and mapping beach-erosion hazards. Coastal erosion on arctic islands has additional climate sensitivity through the impact of warming on permafrost and extensive ground ice, which can lead to accelerated erosion and volume loss, and the potential for higher wave energy if the diminished sea ice results in longer over-water fetch (see Chapter 6, Section 6.2.5; Chapter 15, Section 15.4.6).

While erosion is intuitively the most common response of island shorelines to sea-level rise, it should be recognised that coasts are not passive systems. Instead, they will respond dynamically in different ways dependent on many factors including: the geological setting; coastal type, whether soft or hard shores; the rate of sediment supply relative to rate of submergence; sediment type, sand or gravel; presence or absence of natural shore protection structures such as beach rock or conglomerate outcrops; presence or absence of biotic protection such as mangroves and other strand vegetation; and the health of coral reefs. That several of these factors are interrelated can be illustrated by a model study by Sheppard et al. (2005), who suggest that mass coral mortality over the past decade at some sites in the Seychelles has resulted in a reduction in the level of the fringing reef surface, a consequent rise in wave energy over the reef, and increased coastal erosion. Further declines in reef health are expected to accelerate this trend.

Global change is also creating a number of other stress factors that are very likely to influence the health of coral reefs around islands, as a result of increasing sea surface temperature and sea level, damage from tropical cyclones, and possible decreases in growth rates due to the effects of higher CO2 concentrations on ocean chemistry. Impacts on coral reefs from those factors will not be uniform throughout the small-island realm. For instance, the geographical variability in the required thermal adaptation derived from models and emissions scenarios presented by Donner et al. (2005) suggest that coral reefs in some regions, such as Micronesia and western Polynesia, may be particularly vulnerable to climate change. In addition to these primarily climate-driven factors, the impacts of which are detailed in Chapter 6, Section 6.2.1, there are those associated mainly with other human activities, which combine to subject island coral reefs to multiple stresses, as illustrated in Box 16.2.

16.4.3 Agriculture, fisheries and food security

Small islands have traditionally depended upon subsistence and cash crops for survival and economic development. While subsistence agriculture provides local food security, cash crops (such as sugar cane, bananas and forest products) are exported in order to earn foreign exchange. In Mauritius, the sugar cane industry has provided economic growth and has contributed to the diversification of the economy through linkages with tourism and other related industries (Government of Mauritius, 2002). However, exports have depended upon preferential access to major developed-country markets, which are slowly eroding. Many island states have also experienced a decrease in GDP contributions from agriculture, partly due to the drop in competitiveness of cash crops, cheaper imports from larger countries, increased costs of maintaining soil fertility, and competing uses for water resources, especially from tourism (FAO, 2004).

Local food production is vital to small islands, even those with very limited land areas. In the Pacific islands subsistence agriculture has existed for several hundred years. The ecological dependency of small island economies and societies is well recognised (ADB, 2004). A report by the FAO Commission on Genetic Resources found that some countries' dependence on plant genetic resources ranged from 91% in Comoros, 88% in Jamaica, 85% in Seychelles to 65% in Fiji, 59% in the Bahamas and 37% in Vanuatu (Ximena, 1998).

Projected impacts of climate change include extended periods of drought and, on the other hand, loss of soil fertility and degradation as a result of increased precipitation, both of which will negatively impact on agriculture and food security. In a study of the economic and social implications of climate change and variability for selected Pacific islands, the World Bank (2000) found that in the absence of adaptation, a high island such as Viti Levu, Fiji, could experience damages of US$23 million to 52 million/yr by 2050, (equivalent to 2 to 3% of Fiji's GDP in 1998). A group of low islands such as Tarawa, Kiribati, could face average annual damages of more than US$8 million to 16 million/yr (equivalent to 17 to 18% of Kiribati's GDP in 1998) under the SRES A2 and B2 emissions scenarios.

Box 16.2. Non-climate-change threats to coral reefs of small islands

A large number of non-climate-change stresses and disturbances, mainly driven by human activities, can impact coral reefs (Nystrom et al., 2000; Hughes et al., 2003). It has been suggested that the 'coral reef crisis' is almost certainly the result of complex and synergistic interactions among global-scale climatic stresses and local-scale, human-imposed stresses (Buddemeier et al., 2004).

In a study by Bryant et al. (1998), four human-threat factors - coastal development, marine pollution, over-exploitation and destructive fishing, and sediment and nutrients from inland - provide a composite indicator of the potential risk to coral reefs associated with human activity for 800 reef sites. Their map (Figure 16.1) identifies low-risk (blue) medium-risk (yellow) and high-risk (red) sites, the first being common in the insular central Indian and Pacific Oceans, the last in maritime South-East Asia and the Caribbean archipelago. Details of reefs at risk in the two highest-risk areas have been documented by Burke et al. (2002) and Burke and Maidens (2004), who indicate that about 50% of the reefs in South-East Asia and 45% in the Caribbean are classed in the high- to very high-risk category. There are, however, significant local and regional differences in the scale and type of threats to coral reefs in both continental and small-island situations.

Figure 16.1. The potential risk to coral reefs from human-threat factors. Low risk (blue), medium risk (yellow) and high risk (red). Source: Bryant et al. (1998).

Recognising that coral reefs are especially important for many small island states, Wilkinson (2004) notes that reefs on small islands are often subject to a range of non-climate impacts. Some common types of reef disturbance are listed below, with examples from several island regions and specific islands.

1. Impact of coastal developments and modification of shorelines:

• coastal development on fringing reefs, Langawi Island, Malaysia (Abdullah et al., 2002);

• coastal resort development and tourism impacts in Mauritius (Ramessur, 2002).

2. Mining and harvesting of corals and reef organisms:

• coral harvesting in Fiji for the aquarium trade (Vunisea, 2003).

3. Sedimentation and nutrient pollution from the land:

• sediment smothering reefs in Aria Bay, Palau (Golbuua et al., 2003) and southern islands of Singapore (Dikou and van Woesik, 2006);

• non-point source pollution, Tutuila Island, American Samoa (Houk et al., 2005);

• nutrient pollution and eutrophication, fringing reef, Réunion (Chazottes et al., 2002) and Cocos Lagoon, Guam (Kuffner and Paul, 2001).

4. Over-exploitation and damaging fishing practices:

• blast fishing in the islands of Indonesia (Fox and Caldwell, 2006);

• intensive fish-farming effluent in Philippines (Villanueva et al., 2006);

• subsistence exploitation of reef fish in Fiji (Dulvy et al., 2004);

• giant clam harvesting on reefs, Milne Bay, Papua New Guinea (Kinch, 2002).

5. Introduced and invasive species:

• Non-indigenous species invasion of coral habitats in Guam (Paulay et al., 2002).

There is another category of 'stress' that may inadvertently result in damage to coral reefs - the human component of poor governance (Goldberg and Wilkinson, 2004). This can accompany political instability, one example being problems with contemporary coastal management in the Solomon Islands (Lane, 2006).

Not all effects of climate change on agriculture are expected to be negative. For example, increased temperatures in high-latitude islands are likely to make conditions more suitable for agriculture and provide opportunities to enhance resilience of local food systems (see also Chapter 15, Section 15.5).

If the intensity of tropical cyclones increases, a concomitant rise in significant damage to food crops and infrastructure is likely. For example, Tropical Cyclone Ofa in 1990 turned Niue (in the Pacific) from a food-exporting country into one dependent on imports for the next two years, and Heta in 2004 had an even greater impact on agricultural production in Niue (Wade, 2005). Hurricane Ivan's impact on Grenada (in the Caribbean) in 2004 caused losses in the agricultural sector equivalent to 10% of GDP. The two main crops, nutmeg and cocoa, both of which have long gestation periods, will not make a contribution to GDP or earn foreign exchange for the next 10 years (OECS, 2004).

Fisheries contribute significantly to GDP on many islands; consequently the socio-economic implications of the impact of climate change on fisheries are likely to be important and would exacerbate other anthropogenic stresses such as over-fishing. For example, in the Maldives, variations in tuna catches are especially significant during El Niño and La Niña years. This was shown during the El Niño years of 1972/1973, 1976, 1982/1983, 1987 and 1992/1994, when the skipjack catches decreased and yellow fin increased, whereas during La Niña years skipjack tuna catches increased, whilst catches of other tuna species decreased (MOHA, 2001). Changes in migration patterns and depth are two main factors affecting the distribution and availability of tuna during those periods, and it is expected that changes in climate would cause migratory shifts in tuna aggregations to other locations (McLean et al., 2001). Apart from the study by Lehodey et al. (2003) of potential changes in tuna fisheries, Aaheim and Sygna (2000) surveyed possible economic impacts in terms of quantities and values, and give examples of macroeconomic impacts. The two main effects of climate change on tuna fishing are likely to be a decline in the total stock and a migration of the stock eastwards, both of which will lead to changes in the catch in different countries.

In contrast to agriculture, the mobility of fish makes it difficult to estimate future changes in marine fish resources. Furthermore, since the life cycles of many species of commercially exploited fisheries range from freshwater to ocean water, land-based and coastal activities will also be likely to affect the populations of those species. Coral reefs and other coastal ecosystems which may be severely affected by climate change will also have an impact on fisheries (Graham et al., 2006).

16.4.4 Biodiversity

Oceanic islands often have a unique biodiversity through high endemism (i.e., with regionally restricted distribution) caused by ecological isolation. Moreover, human well-being on most small islands is heavily reliant on ecosystem services such as amenity value and fisheries (Wong et al., 2005). Historically, isolation - by its very nature - normally implies immunity from threats such as invasive species causing the extinction of endemics. However, it is possible that in mid- and high-latitude islands, higher temperature and the retreat and loss of snow cover could enhance conditions for the spread of invasive species and forest cover (Smith et al., 2003; see also Chapter 15, Section 15.6.3). For example, in species-poor, sub-Antarctic island ecosystems, alien microbes, fungi, plants and animals have been extensively documented as causing substantial loss of local biodiversity and changes to ecosystem function (Frenot et al., 2005). With rapid climate change, even greater numbers of introductions and enhanced colonisation by alien species are likely, with consequent increases in impacts on these island ecosystems. Climate-related ecosystem effects are also already evident in the mid-latitudes, such as on the island of Hokkaido, Japan, where a decrease in alpine flora has been reported (Kudo et al., 2004).

Under the SRES scenarios, small islands are shown to be particularly vulnerable to coastal flooding and decreased extent of coastal vegetated wetlands (Nicholls, 2004). There is also a detectable influence on marine and terrestrial pathogens, such as coral diseases and oyster pathogens, linked to ENSO events (Harvell et al., 2002). These changes are in addition to coral bleaching, which could become an annual or biannual event in the next 30 to 50 years or sooner without an increase in thermal tolerance of 0.2 to 1.0°C (Sheppard, 2003; Donner et al., 2005). Furthermore, in the Caribbean, a 0.5 m sea-level rise is projected to cause a decrease in turtle nesting habitat by up to 35% (Fish et al., 2005).

In islands with cloud forest or high elevations, such as the Hawaiian Islands, large volcanoes have created extreme vegetation gradients, ranging from nearly tropical to alpine (Foster, 2001; Daehler, 2005). In these ecosystems, anthropogenic climate change is likely to combine with past land-use changes and biological invasions to drive several species such as endemic birds to extinction (Benning et al., 2002). This trend among Hawaiian forest birds shows concordance with the spread of avian malaria, which has doubled over a decade at upper elevations and is associated with breeding of mosquitoes and warmer summertime air temperatures (Freed et al., 2005).

In the event of increasing extreme events such as cyclones (hurricanes) (see Section 16.3.1.3) forest biodiversity could be severely affected, as adaptation responses on small islands are expected to be slow, and impacts of storms may be cumulative. For example, Ostertag et al. (2005) examined long-term tropical moist forests on the island of Puerto Rico in the Caribbean. Hurricane-induced mortality of trees after 21 months was 5.2%/yr; more than seven times higher than background mortality levels during the non-hurricane periods. These authors show that resistance of trees to hurricane damage is not only correlated with individual and species characteristics, but also with past disturbance history, which suggests that individual storms cannot be treated as discrete, independent events when interpreting the effects of hurricanes on forest structure.

16.4.5 Human settlements and well-being

The concentration of large settlements along with economic and social activities at or near the coast is a well-documented feature of small islands. On Pacific and Indian Ocean atolls, villages are located on low and narrow islands, and in the Caribbean more than half of the population live within 1.5 km of the shoreline. In many regions of small islands, such as along the north coast of Jamaica and along the west and south coasts of Barbados, continuous corridors of development now occupy practically all of the prime coastal lands. Fishing villages, government buildings and important facilities such as hospitals are frequently located close to the shore. Moreover, population growth and internal migration of people are putting additional pressure on coastal settlements, utilities and resources, and creating problems in areas such as pollution, waste disposal and housing. Changes in sea level, and any changes in the magnitude and frequency of storm events, are likely to have serious consequences for these land uses. On the other hand, rural and inland settlements and communities are more likely to be adversely affected by negative impacts on agriculture, given that they are often dependent upon crop production for many of their nutritional requirements.

An important consideration in relation to settlements is housing. In many parts of the Pacific, traditional housing styles, techniques and materials were resistant to damage and/or could be repaired quickly. Moves away from traditional housing have increased vulnerability to thermal stress, slowed housing reconstruction after storms and flooding, and in some countries increased the use of air-conditioning. As a result, human well-being in several major settlements on islands in the Pacific and Indian Oceans has changed over the past two or three decades, and there is growing concern over the possibility that global climate change and sea-level rise are likely to impact human health and well-being, mostly in adverse ways (Hay et al., 2003).

Many small island states currently suffer severe health burdens from climate-sensitive diseases, including morbidity and mortality from extreme weather events, certain vector-borne diseases, and food- and water-borne diseases (Ebi et al., 2006). Tropical cyclones, storm surges, flooding, and drought have both short- and long-term effects on human health, including drowning, injuries, increased disease transmission, decreases in agricultural productivity, and an increased incidence of common mental disorders (Hajat et al., 2003). Because the impacts are complex and far-reaching, the true health burden is rarely appreciated. For example, threats to health posed by extreme weather events in the Caribbean include insect- and rodent-borne diseases, such as dengue, leptospirosis, malaria and yellow fever; water-borne diseases, including schistosomiasis, cryptosporidium and cholera; food-borne diseases, including diarrhoeal diseases, food poisoning, salmonellosis and typhoid; respiratory diseases, including asthma, bronchitis and respiratory allergies and infections; and malnutrition resulting from disturbances in food production or distribution (WHO, 2003a).

Many small island states lie in tropical or sub-tropical zones with weather conducive to the transmission of diseases such as malaria, dengue, filariasis, schistosomiasis, and food- and waterborne diseases. The rates of many of these diseases are increasing in small island states for a number of reasons, including poor public health practices, inadequate infrastructure, poor waste management practices, increasing global travel and changing climatic conditions (WHO, 2003a). In the Caribbean, the incidence of dengue fever increases during the warm years of ENSO cycles (Rawlins et al., 2005). Because the greatestrisk of dengue transmission is during annual wet seasons, vector control programs need to target these periods to reduce disease burdens. The incidence of diarrhoeal diseases is associated with annual average temperature (Singh et al., 2001) and negatively associated with water availability in the Pacific (Singh et al., 2001). Therefore, increasing temperatures and decreasing water availability due to climate change may increase burdens of diarrhoeal and other infectious diseases in some small island states.

Outbreaks of climate-sensitive diseases can be costly in terms of lives and economic impacts. An outbreak of dengue fever in Fiji coincided with the 1997/1998 El Niño; out of a population of approximately 856,000 people, 24,000 were affected, with 13 deaths (World Bank, 2000). The epidemic cost US$3 million to 6 million. Neighbouring islands were also affected.

Ciguatera fish poisoning is common in marine waters, particularly reef waters. Multiple factors contribute to outbreaks of ciguatera poisoning, including pollution and reef degradation. Warmer sea surface temperatures during El Niño events have been associated with ciguatera outbreaks in the Pacific (Hales et al., 1999).

16.4.6 Economic, financial and socio-cultural impacts

Small island states have special economic characteristics which have been documented in several reports (Atkins et al., 2000; ADB, 2004; Briguglio and Kisanga, 2004; Grynberg and Remy, 2004). Small economies are generally more exposed to external shocks, such as extreme events and climate change, than larger countries, because many of them rely on one or a few economic activities such as tourism or fisheries. Recent conflicts in the Gulf region have, for example, affected tourism arrivals in the Maldives and the Seychelles; while internal conflicts associated with coups have had similar effects on the tourism industry in Fiji (Becken, 2004). In the Caribbean, hurricanes cause loss of life, property damage and destruction, and economic losses running into millions of dollars (ECLAC, 2002; OECS, 2004). The reality of island vulnerability is powerfully demonstrated by the near-total devastation experienced on the Caribbean island of Grenada when Hurricane Ivan made landfall in September 2004. Damage assessments indicate that, in real terms, the country's socioeconomic development has been set back at least a decade by this single event that lasted for only a few hours (see Box 16.3).

Tourism is a major economic sector in many small islands, and its importance is increasing. Since their economies depend so highly on tourism, the impacts of climate change on tourism resources in small islands will have significant effects, both direct and indirect (Bigano et al., 2005; Viner, 2006). Sea-level rise and increased sea water temperatures are projected to accelerate beach erosion, cause degradation of natural coastal defences such as mangroves and coral reefs, and result in the loss of cultural heritage on coasts affected by inundation and flooding. These impacts will in turn reduce attractions for coastal tourism. For example, the sustainability of island tourism resorts in Malaysia is expected to be compromised by rising sea level, beach erosion and saline contamination of coastal wells, a major source of water supply for island resorts (Tan and Teh, 2001). Shortage of water and increased risk of vector-borne diseases may steer tourists away from small islands, while warmer climates in the higher-latitude countries may also result in a

Box 16.3. Grenada and Hurricane Ivan

Hurricane Ivan struck Grenada on 7 September 2004, as a category 4 system on the Saffir-Simpson scale. Sustained winds reached 140 mph, with gusts exceeding 160 mph. An official OECS/UN-ECLAC Assessment reported the following:

• overall damages calculated at twice the current GDP,

• 90% of guest rooms in the tourism sector damaged or destroyed, equivalent to approximately 29% GDP,

• losses in telecommunications equivalent to 13% GDP,

• damage to schools and education infrastructure equivalent to 20% GDP,

• losses in agricultural sector equivalent to 10% GDP. The two main crops, nutmeg and cocoa, which have long gestation periods, will not contribute to GDP or earn foreign exchange for the next 10 years,

• damage to electricity installations totalling 9% GDP,

• heavy damage to eco-tourism and cultural heritage sites, resulting in 60% job losses in the sub-sector,

• prior to Hurricane Ivan, Grenada was on course to experience an economic growth rate of approximately 5.7% per annum but negative growth of around -1.4% per annum is now forecast.

Source: OECS (2004).

reduction in the number of people who want to visit small islands in the tropical and sub-tropical regions.

Tourism in small island states is also vulnerable to climate change through extreme events and sea-level rise leading to transport and communication interruption. In a study of tourist resorts in Fiji, Becken (2005) suggested that many operators already prepare for climate-related events, and therefore are adapting to potential impacts from climate change. She also concludes that reducing greenhouse gas emissions from tourist facilities is not important to operators; however, decreasing energy costs is practised for economic reasons.

Climate change may also affect important environmental components of holiday destinations, which could have repercussions for tourism-dependent economies. The importance of environmental attributes in determining the choice and enjoyment of tourists visiting Bonaire and Barbados, two Caribbean islands with markedly different tourism markets and infrastructure, and possible changes resulting from climate change (coral bleaching and beach erosion) have been investigated by Uyarra et al. (2005). They concluded that such changes would have significant impacts on destination selection by visitors, and that island-specific strategies, such as focusing resources on the protection of key tourist assets, may provide a means of reducing the environmental impacts and economic costs of climate change. Equally, the attractions of 'cold water islands' (e.g., the Falklands, Prince Edward Island, Baffin, Banks and Lulea) could be compromised, as these destinations seek to expand their tourism sectors (Baldacchino, 2006).

16.4.7 Infrastructure and transportation

Like settlements and industry, the infrastructural base that supports the vital socio-economic sectors of island economies tends to occupy coastal locations. Hay et al. (2003) have identified several challenges that will confront the transportation sector in Pacific island countries as a result of climate variability and change. These include closure of roads, airports and bridges due to flooding and landslides, and damage to port facilities. The resulting disruption would not be confined to the transportation sector alone, but would impact other key dependent sectors and services including tourism, agriculture, the delivery of health care, clean water, food security and market supplies.

In most small islands, energy is primarily from nonrenewable sources, mainly from imported fossil fuels. In the context of climate change, the main contribution to greenhouse gas emissions is from energy use. The need to introduce and expand renewable energy technologies in small islands has been recognised for many years although progress in implementation has been slow. Often, the advice that small islands receive on options for economic growth is based on the strategies adopted in larger countries, where resources are much greater and alternatives significantly less costly. It has been argued by Roper (2005) that small island states could set an example on green energy use, thereby contributing to local reductions in greenhouse gas emissions and costly imports. Indeed, some have already begun to become 'renewable energy islands'. La Desirade (Caribbean), Fiji, Samsoe (Denmark), Pellworm (Germany) and La Réunion (Indian Ocean) are cited as presently generating more than 50% of their electricity from renewable energy sources (Jensen, 2000).

Almost without exception, international airports on small islands are sited on or within a few kilometres of the coast, and on tiny coral islands. Likewise, the main (and often only) road network runs along the coast (Walker and Barrie, 2006). In the South Pacific region of small islands, Lal (2004) estimates that, since 1950, mean sea level has risen at a rate of approximately 3.5 mm/yr, and he projects a rise of 25 to 58 cm by the middle of this century. Under these conditions, much of the infrastructure in these countries would be at serious risk from inundation, flooding and physical damage associated with coastal land loss. While the risk will vary from country to country, the small islands of the Indian Ocean and the Caribbean - countries such as Malta and Singapore and mid-latitude islands such as the Iles-de-la-Madeleine in the Gulf of St. Lawrence -may be confronted by similar threats. Raksakulthai (2003) has shown that climate change would also increase the risk to critical facilities on the island of Phuket, a premier tourism island in South-East Asia.

The threat from sea-level rise to infrastructure on small islands could be amplified considerably by the passage of tropical cyclones (hurricanes). It has been shown, for instance, that port facilities at Suva, Fiji, and Apia, Samoa, would experience overtopping, damage to wharves, and flooding of the hinterland if there were a 0.5 m rise in sea level combined with waves associated with a 1-in-50 year cyclone (Hay et al., 2003). In the Caribbean, the damage to coastal infrastructure from storm surge alone has been severe. In November 1999, surge damage in St. Lucia associated with Hurricane Lenny was in excess of US$6 million, even though the storm was centred many kilometres offshore.

16.5 Adaptation: practices, options and constraints

16.5.1 Role of adaptation in reducing vulnerability and impacts

It is clear from the previous sections that small islands are presently subjected to a range of climatic and oceanic impacts, and that these impacts will be exacerbated by ongoing climate change and sea-level rise. Moreover, the TAR showed that the overall vulnerability of small island states is primarily a function of four interrelated factors:

• the degree of exposure to climate change;

• their limited capacity to adapt to projected impacts;

• the fact that adaptation to climate change is not a high priority, given the more pressing problems that small islands have to face;

• the uncertainty associated with global climate change projections and their local validity (Nurse et al., 2001).

Several other factors that influence vulnerability and impacts on small islands have also been identified in the present chapter, including both global and local processes. This combination of drivers is likely to continue into the future, which raises the possibility that environmental conditions and the socio-economic well-being of populations on small islands will worsen unless adaptation measures are put in place to reduce impacts, as illustrated in Box 16.4.

While it is clear that implementing anticipatory adaptation strategies early on is desirable (see Box 16.4), there are obstacles associated with the uncertainty of the climate change projections. To overcome this uncertainty, Barnett (2001) has suggested that a better strategy for small islands is to enhance the resilience of whole-island socio-ecological systems, rather than concentrating on sectoral adaptation; a theme that is expanded upon in Section

16.5.5. This is the policy of the Organisation of Eastern Caribbean States (OECS, 2000).

Inhabitants of small islands, individuals, communities and governments, have adapted to interannual variability in climate and sea conditions, as well as to extreme events, over a long period of time. There is no doubt that this experience will be of value in dealing with inter-annual variability and extremes in climate and sea conditions that are likely to accompany the longer-term mean changes in climate and sea level. Certainly, in Polynesia, Melanesia and Micronesia, and in the Arctic, the socio-ecological systems have historically been able to adapt to environmental change (Barnett, 2001; Berkes and Jolly, 2001). However, it is also true that in many islands traditional mechanisms for coping with environmental hazards are being, or have been, lost, although paradoxically the value of such mechanisms is being increasingly recognised in the context of adaptation to climate change (e.g., MESD, 1999; Fox, 2003).

16.5.2 Adaptation options and priorities: examples from small island states

What are the adaptation options and priorities for small islands, and especially for small island states? Since the TAR there have been a number of National Communications to the United Nations Framework Convention on Climate Change (UNFCCC) from small island states that have assessed their own vulnerability to climate change and in-country adaptation strategies. These communications give an insight into national concerns about climate change, the country's vulnerability, and the priorities that different small island states place on adaptation options. They also suggest that to date adaptation has been reactive, and has been centred around responses to the effects of climate variability and particularly climate extremes. Moreover, the range of measures considered, and the priority they are assigned, appear closely linked to the country's key socio-economic sectors, their key environmental concerns, and/or the most vulnerable areas to climate change and/or sea-level rise. Some island states such as Malta (MRAE, 2004) emphasise potential adaptations to economic factors including power generation, transport, and waste management, whereas agriculture and human health figure prominently in communications from the Comoros (GDE, 2002), Vanuatu (Republic of Vanuatu, 1999), and St. Vincent and the Grenadines (NEAB, 2000). In these cases, sea-level rise is not seen as a critical issue, though it is in the low-lying atoll states such as Kiribati, Tuvalu, Marshall Islands and the Maldives. The Maldives provides one example of the sectors it sees as being the most vulnerable to climate change, and the adaptive measures required to reduce vulnerability and enhance resilience (see Box 16.5).

In spite of differences in emphasis and sectoral priorities, there are three common themes.

• First, all National Communications emphasise the urgency for adaptation action and the need for financial resources to support such action.

• Second, freshwater is seen as a critical issue in all small island states, both in terms of water quality and quantity .Water is a multi-sectoral resource that impinges on

Box 16.4. Future island conditions and well-being: the value of adaptation

Global change and regional/local change will interact to impact small islands in the future. Both have physical and human dimensions. Two groups of global drivers are identified in the top panel of Figure 16.2: first, climate change including global warming and sea-level rise and, second, externally driven socio-economic changes such as the globalisation of economic activity and international trade (Singh and Grunbuhel, 2003). In addition to these global processes, small islands are also subject to important local change influences, such as population pressure and urbanisation, which increase demand on the local resource base and expand the ecological footprint (Pelling and Uitto, 2001).

Figure 16.2. Drivers of change in small islands and the implications for island condition and well-being under no adaptation and the near-term and mid-term implementation of adaptation. Adapted from Harvey etal. (2004).

In general, both global and local drivers can be expected to show increases in the future. These will probably impact on island environments and their bio-geophysical conditions, as well as on the socio-economic well-being of island communities (Clark, 2004).

Three possible scenarios are illustrated in the lower panel. Implicitly, and without adaptation, environmental conditions and human well-being are likely to get worse in the future (line 1). On the other hand, if effective adaptation strategies are implemented, both the bio-geophysical conditions and socio-economic well-being of islanders should improve. It is suggested that the earlier this is done, the better the outcome (lines 2 and 3).

Box 16.5. Adaptive measures in the Maldives

Adaptation options in low-lying atoll islands which have been identified as especially vulnerable, are limited, and response measures to climate change or its adverse impacts are potentially very costly. In the Maldives adaptation covers two main types of activities. First, there are adaptive measures involving activities targeted at specific sectors where climate change impacts have been identified. Second, there are adaptive measures aimed at enhancing the capacity of the Maldives to effectively implement adaptations to climate change and sea-level rise. Within these two activities the Maldivian Ministry of Home Affairs, Housing and Environment has identified several vulnerable areas and adaptive measures that could be implemented to reduce climate change impacts.

Vulnerable area

Adaptation response

Land loss and beach erosion

Coastal protection

Population consolidation i.e., reduction in number of inhabited islands Ban on coral mining

Infrastructure and settlement damage

Protection of international airport Upgrading existing airports Increase elevation in the future

Damage to coral reefs

Reduction of human impacts on coral reefs Assigning protection status for more reefs

Damage to tourism industry

Coastal protection of resort islands

Reduce dependency on diving as a primary resort focus

Economy diversification

Agriculture and food security

Explore alternate methods of growing fruits, vegetables and other foods Crop production using hydroponic systems

Water resources

Protection of groundwater

Increasing rainwater harvesting and storage capacity Use of solar distillation Management of storm water

Allocation of groundwater recharge areas in the islands

Lack of capacity to adapt (both financial and technical)

Human resource development Institutional strengthening Research and systematic observation Public awareness and education

Source: M0HA(2001).

Source: M0HA(2001).

all facets of life and livelihood, including security. It is seen as a problem at present and one that will increase in the future.

• Third, many small island states, including all the Least Developed Countries (Small Island Developing States, SIDS), see the need for more integrated planning and management, be that related to water resources, the coastal zone, human health, or tourism. In a case study of tourism in Fiji, for instance, Becken (2004) argues that the current tourism policy focuses on adaptation and measures that are predominantly reactive rather than proactive, whereas climate change measures that offer win-win situations should be pursued. These include adaptation, mitigation, and wider environmental management measures; examples being reforestation of native forest, water conservation, and the use of renewable energy resources (Becken, 2004). A similar view is held by Stern (2007), who notes that climate change adaptation policies and measures, if implemented in a timely and efficient manner, can generate valuable co-benefits such as enhanced energy security and environmental protection.

The need to implement adaptation measures in small islands with some urgency has recently been reinforced by Nurse and Moore (2005), and was also highlighted in the TAR, where it was suggested that risk-reduction strategies, together with other sectoral policy initiatives, in areas such as sustainable development planning, disaster prevention and management, integrated coastal zone management, and health care planning could be usefully employed (Nurse et al., 2001). Since then a number of projects on adaptation in several small islands have adopted this suggestion. These projects aim to build the capacities of individuals, communities and governments so that they are more able to make informed decisions about adaptation to climate change and to enhance their adaptive capacity in the long run.

There are few published studies that have attempted to estimate climate change adaptation costs for small islands, and much more work needs to be undertaken on the subject. The most recent study was conducted by Ng and Mendelsohn (2005), who found coastal protection to be the least-cost strategy to combat sea-level rise in Singapore, under three scenarios. They noted that the annual cost of shoreline protection would increase as sea-level rises, and would range from US$0.3-5.7 million by 2050 to US$0.9-16.8 million by 2100 (Ng and Mendolsohn,

2005). It was concluded that it would be more costly to the country to allow the coast to become inundated than to defend it. Studies of this type could provide useful guidance to island governments in the future, as they are confronted with the difficult task of making adaptation choices.

16.5.3 Adaptation of 'natural' ecosystems in island environments

The natural adaptation of small-island ecosystems is considered in very few National Communications. Instead attention is mostly focused on: (1) protecting those ecosystems that are projected to suffer as a consequence of climate change and sea-level rise; and (2) rehabilitating ecosystems degraded or destroyed as a result of socio-economic developments.

One group of natural island environments in low latitudes are the tropical rainforests, savannas and wetlands that occupy the inland, and often upland, catchment areas of the larger, higher and topographically more complex islands, such as Mauritius in the Indian Ocean, the Solomon Islands in the Pacific, and Dominica in the Caribbean. Very little work has been done on the potential impact of climate change on these highly biodiverse systems, or on their adaptive capacity.

On the other hand, the potential impact of global warming and sea-level rise on natural coastal systems, such as coral reefs and mangrove forests, is now reasonably well known. For these ecosystems several possible adaptation measures have been identified. In those coral reefs and mangrove forests that have not been subjected to significant degradation or destruction as a result of human activities, natural or 'autonomous' adaptation, which represents the system's natural adaptive response and is triggered by changes in climatic stimuli, can take place. For instance, some corals may be able to adapt to higher sea surface and air temperatures by hosting more temperature-tolerant symbiotic algae (see Chapter 4, Box 4.4). They can also grow upwards with the rise in sea level, providing that vertical accommodation space is available (Buddemeier et al., 2004). Similarly, mangrove forests can migrate inland, as they did during the Holocene sea-level transgression, providing that there is horizontal accommodation space and they are not constrained by the presence of infrastructure and buildings; i.e., by 'coastal squeeze' (Alongi, 2002).

In addition to autonomous adaptation, both restoration and rehabilitation of damaged mangrove and reef ecosystems can be seen as 'planned' adaptation mechanisms aimed to increase natural protection against sea-level rise and storms, and to provide resources for coastal communities. In small islands, such projects have usually been community-based and are generally small-scale. In the Pacific islands, successful mangrove rehabilitation projects have been recorded from Kiribati, Northern Mariana Islands, Palau and Tonga, with failed efforts in American Samoa and Papua New Guinea (Gillman et al.,

2006). Improved staff training, capacity building, and information sharing between coastal managers is needed for successful mangrove rehabilitation (Lewis, 2005). More ambitious, costly and technical projects include an ecosystem restoration programme in the Seychelles, which aims ultimately to translocate globally threatened coastal birds as well as rehabilitating native coastal woodlands on eleven islands in the country (Henri et al., 2004).

16.5.4 Adaptation: constraints and opportunities

There are several constraints to adaptation that are inherent in the very nature of many small islands, including small size, limited natural resources, and relative isolation, and it is because of these characteristics that some autonomous small islands have been recognised in the United Nations process as either Least Developed Countries (LDCs) or SIDS. Not all small islands satisfy these criteria, notably those linked closely with global finance or trade, as well as the non-autonomous islands within larger countries. While these two groups of islands will share some of the constraints of small island states, they are not emphasised in this section.

165.4.1 Lack of adaptive capacity

The main determinants of a country's adaptive capacity to climate change are: economic wealth, technology, information and skills, infrastructure, institutions and equity (WHO, 2003b). A common constraint confronting most small island states is the lack of in-country adaptive capacity, or the ease with which they are able to cope with climate change. In many autonomous small islands the cost of adopting and implementing adaptation options is likely to be prohibitive, and a significant proportion of a country's economic wealth. Financial resources that are generally not available to island governments would need to come from outside (Rasmussen, 2004). This need for international support to assist with the adaptation process in vulnerable, developing countries is also strongly emphasised by Stern (2007). Similarly, there are often inadequate human resources available to accommodate, cope with, or benefit from the effects of climate change; a situation that may be compounded by the out-migration of skilled workers (Voigt-Graf, 2003). To overcome this deficiency, the adaptive capacity of small island states will need to be built up in several important areas including human resource development, institutional strengthening, technology and infrastructure, and public awareness and education.

An extreme example of these deficiencies is the recently independent state of Timor Leste (East Timor). Timor Leste is vulnerable to climate change, as evidenced by existing sensitivities to climate events, for example drought and food shortages in the western highlands, and floods in Suai. Barnett et al. (2003) note that relevant planning would address the present problems as well as future climate risks, and conclude that activities that promote sustainable development, human health, food security, and renewable energy can reduce the risk of future damages caused by climate change as well as improving living standards. In short, "change in climate is a long-term problem for Timor Leste, but climate change policies can be positive opportunities" (Barnett et al., 2003).

165.4.2 Adaptation and global integration

This last theme is also developed by Pelling and Uitto (2001), who suggest that change at the global level is a source of new opportunities, as well as constraints, for building local resilience. They argue that small island populations have been mobile, both historically and at present, and that remittances from overseas relatives help to moderate economic risks and increase family resiliency on home islands. They also recognise that this is a critical time for small islands, which must contend with ongoing development pressures, economic liberalisation, and the growing pressures from risks associated with climate change and sea-level rise. They conclude, following a case study of Barbados, that efforts to enhance island resilience must be mainstreamed into general development policy formulation, and that adaptations should not be seen as separate or confined to engineering or land-use planning-based realms (Pelling and Uitto, 2001).

Barnett (2001) discusses the potential impact of economic liberalisation on the resilience of Pacific island communities to climate change. He argues that many small island societies have proved resilient in the past to social and environmental upheaval. The key parameters of this resilience include: opportunities for migration and subsequent remittances; traditional knowledge, institutions and technologies; land and shore tenure regimes; the subsistence economy; and linkages between formal state and customary decision-making processes. However, this resilience may be undermined as the small island states become increasingly integrated into the world economy through, for example, negotiations for fishery rights in their Exclusive Economic Zones, and international tourism (Barnett, 2001).

These global economic processes, together with global warming, sea-level rise, and possibly increased frequency and intensity of extreme weather events, make it difficult for autonomous small islands to achieve an appropriate degree of sustainability, which Barnett and Adger (2003) suggest is one of the goals of adaptation to climate change. They maintain that for the most vulnerable small island states (those composed of low-lying atolls), this combination of global processes interacting with local socio-economic and environmental conditions puts the long-term ability of humans to inhabit atolls at risk, and that this risk constitutes a 'dangerous' level of climatic change that may well undermine their national sovereignty (see Box 16.6).

This discussion highlights the role of resilience - both its biophysical and human aspects - as a critical component in developing the adaptive capacity of small island states, a role that has effectively emerged since publication of the TAR. In a recent study of the Cayman Islands, Tompkins (2005) found that self-efficacy, strong local and international support networks, combined with a willingness to act collectively and to learn from mistakes, appeared to have increased the resilience of the Government to tropical storm risk, implying that such resilience can also contribute to the creation of national level adaptive capacity to climate change, thereby reducing vulnerability.

165.43 Risk-sharing and insurance

Insurance is another way of reducing vulnerability and is increasingly being discussed in the context of small islands and climate change. However, there are several constraints to transferring or sharing risk in small islands. These include the limited size of the risk pool, and the lack of availability of financial instruments and services for risk management. For instance, in 2004, Cyclone Heta devastated the tiny island of Niue in the South-

West Pacific, where no insurance is available against weather extremes, leaving the island almost entirely reliant on overseas aid for reconstruction efforts (Hamilton, 2004). Moreover, the relative costs of natural disasters tend to be far higher in developing countries than in advanced economies. Rasmussen (2004) shows that autonomous small islands are especially vulnerable, with natural disasters in the countries of the Eastern Caribbean shown to have had a discernible macroeconomic impact, including large effects on fiscal and external balances, pointing to an important role for precautionary measures.

Thus, in many small island countries, the implementation of specific instruments and services for risk-sharing may be required. Perhaps recent initiatives on financial risk transfer mechanisms through traditional insurance structures and new financial instruments, such as catastrophe bonds, weather derivatives, micro-insurance, and a regional pooling arrangement for small island states, might provide them with the flexibility for this form of adaptation (Auffret, 2003; Hamilton, 2004; Swiss Re, 2004). However, as Epstein and Mills (2005) point out, the economic costs of adapting to climate-related risks are spread among a range of stakeholders including governments, insurers, business, non-profit entities and individuals. They also note that sustainable development can contribute to managing and maintaining the insurability of climate change risk, though development projects can be stranded where financing is contingent on insurance, particularly with respect to coastlines and shorel

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