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** Protection standards improve as GDP per capita increases, but there is no additional adaptation for sea-level rise.

** Protection standards improve as GDP per capita increases, but there is no additional adaptation for sea-level rise.

Table 6.7. Health effects of climate change and sea-level rise in coastal areas.

Exposure/hazard

Health outcome

Sources

(Catastrophic) flooding

Deaths (drowning, other causes), injuries, infectious disease (respiratory, intestinal, skin), mental health disorders, impacts from interruption of health services and population displacement.

Sections 6.4.2, 6.5.2 and 8.2.2; Box 6.4 (Few and Matthies, 2006)

Impairment of food quality and/or food supplies (loss of crop land, decreased fisheries productivity). Climate change effects on HABs.

Food safety: marine bacteria proliferation, shellfish poisoning, ciguatera. Malnutrition and micro-nutrient deficiencies.

Sections 6.4.1.3 6.4.2.2 and 8.2.4

Reduced water quality and/or access to potable water supplies due to salinisation, flooding or drought.

Diarrhoeal diseases (giardia, cholera), and hepatitis, enteric fevers. Water-washed infections.

Sections 6.4.2.1, 7.5 and 8.2.5

Change in transmission intensity or distribution of vector-borne disease. Changes in vector abundance.

Changes in malaria, and other mosquito-borne infections (some Anopheles vectors breed in brackish water).

Sections 8.2.8 and 16.4.5

Effects on livelihoods, population movement, and potential "environmental refugees".

Health effects are less well described. Large-scale rapid population movement would have severe health implications.

Section 6.4.2.3 and limited health literature.

poisoning (Pascual et al., 2002; Hunter, 2003; Lipp et al., 2004; Peperzak, 2005; McLaughlin et al., 2006).

Convincing evidence of the impacts of observed climate change on coastal disease patterns is absent (Kovats and Haines, 2005). There is an association between ENSO and cholera risk in Bangladesh (Pascual et al., 2002). Rainfall changes associated with ENSO are known to increase the risk of malaria epidemics in coastal regions of Venezuela and Colombia (Kovats et al., 2003). The projection of health impacts of climate change is still difficult and uncertain (Ebi and Gamble, 2005; Kovats et al., 2005), and socio-economic factors may be more critical than climate. There are also complex relationships between ecosystems and human well-being, and the future coastal ecosystem changes discussed in Section 6.4.1 may affect human health (cf. Butler et al., 2005).

6.4.25 Biodiversity

The distribution, production, and many other aspects of species and biodiversity in coastal ecosystems are highly sensitive to variations in weather and climate (Section 6.4.1), affecting the distribution and abundance of the plant and animal species that depend on each coastal system type. Human development patterns also have an important influence on biodiversity among coastal system types. Mangroves, for example, support rich ecological communities of fish and crustaceans, are a source of energy for coastal food chains, and export carbon in the form of plant and animal detritus, stimulating estuarine and nearshore productivity (Jennerjahn and Ittekkot, 2002). Large-scale conversions of coastal mangrove forests to shrimp aquaculture have occurred during the past three decades along the coastlines of Vietnam (Binh et al., 1997), Bangladesh and India (Zweig, 1998), Hong Kong (Tam and Wong, 2002), the Philippines (Spalding et al., 1997), Mexico (Contreras-Espinosa and Warner, 2004), Thailand (Furakawa and Baba, 2001) and Malaysia (Ong, 2001). The additional stressors associated with climate change could lead to further declines in mangroves forests and their biodiversity.

Several recent studies have revealed that climate change is already impacting biodiversity in some coastal systems. Long-

term monitoring of the occurrence and distribution of a series of intertidal and shallow water organisms in south-west Britain has shown several patterns of change, particularly in the case of barnacles, which correlate broadly with changes in temperature over the several decades of record (Hawkins et al., 2003; Mieszkowska et al., 2006). It is clear that responses of intertidal and shallow marine organisms to climate change are more complex than simply latitudinal shifts related to temperature increase, with complex biotic interactions superimposed on the abiotic (Harley et al., 2006; Helmuth et al., 2006). Examples include the northward range extension of a marine snail in California (Zacherl et al., 2003) and the reappearance of the blue mussel in Svalbard (Berge et al., 2005).

Patterns of overwintering of migratory birds on the British coast appear to have changed in response to temperature rise (Rehfisch et al., 2004), and it has been suggested that changes in invertebrate distribution might subsequently influence the distribution of ducks and wading birds (Kendall et al., 2004). However, as detailed studies of redshank have shown, the factors controlling distribution are complex and in many cases are influenced by human activities (Norris et al., 2004). Piersma and Lindstrom (2004) review changes in bird distribution but conclude that none can be convincingly attributed to climate change. Loss of birds from some estuaries appears to be the result of coastal squeeze and relative sea-level rise (Hughes, 2004; Knogge et al., 2004). A report by the United Nations Framework Convention on Biodiversity (CBD, 2006) presents guidance for incorporating biodiversity considerations in climate change adaptation strategies, with examples from several coastal regions.

6.42.6 Recreation and tourism

Climate change has major potential impacts on coastal tourism, which is strongly dependent on 'sun, sea and sand'. Globally, travel to sunny and warm coastal destinations is the major factor for tourists travelling from Northern Europe to the Mediterranean (16% of world's tourists) and from North America to the Caribbean (1% of world's tourists) (WTO, 2003). By 2020, the total number of international tourists is expected to exceed 1.5 billion (WTO, undated).

Climate change may influence tourism directly via the decision-making process by influencing tourists to choose different destinations; and indirectly as a result of sea-level rise and resulting coastal erosion (Agnew and Viner, 2001). The preferences for climates at tourist destinations also differ among age and income groups (Lise and Tol, 2002), suggesting differential responses. Increased awareness of interactions between ozone depletion and climate change and the subsequent impact on the exposure of human skin to ultraviolet light is another factor influencing tourists' travel choice (Diffey, 2004). In general, air temperature rise is most important to tourism, except where factors such as sea-level rise promote beach degradation and viable adaptation options (e.g., nourishment or recycling) are not available (Bigano et al., 2005). Other likely impacts of climate change on coastal tourism are due to coral reef degradation (Box 6.1; Section 6.4.1.5) (Hoegh-Guldberg et al.,

2000). Temperature and rainfall pattern changes may impact water quality in coastal areas and this may lead to more beach closures.

Climate change is likely to affect international tourist flows prior to travel, en route, and at the destination (Becken and Hay, undated). As tourism is still a growth industry, the changes in tourist numbers induced by climate change are likely to be much smaller than those resulting from population and economic growth (Bigano et al., 2005; Hamilton et al., 2005; Table 6.2). Higher temperatures are likely to change summer destination preferences, especially for Europe: summer heatwaves in the Mediterranean may lead to a shift in tourism to spring and autumn (Madisson,

2001) with growth in summer tourism around the Baltic and North Seas (see Chapter 12, Section 12.4.9). Although new climate niches are emerging, the empirical data do not suggest reduced competitiveness of the sun, sea and sand destinations, as they are able to restructure to meet tourists' demands (Aguilo et al., 2005). Within the Caribbean, the rapidly growing cruise industry is not vulnerable to sea-level rise, unlike coastal resorts. On high-risk (e.g., hurricane-prone) coasts, insurance costs for tourism could increase substantially or insurance may no longer be available. This exacerbates the impacts of extreme events or restricts new tourism in high-risk regions (Scott et al., 2005), e.g., four hurricanes in 2004 dealt a heavy toll in infrastructure damage and lost business in Florida's tourism industry (see Chapter 14, Section 14.2.7).

6.4.3 Key vulnerabilities and hotspots

A comprehensive assessment of the potential impacts of climate change must consider at least three components of vulnerability: exposure, sensitivity and adaptive capacity (Section 6.6). Significant regional differences in present climate and expected climate change give rise to different exposure among human populations and natural systems to climate stimuli (IPCC, 2001). The previous sections of this chapter broadly characterise the sensitivity and natural adaptive capacity (or resilience) of several major classes of coastal environments to changes in climate and sea-level rise. Differences in geological, oceanographic and biological processes can also lead to substantially different impacts on a single coastal system at different locations. Some global patterns and hotspots of vulnerability are evident, however, and deltas/estuaries (especially populated megadeltas), coral reefs (especially atolls), and ice-

dominated coasts appear most vulnerable to either climate change or associated sea-level rise and changes. Low-lying coastal wetlands, small islands, sand and gravel beaches and soft rock cliffs may also experience significant changes.

An acceleration of sea-level rise would directly increase the vulnerability of all of the above systems, but sea-level rise will not occur uniformly around the world (Section 6.3.2). Variability of storms and waves, as well as sediment supply and the ability to migrate landward, also influence the vulnerability of many of these coastal system types. Hence, there is an important element of local to regional variation among coastal system types that must be considered when conducting site-specific vulnerability assessments.

Our understanding of human adaptive capacity is less developed than our understanding of responses by natural systems, which limits the degree to which we can quantify societal vulnerability in the world's coastal regions. Nonetheless, several key aspects of human vulnerability have emerged. It is also apparent that multiple and concomitant non-climate stresses will exacerbate the impacts of climate change on most natural coastal systems, leading to much larger and detrimental changes in the 21st century than those of the 20th century. Table 6.8 summarises some of the key hotspots of vulnerability that often arise from the combination of natural and societal factors. Note that some examples such as atolls and small islands and deltas/megadeltas recur, stressing their high vulnerability.

While physical exposure is an important aspect of the vulnerability for both human populations and natural systems to both present and future climate variability and change, a lack of adaptive capacity is often the most important factor that creates a hotspot of human vulnerability. Societal vulnerability is largely dependent upon development status (Yohe and Tol, 2002). Developing nations may have the societal will to relocate people who live in low-lying coastal zones but, without the necessary financial resources, their vulnerability is much greater than that of a developed nation in an identical coastal setting. Looking to the scenarios, the A2 SRES world often appears most vulnerable to climate change in coastal areas, again reflecting socioeconomic controls in addition to the magnitude of climate change (Nicholls, 2004; Nicholls and Tol, 2006). Hence, development is not only a key consideration in evaluating greenhouse gas emissions and climate change, but is also fundamental in assessing adaptive capacity because greater access to wealth and technology generally increases adaptive capacity, while poverty limits adaptation options (Yohe and Tol, 2002). A lack of risk awareness or institutional capacity can also have an important influence on human vulnerability, as experienced in the United States during Hurricane Katrina.

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