1613
29
Small Islands
Coordinating Lead Authors:
Leonard A. Nurse (Barbados), Roger F. McLean (Australia)
Lead Authors:
John Agard (Trinidad and Tobago), Lino Pascal Briguglio (Malta), Virginie Duvat-Magnan
(France), Netatua Pelesikoti (Samoa), Emma Tompkins (UK), Arthur Webb (Fiji)
Contributing Authors:
John Campbell (New Zealand), Dave Chadee (Trinidad and Tobago), Shobha Maharaj
(Trinidad and Tobago), Veronique Morin (Canada), Geert Jan van Oldenborgh (Netherlands),
Rolph Payet (Seychelles), Daniel Scott (Canada)
Review Editors:
Thomas Spencer (UK), Kazuya Yasuhara (Japan)
Volunteer Chapter Scientist:
Veronique Morin (Canada)
This chapter should be cited as:
Nurse
, L.A., R.F. McLean, J. Agard, L.P. Briguglio, V. Duvat-Magnan, N. Pelesikoti, E. Tompkins, and A. Webb, 2014:
Small islands. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part B: Regional Aspects.
Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate
Change [Barros, V.R., C.B. Field, D.J. Dokken, M.D. Mastrandrea, K.J. Mach, T.E. Bilir, M. Chatterjee, K.L. Ebi,
Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White
(eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1613-1654.
29
1614
Executive Summary.......................................................................................................................................................... 1616
29.1. Introduction .......................................................................................................................................................... 1618
29.2. Major Conclusions from Previous Assessments .................................................................................................... 1618
29.3. Observed Impacts of Climate Change, Including Detection and Attribution ....................................................... 1619
29.3.1. Observed Impacts on Island Coasts and Marine Biophysical Systems ............................................................................................ 1619
29.3.1.1. Sea Level Rise, Inundation, and Shoreline Change .......................................................................................................... 1619
29.3.1.2. Coastal Ecosystem Change on Small Islands: Coral Reefs and Coastal Wetlands ............................................................ 1621
29.3.2. Observed Impacts on Terrestrial Systems: Island Biodiversity and Water Resources ........................................................................ 1622
29.3.3. Observed Impacts on Human Systems in Small Islands .................................................................................................................. 1623
29.3.3.1. Observed Impacts on Island Settlements and Tourism ..................................................................................................... 1623
29.3.3.2. Observed Impacts on Human Health ............................................................................................................................... 1624
29.3.3.3. Observed Impacts of Climate Change on Relocation and Migration ............................................................................... 1625
29.3.3.4. Observed Impacts on Island Economies .......................................................................................................................... 1625
29.3.4. Detection and Attribution of Observed Impacts of Climate Change on Small Islands ..................................................................... 1626
29.4. Projected Integrated Climate Change Impacts ..................................................................................................... 1626
29.4.1. Non-formal Scenario-based Projected Impacts ............................................................................................................................... 1626
29.4.2. Projected Impacts for Islands Based on Scenario Projections ......................................................................................................... 1627
29.4.3. Representative Concentration Pathway Projections and Implications for Small Islands .................................................................. 1629
29.5. Inter- and Intra-regional Transboundary Impacts on Small Islands ...................................................................... 1629
29.5.1. Large Ocean Waves from Distant Sources ....................................................................................................................................... 1630
29.5.2. Transcontinental Dust Clouds and Their Impact .............................................................................................................................. 1633
29.5.3. Movement and Impact of Introduced and Invasive Species across Boundaries .............................................................................. 1633
29.5.4. Spread of Aquatic Pathogens within Island Regions ....................................................................................................................... 1633
29.5.5. Transboundary Movements and Human Health .............................................................................................................................. 1634
29.6. Adaptation and Management of Risks ................................................................................................................. 1634
29.6.1. Addressing Current Vulnerabilities on Small Islands ....................................................................................................................... 1635
29.6.2. Practical Experiences of Adaptation on Small Islands ..................................................................................................................... 1636
29.6.2.1. Building Adaptive Capacity with Traditional Knowledge, Technologies, and Skills on Small Islands ................................ 1636
29.6.2.2. Addressing Risks on Small Islands ................................................................................................................................... 1637
29.6.2.3. Working Collectively to Address Climate Impacts on Small Islands ................................................................................. 1638
29.6.2.4. Addressing Long-Term Climate Impacts and Migration on Small Islands ........................................................................ 1639
29.6.3. Barriers and Limits to Adaptation in Small Island Settings ............................................................................................................. 1640
29.6.4. Mainstreaming and Integrating Climate Change into Development Plans and Policies .................................................................. 1640
Table of Contents
29
Small Islands Chapter 29
1615
29.7. Adaptation and Mitigation Interactions ............................................................................................................... 1641
29.7.1. Assumptions/Uncertainties Associated with Adaptation and Mitigation Responses ....................................................................... 1641
29.7.2. Potential Synergies and Conflicts .................................................................................................................................................... 1641
29.8. Facilitating Adaptation and Avoiding Maladaptation ........................................................................................... 1642
29.9. Research and Data Gaps ....................................................................................................................................... 1643
References ....................................................................................................................................................................... 1644
Frequently Asked Questions
29.1: Why is it difficult to detect and attribute changes on small islands to climate change? ................................................................. 1620
29.2: Why is the cost of adaptation to climate change so high in small islands? .................................................................................... 1626
29.3: Is it appropriate to transfer adaptation and mitigation strategies between and within small island countries and regions? ......... 1642
29
Chapter 29 Small Islands
1616
Executive Summary
Current and future climate-related drivers of risk for small islands during the 21st century include sea level rise (SLR), tropical
and extratropical cyclones, increasing air and sea surface temperatures, and changing rainfall patterns (high confidence; robust
evidence, high agreement). {WGI AR5 Chapter 14; Table 29-1}
Current impacts associated with these changes confirm findings reported
on small islands from the Fourth Assessment Report (AR4) and previous IPCC assessments. The future risks associated with these drivers
i
nclude loss of adaptive capacity {29.6.2.1, 29.6.2.3} and ecosystem services critical to lives and livelihoods in small islands. {29.3.1-3}
SLR poses one of the most widely recognized climate change threats to low-lying coastal areas on islands and atolls (high
confidence; robust evidence, high agreement). {29.3.1} It is virtually certain that global mean SLR rates are accelerating. {WGI AR5
13.2.2.1} Projected increases to the year 2100 (RCP4.5: 0.35 m to 0.70 m) {WGI AR5 13.5.1; Table 29-1} superimposed on extreme sea level
events (e.g., swell waves, storm surges, El Niño-Southern Oscillation) present severe sea flood and erosion risks for low-lying coastal areas and
atoll islands (high confidence). Likewise, there is high confidence that wave over-wash of seawater will degrade fresh groundwater resources
{29.3.2} and that sea surface temperature rise will result in increased coral bleaching and reef degradation. {29.3.1.2} Given the dependence of
island communities on coral reef ecosystems for a range of services including coastal protection, subsistence fisheries, and tourism, there is
high confidence that coral reef ecosystem degradation will negatively impact island communities and livelihoods.
Given the inherent physical characteristics of small islands, the AR5 reconfirms the high level of vulnerability of small islands to
multiple stressors, both climate and non-climate (high confidence; robust evidence, high agreement).
However, the distinction
between observed and projected impacts of climate change is often not clear in the literature on small islands (high agreement). {29.3} There is
evidence that this challenge can be partly overcome through improvements in baseline monitoring of island systems and downscaling of climate-
model projections, which would heighten confidence in assessing recent and projected impacts. {WGI AR5 9.6; 29.3-4, 29.9}
Small islands do not have uniform climate change risk profiles (high confidence). Rather, their high diversity in both physical and
human attributes and their response to climate-related drivers means that climate change impacts, vulnerability, and adaptation will be variable
from one island region to another and between countries in the same region. {Figure 29-1; Table 29-3} In the past, this diversity in potential
response has not always been adequately integrated in adaptation planning.
There is increasing recognition of the risks to small islands from climate-related processes originating well beyond the borders
of an individual nation or island.
Such transboundary processes already have a negative impact on small islands (high confidence; robust
evidence, medium agreement). These include air-borne dust from the Sahara and Asia, distant-source ocean swells from mid to high latitudes,
invasive plant and animal species, and the spread of aquatic pathogens. For island communities the risks associated with existing and future
invasive species and human health challenges are projected to increase in a changing climate. {29.5.4}
Adaptation to climate change generates larger benefit to small islands when delivered in conjunction with other development
activities, such as disaster risk reduction and community-based approaches to development (medium confidence). {29.6.4}
Addressing the critical social, economic, and environmental issues of the day, raising awareness, and communicating future risks to local
communities {29.6.3} will likely increase human and environmental resilience to the longer term impacts of climate change. {29.6.1, 29.6.2.3;
Figure 29-5}
Adaptation and mitigation on small islands are not always trade-offs, but can be regarded as complementary components in the
response to climate change (medium confidence).
Examples of adaptation-mitigation interlinkages in small islands include energy supply
and use, tourism infrastructure and activities, and functions and services associated with coastal wetlands. The alignment of these sectors for
potential emission reductions, together with adaptation, offer co-benefits and opportunities in some small islands. {29.7.2, 29.8} Lessons
learned from adaptation and mitigation experiences in one island may offer some guidance to other small island states, though there is low
confidence in the success of wholesale transfer of adaptation and mitigation options when the local lenses through which they are viewed
differ from one island state to the next, given the diverse cultural, socioeconomic, ecological, and political values. {29.6.2, 29.8}
29
Small Islands Chapter 29
1617
The ability of small islands to undertake adaptation and mitigation programs, and their effectiveness, can be substantially
strengthened through appropriate assistance from the international community (medium confidence).
However, caution is needed
to ensure such assistance is not driving the climate change agenda in small islands, as there is a risk that critical challenges confronting island
governments and communities may not be addressed. Opportunities for effective adaptation can be found by, for example, empowering
communities and optimizing the benefits of local practices that have proven to be efficacious through time, and working synergistically to
p
rogress development agendas. {29.6.2.3, 29.6.3, 29.8}
29
Chapter 29 Small Islands
1618
29.1. Introduction
It has long been recognized that greenhouse gas (GHG) emissions from
small islands are negligible in relation to global emissions, but that the
threats of climate change and sea level rise (SLR) to small islands are
very real. Indeed, it has been suggested that the very existence of some
atoll nations is threatened by rising sea levels associated with global
warming. Although such scenarios are not applicable to all small island
nations, there is no doubt that on the whole the impacts of climate
change on small islands will have serious negative effects especially on
socioeconomic conditions and biophysical resources—although impacts
may be reduced through effective adaptation measures.
The small islands considered in this chapter are principally sovereign
states and territories located within the tropics of the southern and
western Pacific Ocean, central and western Indian Ocean, the Caribbean
Sea, and the eastern Atlantic off the coast of West Africa, as well as in
the more temperate Mediterranean Sea.
Although these small islands nations are by no means homogeneous
politically, socially, or culturally, or in terms of physical size and character
or economic development, there has been a tendency to generalize
about the potential impacts on small islands and their adaptive capacity.
In this chapter we attempt to strike a balance between identifying the
differences between small islands and at the same time recognizing
that small islands tend to share a number of common characteristics
that have distinguished them as a particular group in international
affairs. Also in this chapter we reiterate some of the frequently voiced
and key concerns relating to climate change impacts, vulnerability, and
adaptation while emphasizing a number of additional themes that
have emerged in the literature on small islands since the IPCC Fourth
Assessment Report (AR4). These include the relationship among climate
change policy, activities, and development issues; externally generated
transboundary impacts; and the implications of risk in relation to
adaptation and the adaptive capacity of small island nations.
29.2. Major Conclusions
from Previous Assessments
Small islands were not given a separate chapter in the IPCC First
Assessment Report (FAR) in 1990 though they were discussed in the
chapter on “World Oceans and Coastal Zones” (Tsyban et al., 1990).
Two points were highlighted. First, a 30- to 50-cm SLR projected by 2050
would threaten low islands, and a 1-m rise by 2100 “would render some
island countries uninhabitable” (Tegart et al., 1990, p. 4). Second, the
costs of protection works to combat SLR would be extremely high for
small island nations. Indeed, as a percentage of gross domestic product
(GDP), the Maldives, Kiribati, Tuvalu, Tokelau, Anguilla, Turks and Caicos,
Marshall Islands, and Seychelles were ranked among the 10 nations
with the highest protection costs in relation to GDP (Tsyban et al., 1990).
More than 20 years later these two points continue to be emphasized.
For instance, although small islands represent only a fraction of total
global damage projected to occur as a result of a SLR of 1.0 m by 2100
(Special Report on Emission Scenarios (SRES) A1 scenario) the actual
damage costs for the small island states is enormous in relation to the
size of their economies, with several small island nations being included
in the group of 10 countries with the highest relative impact projected
for 2100 (Anthoff et al., 2010).
The Second Assessment Report (SAR) in 1995 confirmed the vulnerable
state of small islands, now included in a specific chapter titled “Coastal
Zones and Small Islands” (Bijlsma et al., 1996). However, importantly,
the SAR recognized that both vulnerability and impacts would be highly
variable between small islands and that impacts were “likely to be
greatest where local environments are already under stress as a result
o
f human activities (Bijlsma et al., 1996, p. 291). The report also
summarized results from the application of a common methodology for
vulnerability and adaptation analysis that gave new insights into the
socioeconomic implications of SLR for small islands including: negative
impacts on virtually all sectors including tourism, freshwater resources,
fisheries and agriculture, human settlements, financial services, and
human health; protection is likely to be very costly; and adaptation
would involve a series of trade-offs. It also noted that major constraints
to adaptation on small islands included lack of technology and human
resource capacity, serious financial limitations, lack of cultural and social
acceptability, and uncertain political and legal frameworks. Integrated
coastal and island management was seen as a way of overcoming some
of these constraints.
The Third Assessment Report (TAR) in 2001 included a specific chapter
on “Small Island States. In confirming previously identified concerns
of small island states two factors were highlighted, the first relating to
sustainability, noting thatwith limited resources and low adaptive
capacity, these islands face the considerable challenge of meeting the
social and economic needs of their populations in a manner that is
sustainable” (Nurse et al., 2001, p. 845). The second noted that there
were other issues faced by small island states, concluding that “for most
small islands the reality of climate change is just one of many serious
challenges with which they are confronted” (Nurse et al., 2001, p. 846).
In the present chapter, both of these themes are raised again and
assessed in light of recent findings.
Until the AR4 in 2007, SLR had dominated vulnerability and impact
studies of small island states. Whilst a broader range of climate change
drivers and geographical spread of islands was included in the “Small
Islandschapter, Mimura et al. (2007) prefaced their assessment by
noting that the number of “independent scientific studies on climate
change and small islands since the TAR” had been quite limited and in
their view “the volume of literature in refereed international journals
relating to small islands and climate change since publication of the
TAR is rather less than that between the SAR in 1995 and TAR in 2001”
(Mimura et al., 2007, p. 690).
Since AR4, the literature on small islands and climate change has
increased substantially. A number of features distinguish the literature
we review here from that included in earlier assessments. First, the
literature appears more sophisticated and does not shirk from dealing
with the complexity of small island vulnerability, impacts, and adaptation
or the differences between islands and island states. Second, and related
to the first, the literature is less one-dimensional, and deals with climate
change in a multidimensional manner as just one of several stressors
on small island nations. Third, the literature also critiques some aspects
of climate change policy, notably in relation to critical present-day
29
Small Islands Chapter 29
1619
development and security needs of small islands (Section 29.3.3.1) as
well as the possibility that some proposed adaptation measures may
prove to be maladaptive (Section 29.8). Fourth, many initiatives have
been identified in recent times that will reduce vulnerability and
enhance resilience of small islands to ongoing global change including
improving risk knowledge and island resource management while also
strengthening socioeconomic systems and livelihoods (Hay, 2013).
29.3. Observed Impacts of Climate Change,
Including Detection and Attribution
The distinction between observed impacts of climate change and projected
impacts is often unclear in the small islands literature and discussions.
Publications frequently deal with both aspects of impacts interchangeably,
and use observed impacts from, for instance an extreme event, as an
analogy to what may happen in the future as a result of climate change
(e.g., Lo-Yat et al., 2011). The key climate and ocean drivers of change
that impact small islands include variations in air and ocean temperatures;
ocean chemistry; rainfall; wind strength and direction; sea levels and
wave climate; and particularly the extremes such as tropical cyclones,
drought, and distant storm swell events. All have varying impacts,
dependent on the magnitude, frequency, and temporal and spatial
extent of the event, as well as on the biophysical nature of the island
(Figure 29-1) and its social, economic, and political setting.
29.3.1. Observed Impacts on Island Coasts
and Marine Biophysical Systems
29.3.1.1. Sea Level Rise, Inundation, and Shoreline Change
SLR poses one of the most widely recognized climate change threats to
low-lying coastal areas (Cazenave and Llovel, 2010; Nicholls and Cazenave,
2010; Church and White, 2011). This is particularly important in small
islands where the majority of human communities and infrastructure is
located in coastal zones with limited on-island relocation opportunities,
especially on atoll islands (Woodroffe, 2008) (Figure 29-1). Over much of
the 20th century, global mean sea level rose at a rate between 1.3 and
1.7 mm yr
1
and since 1993, at a rate between 2.8 and 3.6 mm yr
1
(WGI AR5 Table 13.1), and acceleration is detected in longer records
since 1870 (Merrifield et al., 2009; Church and White, 2011; see also
WGI AR5 Section 13.2.2.1). Rates of SLR, however, are not uniform
a
cross the globe and large regional differences have been detected
including in the Indian Ocean and tropical Pacific, where in some parts
rates have been significantly higher than the global average (Meyssignac
et al., 2012; see also Section 5.3.2.2). In the tropical western Pacific,
where a large number of small island communities exist, rates up to
four times the global average (approximately 12 mm yr
–1
) have been
reported between 1993 and 2009. These are generally thought to describe
short-term variations associated with natural cyclic climate phenomena
such as El Niño-Southern Oscillation (ENSO), which has a strong
modulating effect on sea level variability with lower/higher-than-average
sea level during El Niño/La Niña events of the order of ±20 to 30 cm
(Cazenave and Remy, 2011; Becker et al., 2012). Large interannual
variability in sea level has also been demonstrated from the Indian
Ocean (e.g., Chagos Archipelago; Dunne et al., 2012) while Palanisamy
et al. (2012) found that over the last 60 years the mean rate of SLR in
the Caribbean region was similar to the global average of approximately
1.8 mm yr
–1
.
There are few long-term sea level records available for individual small
island locations. Reported sea flooding and inundation is often associated
with transient phenomena, such as storm waves and surges, deep ocean
swell, and predicted astronomical tidal cycles (Vassie et al., 2004; Zahibo
et al., 2007; Komar and Allan, 2008; Haigh et al., 2011). For example,
high spring tide floods at Fongafale Island, Funafuti Atoll, Tuvalu, have
been well publicized, and areas of the central portion of Fongafale are
NauruTarawa, KiribatiAitutaki, Cook Islands
Rodrigues, MauritiusSt. LuciaTanna, Vanuatu
living
perimeter
reefs
ancient
reef
deposits
Figure 29-1 | Representative tropical island typologies. From top left: A young, active volcanic island (with altitudinal zonation) and limited living perimeter reefs (red zone at
outer reef edge), through to an atoll (center bottom), and raised limestone island (bottom right) dominated by ancient reef deposits (brown + white fleck). Atolls have limited,
low-lying land areas but well developed reef/lagoon systems. Islands composed of continental rocks are not included in this figure, but see Table 29-3.
29
Chapter 29 Small Islands
1620
already below high spring tide level. However, rates of relative SLR at
Funafuti between 1950 and 2009 have been approximately three times
higher than the global average (Becker et al., 2012), and saline flooding
of internal low-lying areas occurs regularly and is expected to become
more frequent and extensive over time (Yamano et al., 2007).
Documented cases of coastal inundation and erosion often cite additional
circumstances such as vertical subsidence, engineering works, development
activities, or beach mining as the causal process. Four examples can be
cited. First, on the Torres Islands, Vanuatu communities have been displaced
as a result of increasing inundation of low-lying settlement areas owing
to a combination of tectonic subsidence and SLR (Ballu et al., 2011).
Second, on Anjouan Island, Comores in the Indian Ocean, Sinane et al.
(2010) found beach aggregate mining was a major contributing factor
influencing rapid beach erosion. Third, the intrinsic exposure of rapidly
expanding settlements and agriculture in the low-lying flood prone
Rewa Delta, Fiji, is shown by Lata and Nunn (2012) to place populations
in increasingly severe conditions of vulnerability to flooding and marine
inundation. Fourth, Hoeke et al. (2013) describe a 2008 widespread
inundation event that displaced some 63,000 people in Papua New
Guinea and Solomon Islands alone. That event was caused primarily by
remotely generated swell waves, and the severity of flooding was
greatly increased by anomalously high regional sea levels linked with
ENSO and ongoing SLR. Such examples serve to highlight that extreme
events superimposed on a rising sea level baseline are the main drivers
that threaten the habitability of low-lying islands as sea levels continue
to rise.
Since the AR4 a number of empirical studies have documented historical
changes in island shorelines. Historical shoreline position change over
20 to 60 years on 27 central Pacific atoll islands showed that total land
area remained relatively stable in 43% of islands, while another 43%
had increased in area, and the rest showed a net reduction in land area
(Webb and Kench, 2010). Dynamic responses were also found in a 4-
year study of 17 relatively pristine islands on two other central Pacific
atolls in Kiribati by Rankey (2011), who concluded that SLR was not
likely to be the main influencing factor in these shoreline changes.
Similarly in French Polynesia, Yates et al. (2013) showed mixed shoreline
change patterns over the last 40 to 50 years with examples of both
erosion and accretion in the 47 atoll islands assessed. SLR did not
appear to be the primary control on shoreline processes on these islands.
On uninhabited Raine Island on the Great Barrier Reef, Dawson and
Smithers (2010) also found that shoreline processes were dynamic but
that island area and volume increased 6 and 4%, respectively, between
1967 and 2007. Overall, these studies of observed shoreline change on
reef islands conclude that for rates of change experienced over recent
decades, normal seasonal erosion and accretion processes appear to
predominate over any long-term morphological trend or signal at this
time. Ford’s (2013) investigation of Wotje Atoll, Marshall Islands, also
found shoreline variability between 1945 and 2010 but that overall
accretion had been more prevalent than erosion up until 2004. From
2004 to the present, 17 out of 18 islands became net erosive, potentially
corresponding to the high sea levels in the region over the last 10 years.
On the high tropical islands of Kauai and Maui, Hawaii, Romine and
Fletcher (2013) found shoreline change was highly variable over the
last century but that recently chronic erosion predominated with over
70% of beaches now being erosive. Finally, it is important to note the
majority of these studies warn that (1) past changes cannot be simply
extrapolated to determine future shoreline responses; and (2) rising sea
level will incrementally increase the rate and extent of erosion in the
future.
In many locations changing patterns of human settlement and direct
impacts on shoreline processes present immediate erosion challenges
in populated islands and coastal zones (Yamano et al., 2007; Novelo-
Casanova and Suarez, 2010; Storey and Hunter, 2010) and mask
attribution to SLR. A study of Majuro atoll (Marshall Islands) found that
erosion was widespread but attribution to SLR was obscured by pervasive
anthropogenic impacts to the coastal system (Ford, 2012; see Section
5.4.4). Similarly a study of three islands in the Rosario Archipelago
(Colombia) reported shoreline retreat over a 50- to 55-year period and
found Grande, Rosario, and Tesoro Islands had lost 6.7, 8.2, and 48.7%
of their land area, respectively. Erosion was largely attributed to poor
management on densely settled Grande Island, while SLR and persistent
Frequently Asked Questions
FAQ 29.1 | Why is it difficult to detect and attribute changes
on small islands to climate change?
In the last 2 or 3 decades many small islands have undergone substantial changes in human settlement patterns
and in socioeconomic and environmental conditions. Those changes may have masked any clear evidence of the
effects of climate change. For example, on many small islands coastal erosion has been widespread and has adversely
affected important tourist facilities, settlements, utilities, and infrastructure. But specific case studies from islands
in the Pacific, Indian, and Atlantic Oceans and the Caribbean have shown that human impacts play an important
role in this erosion, as do episodic extreme events that have long been part of the natural cycle of events affecting
small islands. So although coastal erosion is consistent with models of sea level rise resulting from climate change,
determining just how much of this erosion might have been caused by climate change impacts is difficult. Given
the range of natural processes and human activities that could impact the coasts of small islands in the future,
without more and better empirical monitoring the role of climate change-related processes on small islands may
continue to be difficult to identify and quantify.
29
Small Islands Chapter 29
1621
northeast winds enhanced erosion on uninhabited Rosario and Tesoro
(Restrepo et al., 2012). Likewise, Cambers (2009) reported average
beach erosion rates of 0.5 m yr
–1
in eight Caribbean islands from 1985
to 2000. Although the study could not quantify the extent of attribution
it noted that greater erosion rates were positively correlated with
the number of hurricane events. Alternately, Etienne and Terry (2012)
found a Category 4 tropical cyclone that passed within 30 km of Taveuni
Island (Fiji) nourished shorelines with fresh coralline sediments despite
localized storm damage. Although these studies contribute to improved
u
nderstanding of island shoreline processes and change since AR4, the
warning of increased vulnerability of small island shores and low-lying
areas to inundation and erosion in response to SLR and other potential
climate change stressors is not diminished.
29.3.1.2. Coastal Ecosystem Change on Small Islands:
Coral Reefs and Coastal Wetlands
Coral reefs are an important resource in small tropical islands, and the
well-being of many island communities is linked to their ongoing function
and productivity. Reefs play a significant role in supplying sediment to
island shores and in dissipating wave energy, thus reducing the potential
foreshore erosion. They also provide habitat for a host of marine species
on which many island communities are dependent for subsistence foods
as well as underpinning beach and reef-based tourism and economic
activity (Perch-Nielsen, 2010; Bell et al., 2011). The documented sensitivity
of coral reef ecosystems to climate change is summarized elsewhere
(see Chapter 5; Box CC-CR).
Increased coral bleaching and reduced reef calcification rates due to
thermal stress and increasing carbon dioxide (CO
2
) concentration are
expected to affect the functioning and viability of living reef systems
(Hoegh-Guldberg et al., 2007; Eakin et al., 2009). Some studies already
implicate thermal stress in reduced coral calcification rates (Tanzil et
al., 2009) and regional declines in calcification of corals that form reef
framework (De’ath et al., 2009; Cantin et al., 2010). Unprecedented
bleaching events have been recorded in the remote Phoenix Islands
(Kiribati), with nearly 100% coral mortality in the lagoon and 62%
mortality on the outer leeward slopes of the otherwise pristine reefs of
Kanton Atoll during 2002–2003 (Alling et al., 2007). Similar patterns of
mortality were observed in four other atolls in the Phoenix group and
temperature-induced coral bleaching was also recorded in isolated
Palmyra Atoll during the 2009 ENSO event (Williams et al., 2010). In
2005 extensive bleaching was recorded at 22 sites around Rodrigues
Island in the western Indian Ocean, with up to 75% of the dominant
species affected in some areas (Hardman et al., 2007). Studies of the
severe 1998 El Niño bleaching event in the tropical Indian Ocean
showed reefs in the Maldives, Seychelles, and Chagos Islands were
among the most impacted (Cinner et al., 2012; Tkachenko, 2012). In
2005 a reef survey around Barbados following a Caribbean regional
bleaching event revealed the most severe bleaching ever recorded, with
approximately 70% of corals impacted (Oxenford et al., 2008). Globally,
the incidence and implications of temperature-related coral bleaching
in small islands is well documented, and combined with the effects of
increasing ocean acidification these stressors could threaten the
function and persistence of island coral reef ecosystems (see Chapter 5;
Box CC-OA).
Island coral reefs have limited defenses against thermal stress and
acidification. However, studies such as Cinner et al. (2012) and Tkachenko
(2012) highlight that although recovery from bleaching is variable, some
reefs show greater resilience than others. There is also some evidence
to show that coral reef resilience is enhanced in the absence of other
environmental stresses such as declining water quality. In Belize
chronologies of growth rates in massive corals (Montastraea faveolata)
over the past 75 to 150 years suggest that the bleaching event in 1998
was unprecedented and its severity appeared to stem from reduced
t
hermal tolerance related to human coastal development (Carilli et al.,
2010). Likewise a study over a 40-year period (1960s–2008) in the
Grand Recif of Tulear, Madagascar, concluded that severe degradation
of the reef was mostly ascribed to direct anthropogenic disturbance,
despite an average 1°C increase in temperature over this period (Harris
et al., 2010). Coral recovery following the 2004 bleaching event in the
central Pacific atolls of Tarawa and Abaiang (Kiribati) was also noted to
be improved in the absence of direct human impacts (Donner et al., 2010),
and isolation of bleached reefs was shown by Gilmour et al. (2013) to be
less inhibiting to reef recovery than direct human disturbance.
The loss of coral reef habitat has detrimental implications for coastal
fisheries (Pratchett et al., 2009) in small islands where reef-based
subsistence and tourism activities are often critical to the well-being
and economies of islands (Bell et al., 2011). In Kimbe Bay, Papua New
Guinea, 65% of coastal fish are dependent on living reefs at some stage
in their life cycle and there is evidence that fish abundance declined
following degradation of the reef (Jones et al., 2004). Even where coral
reef recovery has followed bleaching, reef-associated species composition
may not recover to its original state (Pratchett et al., 2009; Donner et al.,
2010). Sea surface temperature (SST) anomaly events can be associated
with a lag in the larval supply of coral reef fishes, as reported by Lo-Yat
et al. (2011) between 1996 and 2000 at Rangiroa Atoll, French Polynesia.
Higher temperatures have also been implicated in negatively affecting
the spawning of adult reef species (Munday et al., 2009; Donelson et
al., 2010).
Like coral reefs, mangroves and seagrass environments provide a range
of ecosystem goods and services (Waycott et al., 2009; Polidoro et al.,
2010) and both habitats play a significant role in the well-being of small
island communities. Mangroves in particular serve a host of commercial
and subsistence uses as well as providing natural coastal protection
from erosion and storm events (Ellison, 2009; Krauss et al., 2010; Waycott
et al., 2011).
SLR is reported as the most significant climate change threat to the
survival of mangroves (Waycott et al., 2011). Loss of the seaward edge
of mangroves at Hungry Bay, Bermuda, has been reported by Ellison
(1993), who attributes this process to SLR and the inability of mangroves
to tolerate increased water depth at the seaward margin. Elsewhere in
the Caribbean and tropical Pacific, observations vary in regard to the
potential for sedimentation rates in mangroves forests to keep pace
with SLR (Krauss et al., 2003; McKee et al., 2007). In Kosrae and Pohnpei
Islands (Federated States of Micronesia), Krauss et al. (2010) found
significant variability in mangrove average soil elevation changes due
to deposition from an accretion deficit of 4.95 mm yr
–1
to an accretion
surplus of 3.28 mm yr
–1
relative to the estimated rate of SLR. Such
surpluses are generally reported from high islands where additional
29
Chapter 29 Small Islands
1622
sediments can be delivered from terrestrial runoff. However, Rankey
(2011) described natural seaward migration (up to 40 m) of some
mangrove areas between 1969 and 2009 in atolls in Kiribati, suggesting
sediment accretion can also occur in sediment-rich reefal areas and in
the absence of terrigenous inputs.
The response of seagrass to climate change is also complex, regionally
variable, and manifest in quite different ways. A study of seven species
of seagrasses from tropical Green Island, Australia, highlighted the
v
ariability in response to heat and light stress (Campbell et al., 2006).
Light reduction may be a limiting factor to seagrass growth due to
increased water depth and sedimentation (Ralph et al., 2007). Ogston
and Field (2010) observed that a 20-cm rise in sea level may double the
suspended sediment loads and turbidity in shallow waters on fringing
reefs of Molokai, Hawaiian Islands, with negative implications to
photosynthetic species such as seagrass. Otherwise, temperature stress
is most commonly reported as the main expected climate change impact
on seagrass (e.g., Campbell et al., 2006; Waycott et al., 2011). Literature
on seagrass diebacks in small islands is scarce but research in the
Balearic Islands (Western Mediterranean) has shown that over a 6-year
study, seagrass shoot mortality and recruitment rates were negatively
influenced by higher temperature (Marbá and Duarte, 2010; see
also Section 5.4.2.3 for further discussion of impacts on mangrove and
seagrass communities).
29.3.2. Observed Impacts on Terrestrial Systems:
Island Biodiversity and Water Resources
Climate change impacts on terrestrial biodiversity on islands, frequently
interacting with several other drivers (Blackburn et al., 2004; Didham
et al., 2005), fall into three general categories, namely: (1) ecosystem
and species horizontal shifts and range decline; (2) altitudinal species
range shifts and decline mainly due to temperature increase on high
islands; and (3) exotic and pest species range increase and invasions
mainly due to temperature increase in high-latitude islands. Owing to
the limited area and isolated nature of most islands, these effects are
generally magnified compared to continental areas and may cause
species loss, especially in tropical islands with high numbers of endemic
species. For example, in two low-lying islands in the Bahamas, Greaver
and Sternberg (2010) found that during periods of reduced rainfall the
shallow freshwater lens subsides and contracts landward and ocean
water infiltrates further inland, negatively impacting on coastal strand
vegetation. SLR has also been observed to threaten the long-term
persistence of freshwater-dependent ecosystems within low-lying
islands in the Florida Keys (Goodman et al., 2012). On Sugarloaf Key,
Ross et al. (2009) found pine forest area declined from 88 to 30 ha from
1935 to 1991 due to increasing salinization and rising groundwater,
with vegetation transitioning to more saline-tolerant species such as
mangroves.
Although there are many studies that report observations associated
with temperature increases in mid- and high-latitude islands, such as
the Falkland Islands and Marion Islands in the south Atlantic and south
Indian Ocean respectively (Le Roux et al., 2005; Bokhorst et al., 2007,
2008) and Svalbard in the Arctic (Webb et al., 1998), there are few
equivalent studies in tropical small islands. A recent study of the tropical
Mauritius kestrel indicates changing rainfall conditions in Mauritius over
the last 50 years have resulted in this species having reduced reproductive
success due to a mismatch between the timing of breeding and peak
food abundance (Senapathi et al., 2011).
Increasing global temperatures may also lead to altitudinal species
range shifts and contractions within high islands, with an upward creep
of the tree line and associated fauna (Benning et al., 2002; Krushelnycky
et al., 2013). For instance, in the central mountain ranges of the subtropical
i
sland of Taiwan, Province of China, historical survey and resurvey data
from 1906 to 2006 showed that the upper altitudinal limits of plant
distributions had risen by about 3.6 m yr
–1
during the last century in
parallel with rising temperatures in the region (Jump et al., 2012).
Comparable effects also occur in the tropics such as in Hawaii Volcano
National Park, where comparison of sample plots over a 40-year period
from 1966/1967 to 2008 show fire-adapted grasses expanded upward
along a warming tropical elevation gradient (Angelo and Daehler, 2013).
Reduction in the numbers and sizes of endemic populations caused by
such habitat constriction and changes in species composition in mountain
systems may result in the demise and possibly extinction of endemic
species (Pauli et al., 2007; Chen et al., 2009; Sekercioglu et al., 2008;
Krushelnycky et al., 2013). Altitudinal temperature change has also been
reported to influence the distribution of disease vectors such as
mosquitoes, potentially threatening biota unaccustomed to such vectors
(Freed et al., 2005; Atkinson and LaPointe, 2009).
Freshwater supply in small island environments has always presented
challenges and has been an issue raised in all previous IPCC reports.
On high volcanic and granitic islands, small and steep river catchments
respond rapidly to rainfall events, and watersheds generally have
restricted storage capacity. On porous limestone and low atoll islands,
surface runoff is minimal and water rapidly passes through the substrate
into the groundwater lens. Rainwater harvesting is also an important
contribution to freshwater access, and alternatives such as desalination
have had mixed success in small island settings owing to operational
costs (White and Falkland, 2010).
Rapidly growing demand, land use change, urbanization, and tourism
are already placing significant strain on the limited freshwater reserves
in small island environments (Emmanuel and Spence, 2009; Cashman
et al., 2010; White and Falkland, 2010). In the Caribbean, where there
is considerable variation in the types of freshwater supplies utilized,
concern over the status of freshwater availability has been expressed
for at least the past 30 years (Cashman et al., 2010). There have also
been economic and management failures in the water sector not only
in the Caribbean (Mycoo, 2007) but also in small islands in the Indian
(Payet and Agricole, 2006) and Pacific Oceans (White et al., 2007; Moglia
et al., 2008a,b).
These issues also occur on a background of decreasing rainfall and
increasing temperature. Rainfall records averaged over the Caribbean
region for 100 years (1900–2000) show a consistent 0.18 mm yr
–1
reduction in rainfall, a trend that is projected to continue (Jury and
Winter, 2010). In contrast, analysis of rainfall data over the past 100
years from the Seychelles has shown substantial variability related to
ENSO. Nevertheless an increase in average rainfall from 1959 to 1997
and an increase in temperature of approximately 0.25°C per decade
29
Small Islands Chapter 29
1623
have occurred (Payet and Agricole, 2006). Long-term reduction in
streamflow (median reduction of 22 to 23%) has been detected in
the Hawaiian Islands over the period 1913–2008, resulting in reduced
freshwater availability for both human use and ecological processes
(Bassiouni and Oki, 2013). Detection of long-term statistical change in
precipitation is an important prerequisite toward a better understanding
the impacts of climate change in small island hydrology and water
resources.
T
here is a paucity of empirical evidence linking saline (seawater) intrusion
into fresh groundwater reserves due simply to incremental SLR at this
time (e.g., Rozell and Wong, 2010). However, this dynamic must be the
subject of improved research given the importance of groundwater
aquifers in small island environments. White and Falkland’s (2010)
review of existing small island studies indicates that a sea level increase
of up to 1 m would have negligible salinity impacts on atoll island
groundwater lenses so long as there is adequate vertical accommodation
space, island shores remain intact, rainfall patterns do not change, and
direct human impacts are managed. However, wave overtopping and
wash-over can be expected to become more frequent with SLR, and this
has been shown to impact freshwater lenses dramatically. On Pukapuka
Atoll, Cook Islands, storm surge over-wash occurred in 2005. This caused
the freshwater lenses to become immediately brackish and took 11
months to recover to conductivity levels appropriate for human use
(Terry and Falkland, 2010). The ability of the freshwater lens to float
upward within the substrate of an island in step with incremental SLR
also means that in low-lying and central areas of many atoll islands the
lens may pond at the surface. This phenomenon already occurs in central
areas of Fongafale Island, Tuvalu, and during extreme high “king” tides
large areas of the inner part of the island become inundated with
brackish waters (Yamano et al., 2007; Locke, 2009).
29.3.3. Observed Impacts on
Human Systems in Small Islands
29.3.3.1. Observed Impacts on Island Settlements and Tourism
While traditional settlements on high islands in the Pacific were often
located inland, the move to coastal locations was encouraged by colonial
and religious authorities and more recently through the development of
tourism (Barnett and Campbell, 2010). Now the majority of settlement,
infrastructure, and development are located on lowlands along the
coastal fringe of small islands. In the case of atoll islands, all development
and settlement is essentially coastal. It follows that populations,
infrastructure, agricultural areas, and fresh groundwater supplies are
all vulnerable to extreme tides, wave and surge events, and SLR (Walsh
et al., 2012). Population drift from outer islands or from inland, together
with rapid population growth in main centers and lack of accommodation
space, drives growing populations into ever more vulnerable locations
(Connell, 2012). In addition, without adequate resources and planning,
engineering solutions such as shoreline reclamation also place
communities and infrastructure in positions of increased risk (Yamano
et al., 2007; Duvat, 2013).
Many of the environmental issues raised by the media relating to Tuvalu,
the Marshall Islands, and Maldives are primarily relevant to the major
population center and its surrounds, which are Funafuti, Majuro, and
Male, respectively. As an example, Storey and Hunter (2010) indicate
the “Kiribatiproblem does not refer to the whole of Kiribati but rather
to the southern part of Tarawa atoll, where preexisting issues of severe
overcrowding, proliferation of informal housing and unplanned settlement,
inadequate water supply, poor sanitation and solid waste disposal,
pollution, and conflict over land ownership are of concern. They argue
that these problems require immediate resolution if the vulnerability
of the South Tarawa community to the “real and alarming threat”
o
f climate change is to be managed effectively (Storey and Hunter,
2010).
On Majuro atoll, rapid urban development and the abandonment of
traditional settlement patterns has resulted in movement from less
vulnerable to more vulnerable locations on the island (Spennemann,
1996). Likewise, geophysical studies of Fongafale Island, the capital of
Tuvalu, show that engineering works during World War II, and rapid
development and population growth since independence, have led to
the settlement of inappropriate shoreline and swampland areas, leaving
communities in heightened conditions of vulnerability (e.g., Yamano et
al., 2007). Ascribing direct climate change impacts in such disturbed
environments is problematic owing to the existing multiple lines of
stress on the island’s biophysical and social systems. However, it is clear
that such preexisting conditions of vulnerability add to the threat of
climate change in such locations. Increased risk can also result from
lack of awareness, particularly in communities in rural areas and outer
islands (“periphery”) of archipelagic countries such as Cook Islands, Fiji,
Kiribati, and Vanuatu, whose climate change knowledge often contrasts
sharply with that of communities in the major centers (“core”). In the
core, communities tend to be better informed and have higher levels of
awareness about the complex issues associated with climate change
than in the periphery (Nunn et al., 2013).
The issue of “coastal squeeze” remains a concern for many small islands
as there is a constant struggle to manage the requirements for physical
development against the need to maintain ecological balance (Fish et
al., 2008; Gero et al., 2011; Mycoo, 2011). Martinique in the Caribbean
exemplifies the point, where physical infrastructure prevents the beach
and wetlands from retreating landward as a spontaneous adaptation
response to increased rates of coastal erosion (Schleupner, 2008).
Moreover, intensive coastal development in the limited coastal zone,
combined with population growth and tourism, has placed great stress
on the coast of some islands and has resulted in dense aggregations of
infrastructure and people in potentially vulnerable locations.
Tourism is an important weather and climate-sensitive sector on many
small islands and has been assessed on several occasions, including in
previous IPCC assessments. There is currently no evidence that observed
climatic changes in small island destinations or source markets have
permanently altered patterns of demand for tourism to small islands,
and the complex mix of factors that actually determines destination
choices under a changing climate still need to be fully evaluated (Scott
et al., 2012a). However, there are cases reported that clearly show
severe weather-related events in a destination country (e.g., heavy,
persistent rainfall in Martinique: Hubner and Gössling, 2012; hurricanes
in Anguilla: Forster et al., 2012) can significantly influence visitors’
perception of the desirability of the location as a vacation choice.
29
Chapter 29 Small Islands
1624
Climate can also impact directly on environmental resources that are
major tourism attractions in small islands. Widespread resource
degradation challenges such as beach erosion and coral bleaching
have been found to negatively impact the perception of destination
attractiveness in various locations, for example, in Martinique (Schleupner,
2008), Barbados, and Bonaire (Uyarra et al., 2005). Similarly, dive
tourists are well aware of coral bleaching, particularly the experienced
diver segment (Gössling et al., 2012a; Klint et al., 2012). Therefore more
acute impacts are felt by tourism operators and resorts that cater to
t
hese markets. Houston (2002) and Buzinde et al. (2010) also indicate
that beach erosion may similarly affect accommodation prices in some
destinations. Consequently, some countries have begun to invest in a
variety of resource restoration initiatives including artificial beach
nourishment, coral and mangrove restoration, and the establishment
of marine parks and protected areas (McClanahan et al., 2008; Mycoo
and Chadwick, 2012). There is no analysis of how widespread such
investments are or their capability to cope effectively with future climate
change. The tourism industry and investors are also beginning to
consider the climate risk of tourism operations (Scott et al., 2012b),
including those associated with the availability of freshwater. Freshwater
is limited on many small islands, and changes in its availability or quality
during drought events linked to climate change have adverse impacts
on tourism operations (UNWTO, 2012). Tourism is a seasonally significant
water user in many island destinations, and in times of drought concerns
over limited supply for residents and other economic activities become
heightened (Gössling et al., 2012b). The increasing use of desalination
plants is one adaptation to reduce the risk of water scarcity in tourism
operations.
29.3.3.2. Observed Impacts on Human Health
Globally, the effects of climate change on human health will be both
direct and indirect, and are expected to exacerbate existing health risks,
especially in the most vulnerable communities, where the burden of
disease is already high (refer to Sections 11.3, 11.5, 11.6.1). Many small
island states currently suffer from climate-sensitive health problems,
including morbidity and mortality from extreme weather events, certain
vector- and food- and water-borne diseases (Lozano, 2006; Barnett and
Campbell, 2010; Cashman et al., 2010; Pulwarty et al., 2010; McMichael
and Lindgren, 2011). Extreme weather and climate events such as
tropical cyclones, storm surges, flooding, and drought can have both short-
and long-term effects on human health, including drowning, injuries,
increased disease transmission, and health problems associated with
deterioration of water quality and quantity. Most small island nations
are in tropical areas with weather conducive to the transmission of
diseases such as malaria, dengue, filariasis, and schistosomiasis.
The linkages between human health, climate variability, and seasonal
weather have been demonstrated in several recent studies. The Caribbean
has been identified as a “highly endemic zone for leptospirosis, with
Trinidad and Tobago, Barbados, and Jamaica representing the highest
annual incidence (12, 10, and 7.8 cases per 100,000, respectively) in
the world, with only the Seychelles being higher (43.2 per 100,000
population) (Pappas et al., 2008). Studies conducted in Guadeloupe
demonstrated a link between El Niño occurrence and leptospirosis
incidence, with rates increasing to 13 per 100,000 population in El Niño
years, as opposed to 4.5 cases per 100,000 inhabitants in La Niña and
neutral years (Herrmann-Storck et al., 2008). In addition, epidemiological
studies conducted in Trinidad reviewed the incidence of leptospirosis
during the period 1996–2007 and showed seasonal patterns in the
occurrence of confirmed leptospirosis cases, with significantly (P < 0.001)
more cases occurring in the wet season, May to November (193 cases),
than during the dry season, December to May (66 cases) (Mohan et al.,
2009). Recently changes in the epidemiology of leptospirosis have been
detected, especially in tropical islands, with the main factors being
c
limatic and anthropogenic ones (Pappas et al., 2008). These factors
may be enhanced with increases in ambient temperature and changes
in precipitation, vegetation, and water availability as a consequence of
climate change (Russell, 2009).
In Pacific islands the incidence of diseases such as malaria and dengue
fever has been increasing, especially endemic dengue in Samoa, Tonga,
and Kiribati (Russell, 2009). Although studies conducted so far in the
Pacific have established a direct link only between malaria, dengue, and
climate variability, these and other health risks including from cholera
are projected to increase as a consequence of climate change (Russell,
2009; see also Sections 11.2.4-5 for detailed discussion on the link
between climate change and projected increases in the outbreak of
dengue and cholera). Dengue incidence is also a major health concern
in other small island countries, including Trinidad and Tobago, Singapore,
Cape Verde, Comoros, and Mauritius (Koh et al., 2008; Chadee, 2009;
Van Kleef et al., 2010; Teles, 2011). In the specific cases of Trinidad and
Tobago and Singapore the outbreaks have been significantly correlated
with rainfall and temperature, respectively (Chadee et al., 2007; Koh et
al., 2008).
Previous IPCC assessments have consistently shown that human health
on islands can be seriously compromised by lack of access to adequate,
safe freshwater and adequate nutrition (Nurse et al., 2001; Mimura et
al., 2007). Lovell (2011) notes that in the Pacific many of the anticipated
health effects of climate change are expected to be indirect, connected
to the increased stress and declining well-being that comes with property
damage, loss of economic livelihood, and threatened communities.
There is also a growing concern in island communities in the Caribbean
Sea and Pacific and Indian Oceans that freshwater scarcity and more
intense droughts and storms could lead to a deterioration in standards of
sanitation and hygiene (Cashman et al., 2010; McMichael and Lindgren,
2011). In such circumstances, increased exposure to a range of health
risks including communicable (transmissible) diseases would be a distinct
possibility.
Ciguatera fish poisoning (CFP) occurs in tropical regions and is the most
common non-bacterial food-borne illness associated with consumption
of fish. Distribution and abundance of the organisms that produce these
toxins, chiefly dinoflagellates of the genus Gambierdiscus, are reported
to correlate positively with water temperature. Consequently, there is
growing concern that increasing temperatures associated with climate
change could increase the incidence of CFP in the island regions of the
Caribbean (Morrison et al., 2008; Tester et al., 2010), Pacific (Chan et
al., 2011; Rongo and van Woesik, 2011), the Mediterranean (Aligizaki
and Nikolaidis, 2008; see also Section 29.5.5), and the Canary Islands
in the Atlantic (Pérez-Arellano et al., 2005). A recent Caribbean study
sought to characterize the relationship between SSTs and CFP incidence
29
Small Islands Chapter 29
1625
and to determine the effects of temperature on the growth rate of
organisms responsible for CFP. Results from this work show that in the
Lesser Antilles high rates occur in areas that experience the warmest
water temperatures and that show the least temperature variability
(Tester et al., 2010). There are also high rates in the Pacific in Tokelau,
Tuvalu, Kiribati, Cook Islands, and Vanuatu (Chan et al., 2011).
The influence of climatic factors on malaria vector density and parasite
development is well established (Chaves and Koenraadt, 2010; Béguin
e
t al., 2011). Previous studies have assessed the potential influence of
climate change on malaria, using deterministic or statistical models
(Martens et al., 1999; Pascual et al., 2006; Hay et al., 2009; Parham and
Michael, 2010). Although the present incidence of malaria on small
islands is not reported to be high, favorable environmental and social
circumstances for the spread of the disease are present in some island
regions and are expected to be enhanced under projected changes in
climate in Papua New Guinea, Guyana, Suriname, and French Guyana
(Michon et al., 2007; Figueroa, 2008; Rawlins et al., 2008). In the
Caribbean, the occurrence of autochthonous malaria in non-endemic
island countries in the last 10 years suggests that all of the essential
malaria transmission conditions now exist. Rawlins et al. (2008) call for
enhanced surveillance, recognizing the possible impact of climate
change on the spread of the Anopheles mosquito vector and malaria
transmission.
29.3.3.3. Observed Impacts of Climate Change
on Relocation and Migration
Evidence of human migration as a response to climate change is scarce
for small islands. Although there is general agreement that migration
is usually driven by multiple factors (Black et al., 2011), several authors
highlight the lack of empirical studies of the effect of climate-related
factors, such as SLR, on island migration (Mortreux and Barnett, 2009;
Lilleør and Van den Broeck, 2011). Furthermore, there is no evidence of
any government policy that allows for climate “refugees” from islands
to be accepted into another country (Bedford and Bedford, 2010). This
finding contrasts with the early desk-based estimates of migration
under climate change such as the work of Myers (2002). These early
studies have been criticized as they fail to acknowledge the reality of
climate impacts on islands, the capacity of islands and islanders to
adapt, or the actual drivers of migration (Barnett and O’Neill, 2012).
Studies of island migration commonly reveal the complexity of a decision
to migrate and rarely identify a single cause. For example, when looking
at historical process of migration within the Mediterranean, it appears
that rising levels of income, coupled with a decreased dependence on
subsistence agriculture, has left the Mediterranean less vulnerable to
all environmental stressors, resulting in a reduced need for mobility to
cope with environmental or climatic change (de Haas, 2011). Studies
from the Pacific have also shown that culture, lifestyle, and a connection
to place are more significant drivers of migration than climate (Barnett
and Webber, 2010). For example, a Pacific Access Category of migration
has been agreed between New Zealand and Tuvalu that permits 75
Tuvaluans to migrate to New Zealand every year (Kravchenko, 2008).
Instead of enabling climate-driven migration, this agreement is designed
to facilitate economic and social migration as part of the Pacific Island
lifestyle (Shen and Gemenne, 2011). To date there is no unequivocal
evidence that reveals migration from islands is being driven by
anthropogenic climate change.
There is, however, some evidence that environmental change has played
a role in Pacific Island migration in the past (Nunn, 2007). In the Pacific,
environmental change has been shown to affect land use and land rights,
which in turn have become drivers of migration (Bedford and Bedford,
2010). In a survey of 86 case studies of community relocations in Pacific
I
slands, Campbell et al. (2005) found that environmental variability and
natural hazards accounted for 37 communities relocating. In the Pacific,
where land rights are a source of conflict, climate change could increase
levels of stress associated with land rights and impact on migration
(Campbell, 2010; Weir and Virani, 2011). Although there is not yet a
climate fingerprint on migration and resettlement patterns in all small
islands, it is clear that there is the potential for human movement as a
response to climate change. To understand better the impact of climate
change on migration there is an urgent need for robust methods to
identify and measure the effects of the drivers of migration on migration
and resettlement.
29.3.3.4. Observed Impacts on Island Economies
The economic and environmental vulnerabilities of small islands states are
well documented (Briguglio et al., 2009, Bishop, 2012). Such vulnerabilities,
which render the states at risk of being harmed by economic and
environmental conditions, stem from intrinsic features of these vulnerable
states, and are not usually governance induced. However, governance
does remain one of the challenges for island countries in the Pacific in the
pursuit of sustainable development through